Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

17 files changed, 9724 insertions, 0 deletions

diff --git a/arch/s390/mm/Makefile b/arch/s390/mm/Makefile
new file mode 100644
index 0000000000..352ff520fd
--- /dev/null
+++ b/arch/s390/mm/Makefile
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux s390-specific parts of the memory manager.
+#
+
+obj-y		:= init.o fault.o extmem.o mmap.o vmem.o maccess.o
+obj-y		+= page-states.o pageattr.o pgtable.o pgalloc.o extable.o
+
+obj-$(CONFIG_CMM)		+= cmm.o
+obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
+obj-$(CONFIG_PTDUMP_CORE)	+= dump_pagetables.o
+obj-$(CONFIG_PGSTE)		+= gmap.o
+obj-$(CONFIG_PFAULT)		+= pfault.o
diff --git a/arch/s390/mm/cmm.c b/arch/s390/mm/cmm.c
new file mode 100644
index 0000000000..f475153132
--- /dev/null
+++ b/arch/s390/mm/cmm.c
@@ -0,0 +1,431 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Collaborative memory management interface.
+ *
+ *    Copyright IBM Corp 2003, 2010
+ *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
+ *
+ */
+
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/gfp.h>
+#include <linux/sched.h>
+#include <linux/string_helpers.h>
+#include <linux/sysctl.h>
+#include <linux/swap.h>
+#include <linux/kthread.h>
+#include <linux/oom.h>
+#include <linux/uaccess.h>
+
+#include <asm/diag.h>
+
+#ifdef CONFIG_CMM_IUCV
+static char *cmm_default_sender = "VMRMSVM";
+#endif
+static char *sender;
+module_param(sender, charp, 0400);
+MODULE_PARM_DESC(sender,
+		 "Guest name that may send SMSG messages (default VMRMSVM)");
+
+#include "../../../drivers/s390/net/smsgiucv.h"
+
+#define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
+
+struct cmm_page_array {
+	struct cmm_page_array *next;
+	unsigned long index;
+	unsigned long pages[CMM_NR_PAGES];
+};
+
+static long cmm_pages;
+static long cmm_timed_pages;
+static volatile long cmm_pages_target;
+static volatile long cmm_timed_pages_target;
+static long cmm_timeout_pages;
+static long cmm_timeout_seconds;
+
+static struct cmm_page_array *cmm_page_list;
+static struct cmm_page_array *cmm_timed_page_list;
+static DEFINE_SPINLOCK(cmm_lock);
+
+static struct task_struct *cmm_thread_ptr;
+static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait);
+
+static void cmm_timer_fn(struct timer_list *);
+static void cmm_set_timer(void);
+static DEFINE_TIMER(cmm_timer, cmm_timer_fn);
+
+static long cmm_alloc_pages(long nr, long *counter,
+			    struct cmm_page_array **list)
+{
+	struct cmm_page_array *pa, *npa;
+	unsigned long addr;
+
+	while (nr) {
+		addr = __get_free_page(GFP_NOIO);
+		if (!addr)
+			break;
+		spin_lock(&cmm_lock);
+		pa = *list;
+		if (!pa || pa->index >= CMM_NR_PAGES) {
+			/* Need a new page for the page list. */
+			spin_unlock(&cmm_lock);
+			npa = (struct cmm_page_array *)
+				__get_free_page(GFP_NOIO);
+			if (!npa) {
+				free_page(addr);
+				break;
+			}
+			spin_lock(&cmm_lock);
+			pa = *list;
+			if (!pa || pa->index >= CMM_NR_PAGES) {
+				npa->next = pa;
+				npa->index = 0;
+				pa = npa;
+				*list = pa;
+			} else
+				free_page((unsigned long) npa);
+		}
+		diag10_range(virt_to_pfn((void *)addr), 1);
+		pa->pages[pa->index++] = addr;
+		(*counter)++;
+		spin_unlock(&cmm_lock);
+		nr--;
+	}
+	return nr;
+}
+
+static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
+{
+	struct cmm_page_array *pa;
+	unsigned long addr;
+
+	spin_lock(&cmm_lock);
+	pa = *list;
+	while (nr) {
+		if (!pa || pa->index <= 0)
+			break;
+		addr = pa->pages[--pa->index];
+		if (pa->index == 0) {
+			pa = pa->next;
+			free_page((unsigned long) *list);
+			*list = pa;
+		}
+		free_page(addr);
+		(*counter)--;
+		nr--;
+	}
+	spin_unlock(&cmm_lock);
+	return nr;
+}
+
+static int cmm_oom_notify(struct notifier_block *self,
+			  unsigned long dummy, void *parm)
+{
+	unsigned long *freed = parm;
+	long nr = 256;
+
+	nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
+	if (nr > 0)
+		nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
+	cmm_pages_target = cmm_pages;
+	cmm_timed_pages_target = cmm_timed_pages;
+	*freed += 256 - nr;
+	return NOTIFY_OK;
+}
+
+static struct notifier_block cmm_oom_nb = {
+	.notifier_call = cmm_oom_notify,
+};
+
+static int cmm_thread(void *dummy)
+{
+	int rc;
+
+	while (1) {
+		rc = wait_event_interruptible(cmm_thread_wait,
+			cmm_pages != cmm_pages_target ||
+			cmm_timed_pages != cmm_timed_pages_target ||
+			kthread_should_stop());
+		if (kthread_should_stop() || rc == -ERESTARTSYS) {
+			cmm_pages_target = cmm_pages;
+			cmm_timed_pages_target = cmm_timed_pages;
+			break;
+		}
+		if (cmm_pages_target > cmm_pages) {
+			if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
+				cmm_pages_target = cmm_pages;
+		} else if (cmm_pages_target < cmm_pages) {
+			cmm_free_pages(1, &cmm_pages, &cmm_page_list);
+		}
+		if (cmm_timed_pages_target > cmm_timed_pages) {
+			if (cmm_alloc_pages(1, &cmm_timed_pages,
+					   &cmm_timed_page_list))
+				cmm_timed_pages_target = cmm_timed_pages;
+		} else if (cmm_timed_pages_target < cmm_timed_pages) {
+			cmm_free_pages(1, &cmm_timed_pages,
+				       &cmm_timed_page_list);
+		}
+		if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
+			cmm_set_timer();
+	}
+	return 0;
+}
+
+static void cmm_kick_thread(void)
+{
+	wake_up(&cmm_thread_wait);
+}
+
+static void cmm_set_timer(void)
+{
+	if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
+		if (timer_pending(&cmm_timer))
+			del_timer(&cmm_timer);
+		return;
+	}
+	mod_timer(&cmm_timer, jiffies + msecs_to_jiffies(cmm_timeout_seconds * MSEC_PER_SEC));
+}
+
+static void cmm_timer_fn(struct timer_list *unused)
+{
+	long nr;
+
+	nr = cmm_timed_pages_target - cmm_timeout_pages;
+	if (nr < 0)
+		cmm_timed_pages_target = 0;
+	else
+		cmm_timed_pages_target = nr;
+	cmm_kick_thread();
+	cmm_set_timer();
+}
+
+static void cmm_set_pages(long nr)
+{
+	cmm_pages_target = nr;
+	cmm_kick_thread();
+}
+
+static long cmm_get_pages(void)
+{
+	return cmm_pages;
+}
+
+static void cmm_add_timed_pages(long nr)
+{
+	cmm_timed_pages_target += nr;
+	cmm_kick_thread();
+}
+
+static long cmm_get_timed_pages(void)
+{
+	return cmm_timed_pages;
+}
+
+static void cmm_set_timeout(long nr, long seconds)
+{
+	cmm_timeout_pages = nr;
+	cmm_timeout_seconds = seconds;
+	cmm_set_timer();
+}
+
+static int cmm_skip_blanks(char *cp, char **endp)
+{
+	char *str;
+
+	for (str = cp; *str == ' ' || *str == '\t'; str++)
+		;
+	*endp = str;
+	return str != cp;
+}
+
+static int cmm_pages_handler(struct ctl_table *ctl, int write,
+			     void *buffer, size_t *lenp, loff_t *ppos)
+{
+	long nr = cmm_get_pages();
+	struct ctl_table ctl_entry = {
+		.procname	= ctl->procname,
+		.data		= &nr,
+		.maxlen		= sizeof(long),
+	};
+	int rc;
+
+	rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
+	if (rc < 0 || !write)
+		return rc;
+
+	cmm_set_pages(nr);
+	return 0;
+}
+
+static int cmm_timed_pages_handler(struct ctl_table *ctl, int write,
+				   void *buffer, size_t *lenp,
+				   loff_t *ppos)
+{
+	long nr = cmm_get_timed_pages();
+	struct ctl_table ctl_entry = {
+		.procname	= ctl->procname,
+		.data		= &nr,
+		.maxlen		= sizeof(long),
+	};
+	int rc;
+
+	rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
+	if (rc < 0 || !write)
+		return rc;
+
+	cmm_add_timed_pages(nr);
+	return 0;
+}
+
+static int cmm_timeout_handler(struct ctl_table *ctl, int write,
+			       void *buffer, size_t *lenp, loff_t *ppos)
+{
+	char buf[64], *p;
+	long nr, seconds;
+	unsigned int len;
+
+	if (!*lenp || (*ppos && !write)) {
+		*lenp = 0;
+		return 0;
+	}
+
+	if (write) {
+		len = min(*lenp, sizeof(buf));
+		memcpy(buf, buffer, len);
+		buf[len - 1] = '\0';
+		cmm_skip_blanks(buf, &p);
+		nr = simple_strtoul(p, &p, 0);
+		cmm_skip_blanks(p, &p);
+		seconds = simple_strtoul(p, &p, 0);
+		cmm_set_timeout(nr, seconds);
+		*ppos += *lenp;
+	} else {
+		len = sprintf(buf, "%ld %ld\n",
+			      cmm_timeout_pages, cmm_timeout_seconds);
+		if (len > *lenp)
+			len = *lenp;
+		memcpy(buffer, buf, len);
+		*lenp = len;
+		*ppos += len;
+	}
+	return 0;
+}
+
+static struct ctl_table cmm_table[] = {
+	{
+		.procname	= "cmm_pages",
+		.mode		= 0644,
+		.proc_handler	= cmm_pages_handler,
+	},
+	{
+		.procname	= "cmm_timed_pages",
+		.mode		= 0644,
+		.proc_handler	= cmm_timed_pages_handler,
+	},
+	{
+		.procname	= "cmm_timeout",
+		.mode		= 0644,
+		.proc_handler	= cmm_timeout_handler,
+	},
+	{ }
+};
+
+#ifdef CONFIG_CMM_IUCV
+#define SMSG_PREFIX "CMM"
+static void cmm_smsg_target(const char *from, char *msg)
+{
+	long nr, seconds;
+
+	if (strlen(sender) > 0 && strcmp(from, sender) != 0)
+		return;
+	if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
+		return;
+	if (strncmp(msg, "SHRINK", 6) == 0) {
+		if (!cmm_skip_blanks(msg + 6, &msg))
+			return;
+		nr = simple_strtoul(msg, &msg, 0);
+		cmm_skip_blanks(msg, &msg);
+		if (*msg == '\0')
+			cmm_set_pages(nr);
+	} else if (strncmp(msg, "RELEASE", 7) == 0) {
+		if (!cmm_skip_blanks(msg + 7, &msg))
+			return;
+		nr = simple_strtoul(msg, &msg, 0);
+		cmm_skip_blanks(msg, &msg);
+		if (*msg == '\0')
+			cmm_add_timed_pages(nr);
+	} else if (strncmp(msg, "REUSE", 5) == 0) {
+		if (!cmm_skip_blanks(msg + 5, &msg))
+			return;
+		nr = simple_strtoul(msg, &msg, 0);
+		if (!cmm_skip_blanks(msg, &msg))
+			return;
+		seconds = simple_strtoul(msg, &msg, 0);
+		cmm_skip_blanks(msg, &msg);
+		if (*msg == '\0')
+			cmm_set_timeout(nr, seconds);
+	}
+}
+#endif
+
+static struct ctl_table_header *cmm_sysctl_header;
+
+static int __init cmm_init(void)
+{
+	int rc = -ENOMEM;
+
+	cmm_sysctl_header = register_sysctl("vm", cmm_table);
+	if (!cmm_sysctl_header)
+		goto out_sysctl;
+#ifdef CONFIG_CMM_IUCV
+	/* convert sender to uppercase characters */
+	if (sender)
+		string_upper(sender, sender);
+	else
+		sender = cmm_default_sender;
+
+	rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
+	if (rc < 0)
+		goto out_smsg;
+#endif
+	rc = register_oom_notifier(&cmm_oom_nb);
+	if (rc < 0)
+		goto out_oom_notify;
+	cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
+	if (!IS_ERR(cmm_thread_ptr))
+		return 0;
+
+	rc = PTR_ERR(cmm_thread_ptr);
+	unregister_oom_notifier(&cmm_oom_nb);
+out_oom_notify:
+#ifdef CONFIG_CMM_IUCV
+	smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
+out_smsg:
+#endif
+	unregister_sysctl_table(cmm_sysctl_header);
+out_sysctl:
+	del_timer_sync(&cmm_timer);
+	return rc;
+}
+module_init(cmm_init);
+
+static void __exit cmm_exit(void)
+{
+	unregister_sysctl_table(cmm_sysctl_header);
+#ifdef CONFIG_CMM_IUCV
+	smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
+#endif
+	unregister_oom_notifier(&cmm_oom_nb);
+	kthread_stop(cmm_thread_ptr);
+	del_timer_sync(&cmm_timer);
+	cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
+	cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
+}
+module_exit(cmm_exit);
+
+MODULE_LICENSE("GPL");
diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c
new file mode 100644
index 0000000000..b51666967a
--- /dev/null
+++ b/arch/s390/mm/dump_pagetables.c
@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/set_memory.h>
+#include <linux/ptdump.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/mm.h>
+#include <linux/kfence.h>
+#include <linux/kasan.h>
+#include <asm/ptdump.h>
+#include <asm/kasan.h>
+#include <asm/abs_lowcore.h>
+#include <asm/nospec-branch.h>
+#include <asm/sections.h>
+#include <asm/maccess.h>
+
+static unsigned long max_addr;
+
+struct addr_marker {
+	unsigned long start_address;
+	const char *name;
+};
+
+enum address_markers_idx {
+	IDENTITY_BEFORE_NR = 0,
+	IDENTITY_BEFORE_END_NR,
+	AMODE31_START_NR,
+	AMODE31_END_NR,
+	KERNEL_START_NR,
+	KERNEL_END_NR,
+#ifdef CONFIG_KFENCE
+	KFENCE_START_NR,
+	KFENCE_END_NR,
+#endif
+	IDENTITY_AFTER_NR,
+	IDENTITY_AFTER_END_NR,
+	VMEMMAP_NR,
+	VMEMMAP_END_NR,
+	VMALLOC_NR,
+	VMALLOC_END_NR,
+	MODULES_NR,
+	MODULES_END_NR,
+	ABS_LOWCORE_NR,
+	ABS_LOWCORE_END_NR,
+	MEMCPY_REAL_NR,
+	MEMCPY_REAL_END_NR,
+#ifdef CONFIG_KASAN
+	KASAN_SHADOW_START_NR,
+	KASAN_SHADOW_END_NR,
+#endif
+};
+
+static struct addr_marker address_markers[] = {
+	[IDENTITY_BEFORE_NR]	= {0, "Identity Mapping Start"},
+	[IDENTITY_BEFORE_END_NR] = {(unsigned long)_stext, "Identity Mapping End"},
+	[AMODE31_START_NR]	= {0, "Amode31 Area Start"},
+	[AMODE31_END_NR]	= {0, "Amode31 Area End"},
+	[KERNEL_START_NR]	= {(unsigned long)_stext, "Kernel Image Start"},
+	[KERNEL_END_NR]		= {(unsigned long)_end, "Kernel Image End"},
+#ifdef CONFIG_KFENCE
+	[KFENCE_START_NR]	= {0, "KFence Pool Start"},
+	[KFENCE_END_NR]		= {0, "KFence Pool End"},
+#endif
+	[IDENTITY_AFTER_NR]	= {(unsigned long)_end, "Identity Mapping Start"},
+	[IDENTITY_AFTER_END_NR]	= {0, "Identity Mapping End"},
+	[VMEMMAP_NR]		= {0, "vmemmap Area Start"},
+	[VMEMMAP_END_NR]	= {0, "vmemmap Area End"},
+	[VMALLOC_NR]		= {0, "vmalloc Area Start"},
+	[VMALLOC_END_NR]	= {0, "vmalloc Area End"},
+	[MODULES_NR]		= {0, "Modules Area Start"},
+	[MODULES_END_NR]	= {0, "Modules Area End"},
+	[ABS_LOWCORE_NR]	= {0, "Lowcore Area Start"},
+	[ABS_LOWCORE_END_NR]	= {0, "Lowcore Area End"},
+	[MEMCPY_REAL_NR]	= {0, "Real Memory Copy Area Start"},
+	[MEMCPY_REAL_END_NR]	= {0, "Real Memory Copy Area End"},
+#ifdef CONFIG_KASAN
+	[KASAN_SHADOW_START_NR]	= {KASAN_SHADOW_START, "Kasan Shadow Start"},
+	[KASAN_SHADOW_END_NR]	= {KASAN_SHADOW_END, "Kasan Shadow End"},
+#endif
+	{ -1, NULL }
+};
+
+struct pg_state {
+	struct ptdump_state ptdump;
+	struct seq_file *seq;
+	int level;
+	unsigned int current_prot;
+	bool check_wx;
+	unsigned long wx_pages;
+	unsigned long start_address;
+	const struct addr_marker *marker;
+};
+
+#define pt_dump_seq_printf(m, fmt, args...)	\
+({						\
+	struct seq_file *__m = (m);		\
+						\
+	if (__m)				\
+		seq_printf(__m, fmt, ##args);	\
+})
+
+#define pt_dump_seq_puts(m, fmt)		\
+({						\
+	struct seq_file *__m = (m);		\
+						\
+	if (__m)				\
+		seq_printf(__m, fmt);		\
+})
+
+static void print_prot(struct seq_file *m, unsigned int pr, int level)
+{
+	static const char * const level_name[] =
+		{ "ASCE", "PGD", "PUD", "PMD", "PTE" };
+
+	pt_dump_seq_printf(m, "%s ", level_name[level]);
+	if (pr & _PAGE_INVALID) {
+		pt_dump_seq_printf(m, "I\n");
+		return;
+	}
+	pt_dump_seq_puts(m, (pr & _PAGE_PROTECT) ? "RO " : "RW ");
+	pt_dump_seq_puts(m, (pr & _PAGE_NOEXEC) ? "NX\n" : "X\n");
+}
+
+static void note_prot_wx(struct pg_state *st, unsigned long addr)
+{
+#ifdef CONFIG_DEBUG_WX
+	if (!st->check_wx)
+		return;
+	if (st->current_prot & _PAGE_INVALID)
+		return;
+	if (st->current_prot & _PAGE_PROTECT)
+		return;
+	if (st->current_prot & _PAGE_NOEXEC)
+		return;
+	/*
+	 * The first lowcore page is W+X if spectre mitigations are using
+	 * trampolines or the BEAR enhancements facility is not installed,
+	 * in which case we have two lpswe instructions in lowcore that need
+	 * to be executable.
+	 */
+	if (addr == PAGE_SIZE && (nospec_uses_trampoline() || !static_key_enabled(&cpu_has_bear)))
+		return;
+	WARN_ONCE(1, "s390/mm: Found insecure W+X mapping at address %pS\n",
+		  (void *)st->start_address);
+	st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
+#endif /* CONFIG_DEBUG_WX */
+}
+
+static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, u64 val)
+{
+	int width = sizeof(unsigned long) * 2;
+	static const char units[] = "KMGTPE";
+	const char *unit = units;
+	unsigned long delta;
+	struct pg_state *st;
+	struct seq_file *m;
+	unsigned int prot;
+
+	st = container_of(pt_st, struct pg_state, ptdump);
+	m = st->seq;
+	prot = val & (_PAGE_PROTECT | _PAGE_NOEXEC);
+	if (level == 4 && (val & _PAGE_INVALID))
+		prot = _PAGE_INVALID;
+	/* For pmd_none() & friends val gets passed as zero. */
+	if (level != 4 && !val)
+		prot = _PAGE_INVALID;
+	/* Final flush from generic code. */
+	if (level == -1)
+		addr = max_addr;
+	if (st->level == -1) {
+		pt_dump_seq_printf(m, "---[ %s ]---\n", st->marker->name);
+		st->start_address = addr;
+		st->current_prot = prot;
+		st->level = level;
+	} else if (prot != st->current_prot || level != st->level ||
+		   addr >= st->marker[1].start_address) {
+		note_prot_wx(st, addr);
+		pt_dump_seq_printf(m, "0x%0*lx-0x%0*lx ",
+				   width, st->start_address,
+				   width, addr);
+		delta = (addr - st->start_address) >> 10;
+		while (!(delta & 0x3ff) && unit[1]) {
+			delta >>= 10;
+			unit++;
+		}
+		pt_dump_seq_printf(m, "%9lu%c ", delta, *unit);
+		print_prot(m, st->current_prot, st->level);
+		while (addr >= st->marker[1].start_address) {
+			st->marker++;
+			pt_dump_seq_printf(m, "---[ %s ]---\n", st->marker->name);
+		}
+		st->start_address = addr;
+		st->current_prot = prot;
+		st->level = level;
+	}
+}
+
+#ifdef CONFIG_DEBUG_WX
+void ptdump_check_wx(void)
+{
+	struct pg_state st = {
+		.ptdump = {
+			.note_page = note_page,
+			.range = (struct ptdump_range[]) {
+				{.start = 0, .end = max_addr},
+				{.start = 0, .end = 0},
+			}
+		},
+		.seq = NULL,
+		.level = -1,
+		.current_prot = 0,
+		.check_wx = true,
+		.wx_pages = 0,
+		.start_address = 0,
+		.marker = (struct addr_marker[]) {
+			{ .start_address =  0, .name = NULL},
+			{ .start_address = -1, .name = NULL},
+		},
+	};
+
+	if (!MACHINE_HAS_NX)
+		return;
+	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
+	if (st.wx_pages)
+		pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found\n", st.wx_pages);
+	else
+		pr_info("Checked W+X mappings: passed, no %sW+X pages found\n",
+			(nospec_uses_trampoline() || !static_key_enabled(&cpu_has_bear)) ?
+			"unexpected " : "");
+}
+#endif /* CONFIG_DEBUG_WX */
+
+#ifdef CONFIG_PTDUMP_DEBUGFS
+static int ptdump_show(struct seq_file *m, void *v)
+{
+	struct pg_state st = {
+		.ptdump = {
+			.note_page = note_page,
+			.range = (struct ptdump_range[]) {
+				{.start = 0, .end = max_addr},
+				{.start = 0, .end = 0},
+			}
+		},
+		.seq = m,
+		.level = -1,
+		.current_prot = 0,
+		.check_wx = false,
+		.wx_pages = 0,
+		.start_address = 0,
+		.marker = address_markers,
+	};
+
+	get_online_mems();
+	mutex_lock(&cpa_mutex);
+	ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
+	mutex_unlock(&cpa_mutex);
+	put_online_mems();
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ptdump);
+#endif /* CONFIG_PTDUMP_DEBUGFS */
+
+/*
+ * Heapsort from lib/sort.c is not a stable sorting algorithm, do a simple
+ * insertion sort to preserve the original order of markers with the same
+ * start address.
+ */
+static void sort_address_markers(void)
+{
+	struct addr_marker tmp;
+	int i, j;
+
+	for (i = 1; i < ARRAY_SIZE(address_markers) - 1; i++) {
+		tmp = address_markers[i];
+		for (j = i - 1; j >= 0 && address_markers[j].start_address > tmp.start_address; j--)
+			address_markers[j + 1] = address_markers[j];
+		address_markers[j + 1] = tmp;
+	}
+}
+
+static int pt_dump_init(void)
+{
+#ifdef CONFIG_KFENCE
+	unsigned long kfence_start = (unsigned long)__kfence_pool;
+#endif
+	/*
+	 * Figure out the maximum virtual address being accessible with the
+	 * kernel ASCE. We need this to keep the page table walker functions
+	 * from accessing non-existent entries.
+	 */
+	max_addr = (S390_lowcore.kernel_asce & _REGION_ENTRY_TYPE_MASK) >> 2;
+	max_addr = 1UL << (max_addr * 11 + 31);
+	address_markers[IDENTITY_AFTER_END_NR].start_address = ident_map_size;
+	address_markers[AMODE31_START_NR].start_address = (unsigned long)__samode31;
+	address_markers[AMODE31_END_NR].start_address = (unsigned long)__eamode31;
+	address_markers[MODULES_NR].start_address = MODULES_VADDR;
+	address_markers[MODULES_END_NR].start_address = MODULES_END;
+	address_markers[ABS_LOWCORE_NR].start_address = __abs_lowcore;
+	address_markers[ABS_LOWCORE_END_NR].start_address = __abs_lowcore + ABS_LOWCORE_MAP_SIZE;
+	address_markers[MEMCPY_REAL_NR].start_address = __memcpy_real_area;
+	address_markers[MEMCPY_REAL_END_NR].start_address = __memcpy_real_area + MEMCPY_REAL_SIZE;
+	address_markers[VMEMMAP_NR].start_address = (unsigned long) vmemmap;
+	address_markers[VMEMMAP_END_NR].start_address = (unsigned long)vmemmap + vmemmap_size;
+	address_markers[VMALLOC_NR].start_address = VMALLOC_START;
+	address_markers[VMALLOC_END_NR].start_address = VMALLOC_END;
+#ifdef CONFIG_KFENCE
+	address_markers[KFENCE_START_NR].start_address = kfence_start;
+	address_markers[KFENCE_END_NR].start_address = kfence_start + KFENCE_POOL_SIZE;
+#endif
+	sort_address_markers();
+#ifdef CONFIG_PTDUMP_DEBUGFS
+	debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, &ptdump_fops);
+#endif /* CONFIG_PTDUMP_DEBUGFS */
+	return 0;
+}
+device_initcall(pt_dump_init);
diff --git a/arch/s390/mm/extable.c b/arch/s390/mm/extable.c
new file mode 100644
index 0000000000..fe87291df9
--- /dev/null
+++ b/arch/s390/mm/extable.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bitfield.h>
+#include <linux/extable.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/panic.h>
+#include <asm/asm-extable.h>
+#include <asm/extable.h>
+
+const struct exception_table_entry *s390_search_extables(unsigned long addr)
+{
+	const struct exception_table_entry *fixup;
+	size_t num;
+
+	fixup = search_exception_tables(addr);
+	if (fixup)
+		return fixup;
+	num = __stop_amode31_ex_table - __start_amode31_ex_table;
+	return search_extable(__start_amode31_ex_table, num, addr);
+}
+
+static bool ex_handler_fixup(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}
+
+static bool ex_handler_ua_store(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+	unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
+
+	regs->gprs[reg_err] = -EFAULT;
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}
+
+static bool ex_handler_ua_load_mem(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+	unsigned int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
+	unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
+	size_t len = FIELD_GET(EX_DATA_LEN, ex->data);
+
+	regs->gprs[reg_err] = -EFAULT;
+	memset((void *)regs->gprs[reg_addr], 0, len);
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}
+
+static bool ex_handler_ua_load_reg(const struct exception_table_entry *ex,
+				   bool pair, struct pt_regs *regs)
+{
+	unsigned int reg_zero = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
+	unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
+
+	regs->gprs[reg_err] = -EFAULT;
+	regs->gprs[reg_zero] = 0;
+	if (pair)
+		regs->gprs[reg_zero + 1] = 0;
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}
+
+bool fixup_exception(struct pt_regs *regs)
+{
+	const struct exception_table_entry *ex;
+
+	ex = s390_search_extables(instruction_pointer(regs));
+	if (!ex)
+		return false;
+	switch (ex->type) {
+	case EX_TYPE_FIXUP:
+		return ex_handler_fixup(ex, regs);
+	case EX_TYPE_BPF:
+		return ex_handler_bpf(ex, regs);
+	case EX_TYPE_UA_STORE:
+		return ex_handler_ua_store(ex, regs);
+	case EX_TYPE_UA_LOAD_MEM:
+		return ex_handler_ua_load_mem(ex, regs);
+	case EX_TYPE_UA_LOAD_REG:
+		return ex_handler_ua_load_reg(ex, false, regs);
+	case EX_TYPE_UA_LOAD_REGPAIR:
+		return ex_handler_ua_load_reg(ex, true, regs);
+	}
+	panic("invalid exception table entry");
+}
diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c
new file mode 100644
index 0000000000..e41869f5cc
--- /dev/null
+++ b/arch/s390/mm/extmem.c
@@ -0,0 +1,660 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author(s)......: Carsten Otte <cotte@de.ibm.com>
+ * 		    Rob M van der Heij <rvdheij@nl.ibm.com>
+ * 		    Steven Shultz <shultzss@us.ibm.com>
+ * Bugreports.to..: <Linux390@de.ibm.com>
+ * Copyright IBM Corp. 2002, 2004
+ */
+
+#define KMSG_COMPONENT "extmem"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/memblock.h>
+#include <linux/ctype.h>
+#include <linux/ioport.h>
+#include <linux/refcount.h>
+#include <linux/pgtable.h>
+#include <asm/diag.h>
+#include <asm/page.h>
+#include <asm/ebcdic.h>
+#include <asm/errno.h>
+#include <asm/extmem.h>
+#include <asm/cpcmd.h>
+#include <asm/setup.h>
+
+#define DCSS_PURGESEG   0x08
+#define DCSS_LOADSHRX	0x20
+#define DCSS_LOADNSRX	0x24
+#define DCSS_FINDSEGX	0x2c
+#define DCSS_SEGEXTX	0x38
+#define DCSS_FINDSEGA   0x0c
+
+struct qrange {
+	unsigned long  start; /* last byte type */
+	unsigned long  end;   /* last byte reserved */
+};
+
+struct qout64 {
+	unsigned long segstart;
+	unsigned long segend;
+	int segcnt;
+	int segrcnt;
+	struct qrange range[6];
+};
+
+struct qin64 {
+	char qopcode;
+	char rsrv1[3];
+	char qrcode;
+	char rsrv2[3];
+	char qname[8];
+	unsigned int qoutptr;
+	short int qoutlen;
+};
+
+struct dcss_segment {
+	struct list_head list;
+	char dcss_name[8];
+	char res_name[16];
+	unsigned long start_addr;
+	unsigned long end;
+	refcount_t ref_count;
+	int do_nonshared;
+	unsigned int vm_segtype;
+	struct qrange range[6];
+	int segcnt;
+	struct resource *res;
+};
+
+static DEFINE_MUTEX(dcss_lock);
+static LIST_HEAD(dcss_list);
+static char *segtype_string[] = { "SW", "EW", "SR", "ER", "SN", "EN", "SC",
+					"EW/EN-MIXED" };
+static int loadshr_scode = DCSS_LOADSHRX;
+static int loadnsr_scode = DCSS_LOADNSRX;
+static int purgeseg_scode = DCSS_PURGESEG;
+static int segext_scode = DCSS_SEGEXTX;
+
+/*
+ * Create the 8 bytes, ebcdic VM segment name from
+ * an ascii name.
+ */
+static void
+dcss_mkname(char *name, char *dcss_name)
+{
+	int i;
+
+	for (i = 0; i < 8; i++) {
+		if (name[i] == '\0')
+			break;
+		dcss_name[i] = toupper(name[i]);
+	}
+	for (; i < 8; i++)
+		dcss_name[i] = ' ';
+	ASCEBC(dcss_name, 8);
+}
+
+
+/*
+ * search all segments in dcss_list, and return the one
+ * namend *name. If not found, return NULL.
+ */
+static struct dcss_segment *
+segment_by_name (char *name)
+{
+	char dcss_name[9];
+	struct list_head *l;
+	struct dcss_segment *tmp, *retval = NULL;
+
+	BUG_ON(!mutex_is_locked(&dcss_lock));
+	dcss_mkname (name, dcss_name);
+	list_for_each (l, &dcss_list) {
+		tmp = list_entry (l, struct dcss_segment, list);
+		if (memcmp(tmp->dcss_name, dcss_name, 8) == 0) {
+			retval = tmp;
+			break;
+		}
+	}
+	return retval;
+}
+
+
+/*
+ * Perform a function on a dcss segment.
+ */
+static inline int
+dcss_diag(int *func, void *parameter,
+           unsigned long *ret1, unsigned long *ret2)
+{
+	unsigned long rx, ry;
+	int rc;
+
+	rx = (unsigned long) parameter;
+	ry = (unsigned long) *func;
+
+	diag_stat_inc(DIAG_STAT_X064);
+	asm volatile(
+		"	diag	%0,%1,0x64\n"
+		"	ipm	%2\n"
+		"	srl	%2,28\n"
+		: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
+	*ret1 = rx;
+	*ret2 = ry;
+	return rc;
+}
+
+static inline int
+dcss_diag_translate_rc (int vm_rc) {
+	if (vm_rc == 44)
+		return -ENOENT;
+	return -EIO;
+}
+
+
+/* do a diag to get info about a segment.
+ * fills start_address, end and vm_segtype fields
+ */
+static int
+query_segment_type (struct dcss_segment *seg)
+{
+	unsigned long dummy, vmrc;
+	int diag_cc, rc, i;
+	struct qout64 *qout;
+	struct qin64 *qin;
+
+	qin = kmalloc(sizeof(*qin), GFP_KERNEL | GFP_DMA);
+	qout = kmalloc(sizeof(*qout), GFP_KERNEL | GFP_DMA);
+	if ((qin == NULL) || (qout == NULL)) {
+		rc = -ENOMEM;
+		goto out_free;
+	}
+
+	/* initialize diag input parameters */
+	qin->qopcode = DCSS_FINDSEGA;
+	qin->qoutptr = (unsigned long) qout;
+	qin->qoutlen = sizeof(struct qout64);
+	memcpy (qin->qname, seg->dcss_name, 8);
+
+	diag_cc = dcss_diag(&segext_scode, qin, &dummy, &vmrc);
+
+	if (diag_cc < 0) {
+		rc = diag_cc;
+		goto out_free;
+	}
+	if (diag_cc > 1) {
+		pr_warn("Querying a DCSS type failed with rc=%ld\n", vmrc);
+		rc = dcss_diag_translate_rc (vmrc);
+		goto out_free;
+	}
+
+	if (qout->segcnt > 6) {
+		rc = -EOPNOTSUPP;
+		goto out_free;
+	}
+
+	if (qout->segcnt == 1) {
+		seg->vm_segtype = qout->range[0].start & 0xff;
+	} else {
+		/* multi-part segment. only one type supported here:
+		    - all parts are contiguous
+		    - all parts are either EW or EN type
+		    - maximum 6 parts allowed */
+		unsigned long start = qout->segstart >> PAGE_SHIFT;
+		for (i=0; i<qout->segcnt; i++) {
+			if (((qout->range[i].start & 0xff) != SEG_TYPE_EW) &&
+			    ((qout->range[i].start & 0xff) != SEG_TYPE_EN)) {
+				rc = -EOPNOTSUPP;
+				goto out_free;
+			}
+			if (start != qout->range[i].start >> PAGE_SHIFT) {
+				rc = -EOPNOTSUPP;
+				goto out_free;
+			}
+			start = (qout->range[i].end >> PAGE_SHIFT) + 1;
+		}
+		seg->vm_segtype = SEG_TYPE_EWEN;
+	}
+
+	/* analyze diag output and update seg */
+	seg->start_addr = qout->segstart;
+	seg->end = qout->segend;
+
+	memcpy (seg->range, qout->range, 6*sizeof(struct qrange));
+	seg->segcnt = qout->segcnt;
+
+	rc = 0;
+
+ out_free:
+	kfree(qin);
+	kfree(qout);
+	return rc;
+}
+
+/*
+ * get info about a segment
+ * possible return values:
+ * -ENOSYS  : we are not running on VM
+ * -EIO     : could not perform query diagnose
+ * -ENOENT  : no such segment
+ * -EOPNOTSUPP: multi-part segment cannot be used with linux
+ * -ENOMEM  : out of memory
+ * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
+ */
+int
+segment_type (char* name)
+{
+	int rc;
+	struct dcss_segment seg;
+
+	if (!MACHINE_IS_VM)
+		return -ENOSYS;
+
+	dcss_mkname(name, seg.dcss_name);
+	rc = query_segment_type (&seg);
+	if (rc < 0)
+		return rc;
+	return seg.vm_segtype;
+}
+
+/*
+ * check if segment collides with other segments that are currently loaded
+ * returns 1 if this is the case, 0 if no collision was found
+ */
+static int
+segment_overlaps_others (struct dcss_segment *seg)
+{
+	struct list_head *l;
+	struct dcss_segment *tmp;
+
+	BUG_ON(!mutex_is_locked(&dcss_lock));
+	list_for_each(l, &dcss_list) {
+		tmp = list_entry(l, struct dcss_segment, list);
+		if ((tmp->start_addr >> 20) > (seg->end >> 20))
+			continue;
+		if ((tmp->end >> 20) < (seg->start_addr >> 20))
+			continue;
+		if (seg == tmp)
+			continue;
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * real segment loading function, called from segment_load
+ * Must return either an error code < 0, or the segment type code >= 0
+ */
+static int
+__segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long *end)
+{
+	unsigned long start_addr, end_addr, dummy;
+	struct dcss_segment *seg;
+	int rc, diag_cc, segtype;
+
+	start_addr = end_addr = 0;
+	segtype = -1;
+	seg = kmalloc(sizeof(*seg), GFP_KERNEL | GFP_DMA);
+	if (seg == NULL) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	dcss_mkname (name, seg->dcss_name);
+	rc = query_segment_type (seg);
+	if (rc < 0)
+		goto out_free;
+
+	if (segment_overlaps_others(seg)) {
+		rc = -EBUSY;
+		goto out_free;
+	}
+
+	seg->res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+	if (seg->res == NULL) {
+		rc = -ENOMEM;
+		goto out_free;
+	}
+	seg->res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
+	seg->res->start = seg->start_addr;
+	seg->res->end = seg->end;
+	memcpy(&seg->res_name, seg->dcss_name, 8);
+	EBCASC(seg->res_name, 8);
+	seg->res_name[8] = '\0';
+	strlcat(seg->res_name, " (DCSS)", sizeof(seg->res_name));
+	seg->res->name = seg->res_name;
+	segtype = seg->vm_segtype;
+	if (segtype == SEG_TYPE_SC ||
+	    ((segtype == SEG_TYPE_SR || segtype == SEG_TYPE_ER) && !do_nonshared))
+		seg->res->flags |= IORESOURCE_READONLY;
+
+	/* Check for overlapping resources before adding the mapping. */
+	if (request_resource(&iomem_resource, seg->res)) {
+		rc = -EBUSY;
+		goto out_free_resource;
+	}
+
+	rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
+	if (rc)
+		goto out_resource;
+
+	if (do_nonshared)
+		diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
+				&start_addr, &end_addr);
+	else
+		diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
+				&start_addr, &end_addr);
+	if (diag_cc < 0) {
+		dcss_diag(&purgeseg_scode, seg->dcss_name,
+				&dummy, &dummy);
+		rc = diag_cc;
+		goto out_mapping;
+	}
+	if (diag_cc > 1) {
+		pr_warn("Loading DCSS %s failed with rc=%ld\n", name, end_addr);
+		rc = dcss_diag_translate_rc(end_addr);
+		dcss_diag(&purgeseg_scode, seg->dcss_name,
+				&dummy, &dummy);
+		goto out_mapping;
+	}
+	seg->start_addr = start_addr;
+	seg->end = end_addr;
+	seg->do_nonshared = do_nonshared;
+	refcount_set(&seg->ref_count, 1);
+	list_add(&seg->list, &dcss_list);
+	*addr = seg->start_addr;
+	*end  = seg->end;
+	if (do_nonshared)
+		pr_info("DCSS %s of range %px to %px and type %s loaded as "
+			"exclusive-writable\n", name, (void*) seg->start_addr,
+			(void*) seg->end, segtype_string[seg->vm_segtype]);
+	else {
+		pr_info("DCSS %s of range %px to %px and type %s loaded in "
+			"shared access mode\n", name, (void*) seg->start_addr,
+			(void*) seg->end, segtype_string[seg->vm_segtype]);
+	}
+	goto out;
+ out_mapping:
+	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
+ out_resource:
+	release_resource(seg->res);
+ out_free_resource:
+	kfree(seg->res);
+ out_free:
+	kfree(seg);
+ out:
+	return rc < 0 ? rc : segtype;
+}
+
+/*
+ * this function loads a DCSS segment
+ * name         : name of the DCSS
+ * do_nonshared : 0 indicates that the dcss should be shared with other linux images
+ *                1 indicates that the dcss should be exclusive for this linux image
+ * addr         : will be filled with start address of the segment
+ * end          : will be filled with end address of the segment
+ * return values:
+ * -ENOSYS  : we are not running on VM
+ * -EIO     : could not perform query or load diagnose
+ * -ENOENT  : no such segment
+ * -EOPNOTSUPP: multi-part segment cannot be used with linux
+ * -EBUSY   : segment cannot be used (overlaps with dcss or storage)
+ * -ERANGE  : segment cannot be used (exceeds kernel mapping range)
+ * -EPERM   : segment is currently loaded with incompatible permissions
+ * -ENOMEM  : out of memory
+ * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
+ */
+int
+segment_load (char *name, int do_nonshared, unsigned long *addr,
+		unsigned long *end)
+{
+	struct dcss_segment *seg;
+	int rc;
+
+	if (!MACHINE_IS_VM)
+		return -ENOSYS;
+
+	mutex_lock(&dcss_lock);
+	seg = segment_by_name (name);
+	if (seg == NULL)
+		rc = __segment_load (name, do_nonshared, addr, end);
+	else {
+		if (do_nonshared == seg->do_nonshared) {
+			refcount_inc(&seg->ref_count);
+			*addr = seg->start_addr;
+			*end  = seg->end;
+			rc    = seg->vm_segtype;
+		} else {
+			*addr = *end = 0;
+			rc    = -EPERM;
+		}
+	}
+	mutex_unlock(&dcss_lock);
+	return rc;
+}
+
+/*
+ * this function modifies the shared state of a DCSS segment. note that
+ * name         : name of the DCSS
+ * do_nonshared : 0 indicates that the dcss should be shared with other linux images
+ *                1 indicates that the dcss should be exclusive for this linux image
+ * return values:
+ * -EIO     : could not perform load diagnose (segment gone!)
+ * -ENOENT  : no such segment (segment gone!)
+ * -EAGAIN  : segment is in use by other exploiters, try later
+ * -EINVAL  : no segment with the given name is currently loaded - name invalid
+ * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
+ * 0	    : operation succeeded
+ */
+int
+segment_modify_shared (char *name, int do_nonshared)
+{
+	struct dcss_segment *seg;
+	unsigned long start_addr, end_addr, dummy;
+	int rc, diag_cc;
+
+	start_addr = end_addr = 0;
+	mutex_lock(&dcss_lock);
+	seg = segment_by_name (name);
+	if (seg == NULL) {
+		rc = -EINVAL;
+		goto out_unlock;
+	}
+	if (do_nonshared == seg->do_nonshared) {
+		pr_info("DCSS %s is already in the requested access "
+			"mode\n", name);
+		rc = 0;
+		goto out_unlock;
+	}
+	if (refcount_read(&seg->ref_count) != 1) {
+		pr_warn("DCSS %s is in use and cannot be reloaded\n", name);
+		rc = -EAGAIN;
+		goto out_unlock;
+	}
+	release_resource(seg->res);
+	if (do_nonshared)
+		seg->res->flags &= ~IORESOURCE_READONLY;
+	else
+		if (seg->vm_segtype == SEG_TYPE_SR ||
+		    seg->vm_segtype == SEG_TYPE_ER)
+			seg->res->flags |= IORESOURCE_READONLY;
+
+	if (request_resource(&iomem_resource, seg->res)) {
+		pr_warn("DCSS %s overlaps with used memory resources and cannot be reloaded\n",
+			name);
+		rc = -EBUSY;
+		kfree(seg->res);
+		goto out_del_mem;
+	}
+
+	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
+	if (do_nonshared)
+		diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
+				&start_addr, &end_addr);
+	else
+		diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
+				&start_addr, &end_addr);
+	if (diag_cc < 0) {
+		rc = diag_cc;
+		goto out_del_res;
+	}
+	if (diag_cc > 1) {
+		pr_warn("Reloading DCSS %s failed with rc=%ld\n",
+			name, end_addr);
+		rc = dcss_diag_translate_rc(end_addr);
+		goto out_del_res;
+	}
+	seg->start_addr = start_addr;
+	seg->end = end_addr;
+	seg->do_nonshared = do_nonshared;
+	rc = 0;
+	goto out_unlock;
+ out_del_res:
+	release_resource(seg->res);
+	kfree(seg->res);
+ out_del_mem:
+	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
+	list_del(&seg->list);
+	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
+	kfree(seg);
+ out_unlock:
+	mutex_unlock(&dcss_lock);
+	return rc;
+}
+
+/*
+ * Decrease the use count of a DCSS segment and remove
+ * it from the address space if nobody is using it
+ * any longer.
+ */
+void
+segment_unload(char *name)
+{
+	unsigned long dummy;
+	struct dcss_segment *seg;
+
+	if (!MACHINE_IS_VM)
+		return;
+
+	mutex_lock(&dcss_lock);
+	seg = segment_by_name (name);
+	if (seg == NULL) {
+		pr_err("Unloading unknown DCSS %s failed\n", name);
+		goto out_unlock;
+	}
+	if (!refcount_dec_and_test(&seg->ref_count))
+		goto out_unlock;
+	release_resource(seg->res);
+	kfree(seg->res);
+	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
+	list_del(&seg->list);
+	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
+	kfree(seg);
+out_unlock:
+	mutex_unlock(&dcss_lock);
+}
+
+/*
+ * save segment content permanently
+ */
+void
+segment_save(char *name)
+{
+	struct dcss_segment *seg;
+	char cmd1[160];
+	char cmd2[80];
+	int i, response;
+
+	if (!MACHINE_IS_VM)
+		return;
+
+	mutex_lock(&dcss_lock);
+	seg = segment_by_name (name);
+
+	if (seg == NULL) {
+		pr_err("Saving unknown DCSS %s failed\n", name);
+		goto out;
+	}
+
+	sprintf(cmd1, "DEFSEG %s", name);
+	for (i=0; i<seg->segcnt; i++) {
+		sprintf(cmd1+strlen(cmd1), " %lX-%lX %s",
+			seg->range[i].start >> PAGE_SHIFT,
+			seg->range[i].end >> PAGE_SHIFT,
+			segtype_string[seg->range[i].start & 0xff]);
+	}
+	sprintf(cmd2, "SAVESEG %s", name);
+	response = 0;
+	cpcmd(cmd1, NULL, 0, &response);
+	if (response) {
+		pr_err("Saving a DCSS failed with DEFSEG response code "
+		       "%i\n", response);
+		goto out;
+	}
+	cpcmd(cmd2, NULL, 0, &response);
+	if (response) {
+		pr_err("Saving a DCSS failed with SAVESEG response code "
+		       "%i\n", response);
+		goto out;
+	}
+out:
+	mutex_unlock(&dcss_lock);
+}
+
+/*
+ * print appropriate error message for segment_load()/segment_type()
+ * return code
+ */
+void segment_warning(int rc, char *seg_name)
+{
+	switch (rc) {
+	case -ENOENT:
+		pr_err("DCSS %s cannot be loaded or queried\n", seg_name);
+		break;
+	case -ENOSYS:
+		pr_err("DCSS %s cannot be loaded or queried without "
+		       "z/VM\n", seg_name);
+		break;
+	case -EIO:
+		pr_err("Loading or querying DCSS %s resulted in a "
+		       "hardware error\n", seg_name);
+		break;
+	case -EOPNOTSUPP:
+		pr_err("DCSS %s has multiple page ranges and cannot be "
+		       "loaded or queried\n", seg_name);
+		break;
+	case -EBUSY:
+		pr_err("%s needs used memory resources and cannot be "
+		       "loaded or queried\n", seg_name);
+		break;
+	case -EPERM:
+		pr_err("DCSS %s is already loaded in a different access "
+		       "mode\n", seg_name);
+		break;
+	case -ENOMEM:
+		pr_err("There is not enough memory to load or query "
+		       "DCSS %s\n", seg_name);
+		break;
+	case -ERANGE: {
+		struct range mhp_range = arch_get_mappable_range();
+
+		pr_err("DCSS %s exceeds the kernel mapping range (%llu) "
+		       "and cannot be loaded\n", seg_name, mhp_range.end + 1);
+		break;
+	}
+	default:
+		break;
+	}
+}
+
+EXPORT_SYMBOL(segment_load);
+EXPORT_SYMBOL(segment_unload);
+EXPORT_SYMBOL(segment_save);
+EXPORT_SYMBOL(segment_type);
+EXPORT_SYMBOL(segment_modify_shared);
+EXPORT_SYMBOL(segment_warning);
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
new file mode 100644
index 0000000000..b678295931
--- /dev/null
+++ b/arch/s390/mm/fault.c
@@ -0,0 +1,708 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  S390 version
+ *    Copyright IBM Corp. 1999
+ *    Author(s): Hartmut Penner (hp@de.ibm.com)
+ *               Ulrich Weigand (uweigand@de.ibm.com)
+ *
+ *  Derived from "arch/i386/mm/fault.c"
+ *    Copyright (C) 1995  Linus Torvalds
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/perf_event.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/compat.h>
+#include <linux/smp.h>
+#include <linux/kdebug.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/extable.h>
+#include <linux/hardirq.h>
+#include <linux/kprobes.h>
+#include <linux/uaccess.h>
+#include <linux/hugetlb.h>
+#include <linux/kfence.h>
+#include <asm/asm-extable.h>
+#include <asm/asm-offsets.h>
+#include <asm/diag.h>
+#include <asm/gmap.h>
+#include <asm/irq.h>
+#include <asm/mmu_context.h>
+#include <asm/facility.h>
+#include <asm/uv.h>
+#include "../kernel/entry.h"
+
+#define __FAIL_ADDR_MASK -4096L
+
+/*
+ * Allocate private vm_fault_reason from top.  Please make sure it won't
+ * collide with vm_fault_reason.
+ */
+#define VM_FAULT_BADCONTEXT	((__force vm_fault_t)0x80000000)
+#define VM_FAULT_BADMAP		((__force vm_fault_t)0x40000000)
+#define VM_FAULT_BADACCESS	((__force vm_fault_t)0x20000000)
+#define VM_FAULT_SIGNAL		((__force vm_fault_t)0x10000000)
+#define VM_FAULT_PFAULT		((__force vm_fault_t)0x8000000)
+
+enum fault_type {
+	KERNEL_FAULT,
+	USER_FAULT,
+	GMAP_FAULT,
+};
+
+static unsigned long store_indication __read_mostly;
+
+static int __init fault_init(void)
+{
+	if (test_facility(75))
+		store_indication = 0xc00;
+	return 0;
+}
+early_initcall(fault_init);
+
+/*
+ * Find out which address space caused the exception.
+ */
+static enum fault_type get_fault_type(struct pt_regs *regs)
+{
+	unsigned long trans_exc_code;
+
+	trans_exc_code = regs->int_parm_long & 3;
+	if (likely(trans_exc_code == 0)) {
+		/* primary space exception */
+		if (user_mode(regs))
+			return USER_FAULT;
+		if (!IS_ENABLED(CONFIG_PGSTE))
+			return KERNEL_FAULT;
+		if (test_pt_regs_flag(regs, PIF_GUEST_FAULT))
+			return GMAP_FAULT;
+		return KERNEL_FAULT;
+	}
+	if (trans_exc_code == 2)
+		return USER_FAULT;
+	if (trans_exc_code == 1) {
+		/* access register mode, not used in the kernel */
+		return USER_FAULT;
+	}
+	/* home space exception -> access via kernel ASCE */
+	return KERNEL_FAULT;
+}
+
+static unsigned long get_fault_address(struct pt_regs *regs)
+{
+	unsigned long trans_exc_code = regs->int_parm_long;
+
+	return trans_exc_code & __FAIL_ADDR_MASK;
+}
+
+static bool fault_is_write(struct pt_regs *regs)
+{
+	unsigned long trans_exc_code = regs->int_parm_long;
+
+	return (trans_exc_code & store_indication) == 0x400;
+}
+
+static int bad_address(void *p)
+{
+	unsigned long dummy;
+
+	return get_kernel_nofault(dummy, (unsigned long *)p);
+}
+
+static void dump_pagetable(unsigned long asce, unsigned long address)
+{
+	unsigned long *table = __va(asce & _ASCE_ORIGIN);
+
+	pr_alert("AS:%016lx ", asce);
+	switch (asce & _ASCE_TYPE_MASK) {
+	case _ASCE_TYPE_REGION1:
+		table += (address & _REGION1_INDEX) >> _REGION1_SHIFT;
+		if (bad_address(table))
+			goto bad;
+		pr_cont("R1:%016lx ", *table);
+		if (*table & _REGION_ENTRY_INVALID)
+			goto out;
+		table = __va(*table & _REGION_ENTRY_ORIGIN);
+		fallthrough;
+	case _ASCE_TYPE_REGION2:
+		table += (address & _REGION2_INDEX) >> _REGION2_SHIFT;
+		if (bad_address(table))
+			goto bad;
+		pr_cont("R2:%016lx ", *table);
+		if (*table & _REGION_ENTRY_INVALID)
+			goto out;
+		table = __va(*table & _REGION_ENTRY_ORIGIN);
+		fallthrough;
+	case _ASCE_TYPE_REGION3:
+		table += (address & _REGION3_INDEX) >> _REGION3_SHIFT;
+		if (bad_address(table))
+			goto bad;
+		pr_cont("R3:%016lx ", *table);
+		if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE))
+			goto out;
+		table = __va(*table & _REGION_ENTRY_ORIGIN);
+		fallthrough;
+	case _ASCE_TYPE_SEGMENT:
+		table += (address & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
+		if (bad_address(table))
+			goto bad;
+		pr_cont("S:%016lx ", *table);
+		if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE))
+			goto out;
+		table = __va(*table & _SEGMENT_ENTRY_ORIGIN);
+	}
+	table += (address & _PAGE_INDEX) >> _PAGE_SHIFT;
+	if (bad_address(table))
+		goto bad;
+	pr_cont("P:%016lx ", *table);
+out:
+	pr_cont("\n");
+	return;
+bad:
+	pr_cont("BAD\n");
+}
+
+static void dump_fault_info(struct pt_regs *regs)
+{
+	unsigned long asce;
+
+	pr_alert("Failing address: %016lx TEID: %016lx\n",
+		 regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long);
+	pr_alert("Fault in ");
+	switch (regs->int_parm_long & 3) {
+	case 3:
+		pr_cont("home space ");
+		break;
+	case 2:
+		pr_cont("secondary space ");
+		break;
+	case 1:
+		pr_cont("access register ");
+		break;
+	case 0:
+		pr_cont("primary space ");
+		break;
+	}
+	pr_cont("mode while using ");
+	switch (get_fault_type(regs)) {
+	case USER_FAULT:
+		asce = S390_lowcore.user_asce;
+		pr_cont("user ");
+		break;
+	case GMAP_FAULT:
+		asce = ((struct gmap *) S390_lowcore.gmap)->asce;
+		pr_cont("gmap ");
+		break;
+	case KERNEL_FAULT:
+		asce = S390_lowcore.kernel_asce;
+		pr_cont("kernel ");
+		break;
+	default:
+		unreachable();
+	}
+	pr_cont("ASCE.\n");
+	dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK);
+}
+
+int show_unhandled_signals = 1;
+
+void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault)
+{
+	if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
+		return;
+	if (!unhandled_signal(current, signr))
+		return;
+	if (!printk_ratelimit())
+		return;
+	printk(KERN_ALERT "User process fault: interruption code %04x ilc:%d ",
+	       regs->int_code & 0xffff, regs->int_code >> 17);
+	print_vma_addr(KERN_CONT "in ", regs->psw.addr);
+	printk(KERN_CONT "\n");
+	if (is_mm_fault)
+		dump_fault_info(regs);
+	show_regs(regs);
+}
+
+/*
+ * Send SIGSEGV to task.  This is an external routine
+ * to keep the stack usage of do_page_fault small.
+ */
+static noinline void do_sigsegv(struct pt_regs *regs, int si_code)
+{
+	report_user_fault(regs, SIGSEGV, 1);
+	force_sig_fault(SIGSEGV, si_code,
+			(void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK));
+}
+
+static noinline void do_no_context(struct pt_regs *regs, vm_fault_t fault)
+{
+	enum fault_type fault_type;
+	unsigned long address;
+	bool is_write;
+
+	if (fixup_exception(regs))
+		return;
+	fault_type = get_fault_type(regs);
+	if ((fault_type == KERNEL_FAULT) && (fault == VM_FAULT_BADCONTEXT)) {
+		address = get_fault_address(regs);
+		is_write = fault_is_write(regs);
+		if (kfence_handle_page_fault(address, is_write, regs))
+			return;
+	}
+	/*
+	 * Oops. The kernel tried to access some bad page. We'll have to
+	 * terminate things with extreme prejudice.
+	 */
+	if (fault_type == KERNEL_FAULT)
+		printk(KERN_ALERT "Unable to handle kernel pointer dereference"
+		       " in virtual kernel address space\n");
+	else
+		printk(KERN_ALERT "Unable to handle kernel paging request"
+		       " in virtual user address space\n");
+	dump_fault_info(regs);
+	die(regs, "Oops");
+}
+
+static noinline void do_low_address(struct pt_regs *regs)
+{
+	/* Low-address protection hit in kernel mode means
+	   NULL pointer write access in kernel mode.  */
+	if (regs->psw.mask & PSW_MASK_PSTATE) {
+		/* Low-address protection hit in user mode 'cannot happen'. */
+		die (regs, "Low-address protection");
+	}
+
+	do_no_context(regs, VM_FAULT_BADACCESS);
+}
+
+static noinline void do_sigbus(struct pt_regs *regs)
+{
+	/*
+	 * Send a sigbus, regardless of whether we were in kernel
+	 * or user mode.
+	 */
+	force_sig_fault(SIGBUS, BUS_ADRERR,
+			(void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK));
+}
+
+static noinline void do_fault_error(struct pt_regs *regs, vm_fault_t fault)
+{
+	int si_code;
+
+	switch (fault) {
+	case VM_FAULT_BADACCESS:
+	case VM_FAULT_BADMAP:
+		/* Bad memory access. Check if it is kernel or user space. */
+		if (user_mode(regs)) {
+			/* User mode accesses just cause a SIGSEGV */
+			si_code = (fault == VM_FAULT_BADMAP) ?
+				SEGV_MAPERR : SEGV_ACCERR;
+			do_sigsegv(regs, si_code);
+			break;
+		}
+		fallthrough;
+	case VM_FAULT_BADCONTEXT:
+	case VM_FAULT_PFAULT:
+		do_no_context(regs, fault);
+		break;
+	case VM_FAULT_SIGNAL:
+		if (!user_mode(regs))
+			do_no_context(regs, fault);
+		break;
+	default: /* fault & VM_FAULT_ERROR */
+		if (fault & VM_FAULT_OOM) {
+			if (!user_mode(regs))
+				do_no_context(regs, fault);
+			else
+				pagefault_out_of_memory();
+		} else if (fault & VM_FAULT_SIGSEGV) {
+			/* Kernel mode? Handle exceptions or die */
+			if (!user_mode(regs))
+				do_no_context(regs, fault);
+			else
+				do_sigsegv(regs, SEGV_MAPERR);
+		} else if (fault & VM_FAULT_SIGBUS) {
+			/* Kernel mode? Handle exceptions or die */
+			if (!user_mode(regs))
+				do_no_context(regs, fault);
+			else
+				do_sigbus(regs);
+		} else
+			BUG();
+		break;
+	}
+}
+
+/*
+ * This routine handles page faults.  It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ *
+ * interruption code (int_code):
+ *   04       Protection           ->  Write-Protection  (suppression)
+ *   10       Segment translation  ->  Not present       (nullification)
+ *   11       Page translation     ->  Not present       (nullification)
+ *   3b       Region third trans.  ->  Not present       (nullification)
+ */
+static inline vm_fault_t do_exception(struct pt_regs *regs, int access)
+{
+	struct gmap *gmap;
+	struct task_struct *tsk;
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	enum fault_type type;
+	unsigned long address;
+	unsigned int flags;
+	vm_fault_t fault;
+	bool is_write;
+
+	tsk = current;
+	/*
+	 * The instruction that caused the program check has
+	 * been nullified. Don't signal single step via SIGTRAP.
+	 */
+	clear_thread_flag(TIF_PER_TRAP);
+
+	if (kprobe_page_fault(regs, 14))
+		return 0;
+
+	mm = tsk->mm;
+	address = get_fault_address(regs);
+	is_write = fault_is_write(regs);
+
+	/*
+	 * Verify that the fault happened in user space, that
+	 * we are not in an interrupt and that there is a 
+	 * user context.
+	 */
+	fault = VM_FAULT_BADCONTEXT;
+	type = get_fault_type(regs);
+	switch (type) {
+	case KERNEL_FAULT:
+		goto out;
+	case USER_FAULT:
+	case GMAP_FAULT:
+		if (faulthandler_disabled() || !mm)
+			goto out;
+		break;
+	}
+
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+	flags = FAULT_FLAG_DEFAULT;
+	if (user_mode(regs))
+		flags |= FAULT_FLAG_USER;
+	if (is_write)
+		access = VM_WRITE;
+	if (access == VM_WRITE)
+		flags |= FAULT_FLAG_WRITE;
+	if (!(flags & FAULT_FLAG_USER))
+		goto lock_mmap;
+	vma = lock_vma_under_rcu(mm, address);
+	if (!vma)
+		goto lock_mmap;
+	if (!(vma->vm_flags & access)) {
+		vma_end_read(vma);
+		goto lock_mmap;
+	}
+	fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs);
+	if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))
+		vma_end_read(vma);
+	if (!(fault & VM_FAULT_RETRY)) {
+		count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
+		if (likely(!(fault & VM_FAULT_ERROR)))
+			fault = 0;
+		goto out;
+	}
+	count_vm_vma_lock_event(VMA_LOCK_RETRY);
+	/* Quick path to respond to signals */
+	if (fault_signal_pending(fault, regs)) {
+		fault = VM_FAULT_SIGNAL;
+		goto out;
+	}
+lock_mmap:
+	mmap_read_lock(mm);
+
+	gmap = NULL;
+	if (IS_ENABLED(CONFIG_PGSTE) && type == GMAP_FAULT) {
+		gmap = (struct gmap *) S390_lowcore.gmap;
+		current->thread.gmap_addr = address;
+		current->thread.gmap_write_flag = !!(flags & FAULT_FLAG_WRITE);
+		current->thread.gmap_int_code = regs->int_code & 0xffff;
+		address = __gmap_translate(gmap, address);
+		if (address == -EFAULT) {
+			fault = VM_FAULT_BADMAP;
+			goto out_up;
+		}
+		if (gmap->pfault_enabled)
+			flags |= FAULT_FLAG_RETRY_NOWAIT;
+	}
+
+retry:
+	fault = VM_FAULT_BADMAP;
+	vma = find_vma(mm, address);
+	if (!vma)
+		goto out_up;
+
+	if (unlikely(vma->vm_start > address)) {
+		if (!(vma->vm_flags & VM_GROWSDOWN))
+			goto out_up;
+		vma = expand_stack(mm, address);
+		if (!vma)
+			goto out;
+	}
+
+	/*
+	 * Ok, we have a good vm_area for this memory access, so
+	 * we can handle it..
+	 */
+	fault = VM_FAULT_BADACCESS;
+	if (unlikely(!(vma->vm_flags & access)))
+		goto out_up;
+
+	/*
+	 * If for any reason at all we couldn't handle the fault,
+	 * make sure we exit gracefully rather than endlessly redo
+	 * the fault.
+	 */
+	fault = handle_mm_fault(vma, address, flags, regs);
+	if (fault_signal_pending(fault, regs)) {
+		fault = VM_FAULT_SIGNAL;
+		if (flags & FAULT_FLAG_RETRY_NOWAIT)
+			goto out_up;
+		goto out;
+	}
+
+	/* The fault is fully completed (including releasing mmap lock) */
+	if (fault & VM_FAULT_COMPLETED) {
+		if (gmap) {
+			mmap_read_lock(mm);
+			goto out_gmap;
+		}
+		fault = 0;
+		goto out;
+	}
+
+	if (unlikely(fault & VM_FAULT_ERROR))
+		goto out_up;
+
+	if (fault & VM_FAULT_RETRY) {
+		if (IS_ENABLED(CONFIG_PGSTE) && gmap &&
+			(flags & FAULT_FLAG_RETRY_NOWAIT)) {
+			/*
+			 * FAULT_FLAG_RETRY_NOWAIT has been set, mmap_lock has
+			 * not been released
+			 */
+			current->thread.gmap_pfault = 1;
+			fault = VM_FAULT_PFAULT;
+			goto out_up;
+		}
+		flags &= ~FAULT_FLAG_RETRY_NOWAIT;
+		flags |= FAULT_FLAG_TRIED;
+		mmap_read_lock(mm);
+		goto retry;
+	}
+out_gmap:
+	if (IS_ENABLED(CONFIG_PGSTE) && gmap) {
+		address =  __gmap_link(gmap, current->thread.gmap_addr,
+				       address);
+		if (address == -EFAULT) {
+			fault = VM_FAULT_BADMAP;
+			goto out_up;
+		}
+		if (address == -ENOMEM) {
+			fault = VM_FAULT_OOM;
+			goto out_up;
+		}
+	}
+	fault = 0;
+out_up:
+	mmap_read_unlock(mm);
+out:
+	return fault;
+}
+
+void do_protection_exception(struct pt_regs *regs)
+{
+	unsigned long trans_exc_code;
+	int access;
+	vm_fault_t fault;
+
+	trans_exc_code = regs->int_parm_long;
+	/*
+	 * Protection exceptions are suppressing, decrement psw address.
+	 * The exception to this rule are aborted transactions, for these
+	 * the PSW already points to the correct location.
+	 */
+	if (!(regs->int_code & 0x200))
+		regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16);
+	/*
+	 * Check for low-address protection.  This needs to be treated
+	 * as a special case because the translation exception code
+	 * field is not guaranteed to contain valid data in this case.
+	 */
+	if (unlikely(!(trans_exc_code & 4))) {
+		do_low_address(regs);
+		return;
+	}
+	if (unlikely(MACHINE_HAS_NX && (trans_exc_code & 0x80))) {
+		regs->int_parm_long = (trans_exc_code & ~PAGE_MASK) |
+					(regs->psw.addr & PAGE_MASK);
+		access = VM_EXEC;
+		fault = VM_FAULT_BADACCESS;
+	} else {
+		access = VM_WRITE;
+		fault = do_exception(regs, access);
+	}
+	if (unlikely(fault))
+		do_fault_error(regs, fault);
+}
+NOKPROBE_SYMBOL(do_protection_exception);
+
+void do_dat_exception(struct pt_regs *regs)
+{
+	int access;
+	vm_fault_t fault;
+
+	access = VM_ACCESS_FLAGS;
+	fault = do_exception(regs, access);
+	if (unlikely(fault))
+		do_fault_error(regs, fault);
+}
+NOKPROBE_SYMBOL(do_dat_exception);
+
+#if IS_ENABLED(CONFIG_PGSTE)
+
+void do_secure_storage_access(struct pt_regs *regs)
+{
+	unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK;
+	struct vm_area_struct *vma;
+	struct mm_struct *mm;
+	struct page *page;
+	struct gmap *gmap;
+	int rc;
+
+	/*
+	 * bit 61 tells us if the address is valid, if it's not we
+	 * have a major problem and should stop the kernel or send a
+	 * SIGSEGV to the process. Unfortunately bit 61 is not
+	 * reliable without the misc UV feature so we need to check
+	 * for that as well.
+	 */
+	if (uv_has_feature(BIT_UV_FEAT_MISC) &&
+	    !test_bit_inv(61, &regs->int_parm_long)) {
+		/*
+		 * When this happens, userspace did something that it
+		 * was not supposed to do, e.g. branching into secure
+		 * memory. Trigger a segmentation fault.
+		 */
+		if (user_mode(regs)) {
+			send_sig(SIGSEGV, current, 0);
+			return;
+		}
+
+		/*
+		 * The kernel should never run into this case and we
+		 * have no way out of this situation.
+		 */
+		panic("Unexpected PGM 0x3d with TEID bit 61=0");
+	}
+
+	switch (get_fault_type(regs)) {
+	case GMAP_FAULT:
+		mm = current->mm;
+		gmap = (struct gmap *)S390_lowcore.gmap;
+		mmap_read_lock(mm);
+		addr = __gmap_translate(gmap, addr);
+		mmap_read_unlock(mm);
+		if (IS_ERR_VALUE(addr)) {
+			do_fault_error(regs, VM_FAULT_BADMAP);
+			break;
+		}
+		fallthrough;
+	case USER_FAULT:
+		mm = current->mm;
+		mmap_read_lock(mm);
+		vma = find_vma(mm, addr);
+		if (!vma) {
+			mmap_read_unlock(mm);
+			do_fault_error(regs, VM_FAULT_BADMAP);
+			break;
+		}
+		page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET);
+		if (IS_ERR_OR_NULL(page)) {
+			mmap_read_unlock(mm);
+			break;
+		}
+		if (arch_make_page_accessible(page))
+			send_sig(SIGSEGV, current, 0);
+		put_page(page);
+		mmap_read_unlock(mm);
+		break;
+	case KERNEL_FAULT:
+		page = phys_to_page(addr);
+		if (unlikely(!try_get_page(page)))
+			break;
+		rc = arch_make_page_accessible(page);
+		put_page(page);
+		if (rc)
+			BUG();
+		break;
+	default:
+		do_fault_error(regs, VM_FAULT_BADMAP);
+		WARN_ON_ONCE(1);
+	}
+}
+NOKPROBE_SYMBOL(do_secure_storage_access);
+
+void do_non_secure_storage_access(struct pt_regs *regs)
+{
+	unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK;
+	struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
+
+	if (get_fault_type(regs) != GMAP_FAULT) {
+		do_fault_error(regs, VM_FAULT_BADMAP);
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	if (gmap_convert_to_secure(gmap, gaddr) == -EINVAL)
+		send_sig(SIGSEGV, current, 0);
+}
+NOKPROBE_SYMBOL(do_non_secure_storage_access);
+
+void do_secure_storage_violation(struct pt_regs *regs)
+{
+	unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK;
+	struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
+
+	/*
+	 * If the VM has been rebooted, its address space might still contain
+	 * secure pages from the previous boot.
+	 * Clear the page so it can be reused.
+	 */
+	if (!gmap_destroy_page(gmap, gaddr))
+		return;
+	/*
+	 * Either KVM messed up the secure guest mapping or the same
+	 * page is mapped into multiple secure guests.
+	 *
+	 * This exception is only triggered when a guest 2 is running
+	 * and can therefore never occur in kernel context.
+	 */
+	printk_ratelimited(KERN_WARNING
+			   "Secure storage violation in task: %s, pid %d\n",
+			   current->comm, current->pid);
+	send_sig(SIGSEGV, current, 0);
+}
+
+#endif /* CONFIG_PGSTE */
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
new file mode 100644
index 0000000000..20786f6883
--- /dev/null
+++ b/arch/s390/mm/gmap.c
@@ -0,0 +1,2894 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  KVM guest address space mapping code
+ *
+ *    Copyright IBM Corp. 2007, 2020
+ *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ *		 David Hildenbrand <david@redhat.com>
+ *		 Janosch Frank <frankja@linux.vnet.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/pagewalk.h>
+#include <linux/swap.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/swapops.h>
+#include <linux/ksm.h>
+#include <linux/mman.h>
+#include <linux/pgtable.h>
+
+#include <asm/pgalloc.h>
+#include <asm/gmap.h>
+#include <asm/page.h>
+#include <asm/tlb.h>
+
+#define GMAP_SHADOW_FAKE_TABLE 1ULL
+
+static struct page *gmap_alloc_crst(void)
+{
+	struct page *page;
+
+	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
+	if (!page)
+		return NULL;
+	arch_set_page_dat(page, CRST_ALLOC_ORDER);
+	return page;
+}
+
+/**
+ * gmap_alloc - allocate and initialize a guest address space
+ * @limit: maximum address of the gmap address space
+ *
+ * Returns a guest address space structure.
+ */
+static struct gmap *gmap_alloc(unsigned long limit)
+{
+	struct gmap *gmap;
+	struct page *page;
+	unsigned long *table;
+	unsigned long etype, atype;
+
+	if (limit < _REGION3_SIZE) {
+		limit = _REGION3_SIZE - 1;
+		atype = _ASCE_TYPE_SEGMENT;
+		etype = _SEGMENT_ENTRY_EMPTY;
+	} else if (limit < _REGION2_SIZE) {
+		limit = _REGION2_SIZE - 1;
+		atype = _ASCE_TYPE_REGION3;
+		etype = _REGION3_ENTRY_EMPTY;
+	} else if (limit < _REGION1_SIZE) {
+		limit = _REGION1_SIZE - 1;
+		atype = _ASCE_TYPE_REGION2;
+		etype = _REGION2_ENTRY_EMPTY;
+	} else {
+		limit = -1UL;
+		atype = _ASCE_TYPE_REGION1;
+		etype = _REGION1_ENTRY_EMPTY;
+	}
+	gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL_ACCOUNT);
+	if (!gmap)
+		goto out;
+	INIT_LIST_HEAD(&gmap->crst_list);
+	INIT_LIST_HEAD(&gmap->children);
+	INIT_LIST_HEAD(&gmap->pt_list);
+	INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL_ACCOUNT);
+	INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC | __GFP_ACCOUNT);
+	INIT_RADIX_TREE(&gmap->host_to_rmap, GFP_ATOMIC | __GFP_ACCOUNT);
+	spin_lock_init(&gmap->guest_table_lock);
+	spin_lock_init(&gmap->shadow_lock);
+	refcount_set(&gmap->ref_count, 1);
+	page = gmap_alloc_crst();
+	if (!page)
+		goto out_free;
+	page->index = 0;
+	list_add(&page->lru, &gmap->crst_list);
+	table = page_to_virt(page);
+	crst_table_init(table, etype);
+	gmap->table = table;
+	gmap->asce = atype | _ASCE_TABLE_LENGTH |
+		_ASCE_USER_BITS | __pa(table);
+	gmap->asce_end = limit;
+	return gmap;
+
+out_free:
+	kfree(gmap);
+out:
+	return NULL;
+}
+
+/**
+ * gmap_create - create a guest address space
+ * @mm: pointer to the parent mm_struct
+ * @limit: maximum size of the gmap address space
+ *
+ * Returns a guest address space structure.
+ */
+struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit)
+{
+	struct gmap *gmap;
+	unsigned long gmap_asce;
+
+	gmap = gmap_alloc(limit);
+	if (!gmap)
+		return NULL;
+	gmap->mm = mm;
+	spin_lock(&mm->context.lock);
+	list_add_rcu(&gmap->list, &mm->context.gmap_list);
+	if (list_is_singular(&mm->context.gmap_list))
+		gmap_asce = gmap->asce;
+	else
+		gmap_asce = -1UL;
+	WRITE_ONCE(mm->context.gmap_asce, gmap_asce);
+	spin_unlock(&mm->context.lock);
+	return gmap;
+}
+EXPORT_SYMBOL_GPL(gmap_create);
+
+static void gmap_flush_tlb(struct gmap *gmap)
+{
+	if (MACHINE_HAS_IDTE)
+		__tlb_flush_idte(gmap->asce);
+	else
+		__tlb_flush_global();
+}
+
+static void gmap_radix_tree_free(struct radix_tree_root *root)
+{
+	struct radix_tree_iter iter;
+	unsigned long indices[16];
+	unsigned long index;
+	void __rcu **slot;
+	int i, nr;
+
+	/* A radix tree is freed by deleting all of its entries */
+	index = 0;
+	do {
+		nr = 0;
+		radix_tree_for_each_slot(slot, root, &iter, index) {
+			indices[nr] = iter.index;
+			if (++nr == 16)
+				break;
+		}
+		for (i = 0; i < nr; i++) {
+			index = indices[i];
+			radix_tree_delete(root, index);
+		}
+	} while (nr > 0);
+}
+
+static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
+{
+	struct gmap_rmap *rmap, *rnext, *head;
+	struct radix_tree_iter iter;
+	unsigned long indices[16];
+	unsigned long index;
+	void __rcu **slot;
+	int i, nr;
+
+	/* A radix tree is freed by deleting all of its entries */
+	index = 0;
+	do {
+		nr = 0;
+		radix_tree_for_each_slot(slot, root, &iter, index) {
+			indices[nr] = iter.index;
+			if (++nr == 16)
+				break;
+		}
+		for (i = 0; i < nr; i++) {
+			index = indices[i];
+			head = radix_tree_delete(root, index);
+			gmap_for_each_rmap_safe(rmap, rnext, head)
+				kfree(rmap);
+		}
+	} while (nr > 0);
+}
+
+/**
+ * gmap_free - free a guest address space
+ * @gmap: pointer to the guest address space structure
+ *
+ * No locks required. There are no references to this gmap anymore.
+ */
+static void gmap_free(struct gmap *gmap)
+{
+	struct page *page, *next;
+
+	/* Flush tlb of all gmaps (if not already done for shadows) */
+	if (!(gmap_is_shadow(gmap) && gmap->removed))
+		gmap_flush_tlb(gmap);
+	/* Free all segment & region tables. */
+	list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
+		__free_pages(page, CRST_ALLOC_ORDER);
+	gmap_radix_tree_free(&gmap->guest_to_host);
+	gmap_radix_tree_free(&gmap->host_to_guest);
+
+	/* Free additional data for a shadow gmap */
+	if (gmap_is_shadow(gmap)) {
+		/* Free all page tables. */
+		list_for_each_entry_safe(page, next, &gmap->pt_list, lru)
+			page_table_free_pgste(page);
+		gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
+		/* Release reference to the parent */
+		gmap_put(gmap->parent);
+	}
+
+	kfree(gmap);
+}
+
+/**
+ * gmap_get - increase reference counter for guest address space
+ * @gmap: pointer to the guest address space structure
+ *
+ * Returns the gmap pointer
+ */
+struct gmap *gmap_get(struct gmap *gmap)
+{
+	refcount_inc(&gmap->ref_count);
+	return gmap;
+}
+EXPORT_SYMBOL_GPL(gmap_get);
+
+/**
+ * gmap_put - decrease reference counter for guest address space
+ * @gmap: pointer to the guest address space structure
+ *
+ * If the reference counter reaches zero the guest address space is freed.
+ */
+void gmap_put(struct gmap *gmap)
+{
+	if (refcount_dec_and_test(&gmap->ref_count))
+		gmap_free(gmap);
+}
+EXPORT_SYMBOL_GPL(gmap_put);
+
+/**
+ * gmap_remove - remove a guest address space but do not free it yet
+ * @gmap: pointer to the guest address space structure
+ */
+void gmap_remove(struct gmap *gmap)
+{
+	struct gmap *sg, *next;
+	unsigned long gmap_asce;
+
+	/* Remove all shadow gmaps linked to this gmap */
+	if (!list_empty(&gmap->children)) {
+		spin_lock(&gmap->shadow_lock);
+		list_for_each_entry_safe(sg, next, &gmap->children, list) {
+			list_del(&sg->list);
+			gmap_put(sg);
+		}
+		spin_unlock(&gmap->shadow_lock);
+	}
+	/* Remove gmap from the pre-mm list */
+	spin_lock(&gmap->mm->context.lock);
+	list_del_rcu(&gmap->list);
+	if (list_empty(&gmap->mm->context.gmap_list))
+		gmap_asce = 0;
+	else if (list_is_singular(&gmap->mm->context.gmap_list))
+		gmap_asce = list_first_entry(&gmap->mm->context.gmap_list,
+					     struct gmap, list)->asce;
+	else
+		gmap_asce = -1UL;
+	WRITE_ONCE(gmap->mm->context.gmap_asce, gmap_asce);
+	spin_unlock(&gmap->mm->context.lock);
+	synchronize_rcu();
+	/* Put reference */
+	gmap_put(gmap);
+}
+EXPORT_SYMBOL_GPL(gmap_remove);
+
+/**
+ * gmap_enable - switch primary space to the guest address space
+ * @gmap: pointer to the guest address space structure
+ */
+void gmap_enable(struct gmap *gmap)
+{
+	S390_lowcore.gmap = (unsigned long) gmap;
+}
+EXPORT_SYMBOL_GPL(gmap_enable);
+
+/**
+ * gmap_disable - switch back to the standard primary address space
+ * @gmap: pointer to the guest address space structure
+ */
+void gmap_disable(struct gmap *gmap)
+{
+	S390_lowcore.gmap = 0UL;
+}
+EXPORT_SYMBOL_GPL(gmap_disable);
+
+/**
+ * gmap_get_enabled - get a pointer to the currently enabled gmap
+ *
+ * Returns a pointer to the currently enabled gmap. 0 if none is enabled.
+ */
+struct gmap *gmap_get_enabled(void)
+{
+	return (struct gmap *) S390_lowcore.gmap;
+}
+EXPORT_SYMBOL_GPL(gmap_get_enabled);
+
+/*
+ * gmap_alloc_table is assumed to be called with mmap_lock held
+ */
+static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
+			    unsigned long init, unsigned long gaddr)
+{
+	struct page *page;
+	unsigned long *new;
+
+	/* since we dont free the gmap table until gmap_free we can unlock */
+	page = gmap_alloc_crst();
+	if (!page)
+		return -ENOMEM;
+	new = page_to_virt(page);
+	crst_table_init(new, init);
+	spin_lock(&gmap->guest_table_lock);
+	if (*table & _REGION_ENTRY_INVALID) {
+		list_add(&page->lru, &gmap->crst_list);
+		*table = __pa(new) | _REGION_ENTRY_LENGTH |
+			(*table & _REGION_ENTRY_TYPE_MASK);
+		page->index = gaddr;
+		page = NULL;
+	}
+	spin_unlock(&gmap->guest_table_lock);
+	if (page)
+		__free_pages(page, CRST_ALLOC_ORDER);
+	return 0;
+}
+
+/**
+ * __gmap_segment_gaddr - find virtual address from segment pointer
+ * @entry: pointer to a segment table entry in the guest address space
+ *
+ * Returns the virtual address in the guest address space for the segment
+ */
+static unsigned long __gmap_segment_gaddr(unsigned long *entry)
+{
+	struct page *page;
+	unsigned long offset;
+
+	offset = (unsigned long) entry / sizeof(unsigned long);
+	offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
+	page = pmd_pgtable_page((pmd_t *) entry);
+	return page->index + offset;
+}
+
+/**
+ * __gmap_unlink_by_vmaddr - unlink a single segment via a host address
+ * @gmap: pointer to the guest address space structure
+ * @vmaddr: address in the host process address space
+ *
+ * Returns 1 if a TLB flush is required
+ */
+static int __gmap_unlink_by_vmaddr(struct gmap *gmap, unsigned long vmaddr)
+{
+	unsigned long *entry;
+	int flush = 0;
+
+	BUG_ON(gmap_is_shadow(gmap));
+	spin_lock(&gmap->guest_table_lock);
+	entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT);
+	if (entry) {
+		flush = (*entry != _SEGMENT_ENTRY_EMPTY);
+		*entry = _SEGMENT_ENTRY_EMPTY;
+	}
+	spin_unlock(&gmap->guest_table_lock);
+	return flush;
+}
+
+/**
+ * __gmap_unmap_by_gaddr - unmap a single segment via a guest address
+ * @gmap: pointer to the guest address space structure
+ * @gaddr: address in the guest address space
+ *
+ * Returns 1 if a TLB flush is required
+ */
+static int __gmap_unmap_by_gaddr(struct gmap *gmap, unsigned long gaddr)
+{
+	unsigned long vmaddr;
+
+	vmaddr = (unsigned long) radix_tree_delete(&gmap->guest_to_host,
+						   gaddr >> PMD_SHIFT);
+	return vmaddr ? __gmap_unlink_by_vmaddr(gmap, vmaddr) : 0;
+}
+
+/**
+ * gmap_unmap_segment - unmap segment from the guest address space
+ * @gmap: pointer to the guest address space structure
+ * @to: address in the guest address space
+ * @len: length of the memory area to unmap
+ *
+ * Returns 0 if the unmap succeeded, -EINVAL if not.
+ */
+int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
+{
+	unsigned long off;
+	int flush;
+
+	BUG_ON(gmap_is_shadow(gmap));
+	if ((to | len) & (PMD_SIZE - 1))
+		return -EINVAL;
+	if (len == 0 || to + len < to)
+		return -EINVAL;
+
+	flush = 0;
+	mmap_write_lock(gmap->mm);
+	for (off = 0; off < len; off += PMD_SIZE)
+		flush |= __gmap_unmap_by_gaddr(gmap, to + off);
+	mmap_write_unlock(gmap->mm);
+	if (flush)
+		gmap_flush_tlb(gmap);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gmap_unmap_segment);
+
+/**
+ * gmap_map_segment - map a segment to the guest address space
+ * @gmap: pointer to the guest address space structure
+ * @from: source address in the parent address space
+ * @to: target address in the guest address space
+ * @len: length of the memory area to map
+ *
+ * Returns 0 if the mmap succeeded, -EINVAL or -ENOMEM if not.
+ */
+int gmap_map_segment(struct gmap *gmap, unsigned long from,
+		     unsigned long to, unsigned long len)
+{
+	unsigned long off;
+	int flush;
+
+	BUG_ON(gmap_is_shadow(gmap));
+	if ((from | to | len) & (PMD_SIZE - 1))
+		return -EINVAL;
+	if (len == 0 || from + len < from || to + len < to ||
+	    from + len - 1 > TASK_SIZE_MAX || to + len - 1 > gmap->asce_end)
+		return -EINVAL;
+
+	flush = 0;
+	mmap_write_lock(gmap->mm);
+	for (off = 0; off < len; off += PMD_SIZE) {
+		/* Remove old translation */
+		flush |= __gmap_unmap_by_gaddr(gmap, to + off);
+		/* Store new translation */
+		if (radix_tree_insert(&gmap->guest_to_host,
+				      (to + off) >> PMD_SHIFT,
+				      (void *) from + off))
+			break;
+	}
+	mmap_write_unlock(gmap->mm);
+	if (flush)
+		gmap_flush_tlb(gmap);
+	if (off >= len)
+		return 0;
+	gmap_unmap_segment(gmap, to, len);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(gmap_map_segment);
+
+/**
+ * __gmap_translate - translate a guest address to a user space address
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: guest address
+ *
+ * Returns user space address which corresponds to the guest address or
+ * -EFAULT if no such mapping exists.
+ * This function does not establish potentially missing page table entries.
+ * The mmap_lock of the mm that belongs to the address space must be held
+ * when this function gets called.
+ *
+ * Note: Can also be called for shadow gmaps.
+ */
+unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr)
+{
+	unsigned long vmaddr;
+
+	vmaddr = (unsigned long)
+		radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT);
+	/* Note: guest_to_host is empty for a shadow gmap */
+	return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT;
+}
+EXPORT_SYMBOL_GPL(__gmap_translate);
+
+/**
+ * gmap_translate - translate a guest address to a user space address
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: guest address
+ *
+ * Returns user space address which corresponds to the guest address or
+ * -EFAULT if no such mapping exists.
+ * This function does not establish potentially missing page table entries.
+ */
+unsigned long gmap_translate(struct gmap *gmap, unsigned long gaddr)
+{
+	unsigned long rc;
+
+	mmap_read_lock(gmap->mm);
+	rc = __gmap_translate(gmap, gaddr);
+	mmap_read_unlock(gmap->mm);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_translate);
+
+/**
+ * gmap_unlink - disconnect a page table from the gmap shadow tables
+ * @mm: pointer to the parent mm_struct
+ * @table: pointer to the host page table
+ * @vmaddr: vm address associated with the host page table
+ */
+void gmap_unlink(struct mm_struct *mm, unsigned long *table,
+		 unsigned long vmaddr)
+{
+	struct gmap *gmap;
+	int flush;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
+		flush = __gmap_unlink_by_vmaddr(gmap, vmaddr);
+		if (flush)
+			gmap_flush_tlb(gmap);
+	}
+	rcu_read_unlock();
+}
+
+static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *old, pmd_t new,
+			   unsigned long gaddr);
+
+/**
+ * __gmap_link - set up shadow page tables to connect a host to a guest address
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: guest address
+ * @vmaddr: vm address
+ *
+ * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
+ * if the vm address is already mapped to a different guest segment.
+ * The mmap_lock of the mm that belongs to the address space must be held
+ * when this function gets called.
+ */
+int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
+{
+	struct mm_struct *mm;
+	unsigned long *table;
+	spinlock_t *ptl;
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+	u64 unprot;
+	int rc;
+
+	BUG_ON(gmap_is_shadow(gmap));
+	/* Create higher level tables in the gmap page table */
+	table = gmap->table;
+	if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) {
+		table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
+		if ((*table & _REGION_ENTRY_INVALID) &&
+		    gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY,
+				     gaddr & _REGION1_MASK))
+			return -ENOMEM;
+		table = __va(*table & _REGION_ENTRY_ORIGIN);
+	}
+	if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) {
+		table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
+		if ((*table & _REGION_ENTRY_INVALID) &&
+		    gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY,
+				     gaddr & _REGION2_MASK))
+			return -ENOMEM;
+		table = __va(*table & _REGION_ENTRY_ORIGIN);
+	}
+	if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) {
+		table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
+		if ((*table & _REGION_ENTRY_INVALID) &&
+		    gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY,
+				     gaddr & _REGION3_MASK))
+			return -ENOMEM;
+		table = __va(*table & _REGION_ENTRY_ORIGIN);
+	}
+	table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
+	/* Walk the parent mm page table */
+	mm = gmap->mm;
+	pgd = pgd_offset(mm, vmaddr);
+	VM_BUG_ON(pgd_none(*pgd));
+	p4d = p4d_offset(pgd, vmaddr);
+	VM_BUG_ON(p4d_none(*p4d));
+	pud = pud_offset(p4d, vmaddr);
+	VM_BUG_ON(pud_none(*pud));
+	/* large puds cannot yet be handled */
+	if (pud_large(*pud))
+		return -EFAULT;
+	pmd = pmd_offset(pud, vmaddr);
+	VM_BUG_ON(pmd_none(*pmd));
+	/* Are we allowed to use huge pages? */
+	if (pmd_large(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m)
+		return -EFAULT;
+	/* Link gmap segment table entry location to page table. */
+	rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
+	if (rc)
+		return rc;
+	ptl = pmd_lock(mm, pmd);
+	spin_lock(&gmap->guest_table_lock);
+	if (*table == _SEGMENT_ENTRY_EMPTY) {
+		rc = radix_tree_insert(&gmap->host_to_guest,
+				       vmaddr >> PMD_SHIFT, table);
+		if (!rc) {
+			if (pmd_large(*pmd)) {
+				*table = (pmd_val(*pmd) &
+					  _SEGMENT_ENTRY_HARDWARE_BITS_LARGE)
+					| _SEGMENT_ENTRY_GMAP_UC;
+			} else
+				*table = pmd_val(*pmd) &
+					_SEGMENT_ENTRY_HARDWARE_BITS;
+		}
+	} else if (*table & _SEGMENT_ENTRY_PROTECT &&
+		   !(pmd_val(*pmd) & _SEGMENT_ENTRY_PROTECT)) {
+		unprot = (u64)*table;
+		unprot &= ~_SEGMENT_ENTRY_PROTECT;
+		unprot |= _SEGMENT_ENTRY_GMAP_UC;
+		gmap_pmdp_xchg(gmap, (pmd_t *)table, __pmd(unprot), gaddr);
+	}
+	spin_unlock(&gmap->guest_table_lock);
+	spin_unlock(ptl);
+	radix_tree_preload_end();
+	return rc;
+}
+
+/**
+ * gmap_fault - resolve a fault on a guest address
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: guest address
+ * @fault_flags: flags to pass down to handle_mm_fault()
+ *
+ * Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
+ * if the vm address is already mapped to a different guest segment.
+ */
+int gmap_fault(struct gmap *gmap, unsigned long gaddr,
+	       unsigned int fault_flags)
+{
+	unsigned long vmaddr;
+	int rc;
+	bool unlocked;
+
+	mmap_read_lock(gmap->mm);
+
+retry:
+	unlocked = false;
+	vmaddr = __gmap_translate(gmap, gaddr);
+	if (IS_ERR_VALUE(vmaddr)) {
+		rc = vmaddr;
+		goto out_up;
+	}
+	if (fixup_user_fault(gmap->mm, vmaddr, fault_flags,
+			     &unlocked)) {
+		rc = -EFAULT;
+		goto out_up;
+	}
+	/*
+	 * In the case that fixup_user_fault unlocked the mmap_lock during
+	 * faultin redo __gmap_translate to not race with a map/unmap_segment.
+	 */
+	if (unlocked)
+		goto retry;
+
+	rc = __gmap_link(gmap, gaddr, vmaddr);
+out_up:
+	mmap_read_unlock(gmap->mm);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_fault);
+
+/*
+ * this function is assumed to be called with mmap_lock held
+ */
+void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
+{
+	struct vm_area_struct *vma;
+	unsigned long vmaddr;
+	spinlock_t *ptl;
+	pte_t *ptep;
+
+	/* Find the vm address for the guest address */
+	vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host,
+						   gaddr >> PMD_SHIFT);
+	if (vmaddr) {
+		vmaddr |= gaddr & ~PMD_MASK;
+
+		vma = vma_lookup(gmap->mm, vmaddr);
+		if (!vma || is_vm_hugetlb_page(vma))
+			return;
+
+		/* Get pointer to the page table entry */
+		ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
+		if (likely(ptep)) {
+			ptep_zap_unused(gmap->mm, vmaddr, ptep, 0);
+			pte_unmap_unlock(ptep, ptl);
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(__gmap_zap);
+
+void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to)
+{
+	unsigned long gaddr, vmaddr, size;
+	struct vm_area_struct *vma;
+
+	mmap_read_lock(gmap->mm);
+	for (gaddr = from; gaddr < to;
+	     gaddr = (gaddr + PMD_SIZE) & PMD_MASK) {
+		/* Find the vm address for the guest address */
+		vmaddr = (unsigned long)
+			radix_tree_lookup(&gmap->guest_to_host,
+					  gaddr >> PMD_SHIFT);
+		if (!vmaddr)
+			continue;
+		vmaddr |= gaddr & ~PMD_MASK;
+		/* Find vma in the parent mm */
+		vma = find_vma(gmap->mm, vmaddr);
+		if (!vma)
+			continue;
+		/*
+		 * We do not discard pages that are backed by
+		 * hugetlbfs, so we don't have to refault them.
+		 */
+		if (is_vm_hugetlb_page(vma))
+			continue;
+		size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
+		zap_page_range_single(vma, vmaddr, size, NULL);
+	}
+	mmap_read_unlock(gmap->mm);
+}
+EXPORT_SYMBOL_GPL(gmap_discard);
+
+static LIST_HEAD(gmap_notifier_list);
+static DEFINE_SPINLOCK(gmap_notifier_lock);
+
+/**
+ * gmap_register_pte_notifier - register a pte invalidation callback
+ * @nb: pointer to the gmap notifier block
+ */
+void gmap_register_pte_notifier(struct gmap_notifier *nb)
+{
+	spin_lock(&gmap_notifier_lock);
+	list_add_rcu(&nb->list, &gmap_notifier_list);
+	spin_unlock(&gmap_notifier_lock);
+}
+EXPORT_SYMBOL_GPL(gmap_register_pte_notifier);
+
+/**
+ * gmap_unregister_pte_notifier - remove a pte invalidation callback
+ * @nb: pointer to the gmap notifier block
+ */
+void gmap_unregister_pte_notifier(struct gmap_notifier *nb)
+{
+	spin_lock(&gmap_notifier_lock);
+	list_del_rcu(&nb->list);
+	spin_unlock(&gmap_notifier_lock);
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(gmap_unregister_pte_notifier);
+
+/**
+ * gmap_call_notifier - call all registered invalidation callbacks
+ * @gmap: pointer to guest mapping meta data structure
+ * @start: start virtual address in the guest address space
+ * @end: end virtual address in the guest address space
+ */
+static void gmap_call_notifier(struct gmap *gmap, unsigned long start,
+			       unsigned long end)
+{
+	struct gmap_notifier *nb;
+
+	list_for_each_entry(nb, &gmap_notifier_list, list)
+		nb->notifier_call(gmap, start, end);
+}
+
+/**
+ * gmap_table_walk - walk the gmap page tables
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ * @level: page table level to stop at
+ *
+ * Returns a table entry pointer for the given guest address and @level
+ * @level=0 : returns a pointer to a page table table entry (or NULL)
+ * @level=1 : returns a pointer to a segment table entry (or NULL)
+ * @level=2 : returns a pointer to a region-3 table entry (or NULL)
+ * @level=3 : returns a pointer to a region-2 table entry (or NULL)
+ * @level=4 : returns a pointer to a region-1 table entry (or NULL)
+ *
+ * Returns NULL if the gmap page tables could not be walked to the
+ * requested level.
+ *
+ * Note: Can also be called for shadow gmaps.
+ */
+static inline unsigned long *gmap_table_walk(struct gmap *gmap,
+					     unsigned long gaddr, int level)
+{
+	const int asce_type = gmap->asce & _ASCE_TYPE_MASK;
+	unsigned long *table = gmap->table;
+
+	if (gmap_is_shadow(gmap) && gmap->removed)
+		return NULL;
+
+	if (WARN_ON_ONCE(level > (asce_type >> 2) + 1))
+		return NULL;
+
+	if (asce_type != _ASCE_TYPE_REGION1 &&
+	    gaddr & (-1UL << (31 + (asce_type >> 2) * 11)))
+		return NULL;
+
+	switch (asce_type) {
+	case _ASCE_TYPE_REGION1:
+		table += (gaddr & _REGION1_INDEX) >> _REGION1_SHIFT;
+		if (level == 4)
+			break;
+		if (*table & _REGION_ENTRY_INVALID)
+			return NULL;
+		table = __va(*table & _REGION_ENTRY_ORIGIN);
+		fallthrough;
+	case _ASCE_TYPE_REGION2:
+		table += (gaddr & _REGION2_INDEX) >> _REGION2_SHIFT;
+		if (level == 3)
+			break;
+		if (*table & _REGION_ENTRY_INVALID)
+			return NULL;
+		table = __va(*table & _REGION_ENTRY_ORIGIN);
+		fallthrough;
+	case _ASCE_TYPE_REGION3:
+		table += (gaddr & _REGION3_INDEX) >> _REGION3_SHIFT;
+		if (level == 2)
+			break;
+		if (*table & _REGION_ENTRY_INVALID)
+			return NULL;
+		table = __va(*table & _REGION_ENTRY_ORIGIN);
+		fallthrough;
+	case _ASCE_TYPE_SEGMENT:
+		table += (gaddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
+		if (level == 1)
+			break;
+		if (*table & _REGION_ENTRY_INVALID)
+			return NULL;
+		table = __va(*table & _SEGMENT_ENTRY_ORIGIN);
+		table += (gaddr & _PAGE_INDEX) >> _PAGE_SHIFT;
+	}
+	return table;
+}
+
+/**
+ * gmap_pte_op_walk - walk the gmap page table, get the page table lock
+ *		      and return the pte pointer
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ * @ptl: pointer to the spinlock pointer
+ *
+ * Returns a pointer to the locked pte for a guest address, or NULL
+ */
+static pte_t *gmap_pte_op_walk(struct gmap *gmap, unsigned long gaddr,
+			       spinlock_t **ptl)
+{
+	unsigned long *table;
+
+	BUG_ON(gmap_is_shadow(gmap));
+	/* Walk the gmap page table, lock and get pte pointer */
+	table = gmap_table_walk(gmap, gaddr, 1); /* get segment pointer */
+	if (!table || *table & _SEGMENT_ENTRY_INVALID)
+		return NULL;
+	return pte_alloc_map_lock(gmap->mm, (pmd_t *) table, gaddr, ptl);
+}
+
+/**
+ * gmap_pte_op_fixup - force a page in and connect the gmap page table
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ * @vmaddr: address in the host process address space
+ * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
+ *
+ * Returns 0 if the caller can retry __gmap_translate (might fail again),
+ * -ENOMEM if out of memory and -EFAULT if anything goes wrong while fixing
+ * up or connecting the gmap page table.
+ */
+static int gmap_pte_op_fixup(struct gmap *gmap, unsigned long gaddr,
+			     unsigned long vmaddr, int prot)
+{
+	struct mm_struct *mm = gmap->mm;
+	unsigned int fault_flags;
+	bool unlocked = false;
+
+	BUG_ON(gmap_is_shadow(gmap));
+	fault_flags = (prot == PROT_WRITE) ? FAULT_FLAG_WRITE : 0;
+	if (fixup_user_fault(mm, vmaddr, fault_flags, &unlocked))
+		return -EFAULT;
+	if (unlocked)
+		/* lost mmap_lock, caller has to retry __gmap_translate */
+		return 0;
+	/* Connect the page tables */
+	return __gmap_link(gmap, gaddr, vmaddr);
+}
+
+/**
+ * gmap_pte_op_end - release the page table lock
+ * @ptep: pointer to the locked pte
+ * @ptl: pointer to the page table spinlock
+ */
+static void gmap_pte_op_end(pte_t *ptep, spinlock_t *ptl)
+{
+	pte_unmap_unlock(ptep, ptl);
+}
+
+/**
+ * gmap_pmd_op_walk - walk the gmap tables, get the guest table lock
+ *		      and return the pmd pointer
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ *
+ * Returns a pointer to the pmd for a guest address, or NULL
+ */
+static inline pmd_t *gmap_pmd_op_walk(struct gmap *gmap, unsigned long gaddr)
+{
+	pmd_t *pmdp;
+
+	BUG_ON(gmap_is_shadow(gmap));
+	pmdp = (pmd_t *) gmap_table_walk(gmap, gaddr, 1);
+	if (!pmdp)
+		return NULL;
+
+	/* without huge pages, there is no need to take the table lock */
+	if (!gmap->mm->context.allow_gmap_hpage_1m)
+		return pmd_none(*pmdp) ? NULL : pmdp;
+
+	spin_lock(&gmap->guest_table_lock);
+	if (pmd_none(*pmdp)) {
+		spin_unlock(&gmap->guest_table_lock);
+		return NULL;
+	}
+
+	/* 4k page table entries are locked via the pte (pte_alloc_map_lock). */
+	if (!pmd_large(*pmdp))
+		spin_unlock(&gmap->guest_table_lock);
+	return pmdp;
+}
+
+/**
+ * gmap_pmd_op_end - release the guest_table_lock if needed
+ * @gmap: pointer to the guest mapping meta data structure
+ * @pmdp: pointer to the pmd
+ */
+static inline void gmap_pmd_op_end(struct gmap *gmap, pmd_t *pmdp)
+{
+	if (pmd_large(*pmdp))
+		spin_unlock(&gmap->guest_table_lock);
+}
+
+/*
+ * gmap_protect_pmd - remove access rights to memory and set pmd notification bits
+ * @pmdp: pointer to the pmd to be protected
+ * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
+ * @bits: notification bits to set
+ *
+ * Returns:
+ * 0 if successfully protected
+ * -EAGAIN if a fixup is needed
+ * -EINVAL if unsupported notifier bits have been specified
+ *
+ * Expected to be called with sg->mm->mmap_lock in read and
+ * guest_table_lock held.
+ */
+static int gmap_protect_pmd(struct gmap *gmap, unsigned long gaddr,
+			    pmd_t *pmdp, int prot, unsigned long bits)
+{
+	int pmd_i = pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID;
+	int pmd_p = pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT;
+	pmd_t new = *pmdp;
+
+	/* Fixup needed */
+	if ((pmd_i && (prot != PROT_NONE)) || (pmd_p && (prot == PROT_WRITE)))
+		return -EAGAIN;
+
+	if (prot == PROT_NONE && !pmd_i) {
+		new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
+		gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
+	}
+
+	if (prot == PROT_READ && !pmd_p) {
+		new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
+		new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_PROTECT));
+		gmap_pmdp_xchg(gmap, pmdp, new, gaddr);
+	}
+
+	if (bits & GMAP_NOTIFY_MPROT)
+		set_pmd(pmdp, set_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN)));
+
+	/* Shadow GMAP protection needs split PMDs */
+	if (bits & GMAP_NOTIFY_SHADOW)
+		return -EINVAL;
+
+	return 0;
+}
+
+/*
+ * gmap_protect_pte - remove access rights to memory and set pgste bits
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ * @pmdp: pointer to the pmd associated with the pte
+ * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
+ * @bits: notification bits to set
+ *
+ * Returns 0 if successfully protected, -ENOMEM if out of memory and
+ * -EAGAIN if a fixup is needed.
+ *
+ * Expected to be called with sg->mm->mmap_lock in read
+ */
+static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
+			    pmd_t *pmdp, int prot, unsigned long bits)
+{
+	int rc;
+	pte_t *ptep;
+	spinlock_t *ptl;
+	unsigned long pbits = 0;
+
+	if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
+		return -EAGAIN;
+
+	ptep = pte_alloc_map_lock(gmap->mm, pmdp, gaddr, &ptl);
+	if (!ptep)
+		return -ENOMEM;
+
+	pbits |= (bits & GMAP_NOTIFY_MPROT) ? PGSTE_IN_BIT : 0;
+	pbits |= (bits & GMAP_NOTIFY_SHADOW) ? PGSTE_VSIE_BIT : 0;
+	/* Protect and unlock. */
+	rc = ptep_force_prot(gmap->mm, gaddr, ptep, prot, pbits);
+	gmap_pte_op_end(ptep, ptl);
+	return rc;
+}
+
+/*
+ * gmap_protect_range - remove access rights to memory and set pgste bits
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ * @len: size of area
+ * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
+ * @bits: pgste notification bits to set
+ *
+ * Returns 0 if successfully protected, -ENOMEM if out of memory and
+ * -EFAULT if gaddr is invalid (or mapping for shadows is missing).
+ *
+ * Called with sg->mm->mmap_lock in read.
+ */
+static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
+			      unsigned long len, int prot, unsigned long bits)
+{
+	unsigned long vmaddr, dist;
+	pmd_t *pmdp;
+	int rc;
+
+	BUG_ON(gmap_is_shadow(gmap));
+	while (len) {
+		rc = -EAGAIN;
+		pmdp = gmap_pmd_op_walk(gmap, gaddr);
+		if (pmdp) {
+			if (!pmd_large(*pmdp)) {
+				rc = gmap_protect_pte(gmap, gaddr, pmdp, prot,
+						      bits);
+				if (!rc) {
+					len -= PAGE_SIZE;
+					gaddr += PAGE_SIZE;
+				}
+			} else {
+				rc = gmap_protect_pmd(gmap, gaddr, pmdp, prot,
+						      bits);
+				if (!rc) {
+					dist = HPAGE_SIZE - (gaddr & ~HPAGE_MASK);
+					len = len < dist ? 0 : len - dist;
+					gaddr = (gaddr & HPAGE_MASK) + HPAGE_SIZE;
+				}
+			}
+			gmap_pmd_op_end(gmap, pmdp);
+		}
+		if (rc) {
+			if (rc == -EINVAL)
+				return rc;
+
+			/* -EAGAIN, fixup of userspace mm and gmap */
+			vmaddr = __gmap_translate(gmap, gaddr);
+			if (IS_ERR_VALUE(vmaddr))
+				return vmaddr;
+			rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, prot);
+			if (rc)
+				return rc;
+		}
+	}
+	return 0;
+}
+
+/**
+ * gmap_mprotect_notify - change access rights for a range of ptes and
+ *                        call the notifier if any pte changes again
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ * @len: size of area
+ * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
+ *
+ * Returns 0 if for each page in the given range a gmap mapping exists,
+ * the new access rights could be set and the notifier could be armed.
+ * If the gmap mapping is missing for one or more pages -EFAULT is
+ * returned. If no memory could be allocated -ENOMEM is returned.
+ * This function establishes missing page table entries.
+ */
+int gmap_mprotect_notify(struct gmap *gmap, unsigned long gaddr,
+			 unsigned long len, int prot)
+{
+	int rc;
+
+	if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK) || gmap_is_shadow(gmap))
+		return -EINVAL;
+	if (!MACHINE_HAS_ESOP && prot == PROT_READ)
+		return -EINVAL;
+	mmap_read_lock(gmap->mm);
+	rc = gmap_protect_range(gmap, gaddr, len, prot, GMAP_NOTIFY_MPROT);
+	mmap_read_unlock(gmap->mm);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_mprotect_notify);
+
+/**
+ * gmap_read_table - get an unsigned long value from a guest page table using
+ *                   absolute addressing, without marking the page referenced.
+ * @gmap: pointer to guest mapping meta data structure
+ * @gaddr: virtual address in the guest address space
+ * @val: pointer to the unsigned long value to return
+ *
+ * Returns 0 if the value was read, -ENOMEM if out of memory and -EFAULT
+ * if reading using the virtual address failed. -EINVAL if called on a gmap
+ * shadow.
+ *
+ * Called with gmap->mm->mmap_lock in read.
+ */
+int gmap_read_table(struct gmap *gmap, unsigned long gaddr, unsigned long *val)
+{
+	unsigned long address, vmaddr;
+	spinlock_t *ptl;
+	pte_t *ptep, pte;
+	int rc;
+
+	if (gmap_is_shadow(gmap))
+		return -EINVAL;
+
+	while (1) {
+		rc = -EAGAIN;
+		ptep = gmap_pte_op_walk(gmap, gaddr, &ptl);
+		if (ptep) {
+			pte = *ptep;
+			if (pte_present(pte) && (pte_val(pte) & _PAGE_READ)) {
+				address = pte_val(pte) & PAGE_MASK;
+				address += gaddr & ~PAGE_MASK;
+				*val = *(unsigned long *)__va(address);
+				set_pte(ptep, set_pte_bit(*ptep, __pgprot(_PAGE_YOUNG)));
+				/* Do *NOT* clear the _PAGE_INVALID bit! */
+				rc = 0;
+			}
+			gmap_pte_op_end(ptep, ptl);
+		}
+		if (!rc)
+			break;
+		vmaddr = __gmap_translate(gmap, gaddr);
+		if (IS_ERR_VALUE(vmaddr)) {
+			rc = vmaddr;
+			break;
+		}
+		rc = gmap_pte_op_fixup(gmap, gaddr, vmaddr, PROT_READ);
+		if (rc)
+			break;
+	}
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_read_table);
+
+/**
+ * gmap_insert_rmap - add a rmap to the host_to_rmap radix tree
+ * @sg: pointer to the shadow guest address space structure
+ * @vmaddr: vm address associated with the rmap
+ * @rmap: pointer to the rmap structure
+ *
+ * Called with the sg->guest_table_lock
+ */
+static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr,
+				    struct gmap_rmap *rmap)
+{
+	struct gmap_rmap *temp;
+	void __rcu **slot;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	slot = radix_tree_lookup_slot(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
+	if (slot) {
+		rmap->next = radix_tree_deref_slot_protected(slot,
+							&sg->guest_table_lock);
+		for (temp = rmap->next; temp; temp = temp->next) {
+			if (temp->raddr == rmap->raddr) {
+				kfree(rmap);
+				return;
+			}
+		}
+		radix_tree_replace_slot(&sg->host_to_rmap, slot, rmap);
+	} else {
+		rmap->next = NULL;
+		radix_tree_insert(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT,
+				  rmap);
+	}
+}
+
+/**
+ * gmap_protect_rmap - restrict access rights to memory (RO) and create an rmap
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: rmap address in the shadow gmap
+ * @paddr: address in the parent guest address space
+ * @len: length of the memory area to protect
+ *
+ * Returns 0 if successfully protected and the rmap was created, -ENOMEM
+ * if out of memory and -EFAULT if paddr is invalid.
+ */
+static int gmap_protect_rmap(struct gmap *sg, unsigned long raddr,
+			     unsigned long paddr, unsigned long len)
+{
+	struct gmap *parent;
+	struct gmap_rmap *rmap;
+	unsigned long vmaddr;
+	spinlock_t *ptl;
+	pte_t *ptep;
+	int rc;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	parent = sg->parent;
+	while (len) {
+		vmaddr = __gmap_translate(parent, paddr);
+		if (IS_ERR_VALUE(vmaddr))
+			return vmaddr;
+		rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT);
+		if (!rmap)
+			return -ENOMEM;
+		rmap->raddr = raddr;
+		rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
+		if (rc) {
+			kfree(rmap);
+			return rc;
+		}
+		rc = -EAGAIN;
+		ptep = gmap_pte_op_walk(parent, paddr, &ptl);
+		if (ptep) {
+			spin_lock(&sg->guest_table_lock);
+			rc = ptep_force_prot(parent->mm, paddr, ptep, PROT_READ,
+					     PGSTE_VSIE_BIT);
+			if (!rc)
+				gmap_insert_rmap(sg, vmaddr, rmap);
+			spin_unlock(&sg->guest_table_lock);
+			gmap_pte_op_end(ptep, ptl);
+		}
+		radix_tree_preload_end();
+		if (rc) {
+			kfree(rmap);
+			rc = gmap_pte_op_fixup(parent, paddr, vmaddr, PROT_READ);
+			if (rc)
+				return rc;
+			continue;
+		}
+		paddr += PAGE_SIZE;
+		len -= PAGE_SIZE;
+	}
+	return 0;
+}
+
+#define _SHADOW_RMAP_MASK	0x7
+#define _SHADOW_RMAP_REGION1	0x5
+#define _SHADOW_RMAP_REGION2	0x4
+#define _SHADOW_RMAP_REGION3	0x3
+#define _SHADOW_RMAP_SEGMENT	0x2
+#define _SHADOW_RMAP_PGTABLE	0x1
+
+/**
+ * gmap_idte_one - invalidate a single region or segment table entry
+ * @asce: region or segment table *origin* + table-type bits
+ * @vaddr: virtual address to identify the table entry to flush
+ *
+ * The invalid bit of a single region or segment table entry is set
+ * and the associated TLB entries depending on the entry are flushed.
+ * The table-type of the @asce identifies the portion of the @vaddr
+ * that is used as the invalidation index.
+ */
+static inline void gmap_idte_one(unsigned long asce, unsigned long vaddr)
+{
+	asm volatile(
+		"	idte	%0,0,%1"
+		: : "a" (asce), "a" (vaddr) : "cc", "memory");
+}
+
+/**
+ * gmap_unshadow_page - remove a page from a shadow page table
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: rmap address in the shadow guest address space
+ *
+ * Called with the sg->guest_table_lock
+ */
+static void gmap_unshadow_page(struct gmap *sg, unsigned long raddr)
+{
+	unsigned long *table;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	table = gmap_table_walk(sg, raddr, 0); /* get page table pointer */
+	if (!table || *table & _PAGE_INVALID)
+		return;
+	gmap_call_notifier(sg, raddr, raddr + _PAGE_SIZE - 1);
+	ptep_unshadow_pte(sg->mm, raddr, (pte_t *) table);
+}
+
+/**
+ * __gmap_unshadow_pgt - remove all entries from a shadow page table
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: rmap address in the shadow guest address space
+ * @pgt: pointer to the start of a shadow page table
+ *
+ * Called with the sg->guest_table_lock
+ */
+static void __gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr,
+				unsigned long *pgt)
+{
+	int i;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	for (i = 0; i < _PAGE_ENTRIES; i++, raddr += _PAGE_SIZE)
+		pgt[i] = _PAGE_INVALID;
+}
+
+/**
+ * gmap_unshadow_pgt - remove a shadow page table from a segment entry
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: address in the shadow guest address space
+ *
+ * Called with the sg->guest_table_lock
+ */
+static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
+{
+	unsigned long *ste;
+	phys_addr_t sto, pgt;
+	struct page *page;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */
+	if (!ste || !(*ste & _SEGMENT_ENTRY_ORIGIN))
+		return;
+	gmap_call_notifier(sg, raddr, raddr + _SEGMENT_SIZE - 1);
+	sto = __pa(ste - ((raddr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT));
+	gmap_idte_one(sto | _ASCE_TYPE_SEGMENT, raddr);
+	pgt = *ste & _SEGMENT_ENTRY_ORIGIN;
+	*ste = _SEGMENT_ENTRY_EMPTY;
+	__gmap_unshadow_pgt(sg, raddr, __va(pgt));
+	/* Free page table */
+	page = phys_to_page(pgt);
+	list_del(&page->lru);
+	page_table_free_pgste(page);
+}
+
+/**
+ * __gmap_unshadow_sgt - remove all entries from a shadow segment table
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: rmap address in the shadow guest address space
+ * @sgt: pointer to the start of a shadow segment table
+ *
+ * Called with the sg->guest_table_lock
+ */
+static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
+				unsigned long *sgt)
+{
+	struct page *page;
+	phys_addr_t pgt;
+	int i;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	for (i = 0; i < _CRST_ENTRIES; i++, raddr += _SEGMENT_SIZE) {
+		if (!(sgt[i] & _SEGMENT_ENTRY_ORIGIN))
+			continue;
+		pgt = sgt[i] & _REGION_ENTRY_ORIGIN;
+		sgt[i] = _SEGMENT_ENTRY_EMPTY;
+		__gmap_unshadow_pgt(sg, raddr, __va(pgt));
+		/* Free page table */
+		page = phys_to_page(pgt);
+		list_del(&page->lru);
+		page_table_free_pgste(page);
+	}
+}
+
+/**
+ * gmap_unshadow_sgt - remove a shadow segment table from a region-3 entry
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: rmap address in the shadow guest address space
+ *
+ * Called with the shadow->guest_table_lock
+ */
+static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
+{
+	unsigned long r3o, *r3e;
+	phys_addr_t sgt;
+	struct page *page;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */
+	if (!r3e || !(*r3e & _REGION_ENTRY_ORIGIN))
+		return;
+	gmap_call_notifier(sg, raddr, raddr + _REGION3_SIZE - 1);
+	r3o = (unsigned long) (r3e - ((raddr & _REGION3_INDEX) >> _REGION3_SHIFT));
+	gmap_idte_one(__pa(r3o) | _ASCE_TYPE_REGION3, raddr);
+	sgt = *r3e & _REGION_ENTRY_ORIGIN;
+	*r3e = _REGION3_ENTRY_EMPTY;
+	__gmap_unshadow_sgt(sg, raddr, __va(sgt));
+	/* Free segment table */
+	page = phys_to_page(sgt);
+	list_del(&page->lru);
+	__free_pages(page, CRST_ALLOC_ORDER);
+}
+
+/**
+ * __gmap_unshadow_r3t - remove all entries from a shadow region-3 table
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: address in the shadow guest address space
+ * @r3t: pointer to the start of a shadow region-3 table
+ *
+ * Called with the sg->guest_table_lock
+ */
+static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
+				unsigned long *r3t)
+{
+	struct page *page;
+	phys_addr_t sgt;
+	int i;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION3_SIZE) {
+		if (!(r3t[i] & _REGION_ENTRY_ORIGIN))
+			continue;
+		sgt = r3t[i] & _REGION_ENTRY_ORIGIN;
+		r3t[i] = _REGION3_ENTRY_EMPTY;
+		__gmap_unshadow_sgt(sg, raddr, __va(sgt));
+		/* Free segment table */
+		page = phys_to_page(sgt);
+		list_del(&page->lru);
+		__free_pages(page, CRST_ALLOC_ORDER);
+	}
+}
+
+/**
+ * gmap_unshadow_r3t - remove a shadow region-3 table from a region-2 entry
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: rmap address in the shadow guest address space
+ *
+ * Called with the sg->guest_table_lock
+ */
+static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
+{
+	unsigned long r2o, *r2e;
+	phys_addr_t r3t;
+	struct page *page;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */
+	if (!r2e || !(*r2e & _REGION_ENTRY_ORIGIN))
+		return;
+	gmap_call_notifier(sg, raddr, raddr + _REGION2_SIZE - 1);
+	r2o = (unsigned long) (r2e - ((raddr & _REGION2_INDEX) >> _REGION2_SHIFT));
+	gmap_idte_one(__pa(r2o) | _ASCE_TYPE_REGION2, raddr);
+	r3t = *r2e & _REGION_ENTRY_ORIGIN;
+	*r2e = _REGION2_ENTRY_EMPTY;
+	__gmap_unshadow_r3t(sg, raddr, __va(r3t));
+	/* Free region 3 table */
+	page = phys_to_page(r3t);
+	list_del(&page->lru);
+	__free_pages(page, CRST_ALLOC_ORDER);
+}
+
+/**
+ * __gmap_unshadow_r2t - remove all entries from a shadow region-2 table
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: rmap address in the shadow guest address space
+ * @r2t: pointer to the start of a shadow region-2 table
+ *
+ * Called with the sg->guest_table_lock
+ */
+static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
+				unsigned long *r2t)
+{
+	phys_addr_t r3t;
+	struct page *page;
+	int i;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION2_SIZE) {
+		if (!(r2t[i] & _REGION_ENTRY_ORIGIN))
+			continue;
+		r3t = r2t[i] & _REGION_ENTRY_ORIGIN;
+		r2t[i] = _REGION2_ENTRY_EMPTY;
+		__gmap_unshadow_r3t(sg, raddr, __va(r3t));
+		/* Free region 3 table */
+		page = phys_to_page(r3t);
+		list_del(&page->lru);
+		__free_pages(page, CRST_ALLOC_ORDER);
+	}
+}
+
+/**
+ * gmap_unshadow_r2t - remove a shadow region-2 table from a region-1 entry
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: rmap address in the shadow guest address space
+ *
+ * Called with the sg->guest_table_lock
+ */
+static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
+{
+	unsigned long r1o, *r1e;
+	struct page *page;
+	phys_addr_t r2t;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	r1e = gmap_table_walk(sg, raddr, 4); /* get region-1 pointer */
+	if (!r1e || !(*r1e & _REGION_ENTRY_ORIGIN))
+		return;
+	gmap_call_notifier(sg, raddr, raddr + _REGION1_SIZE - 1);
+	r1o = (unsigned long) (r1e - ((raddr & _REGION1_INDEX) >> _REGION1_SHIFT));
+	gmap_idte_one(__pa(r1o) | _ASCE_TYPE_REGION1, raddr);
+	r2t = *r1e & _REGION_ENTRY_ORIGIN;
+	*r1e = _REGION1_ENTRY_EMPTY;
+	__gmap_unshadow_r2t(sg, raddr, __va(r2t));
+	/* Free region 2 table */
+	page = phys_to_page(r2t);
+	list_del(&page->lru);
+	__free_pages(page, CRST_ALLOC_ORDER);
+}
+
+/**
+ * __gmap_unshadow_r1t - remove all entries from a shadow region-1 table
+ * @sg: pointer to the shadow guest address space structure
+ * @raddr: rmap address in the shadow guest address space
+ * @r1t: pointer to the start of a shadow region-1 table
+ *
+ * Called with the shadow->guest_table_lock
+ */
+static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
+				unsigned long *r1t)
+{
+	unsigned long asce;
+	struct page *page;
+	phys_addr_t r2t;
+	int i;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	asce = __pa(r1t) | _ASCE_TYPE_REGION1;
+	for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION1_SIZE) {
+		if (!(r1t[i] & _REGION_ENTRY_ORIGIN))
+			continue;
+		r2t = r1t[i] & _REGION_ENTRY_ORIGIN;
+		__gmap_unshadow_r2t(sg, raddr, __va(r2t));
+		/* Clear entry and flush translation r1t -> r2t */
+		gmap_idte_one(asce, raddr);
+		r1t[i] = _REGION1_ENTRY_EMPTY;
+		/* Free region 2 table */
+		page = phys_to_page(r2t);
+		list_del(&page->lru);
+		__free_pages(page, CRST_ALLOC_ORDER);
+	}
+}
+
+/**
+ * gmap_unshadow - remove a shadow page table completely
+ * @sg: pointer to the shadow guest address space structure
+ *
+ * Called with sg->guest_table_lock
+ */
+static void gmap_unshadow(struct gmap *sg)
+{
+	unsigned long *table;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	if (sg->removed)
+		return;
+	sg->removed = 1;
+	gmap_call_notifier(sg, 0, -1UL);
+	gmap_flush_tlb(sg);
+	table = __va(sg->asce & _ASCE_ORIGIN);
+	switch (sg->asce & _ASCE_TYPE_MASK) {
+	case _ASCE_TYPE_REGION1:
+		__gmap_unshadow_r1t(sg, 0, table);
+		break;
+	case _ASCE_TYPE_REGION2:
+		__gmap_unshadow_r2t(sg, 0, table);
+		break;
+	case _ASCE_TYPE_REGION3:
+		__gmap_unshadow_r3t(sg, 0, table);
+		break;
+	case _ASCE_TYPE_SEGMENT:
+		__gmap_unshadow_sgt(sg, 0, table);
+		break;
+	}
+}
+
+/**
+ * gmap_find_shadow - find a specific asce in the list of shadow tables
+ * @parent: pointer to the parent gmap
+ * @asce: ASCE for which the shadow table is created
+ * @edat_level: edat level to be used for the shadow translation
+ *
+ * Returns the pointer to a gmap if a shadow table with the given asce is
+ * already available, ERR_PTR(-EAGAIN) if another one is just being created,
+ * otherwise NULL
+ */
+static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce,
+				     int edat_level)
+{
+	struct gmap *sg;
+
+	list_for_each_entry(sg, &parent->children, list) {
+		if (sg->orig_asce != asce || sg->edat_level != edat_level ||
+		    sg->removed)
+			continue;
+		if (!sg->initialized)
+			return ERR_PTR(-EAGAIN);
+		refcount_inc(&sg->ref_count);
+		return sg;
+	}
+	return NULL;
+}
+
+/**
+ * gmap_shadow_valid - check if a shadow guest address space matches the
+ *                     given properties and is still valid
+ * @sg: pointer to the shadow guest address space structure
+ * @asce: ASCE for which the shadow table is requested
+ * @edat_level: edat level to be used for the shadow translation
+ *
+ * Returns 1 if the gmap shadow is still valid and matches the given
+ * properties, the caller can continue using it. Returns 0 otherwise, the
+ * caller has to request a new shadow gmap in this case.
+ *
+ */
+int gmap_shadow_valid(struct gmap *sg, unsigned long asce, int edat_level)
+{
+	if (sg->removed)
+		return 0;
+	return sg->orig_asce == asce && sg->edat_level == edat_level;
+}
+EXPORT_SYMBOL_GPL(gmap_shadow_valid);
+
+/**
+ * gmap_shadow - create/find a shadow guest address space
+ * @parent: pointer to the parent gmap
+ * @asce: ASCE for which the shadow table is created
+ * @edat_level: edat level to be used for the shadow translation
+ *
+ * The pages of the top level page table referred by the asce parameter
+ * will be set to read-only and marked in the PGSTEs of the kvm process.
+ * The shadow table will be removed automatically on any change to the
+ * PTE mapping for the source table.
+ *
+ * Returns a guest address space structure, ERR_PTR(-ENOMEM) if out of memory,
+ * ERR_PTR(-EAGAIN) if the caller has to retry and ERR_PTR(-EFAULT) if the
+ * parent gmap table could not be protected.
+ */
+struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
+			 int edat_level)
+{
+	struct gmap *sg, *new;
+	unsigned long limit;
+	int rc;
+
+	BUG_ON(parent->mm->context.allow_gmap_hpage_1m);
+	BUG_ON(gmap_is_shadow(parent));
+	spin_lock(&parent->shadow_lock);
+	sg = gmap_find_shadow(parent, asce, edat_level);
+	spin_unlock(&parent->shadow_lock);
+	if (sg)
+		return sg;
+	/* Create a new shadow gmap */
+	limit = -1UL >> (33 - (((asce & _ASCE_TYPE_MASK) >> 2) * 11));
+	if (asce & _ASCE_REAL_SPACE)
+		limit = -1UL;
+	new = gmap_alloc(limit);
+	if (!new)
+		return ERR_PTR(-ENOMEM);
+	new->mm = parent->mm;
+	new->parent = gmap_get(parent);
+	new->orig_asce = asce;
+	new->edat_level = edat_level;
+	new->initialized = false;
+	spin_lock(&parent->shadow_lock);
+	/* Recheck if another CPU created the same shadow */
+	sg = gmap_find_shadow(parent, asce, edat_level);
+	if (sg) {
+		spin_unlock(&parent->shadow_lock);
+		gmap_free(new);
+		return sg;
+	}
+	if (asce & _ASCE_REAL_SPACE) {
+		/* only allow one real-space gmap shadow */
+		list_for_each_entry(sg, &parent->children, list) {
+			if (sg->orig_asce & _ASCE_REAL_SPACE) {
+				spin_lock(&sg->guest_table_lock);
+				gmap_unshadow(sg);
+				spin_unlock(&sg->guest_table_lock);
+				list_del(&sg->list);
+				gmap_put(sg);
+				break;
+			}
+		}
+	}
+	refcount_set(&new->ref_count, 2);
+	list_add(&new->list, &parent->children);
+	if (asce & _ASCE_REAL_SPACE) {
+		/* nothing to protect, return right away */
+		new->initialized = true;
+		spin_unlock(&parent->shadow_lock);
+		return new;
+	}
+	spin_unlock(&parent->shadow_lock);
+	/* protect after insertion, so it will get properly invalidated */
+	mmap_read_lock(parent->mm);
+	rc = gmap_protect_range(parent, asce & _ASCE_ORIGIN,
+				((asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE,
+				PROT_READ, GMAP_NOTIFY_SHADOW);
+	mmap_read_unlock(parent->mm);
+	spin_lock(&parent->shadow_lock);
+	new->initialized = true;
+	if (rc) {
+		list_del(&new->list);
+		gmap_free(new);
+		new = ERR_PTR(rc);
+	}
+	spin_unlock(&parent->shadow_lock);
+	return new;
+}
+EXPORT_SYMBOL_GPL(gmap_shadow);
+
+/**
+ * gmap_shadow_r2t - create an empty shadow region 2 table
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: faulting address in the shadow gmap
+ * @r2t: parent gmap address of the region 2 table to get shadowed
+ * @fake: r2t references contiguous guest memory block, not a r2t
+ *
+ * The r2t parameter specifies the address of the source table. The
+ * four pages of the source table are made read-only in the parent gmap
+ * address space. A write to the source table area @r2t will automatically
+ * remove the shadow r2 table and all of its descendants.
+ *
+ * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
+ * shadow table structure is incomplete, -ENOMEM if out of memory and
+ * -EFAULT if an address in the parent gmap could not be resolved.
+ *
+ * Called with sg->mm->mmap_lock in read.
+ */
+int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
+		    int fake)
+{
+	unsigned long raddr, origin, offset, len;
+	unsigned long *table;
+	phys_addr_t s_r2t;
+	struct page *page;
+	int rc;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	/* Allocate a shadow region second table */
+	page = gmap_alloc_crst();
+	if (!page)
+		return -ENOMEM;
+	page->index = r2t & _REGION_ENTRY_ORIGIN;
+	if (fake)
+		page->index |= GMAP_SHADOW_FAKE_TABLE;
+	s_r2t = page_to_phys(page);
+	/* Install shadow region second table */
+	spin_lock(&sg->guest_table_lock);
+	table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */
+	if (!table) {
+		rc = -EAGAIN;		/* Race with unshadow */
+		goto out_free;
+	}
+	if (!(*table & _REGION_ENTRY_INVALID)) {
+		rc = 0;			/* Already established */
+		goto out_free;
+	} else if (*table & _REGION_ENTRY_ORIGIN) {
+		rc = -EAGAIN;		/* Race with shadow */
+		goto out_free;
+	}
+	crst_table_init(__va(s_r2t), _REGION2_ENTRY_EMPTY);
+	/* mark as invalid as long as the parent table is not protected */
+	*table = s_r2t | _REGION_ENTRY_LENGTH |
+		 _REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID;
+	if (sg->edat_level >= 1)
+		*table |= (r2t & _REGION_ENTRY_PROTECT);
+	list_add(&page->lru, &sg->crst_list);
+	if (fake) {
+		/* nothing to protect for fake tables */
+		*table &= ~_REGION_ENTRY_INVALID;
+		spin_unlock(&sg->guest_table_lock);
+		return 0;
+	}
+	spin_unlock(&sg->guest_table_lock);
+	/* Make r2t read-only in parent gmap page table */
+	raddr = (saddr & _REGION1_MASK) | _SHADOW_RMAP_REGION1;
+	origin = r2t & _REGION_ENTRY_ORIGIN;
+	offset = ((r2t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
+	len = ((r2t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
+	rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
+	spin_lock(&sg->guest_table_lock);
+	if (!rc) {
+		table = gmap_table_walk(sg, saddr, 4);
+		if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r2t)
+			rc = -EAGAIN;		/* Race with unshadow */
+		else
+			*table &= ~_REGION_ENTRY_INVALID;
+	} else {
+		gmap_unshadow_r2t(sg, raddr);
+	}
+	spin_unlock(&sg->guest_table_lock);
+	return rc;
+out_free:
+	spin_unlock(&sg->guest_table_lock);
+	__free_pages(page, CRST_ALLOC_ORDER);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_shadow_r2t);
+
+/**
+ * gmap_shadow_r3t - create a shadow region 3 table
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: faulting address in the shadow gmap
+ * @r3t: parent gmap address of the region 3 table to get shadowed
+ * @fake: r3t references contiguous guest memory block, not a r3t
+ *
+ * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
+ * shadow table structure is incomplete, -ENOMEM if out of memory and
+ * -EFAULT if an address in the parent gmap could not be resolved.
+ *
+ * Called with sg->mm->mmap_lock in read.
+ */
+int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
+		    int fake)
+{
+	unsigned long raddr, origin, offset, len;
+	unsigned long *table;
+	phys_addr_t s_r3t;
+	struct page *page;
+	int rc;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	/* Allocate a shadow region second table */
+	page = gmap_alloc_crst();
+	if (!page)
+		return -ENOMEM;
+	page->index = r3t & _REGION_ENTRY_ORIGIN;
+	if (fake)
+		page->index |= GMAP_SHADOW_FAKE_TABLE;
+	s_r3t = page_to_phys(page);
+	/* Install shadow region second table */
+	spin_lock(&sg->guest_table_lock);
+	table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */
+	if (!table) {
+		rc = -EAGAIN;		/* Race with unshadow */
+		goto out_free;
+	}
+	if (!(*table & _REGION_ENTRY_INVALID)) {
+		rc = 0;			/* Already established */
+		goto out_free;
+	} else if (*table & _REGION_ENTRY_ORIGIN) {
+		rc = -EAGAIN;		/* Race with shadow */
+		goto out_free;
+	}
+	crst_table_init(__va(s_r3t), _REGION3_ENTRY_EMPTY);
+	/* mark as invalid as long as the parent table is not protected */
+	*table = s_r3t | _REGION_ENTRY_LENGTH |
+		 _REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID;
+	if (sg->edat_level >= 1)
+		*table |= (r3t & _REGION_ENTRY_PROTECT);
+	list_add(&page->lru, &sg->crst_list);
+	if (fake) {
+		/* nothing to protect for fake tables */
+		*table &= ~_REGION_ENTRY_INVALID;
+		spin_unlock(&sg->guest_table_lock);
+		return 0;
+	}
+	spin_unlock(&sg->guest_table_lock);
+	/* Make r3t read-only in parent gmap page table */
+	raddr = (saddr & _REGION2_MASK) | _SHADOW_RMAP_REGION2;
+	origin = r3t & _REGION_ENTRY_ORIGIN;
+	offset = ((r3t & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
+	len = ((r3t & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
+	rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
+	spin_lock(&sg->guest_table_lock);
+	if (!rc) {
+		table = gmap_table_walk(sg, saddr, 3);
+		if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_r3t)
+			rc = -EAGAIN;		/* Race with unshadow */
+		else
+			*table &= ~_REGION_ENTRY_INVALID;
+	} else {
+		gmap_unshadow_r3t(sg, raddr);
+	}
+	spin_unlock(&sg->guest_table_lock);
+	return rc;
+out_free:
+	spin_unlock(&sg->guest_table_lock);
+	__free_pages(page, CRST_ALLOC_ORDER);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_shadow_r3t);
+
+/**
+ * gmap_shadow_sgt - create a shadow segment table
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: faulting address in the shadow gmap
+ * @sgt: parent gmap address of the segment table to get shadowed
+ * @fake: sgt references contiguous guest memory block, not a sgt
+ *
+ * Returns: 0 if successfully shadowed or already shadowed, -EAGAIN if the
+ * shadow table structure is incomplete, -ENOMEM if out of memory and
+ * -EFAULT if an address in the parent gmap could not be resolved.
+ *
+ * Called with sg->mm->mmap_lock in read.
+ */
+int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
+		    int fake)
+{
+	unsigned long raddr, origin, offset, len;
+	unsigned long *table;
+	phys_addr_t s_sgt;
+	struct page *page;
+	int rc;
+
+	BUG_ON(!gmap_is_shadow(sg) || (sgt & _REGION3_ENTRY_LARGE));
+	/* Allocate a shadow segment table */
+	page = gmap_alloc_crst();
+	if (!page)
+		return -ENOMEM;
+	page->index = sgt & _REGION_ENTRY_ORIGIN;
+	if (fake)
+		page->index |= GMAP_SHADOW_FAKE_TABLE;
+	s_sgt = page_to_phys(page);
+	/* Install shadow region second table */
+	spin_lock(&sg->guest_table_lock);
+	table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */
+	if (!table) {
+		rc = -EAGAIN;		/* Race with unshadow */
+		goto out_free;
+	}
+	if (!(*table & _REGION_ENTRY_INVALID)) {
+		rc = 0;			/* Already established */
+		goto out_free;
+	} else if (*table & _REGION_ENTRY_ORIGIN) {
+		rc = -EAGAIN;		/* Race with shadow */
+		goto out_free;
+	}
+	crst_table_init(__va(s_sgt), _SEGMENT_ENTRY_EMPTY);
+	/* mark as invalid as long as the parent table is not protected */
+	*table = s_sgt | _REGION_ENTRY_LENGTH |
+		 _REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID;
+	if (sg->edat_level >= 1)
+		*table |= sgt & _REGION_ENTRY_PROTECT;
+	list_add(&page->lru, &sg->crst_list);
+	if (fake) {
+		/* nothing to protect for fake tables */
+		*table &= ~_REGION_ENTRY_INVALID;
+		spin_unlock(&sg->guest_table_lock);
+		return 0;
+	}
+	spin_unlock(&sg->guest_table_lock);
+	/* Make sgt read-only in parent gmap page table */
+	raddr = (saddr & _REGION3_MASK) | _SHADOW_RMAP_REGION3;
+	origin = sgt & _REGION_ENTRY_ORIGIN;
+	offset = ((sgt & _REGION_ENTRY_OFFSET) >> 6) * PAGE_SIZE;
+	len = ((sgt & _REGION_ENTRY_LENGTH) + 1) * PAGE_SIZE - offset;
+	rc = gmap_protect_rmap(sg, raddr, origin + offset, len);
+	spin_lock(&sg->guest_table_lock);
+	if (!rc) {
+		table = gmap_table_walk(sg, saddr, 2);
+		if (!table || (*table & _REGION_ENTRY_ORIGIN) != s_sgt)
+			rc = -EAGAIN;		/* Race with unshadow */
+		else
+			*table &= ~_REGION_ENTRY_INVALID;
+	} else {
+		gmap_unshadow_sgt(sg, raddr);
+	}
+	spin_unlock(&sg->guest_table_lock);
+	return rc;
+out_free:
+	spin_unlock(&sg->guest_table_lock);
+	__free_pages(page, CRST_ALLOC_ORDER);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_shadow_sgt);
+
+/**
+ * gmap_shadow_pgt_lookup - find a shadow page table
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: the address in the shadow aguest address space
+ * @pgt: parent gmap address of the page table to get shadowed
+ * @dat_protection: if the pgtable is marked as protected by dat
+ * @fake: pgt references contiguous guest memory block, not a pgtable
+ *
+ * Returns 0 if the shadow page table was found and -EAGAIN if the page
+ * table was not found.
+ *
+ * Called with sg->mm->mmap_lock in read.
+ */
+int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
+			   unsigned long *pgt, int *dat_protection,
+			   int *fake)
+{
+	unsigned long *table;
+	struct page *page;
+	int rc;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	spin_lock(&sg->guest_table_lock);
+	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
+	if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
+		/* Shadow page tables are full pages (pte+pgste) */
+		page = pfn_to_page(*table >> PAGE_SHIFT);
+		*pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
+		*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
+		*fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
+		rc = 0;
+	} else  {
+		rc = -EAGAIN;
+	}
+	spin_unlock(&sg->guest_table_lock);
+	return rc;
+
+}
+EXPORT_SYMBOL_GPL(gmap_shadow_pgt_lookup);
+
+/**
+ * gmap_shadow_pgt - instantiate a shadow page table
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: faulting address in the shadow gmap
+ * @pgt: parent gmap address of the page table to get shadowed
+ * @fake: pgt references contiguous guest memory block, not a pgtable
+ *
+ * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
+ * shadow table structure is incomplete, -ENOMEM if out of memory,
+ * -EFAULT if an address in the parent gmap could not be resolved and
+ *
+ * Called with gmap->mm->mmap_lock in read
+ */
+int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
+		    int fake)
+{
+	unsigned long raddr, origin;
+	unsigned long *table;
+	struct page *page;
+	phys_addr_t s_pgt;
+	int rc;
+
+	BUG_ON(!gmap_is_shadow(sg) || (pgt & _SEGMENT_ENTRY_LARGE));
+	/* Allocate a shadow page table */
+	page = page_table_alloc_pgste(sg->mm);
+	if (!page)
+		return -ENOMEM;
+	page->index = pgt & _SEGMENT_ENTRY_ORIGIN;
+	if (fake)
+		page->index |= GMAP_SHADOW_FAKE_TABLE;
+	s_pgt = page_to_phys(page);
+	/* Install shadow page table */
+	spin_lock(&sg->guest_table_lock);
+	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
+	if (!table) {
+		rc = -EAGAIN;		/* Race with unshadow */
+		goto out_free;
+	}
+	if (!(*table & _SEGMENT_ENTRY_INVALID)) {
+		rc = 0;			/* Already established */
+		goto out_free;
+	} else if (*table & _SEGMENT_ENTRY_ORIGIN) {
+		rc = -EAGAIN;		/* Race with shadow */
+		goto out_free;
+	}
+	/* mark as invalid as long as the parent table is not protected */
+	*table = (unsigned long) s_pgt | _SEGMENT_ENTRY |
+		 (pgt & _SEGMENT_ENTRY_PROTECT) | _SEGMENT_ENTRY_INVALID;
+	list_add(&page->lru, &sg->pt_list);
+	if (fake) {
+		/* nothing to protect for fake tables */
+		*table &= ~_SEGMENT_ENTRY_INVALID;
+		spin_unlock(&sg->guest_table_lock);
+		return 0;
+	}
+	spin_unlock(&sg->guest_table_lock);
+	/* Make pgt read-only in parent gmap page table (not the pgste) */
+	raddr = (saddr & _SEGMENT_MASK) | _SHADOW_RMAP_SEGMENT;
+	origin = pgt & _SEGMENT_ENTRY_ORIGIN & PAGE_MASK;
+	rc = gmap_protect_rmap(sg, raddr, origin, PAGE_SIZE);
+	spin_lock(&sg->guest_table_lock);
+	if (!rc) {
+		table = gmap_table_walk(sg, saddr, 1);
+		if (!table || (*table & _SEGMENT_ENTRY_ORIGIN) != s_pgt)
+			rc = -EAGAIN;		/* Race with unshadow */
+		else
+			*table &= ~_SEGMENT_ENTRY_INVALID;
+	} else {
+		gmap_unshadow_pgt(sg, raddr);
+	}
+	spin_unlock(&sg->guest_table_lock);
+	return rc;
+out_free:
+	spin_unlock(&sg->guest_table_lock);
+	page_table_free_pgste(page);
+	return rc;
+
+}
+EXPORT_SYMBOL_GPL(gmap_shadow_pgt);
+
+/**
+ * gmap_shadow_page - create a shadow page mapping
+ * @sg: pointer to the shadow guest address space structure
+ * @saddr: faulting address in the shadow gmap
+ * @pte: pte in parent gmap address space to get shadowed
+ *
+ * Returns 0 if successfully shadowed or already shadowed, -EAGAIN if the
+ * shadow table structure is incomplete, -ENOMEM if out of memory and
+ * -EFAULT if an address in the parent gmap could not be resolved.
+ *
+ * Called with sg->mm->mmap_lock in read.
+ */
+int gmap_shadow_page(struct gmap *sg, unsigned long saddr, pte_t pte)
+{
+	struct gmap *parent;
+	struct gmap_rmap *rmap;
+	unsigned long vmaddr, paddr;
+	spinlock_t *ptl;
+	pte_t *sptep, *tptep;
+	int prot;
+	int rc;
+
+	BUG_ON(!gmap_is_shadow(sg));
+	parent = sg->parent;
+	prot = (pte_val(pte) & _PAGE_PROTECT) ? PROT_READ : PROT_WRITE;
+
+	rmap = kzalloc(sizeof(*rmap), GFP_KERNEL_ACCOUNT);
+	if (!rmap)
+		return -ENOMEM;
+	rmap->raddr = (saddr & PAGE_MASK) | _SHADOW_RMAP_PGTABLE;
+
+	while (1) {
+		paddr = pte_val(pte) & PAGE_MASK;
+		vmaddr = __gmap_translate(parent, paddr);
+		if (IS_ERR_VALUE(vmaddr)) {
+			rc = vmaddr;
+			break;
+		}
+		rc = radix_tree_preload(GFP_KERNEL_ACCOUNT);
+		if (rc)
+			break;
+		rc = -EAGAIN;
+		sptep = gmap_pte_op_walk(parent, paddr, &ptl);
+		if (sptep) {
+			spin_lock(&sg->guest_table_lock);
+			/* Get page table pointer */
+			tptep = (pte_t *) gmap_table_walk(sg, saddr, 0);
+			if (!tptep) {
+				spin_unlock(&sg->guest_table_lock);
+				gmap_pte_op_end(sptep, ptl);
+				radix_tree_preload_end();
+				break;
+			}
+			rc = ptep_shadow_pte(sg->mm, saddr, sptep, tptep, pte);
+			if (rc > 0) {
+				/* Success and a new mapping */
+				gmap_insert_rmap(sg, vmaddr, rmap);
+				rmap = NULL;
+				rc = 0;
+			}
+			gmap_pte_op_end(sptep, ptl);
+			spin_unlock(&sg->guest_table_lock);
+		}
+		radix_tree_preload_end();
+		if (!rc)
+			break;
+		rc = gmap_pte_op_fixup(parent, paddr, vmaddr, prot);
+		if (rc)
+			break;
+	}
+	kfree(rmap);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_shadow_page);
+
+/*
+ * gmap_shadow_notify - handle notifications for shadow gmap
+ *
+ * Called with sg->parent->shadow_lock.
+ */
+static void gmap_shadow_notify(struct gmap *sg, unsigned long vmaddr,
+			       unsigned long gaddr)
+{
+	struct gmap_rmap *rmap, *rnext, *head;
+	unsigned long start, end, bits, raddr;
+
+	BUG_ON(!gmap_is_shadow(sg));
+
+	spin_lock(&sg->guest_table_lock);
+	if (sg->removed) {
+		spin_unlock(&sg->guest_table_lock);
+		return;
+	}
+	/* Check for top level table */
+	start = sg->orig_asce & _ASCE_ORIGIN;
+	end = start + ((sg->orig_asce & _ASCE_TABLE_LENGTH) + 1) * PAGE_SIZE;
+	if (!(sg->orig_asce & _ASCE_REAL_SPACE) && gaddr >= start &&
+	    gaddr < end) {
+		/* The complete shadow table has to go */
+		gmap_unshadow(sg);
+		spin_unlock(&sg->guest_table_lock);
+		list_del(&sg->list);
+		gmap_put(sg);
+		return;
+	}
+	/* Remove the page table tree from on specific entry */
+	head = radix_tree_delete(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT);
+	gmap_for_each_rmap_safe(rmap, rnext, head) {
+		bits = rmap->raddr & _SHADOW_RMAP_MASK;
+		raddr = rmap->raddr ^ bits;
+		switch (bits) {
+		case _SHADOW_RMAP_REGION1:
+			gmap_unshadow_r2t(sg, raddr);
+			break;
+		case _SHADOW_RMAP_REGION2:
+			gmap_unshadow_r3t(sg, raddr);
+			break;
+		case _SHADOW_RMAP_REGION3:
+			gmap_unshadow_sgt(sg, raddr);
+			break;
+		case _SHADOW_RMAP_SEGMENT:
+			gmap_unshadow_pgt(sg, raddr);
+			break;
+		case _SHADOW_RMAP_PGTABLE:
+			gmap_unshadow_page(sg, raddr);
+			break;
+		}
+		kfree(rmap);
+	}
+	spin_unlock(&sg->guest_table_lock);
+}
+
+/**
+ * ptep_notify - call all invalidation callbacks for a specific pte.
+ * @mm: pointer to the process mm_struct
+ * @vmaddr: virtual address in the process address space
+ * @pte: pointer to the page table entry
+ * @bits: bits from the pgste that caused the notify call
+ *
+ * This function is assumed to be called with the page table lock held
+ * for the pte to notify.
+ */
+void ptep_notify(struct mm_struct *mm, unsigned long vmaddr,
+		 pte_t *pte, unsigned long bits)
+{
+	unsigned long offset, gaddr = 0;
+	unsigned long *table;
+	struct gmap *gmap, *sg, *next;
+
+	offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
+	offset = offset * (PAGE_SIZE / sizeof(pte_t));
+	rcu_read_lock();
+	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
+		spin_lock(&gmap->guest_table_lock);
+		table = radix_tree_lookup(&gmap->host_to_guest,
+					  vmaddr >> PMD_SHIFT);
+		if (table)
+			gaddr = __gmap_segment_gaddr(table) + offset;
+		spin_unlock(&gmap->guest_table_lock);
+		if (!table)
+			continue;
+
+		if (!list_empty(&gmap->children) && (bits & PGSTE_VSIE_BIT)) {
+			spin_lock(&gmap->shadow_lock);
+			list_for_each_entry_safe(sg, next,
+						 &gmap->children, list)
+				gmap_shadow_notify(sg, vmaddr, gaddr);
+			spin_unlock(&gmap->shadow_lock);
+		}
+		if (bits & PGSTE_IN_BIT)
+			gmap_call_notifier(gmap, gaddr, gaddr + PAGE_SIZE - 1);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(ptep_notify);
+
+static void pmdp_notify_gmap(struct gmap *gmap, pmd_t *pmdp,
+			     unsigned long gaddr)
+{
+	set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_IN)));
+	gmap_call_notifier(gmap, gaddr, gaddr + HPAGE_SIZE - 1);
+}
+
+/**
+ * gmap_pmdp_xchg - exchange a gmap pmd with another
+ * @gmap: pointer to the guest address space structure
+ * @pmdp: pointer to the pmd entry
+ * @new: replacement entry
+ * @gaddr: the affected guest address
+ *
+ * This function is assumed to be called with the guest_table_lock
+ * held.
+ */
+static void gmap_pmdp_xchg(struct gmap *gmap, pmd_t *pmdp, pmd_t new,
+			   unsigned long gaddr)
+{
+	gaddr &= HPAGE_MASK;
+	pmdp_notify_gmap(gmap, pmdp, gaddr);
+	new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_GMAP_IN));
+	if (MACHINE_HAS_TLB_GUEST)
+		__pmdp_idte(gaddr, (pmd_t *)pmdp, IDTE_GUEST_ASCE, gmap->asce,
+			    IDTE_GLOBAL);
+	else if (MACHINE_HAS_IDTE)
+		__pmdp_idte(gaddr, (pmd_t *)pmdp, 0, 0, IDTE_GLOBAL);
+	else
+		__pmdp_csp(pmdp);
+	set_pmd(pmdp, new);
+}
+
+static void gmap_pmdp_clear(struct mm_struct *mm, unsigned long vmaddr,
+			    int purge)
+{
+	pmd_t *pmdp;
+	struct gmap *gmap;
+	unsigned long gaddr;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
+		spin_lock(&gmap->guest_table_lock);
+		pmdp = (pmd_t *)radix_tree_delete(&gmap->host_to_guest,
+						  vmaddr >> PMD_SHIFT);
+		if (pmdp) {
+			gaddr = __gmap_segment_gaddr((unsigned long *)pmdp);
+			pmdp_notify_gmap(gmap, pmdp, gaddr);
+			WARN_ON(pmd_val(*pmdp) & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
+						   _SEGMENT_ENTRY_GMAP_UC));
+			if (purge)
+				__pmdp_csp(pmdp);
+			set_pmd(pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
+		}
+		spin_unlock(&gmap->guest_table_lock);
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * gmap_pmdp_invalidate - invalidate all affected guest pmd entries without
+ *                        flushing
+ * @mm: pointer to the process mm_struct
+ * @vmaddr: virtual address in the process address space
+ */
+void gmap_pmdp_invalidate(struct mm_struct *mm, unsigned long vmaddr)
+{
+	gmap_pmdp_clear(mm, vmaddr, 0);
+}
+EXPORT_SYMBOL_GPL(gmap_pmdp_invalidate);
+
+/**
+ * gmap_pmdp_csp - csp all affected guest pmd entries
+ * @mm: pointer to the process mm_struct
+ * @vmaddr: virtual address in the process address space
+ */
+void gmap_pmdp_csp(struct mm_struct *mm, unsigned long vmaddr)
+{
+	gmap_pmdp_clear(mm, vmaddr, 1);
+}
+EXPORT_SYMBOL_GPL(gmap_pmdp_csp);
+
+/**
+ * gmap_pmdp_idte_local - invalidate and clear a guest pmd entry
+ * @mm: pointer to the process mm_struct
+ * @vmaddr: virtual address in the process address space
+ */
+void gmap_pmdp_idte_local(struct mm_struct *mm, unsigned long vmaddr)
+{
+	unsigned long *entry, gaddr;
+	struct gmap *gmap;
+	pmd_t *pmdp;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
+		spin_lock(&gmap->guest_table_lock);
+		entry = radix_tree_delete(&gmap->host_to_guest,
+					  vmaddr >> PMD_SHIFT);
+		if (entry) {
+			pmdp = (pmd_t *)entry;
+			gaddr = __gmap_segment_gaddr(entry);
+			pmdp_notify_gmap(gmap, pmdp, gaddr);
+			WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
+					   _SEGMENT_ENTRY_GMAP_UC));
+			if (MACHINE_HAS_TLB_GUEST)
+				__pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
+					    gmap->asce, IDTE_LOCAL);
+			else if (MACHINE_HAS_IDTE)
+				__pmdp_idte(gaddr, pmdp, 0, 0, IDTE_LOCAL);
+			*entry = _SEGMENT_ENTRY_EMPTY;
+		}
+		spin_unlock(&gmap->guest_table_lock);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(gmap_pmdp_idte_local);
+
+/**
+ * gmap_pmdp_idte_global - invalidate and clear a guest pmd entry
+ * @mm: pointer to the process mm_struct
+ * @vmaddr: virtual address in the process address space
+ */
+void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr)
+{
+	unsigned long *entry, gaddr;
+	struct gmap *gmap;
+	pmd_t *pmdp;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(gmap, &mm->context.gmap_list, list) {
+		spin_lock(&gmap->guest_table_lock);
+		entry = radix_tree_delete(&gmap->host_to_guest,
+					  vmaddr >> PMD_SHIFT);
+		if (entry) {
+			pmdp = (pmd_t *)entry;
+			gaddr = __gmap_segment_gaddr(entry);
+			pmdp_notify_gmap(gmap, pmdp, gaddr);
+			WARN_ON(*entry & ~(_SEGMENT_ENTRY_HARDWARE_BITS_LARGE |
+					   _SEGMENT_ENTRY_GMAP_UC));
+			if (MACHINE_HAS_TLB_GUEST)
+				__pmdp_idte(gaddr, pmdp, IDTE_GUEST_ASCE,
+					    gmap->asce, IDTE_GLOBAL);
+			else if (MACHINE_HAS_IDTE)
+				__pmdp_idte(gaddr, pmdp, 0, 0, IDTE_GLOBAL);
+			else
+				__pmdp_csp(pmdp);
+			*entry = _SEGMENT_ENTRY_EMPTY;
+		}
+		spin_unlock(&gmap->guest_table_lock);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(gmap_pmdp_idte_global);
+
+/**
+ * gmap_test_and_clear_dirty_pmd - test and reset segment dirty status
+ * @gmap: pointer to guest address space
+ * @pmdp: pointer to the pmd to be tested
+ * @gaddr: virtual address in the guest address space
+ *
+ * This function is assumed to be called with the guest_table_lock
+ * held.
+ */
+static bool gmap_test_and_clear_dirty_pmd(struct gmap *gmap, pmd_t *pmdp,
+					  unsigned long gaddr)
+{
+	if (pmd_val(*pmdp) & _SEGMENT_ENTRY_INVALID)
+		return false;
+
+	/* Already protected memory, which did not change is clean */
+	if (pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT &&
+	    !(pmd_val(*pmdp) & _SEGMENT_ENTRY_GMAP_UC))
+		return false;
+
+	/* Clear UC indication and reset protection */
+	set_pmd(pmdp, clear_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_GMAP_UC)));
+	gmap_protect_pmd(gmap, gaddr, pmdp, PROT_READ, 0);
+	return true;
+}
+
+/**
+ * gmap_sync_dirty_log_pmd - set bitmap based on dirty status of segment
+ * @gmap: pointer to guest address space
+ * @bitmap: dirty bitmap for this pmd
+ * @gaddr: virtual address in the guest address space
+ * @vmaddr: virtual address in the host address space
+ *
+ * This function is assumed to be called with the guest_table_lock
+ * held.
+ */
+void gmap_sync_dirty_log_pmd(struct gmap *gmap, unsigned long bitmap[4],
+			     unsigned long gaddr, unsigned long vmaddr)
+{
+	int i;
+	pmd_t *pmdp;
+	pte_t *ptep;
+	spinlock_t *ptl;
+
+	pmdp = gmap_pmd_op_walk(gmap, gaddr);
+	if (!pmdp)
+		return;
+
+	if (pmd_large(*pmdp)) {
+		if (gmap_test_and_clear_dirty_pmd(gmap, pmdp, gaddr))
+			bitmap_fill(bitmap, _PAGE_ENTRIES);
+	} else {
+		for (i = 0; i < _PAGE_ENTRIES; i++, vmaddr += PAGE_SIZE) {
+			ptep = pte_alloc_map_lock(gmap->mm, pmdp, vmaddr, &ptl);
+			if (!ptep)
+				continue;
+			if (ptep_test_and_clear_uc(gmap->mm, vmaddr, ptep))
+				set_bit(i, bitmap);
+			pte_unmap_unlock(ptep, ptl);
+		}
+	}
+	gmap_pmd_op_end(gmap, pmdp);
+}
+EXPORT_SYMBOL_GPL(gmap_sync_dirty_log_pmd);
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static int thp_split_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
+				    unsigned long end, struct mm_walk *walk)
+{
+	struct vm_area_struct *vma = walk->vma;
+
+	split_huge_pmd(vma, pmd, addr);
+	return 0;
+}
+
+static const struct mm_walk_ops thp_split_walk_ops = {
+	.pmd_entry	= thp_split_walk_pmd_entry,
+	.walk_lock	= PGWALK_WRLOCK_VERIFY,
+};
+
+static inline void thp_split_mm(struct mm_struct *mm)
+{
+	struct vm_area_struct *vma;
+	VMA_ITERATOR(vmi, mm, 0);
+
+	for_each_vma(vmi, vma) {
+		vm_flags_mod(vma, VM_NOHUGEPAGE, VM_HUGEPAGE);
+		walk_page_vma(vma, &thp_split_walk_ops, NULL);
+	}
+	mm->def_flags |= VM_NOHUGEPAGE;
+}
+#else
+static inline void thp_split_mm(struct mm_struct *mm)
+{
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+/*
+ * Remove all empty zero pages from the mapping for lazy refaulting
+ * - This must be called after mm->context.has_pgste is set, to avoid
+ *   future creation of zero pages
+ * - This must be called after THP was disabled.
+ *
+ * mm contracts with s390, that even if mm were to remove a page table,
+ * racing with the loop below and so causing pte_offset_map_lock() to fail,
+ * it will never insert a page table containing empty zero pages once
+ * mm_forbids_zeropage(mm) i.e. mm->context.has_pgste is set.
+ */
+static int __zap_zero_pages(pmd_t *pmd, unsigned long start,
+			   unsigned long end, struct mm_walk *walk)
+{
+	unsigned long addr;
+
+	for (addr = start; addr != end; addr += PAGE_SIZE) {
+		pte_t *ptep;
+		spinlock_t *ptl;
+
+		ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+		if (!ptep)
+			break;
+		if (is_zero_pfn(pte_pfn(*ptep)))
+			ptep_xchg_direct(walk->mm, addr, ptep, __pte(_PAGE_INVALID));
+		pte_unmap_unlock(ptep, ptl);
+	}
+	return 0;
+}
+
+static const struct mm_walk_ops zap_zero_walk_ops = {
+	.pmd_entry	= __zap_zero_pages,
+	.walk_lock	= PGWALK_WRLOCK,
+};
+
+/*
+ * switch on pgstes for its userspace process (for kvm)
+ */
+int s390_enable_sie(void)
+{
+	struct mm_struct *mm = current->mm;
+
+	/* Do we have pgstes? if yes, we are done */
+	if (mm_has_pgste(mm))
+		return 0;
+	/* Fail if the page tables are 2K */
+	if (!mm_alloc_pgste(mm))
+		return -EINVAL;
+	mmap_write_lock(mm);
+	mm->context.has_pgste = 1;
+	/* split thp mappings and disable thp for future mappings */
+	thp_split_mm(mm);
+	walk_page_range(mm, 0, TASK_SIZE, &zap_zero_walk_ops, NULL);
+	mmap_write_unlock(mm);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(s390_enable_sie);
+
+int gmap_mark_unmergeable(void)
+{
+	/*
+	 * Make sure to disable KSM (if enabled for the whole process or
+	 * individual VMAs). Note that nothing currently hinders user space
+	 * from re-enabling it.
+	 */
+	return ksm_disable(current->mm);
+}
+EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
+
+/*
+ * Enable storage key handling from now on and initialize the storage
+ * keys with the default key.
+ */
+static int __s390_enable_skey_pte(pte_t *pte, unsigned long addr,
+				  unsigned long next, struct mm_walk *walk)
+{
+	/* Clear storage key */
+	ptep_zap_key(walk->mm, addr, pte);
+	return 0;
+}
+
+/*
+ * Give a chance to schedule after setting a key to 256 pages.
+ * We only hold the mm lock, which is a rwsem and the kvm srcu.
+ * Both can sleep.
+ */
+static int __s390_enable_skey_pmd(pmd_t *pmd, unsigned long addr,
+				  unsigned long next, struct mm_walk *walk)
+{
+	cond_resched();
+	return 0;
+}
+
+static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
+				      unsigned long hmask, unsigned long next,
+				      struct mm_walk *walk)
+{
+	pmd_t *pmd = (pmd_t *)pte;
+	unsigned long start, end;
+	struct page *page = pmd_page(*pmd);
+
+	/*
+	 * The write check makes sure we do not set a key on shared
+	 * memory. This is needed as the walker does not differentiate
+	 * between actual guest memory and the process executable or
+	 * shared libraries.
+	 */
+	if (pmd_val(*pmd) & _SEGMENT_ENTRY_INVALID ||
+	    !(pmd_val(*pmd) & _SEGMENT_ENTRY_WRITE))
+		return 0;
+
+	start = pmd_val(*pmd) & HPAGE_MASK;
+	end = start + HPAGE_SIZE - 1;
+	__storage_key_init_range(start, end);
+	set_bit(PG_arch_1, &page->flags);
+	cond_resched();
+	return 0;
+}
+
+static const struct mm_walk_ops enable_skey_walk_ops = {
+	.hugetlb_entry		= __s390_enable_skey_hugetlb,
+	.pte_entry		= __s390_enable_skey_pte,
+	.pmd_entry		= __s390_enable_skey_pmd,
+	.walk_lock		= PGWALK_WRLOCK,
+};
+
+int s390_enable_skey(void)
+{
+	struct mm_struct *mm = current->mm;
+	int rc = 0;
+
+	mmap_write_lock(mm);
+	if (mm_uses_skeys(mm))
+		goto out_up;
+
+	mm->context.uses_skeys = 1;
+	rc = gmap_mark_unmergeable();
+	if (rc) {
+		mm->context.uses_skeys = 0;
+		goto out_up;
+	}
+	walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
+
+out_up:
+	mmap_write_unlock(mm);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(s390_enable_skey);
+
+/*
+ * Reset CMMA state, make all pages stable again.
+ */
+static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
+			     unsigned long next, struct mm_walk *walk)
+{
+	ptep_zap_unused(walk->mm, addr, pte, 1);
+	return 0;
+}
+
+static const struct mm_walk_ops reset_cmma_walk_ops = {
+	.pte_entry		= __s390_reset_cmma,
+	.walk_lock		= PGWALK_WRLOCK,
+};
+
+void s390_reset_cmma(struct mm_struct *mm)
+{
+	mmap_write_lock(mm);
+	walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL);
+	mmap_write_unlock(mm);
+}
+EXPORT_SYMBOL_GPL(s390_reset_cmma);
+
+#define GATHER_GET_PAGES 32
+
+struct reset_walk_state {
+	unsigned long next;
+	unsigned long count;
+	unsigned long pfns[GATHER_GET_PAGES];
+};
+
+static int s390_gather_pages(pte_t *ptep, unsigned long addr,
+			     unsigned long next, struct mm_walk *walk)
+{
+	struct reset_walk_state *p = walk->private;
+	pte_t pte = READ_ONCE(*ptep);
+
+	if (pte_present(pte)) {
+		/* we have a reference from the mapping, take an extra one */
+		get_page(phys_to_page(pte_val(pte)));
+		p->pfns[p->count] = phys_to_pfn(pte_val(pte));
+		p->next = next;
+		p->count++;
+	}
+	return p->count >= GATHER_GET_PAGES;
+}
+
+static const struct mm_walk_ops gather_pages_ops = {
+	.pte_entry = s390_gather_pages,
+	.walk_lock = PGWALK_RDLOCK,
+};
+
+/*
+ * Call the Destroy secure page UVC on each page in the given array of PFNs.
+ * Each page needs to have an extra reference, which will be released here.
+ */
+void s390_uv_destroy_pfns(unsigned long count, unsigned long *pfns)
+{
+	unsigned long i;
+
+	for (i = 0; i < count; i++) {
+		/* we always have an extra reference */
+		uv_destroy_owned_page(pfn_to_phys(pfns[i]));
+		/* get rid of the extra reference */
+		put_page(pfn_to_page(pfns[i]));
+		cond_resched();
+	}
+}
+EXPORT_SYMBOL_GPL(s390_uv_destroy_pfns);
+
+/**
+ * __s390_uv_destroy_range - Call the destroy secure page UVC on each page
+ * in the given range of the given address space.
+ * @mm: the mm to operate on
+ * @start: the start of the range
+ * @end: the end of the range
+ * @interruptible: if not 0, stop when a fatal signal is received
+ *
+ * Walk the given range of the given address space and call the destroy
+ * secure page UVC on each page. Optionally exit early if a fatal signal is
+ * pending.
+ *
+ * Return: 0 on success, -EINTR if the function stopped before completing
+ */
+int __s390_uv_destroy_range(struct mm_struct *mm, unsigned long start,
+			    unsigned long end, bool interruptible)
+{
+	struct reset_walk_state state = { .next = start };
+	int r = 1;
+
+	while (r > 0) {
+		state.count = 0;
+		mmap_read_lock(mm);
+		r = walk_page_range(mm, state.next, end, &gather_pages_ops, &state);
+		mmap_read_unlock(mm);
+		cond_resched();
+		s390_uv_destroy_pfns(state.count, state.pfns);
+		if (interruptible && fatal_signal_pending(current))
+			return -EINTR;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__s390_uv_destroy_range);
+
+/**
+ * s390_unlist_old_asce - Remove the topmost level of page tables from the
+ * list of page tables of the gmap.
+ * @gmap: the gmap whose table is to be removed
+ *
+ * On s390x, KVM keeps a list of all pages containing the page tables of the
+ * gmap (the CRST list). This list is used at tear down time to free all
+ * pages that are now not needed anymore.
+ *
+ * This function removes the topmost page of the tree (the one pointed to by
+ * the ASCE) from the CRST list.
+ *
+ * This means that it will not be freed when the VM is torn down, and needs
+ * to be handled separately by the caller, unless a leak is actually
+ * intended. Notice that this function will only remove the page from the
+ * list, the page will still be used as a top level page table (and ASCE).
+ */
+void s390_unlist_old_asce(struct gmap *gmap)
+{
+	struct page *old;
+
+	old = virt_to_page(gmap->table);
+	spin_lock(&gmap->guest_table_lock);
+	list_del(&old->lru);
+	/*
+	 * Sometimes the topmost page might need to be "removed" multiple
+	 * times, for example if the VM is rebooted into secure mode several
+	 * times concurrently, or if s390_replace_asce fails after calling
+	 * s390_remove_old_asce and is attempted again later. In that case
+	 * the old asce has been removed from the list, and therefore it
+	 * will not be freed when the VM terminates, but the ASCE is still
+	 * in use and still pointed to.
+	 * A subsequent call to replace_asce will follow the pointer and try
+	 * to remove the same page from the list again.
+	 * Therefore it's necessary that the page of the ASCE has valid
+	 * pointers, so list_del can work (and do nothing) without
+	 * dereferencing stale or invalid pointers.
+	 */
+	INIT_LIST_HEAD(&old->lru);
+	spin_unlock(&gmap->guest_table_lock);
+}
+EXPORT_SYMBOL_GPL(s390_unlist_old_asce);
+
+/**
+ * s390_replace_asce - Try to replace the current ASCE of a gmap with a copy
+ * @gmap: the gmap whose ASCE needs to be replaced
+ *
+ * If the ASCE is a SEGMENT type then this function will return -EINVAL,
+ * otherwise the pointers in the host_to_guest radix tree will keep pointing
+ * to the wrong pages, causing use-after-free and memory corruption.
+ * If the allocation of the new top level page table fails, the ASCE is not
+ * replaced.
+ * In any case, the old ASCE is always removed from the gmap CRST list.
+ * Therefore the caller has to make sure to save a pointer to it
+ * beforehand, unless a leak is actually intended.
+ */
+int s390_replace_asce(struct gmap *gmap)
+{
+	unsigned long asce;
+	struct page *page;
+	void *table;
+
+	s390_unlist_old_asce(gmap);
+
+	/* Replacing segment type ASCEs would cause serious issues */
+	if ((gmap->asce & _ASCE_TYPE_MASK) == _ASCE_TYPE_SEGMENT)
+		return -EINVAL;
+
+	page = gmap_alloc_crst();
+	if (!page)
+		return -ENOMEM;
+	page->index = 0;
+	table = page_to_virt(page);
+	memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));
+
+	/*
+	 * The caller has to deal with the old ASCE, but here we make sure
+	 * the new one is properly added to the CRST list, so that
+	 * it will be freed when the VM is torn down.
+	 */
+	spin_lock(&gmap->guest_table_lock);
+	list_add(&page->lru, &gmap->crst_list);
+	spin_unlock(&gmap->guest_table_lock);
+
+	/* Set new table origin while preserving existing ASCE control bits */
+	asce = (gmap->asce & ~_ASCE_ORIGIN) | __pa(table);
+	WRITE_ONCE(gmap->asce, asce);
+	WRITE_ONCE(gmap->mm->context.gmap_asce, asce);
+	WRITE_ONCE(gmap->table, table);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(s390_replace_asce);
diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
new file mode 100644
index 0000000000..297a6d897d
--- /dev/null
+++ b/arch/s390/mm/hugetlbpage.c
@@ -0,0 +1,342 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  IBM System z Huge TLB Page Support for Kernel.
+ *
+ *    Copyright IBM Corp. 2007,2020
+ *    Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "hugetlb"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <asm/pgalloc.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/mman.h>
+#include <linux/sched/mm.h>
+#include <linux/security.h>
+
+/*
+ * If the bit selected by single-bit bitmask "a" is set within "x", move
+ * it to the position indicated by single-bit bitmask "b".
+ */
+#define move_set_bit(x, a, b)	(((x) & (a)) >> ilog2(a) << ilog2(b))
+
+static inline unsigned long __pte_to_rste(pte_t pte)
+{
+	unsigned long rste;
+
+	/*
+	 * Convert encoding		  pte bits	pmd / pud bits
+	 *				lIR.uswrdy.p	dy..R...I...wr
+	 * empty			010.000000.0 -> 00..0...1...00
+	 * prot-none, clean, old	111.000000.1 -> 00..1...1...00
+	 * prot-none, clean, young	111.000001.1 -> 01..1...1...00
+	 * prot-none, dirty, old	111.000010.1 -> 10..1...1...00
+	 * prot-none, dirty, young	111.000011.1 -> 11..1...1...00
+	 * read-only, clean, old	111.000100.1 -> 00..1...1...01
+	 * read-only, clean, young	101.000101.1 -> 01..1...0...01
+	 * read-only, dirty, old	111.000110.1 -> 10..1...1...01
+	 * read-only, dirty, young	101.000111.1 -> 11..1...0...01
+	 * read-write, clean, old	111.001100.1 -> 00..1...1...11
+	 * read-write, clean, young	101.001101.1 -> 01..1...0...11
+	 * read-write, dirty, old	110.001110.1 -> 10..0...1...11
+	 * read-write, dirty, young	100.001111.1 -> 11..0...0...11
+	 * HW-bits: R read-only, I invalid
+	 * SW-bits: p present, y young, d dirty, r read, w write, s special,
+	 *	    u unused, l large
+	 */
+	if (pte_present(pte)) {
+		rste = pte_val(pte) & PAGE_MASK;
+		rste |= move_set_bit(pte_val(pte), _PAGE_READ,
+				     _SEGMENT_ENTRY_READ);
+		rste |= move_set_bit(pte_val(pte), _PAGE_WRITE,
+				     _SEGMENT_ENTRY_WRITE);
+		rste |= move_set_bit(pte_val(pte), _PAGE_INVALID,
+				     _SEGMENT_ENTRY_INVALID);
+		rste |= move_set_bit(pte_val(pte), _PAGE_PROTECT,
+				     _SEGMENT_ENTRY_PROTECT);
+		rste |= move_set_bit(pte_val(pte), _PAGE_DIRTY,
+				     _SEGMENT_ENTRY_DIRTY);
+		rste |= move_set_bit(pte_val(pte), _PAGE_YOUNG,
+				     _SEGMENT_ENTRY_YOUNG);
+#ifdef CONFIG_MEM_SOFT_DIRTY
+		rste |= move_set_bit(pte_val(pte), _PAGE_SOFT_DIRTY,
+				     _SEGMENT_ENTRY_SOFT_DIRTY);
+#endif
+		rste |= move_set_bit(pte_val(pte), _PAGE_NOEXEC,
+				     _SEGMENT_ENTRY_NOEXEC);
+	} else
+		rste = _SEGMENT_ENTRY_EMPTY;
+	return rste;
+}
+
+static inline pte_t __rste_to_pte(unsigned long rste)
+{
+	unsigned long pteval;
+	int present;
+
+	if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
+		present = pud_present(__pud(rste));
+	else
+		present = pmd_present(__pmd(rste));
+
+	/*
+	 * Convert encoding		pmd / pud bits	    pte bits
+	 *				dy..R...I...wr	  lIR.uswrdy.p
+	 * empty			00..0...1...00 -> 010.000000.0
+	 * prot-none, clean, old	00..1...1...00 -> 111.000000.1
+	 * prot-none, clean, young	01..1...1...00 -> 111.000001.1
+	 * prot-none, dirty, old	10..1...1...00 -> 111.000010.1
+	 * prot-none, dirty, young	11..1...1...00 -> 111.000011.1
+	 * read-only, clean, old	00..1...1...01 -> 111.000100.1
+	 * read-only, clean, young	01..1...0...01 -> 101.000101.1
+	 * read-only, dirty, old	10..1...1...01 -> 111.000110.1
+	 * read-only, dirty, young	11..1...0...01 -> 101.000111.1
+	 * read-write, clean, old	00..1...1...11 -> 111.001100.1
+	 * read-write, clean, young	01..1...0...11 -> 101.001101.1
+	 * read-write, dirty, old	10..0...1...11 -> 110.001110.1
+	 * read-write, dirty, young	11..0...0...11 -> 100.001111.1
+	 * HW-bits: R read-only, I invalid
+	 * SW-bits: p present, y young, d dirty, r read, w write, s special,
+	 *	    u unused, l large
+	 */
+	if (present) {
+		pteval = rste & _SEGMENT_ENTRY_ORIGIN_LARGE;
+		pteval |= _PAGE_LARGE | _PAGE_PRESENT;
+		pteval |= move_set_bit(rste, _SEGMENT_ENTRY_READ, _PAGE_READ);
+		pteval |= move_set_bit(rste, _SEGMENT_ENTRY_WRITE, _PAGE_WRITE);
+		pteval |= move_set_bit(rste, _SEGMENT_ENTRY_INVALID, _PAGE_INVALID);
+		pteval |= move_set_bit(rste, _SEGMENT_ENTRY_PROTECT, _PAGE_PROTECT);
+		pteval |= move_set_bit(rste, _SEGMENT_ENTRY_DIRTY, _PAGE_DIRTY);
+		pteval |= move_set_bit(rste, _SEGMENT_ENTRY_YOUNG, _PAGE_YOUNG);
+#ifdef CONFIG_MEM_SOFT_DIRTY
+		pteval |= move_set_bit(rste, _SEGMENT_ENTRY_SOFT_DIRTY, _PAGE_SOFT_DIRTY);
+#endif
+		pteval |= move_set_bit(rste, _SEGMENT_ENTRY_NOEXEC, _PAGE_NOEXEC);
+	} else
+		pteval = _PAGE_INVALID;
+	return __pte(pteval);
+}
+
+static void clear_huge_pte_skeys(struct mm_struct *mm, unsigned long rste)
+{
+	struct page *page;
+	unsigned long size, paddr;
+
+	if (!mm_uses_skeys(mm) ||
+	    rste & _SEGMENT_ENTRY_INVALID)
+		return;
+
+	if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
+		page = pud_page(__pud(rste));
+		size = PUD_SIZE;
+		paddr = rste & PUD_MASK;
+	} else {
+		page = pmd_page(__pmd(rste));
+		size = PMD_SIZE;
+		paddr = rste & PMD_MASK;
+	}
+
+	if (!test_and_set_bit(PG_arch_1, &page->flags))
+		__storage_key_init_range(paddr, paddr + size - 1);
+}
+
+void __set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+		     pte_t *ptep, pte_t pte)
+{
+	unsigned long rste;
+
+	rste = __pte_to_rste(pte);
+	if (!MACHINE_HAS_NX)
+		rste &= ~_SEGMENT_ENTRY_NOEXEC;
+
+	/* Set correct table type for 2G hugepages */
+	if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
+		if (likely(pte_present(pte)))
+			rste |= _REGION3_ENTRY_LARGE;
+		rste |= _REGION_ENTRY_TYPE_R3;
+	} else if (likely(pte_present(pte)))
+		rste |= _SEGMENT_ENTRY_LARGE;
+
+	clear_huge_pte_skeys(mm, rste);
+	set_pte(ptep, __pte(rste));
+}
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+		     pte_t *ptep, pte_t pte, unsigned long sz)
+{
+	__set_huge_pte_at(mm, addr, ptep, pte);
+}
+
+pte_t huge_ptep_get(pte_t *ptep)
+{
+	return __rste_to_pte(pte_val(*ptep));
+}
+
+pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
+			      unsigned long addr, pte_t *ptep)
+{
+	pte_t pte = huge_ptep_get(ptep);
+	pmd_t *pmdp = (pmd_t *) ptep;
+	pud_t *pudp = (pud_t *) ptep;
+
+	if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
+		pudp_xchg_direct(mm, addr, pudp, __pud(_REGION3_ENTRY_EMPTY));
+	else
+		pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
+	return pte;
+}
+
+pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
+			unsigned long addr, unsigned long sz)
+{
+	pgd_t *pgdp;
+	p4d_t *p4dp;
+	pud_t *pudp;
+	pmd_t *pmdp = NULL;
+
+	pgdp = pgd_offset(mm, addr);
+	p4dp = p4d_alloc(mm, pgdp, addr);
+	if (p4dp) {
+		pudp = pud_alloc(mm, p4dp, addr);
+		if (pudp) {
+			if (sz == PUD_SIZE)
+				return (pte_t *) pudp;
+			else if (sz == PMD_SIZE)
+				pmdp = pmd_alloc(mm, pudp, addr);
+		}
+	}
+	return (pte_t *) pmdp;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm,
+		       unsigned long addr, unsigned long sz)
+{
+	pgd_t *pgdp;
+	p4d_t *p4dp;
+	pud_t *pudp;
+	pmd_t *pmdp = NULL;
+
+	pgdp = pgd_offset(mm, addr);
+	if (pgd_present(*pgdp)) {
+		p4dp = p4d_offset(pgdp, addr);
+		if (p4d_present(*p4dp)) {
+			pudp = pud_offset(p4dp, addr);
+			if (pud_present(*pudp)) {
+				if (pud_large(*pudp))
+					return (pte_t *) pudp;
+				pmdp = pmd_offset(pudp, addr);
+			}
+		}
+	}
+	return (pte_t *) pmdp;
+}
+
+int pmd_huge(pmd_t pmd)
+{
+	return pmd_large(pmd);
+}
+
+int pud_huge(pud_t pud)
+{
+	return pud_large(pud);
+}
+
+bool __init arch_hugetlb_valid_size(unsigned long size)
+{
+	if (MACHINE_HAS_EDAT1 && size == PMD_SIZE)
+		return true;
+	else if (MACHINE_HAS_EDAT2 && size == PUD_SIZE)
+		return true;
+	else
+		return false;
+}
+
+static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
+		unsigned long addr, unsigned long len,
+		unsigned long pgoff, unsigned long flags)
+{
+	struct hstate *h = hstate_file(file);
+	struct vm_unmapped_area_info info;
+
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = current->mm->mmap_base;
+	info.high_limit = TASK_SIZE;
+	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
+	info.align_offset = 0;
+	return vm_unmapped_area(&info);
+}
+
+static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
+		unsigned long addr0, unsigned long len,
+		unsigned long pgoff, unsigned long flags)
+{
+	struct hstate *h = hstate_file(file);
+	struct vm_unmapped_area_info info;
+	unsigned long addr;
+
+	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+	info.length = len;
+	info.low_limit = PAGE_SIZE;
+	info.high_limit = current->mm->mmap_base;
+	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
+	info.align_offset = 0;
+	addr = vm_unmapped_area(&info);
+
+	/*
+	 * A failed mmap() very likely causes application failure,
+	 * so fall back to the bottom-up function here. This scenario
+	 * can happen with large stack limits and large mmap()
+	 * allocations.
+	 */
+	if (addr & ~PAGE_MASK) {
+		VM_BUG_ON(addr != -ENOMEM);
+		info.flags = 0;
+		info.low_limit = TASK_UNMAPPED_BASE;
+		info.high_limit = TASK_SIZE;
+		addr = vm_unmapped_area(&info);
+	}
+
+	return addr;
+}
+
+unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
+		unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+	struct hstate *h = hstate_file(file);
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+
+	if (len & ~huge_page_mask(h))
+		return -EINVAL;
+	if (len > TASK_SIZE - mmap_min_addr)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED) {
+		if (prepare_hugepage_range(file, addr, len))
+			return -EINVAL;
+		goto check_asce_limit;
+	}
+
+	if (addr) {
+		addr = ALIGN(addr, huge_page_size(h));
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+		    (!vma || addr + len <= vm_start_gap(vma)))
+			goto check_asce_limit;
+	}
+
+	if (mm->get_unmapped_area == arch_get_unmapped_area)
+		addr = hugetlb_get_unmapped_area_bottomup(file, addr, len,
+				pgoff, flags);
+	else
+		addr = hugetlb_get_unmapped_area_topdown(file, addr, len,
+				pgoff, flags);
+	if (offset_in_page(addr))
+		return addr;
+
+check_asce_limit:
+	return check_asce_limit(mm, addr, len);
+}
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
new file mode 100644
index 0000000000..8b94d2212d
--- /dev/null
+++ b/arch/s390/mm/init.c
@@ -0,0 +1,313 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  S390 version
+ *    Copyright IBM Corp. 1999
+ *    Author(s): Hartmut Penner (hp@de.ibm.com)
+ *
+ *  Derived from "arch/i386/mm/init.c"
+ *    Copyright (C) 1995  Linus Torvalds
+ */
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/swiotlb.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/pagemap.h>
+#include <linux/memblock.h>
+#include <linux/memory.h>
+#include <linux/pfn.h>
+#include <linux/poison.h>
+#include <linux/initrd.h>
+#include <linux/export.h>
+#include <linux/cma.h>
+#include <linux/gfp.h>
+#include <linux/dma-direct.h>
+#include <linux/percpu.h>
+#include <asm/processor.h>
+#include <linux/uaccess.h>
+#include <asm/pgalloc.h>
+#include <asm/kfence.h>
+#include <asm/ptdump.h>
+#include <asm/dma.h>
+#include <asm/abs_lowcore.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+#include <asm/ctl_reg.h>
+#include <asm/sclp.h>
+#include <asm/set_memory.h>
+#include <asm/kasan.h>
+#include <asm/dma-mapping.h>
+#include <asm/uv.h>
+#include <linux/virtio_anchor.h>
+#include <linux/virtio_config.h>
+
+pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(".bss..swapper_pg_dir");
+pgd_t invalid_pg_dir[PTRS_PER_PGD] __section(".bss..invalid_pg_dir");
+
+unsigned long __bootdata_preserved(s390_invalid_asce);
+
+unsigned long empty_zero_page, zero_page_mask;
+EXPORT_SYMBOL(empty_zero_page);
+EXPORT_SYMBOL(zero_page_mask);
+
+static void __init setup_zero_pages(void)
+{
+	unsigned int order;
+	struct page *page;
+	int i;
+
+	/* Latest machines require a mapping granularity of 512KB */
+	order = 7;
+
+	/* Limit number of empty zero pages for small memory sizes */
+	while (order > 2 && (totalram_pages() >> 10) < (1UL << order))
+		order--;
+
+	empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
+	if (!empty_zero_page)
+		panic("Out of memory in setup_zero_pages");
+
+	page = virt_to_page((void *) empty_zero_page);
+	split_page(page, order);
+	for (i = 1 << order; i > 0; i--) {
+		mark_page_reserved(page);
+		page++;
+	}
+
+	zero_page_mask = ((PAGE_SIZE << order) - 1) & PAGE_MASK;
+}
+
+/*
+ * paging_init() sets up the page tables
+ */
+void __init paging_init(void)
+{
+	unsigned long max_zone_pfns[MAX_NR_ZONES];
+
+	vmem_map_init();
+	sparse_init();
+	zone_dma_bits = 31;
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+	max_zone_pfns[ZONE_DMA] = virt_to_pfn(MAX_DMA_ADDRESS);
+	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
+	free_area_init(max_zone_pfns);
+}
+
+void mark_rodata_ro(void)
+{
+	unsigned long size = __end_ro_after_init - __start_ro_after_init;
+
+	__set_memory_ro(__start_ro_after_init, __end_ro_after_init);
+	pr_info("Write protected read-only-after-init data: %luk\n", size >> 10);
+	debug_checkwx();
+}
+
+int set_memory_encrypted(unsigned long vaddr, int numpages)
+{
+	int i;
+
+	/* make specified pages unshared, (swiotlb, dma_free) */
+	for (i = 0; i < numpages; ++i) {
+		uv_remove_shared(virt_to_phys((void *)vaddr));
+		vaddr += PAGE_SIZE;
+	}
+	return 0;
+}
+
+int set_memory_decrypted(unsigned long vaddr, int numpages)
+{
+	int i;
+	/* make specified pages shared (swiotlb, dma_alloca) */
+	for (i = 0; i < numpages; ++i) {
+		uv_set_shared(virt_to_phys((void *)vaddr));
+		vaddr += PAGE_SIZE;
+	}
+	return 0;
+}
+
+/* are we a protected virtualization guest? */
+bool force_dma_unencrypted(struct device *dev)
+{
+	return is_prot_virt_guest();
+}
+
+/* protected virtualization */
+static void pv_init(void)
+{
+	if (!is_prot_virt_guest())
+		return;
+
+	virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
+
+	/* make sure bounce buffers are shared */
+	swiotlb_init(true, SWIOTLB_FORCE | SWIOTLB_VERBOSE);
+	swiotlb_update_mem_attributes();
+}
+
+void __init mem_init(void)
+{
+	cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
+	cpumask_set_cpu(0, mm_cpumask(&init_mm));
+
+	set_max_mapnr(max_low_pfn);
+        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
+
+	pv_init();
+	kfence_split_mapping();
+	/* Setup guest page hinting */
+	cmma_init();
+
+	/* this will put all low memory onto the freelists */
+	memblock_free_all();
+	setup_zero_pages();	/* Setup zeroed pages. */
+
+	cmma_init_nodat();
+}
+
+void free_initmem(void)
+{
+	set_memory_rwnx((unsigned long)_sinittext,
+			(unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT);
+	free_initmem_default(POISON_FREE_INITMEM);
+}
+
+unsigned long memory_block_size_bytes(void)
+{
+	/*
+	 * Make sure the memory block size is always greater
+	 * or equal than the memory increment size.
+	 */
+	return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm);
+}
+
+unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
+EXPORT_SYMBOL(__per_cpu_offset);
+
+static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
+{
+	return LOCAL_DISTANCE;
+}
+
+static int __init pcpu_cpu_to_node(int cpu)
+{
+	return 0;
+}
+
+void __init setup_per_cpu_areas(void)
+{
+	unsigned long delta;
+	unsigned int cpu;
+	int rc;
+
+	/*
+	 * Always reserve area for module percpu variables.  That's
+	 * what the legacy allocator did.
+	 */
+	rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
+				    PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
+				    pcpu_cpu_distance,
+				    pcpu_cpu_to_node);
+	if (rc < 0)
+		panic("Failed to initialize percpu areas.");
+
+	delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
+	for_each_possible_cpu(cpu)
+		__per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+
+#ifdef CONFIG_CMA
+
+/* Prevent memory blocks which contain cma regions from going offline */
+
+struct s390_cma_mem_data {
+	unsigned long start;
+	unsigned long end;
+};
+
+static int s390_cma_check_range(struct cma *cma, void *data)
+{
+	struct s390_cma_mem_data *mem_data;
+	unsigned long start, end;
+
+	mem_data = data;
+	start = cma_get_base(cma);
+	end = start + cma_get_size(cma);
+	if (end < mem_data->start)
+		return 0;
+	if (start >= mem_data->end)
+		return 0;
+	return -EBUSY;
+}
+
+static int s390_cma_mem_notifier(struct notifier_block *nb,
+				 unsigned long action, void *data)
+{
+	struct s390_cma_mem_data mem_data;
+	struct memory_notify *arg;
+	int rc = 0;
+
+	arg = data;
+	mem_data.start = arg->start_pfn << PAGE_SHIFT;
+	mem_data.end = mem_data.start + (arg->nr_pages << PAGE_SHIFT);
+	if (action == MEM_GOING_OFFLINE)
+		rc = cma_for_each_area(s390_cma_check_range, &mem_data);
+	return notifier_from_errno(rc);
+}
+
+static struct notifier_block s390_cma_mem_nb = {
+	.notifier_call = s390_cma_mem_notifier,
+};
+
+static int __init s390_cma_mem_init(void)
+{
+	return register_memory_notifier(&s390_cma_mem_nb);
+}
+device_initcall(s390_cma_mem_init);
+
+#endif /* CONFIG_CMA */
+
+int arch_add_memory(int nid, u64 start, u64 size,
+		    struct mhp_params *params)
+{
+	unsigned long start_pfn = PFN_DOWN(start);
+	unsigned long size_pages = PFN_DOWN(size);
+	int rc;
+
+	if (WARN_ON_ONCE(params->altmap))
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
+		return -EINVAL;
+
+	VM_BUG_ON(!mhp_range_allowed(start, size, true));
+	rc = vmem_add_mapping(start, size);
+	if (rc)
+		return rc;
+
+	rc = __add_pages(nid, start_pfn, size_pages, params);
+	if (rc)
+		vmem_remove_mapping(start, size);
+	return rc;
+}
+
+void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
+{
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+
+	__remove_pages(start_pfn, nr_pages, altmap);
+	vmem_remove_mapping(start, size);
+}
+#endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
new file mode 100644
index 0000000000..c805b3e259
--- /dev/null
+++ b/arch/s390/mm/maccess.c
@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Access kernel memory without faulting -- s390 specific implementation.
+ *
+ * Copyright IBM Corp. 2009, 2015
+ *
+ */
+
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/gfp.h>
+#include <linux/cpu.h>
+#include <linux/uio.h>
+#include <linux/io.h>
+#include <asm/asm-extable.h>
+#include <asm/ctl_reg.h>
+#include <asm/abs_lowcore.h>
+#include <asm/stacktrace.h>
+#include <asm/maccess.h>
+
+unsigned long __bootdata_preserved(__memcpy_real_area);
+pte_t *__bootdata_preserved(memcpy_real_ptep);
+static DEFINE_MUTEX(memcpy_real_mutex);
+
+static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t size)
+{
+	unsigned long aligned, offset, count;
+	char tmp[8];
+
+	aligned = (unsigned long) dst & ~7UL;
+	offset = (unsigned long) dst & 7UL;
+	size = min(8UL - offset, size);
+	count = size - 1;
+	asm volatile(
+		"	bras	1,0f\n"
+		"	mvc	0(1,%4),0(%5)\n"
+		"0:	mvc	0(8,%3),0(%0)\n"
+		"	ex	%1,0(1)\n"
+		"	lg	%1,0(%3)\n"
+		"	lra	%0,0(%0)\n"
+		"	sturg	%1,%0\n"
+		: "+&a" (aligned), "+&a" (count), "=m" (tmp)
+		: "a" (&tmp), "a" (&tmp[offset]), "a" (src)
+		: "cc", "memory", "1");
+	return size;
+}
+
+/*
+ * s390_kernel_write - write to kernel memory bypassing DAT
+ * @dst: destination address
+ * @src: source address
+ * @size: number of bytes to copy
+ *
+ * This function writes to kernel memory bypassing DAT and possible page table
+ * write protection. It writes to the destination using the sturg instruction.
+ * Therefore we have a read-modify-write sequence: the function reads eight
+ * bytes from destination at an eight byte boundary, modifies the bytes
+ * requested and writes the result back in a loop.
+ */
+static DEFINE_SPINLOCK(s390_kernel_write_lock);
+
+notrace void *s390_kernel_write(void *dst, const void *src, size_t size)
+{
+	void *tmp = dst;
+	unsigned long flags;
+	long copied;
+
+	spin_lock_irqsave(&s390_kernel_write_lock, flags);
+	while (size) {
+		copied = s390_kernel_write_odd(tmp, src, size);
+		tmp += copied;
+		src += copied;
+		size -= copied;
+	}
+	spin_unlock_irqrestore(&s390_kernel_write_lock, flags);
+
+	return dst;
+}
+
+size_t memcpy_real_iter(struct iov_iter *iter, unsigned long src, size_t count)
+{
+	size_t len, copied, res = 0;
+	unsigned long phys, offset;
+	void *chunk;
+	pte_t pte;
+
+	BUILD_BUG_ON(MEMCPY_REAL_SIZE != PAGE_SIZE);
+	while (count) {
+		phys = src & MEMCPY_REAL_MASK;
+		offset = src & ~MEMCPY_REAL_MASK;
+		chunk = (void *)(__memcpy_real_area + offset);
+		len = min(count, MEMCPY_REAL_SIZE - offset);
+		pte = mk_pte_phys(phys, PAGE_KERNEL_RO);
+
+		mutex_lock(&memcpy_real_mutex);
+		if (pte_val(pte) != pte_val(*memcpy_real_ptep)) {
+			__ptep_ipte(__memcpy_real_area, memcpy_real_ptep, 0, 0, IPTE_GLOBAL);
+			set_pte(memcpy_real_ptep, pte);
+		}
+		copied = copy_to_iter(chunk, len, iter);
+		mutex_unlock(&memcpy_real_mutex);
+
+		count -= copied;
+		src += copied;
+		res += copied;
+		if (copied < len)
+			break;
+	}
+	return res;
+}
+
+int memcpy_real(void *dest, unsigned long src, size_t count)
+{
+	struct iov_iter iter;
+	struct kvec kvec;
+
+	kvec.iov_base = dest;
+	kvec.iov_len = count;
+	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
+	if (memcpy_real_iter(&iter, src, count) < count)
+		return -EFAULT;
+	return 0;
+}
+
+/*
+ * Find CPU that owns swapped prefix page
+ */
+static int get_swapped_owner(phys_addr_t addr)
+{
+	phys_addr_t lc;
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		lc = virt_to_phys(lowcore_ptr[cpu]);
+		if (addr > lc + sizeof(struct lowcore) - 1 || addr < lc)
+			continue;
+		return cpu;
+	}
+	return -1;
+}
+
+/*
+ * Convert a physical pointer for /dev/mem access
+ *
+ * For swapped prefix pages a new buffer is returned that contains a copy of
+ * the absolute memory. The buffer size is maximum one page large.
+ */
+void *xlate_dev_mem_ptr(phys_addr_t addr)
+{
+	void *ptr = phys_to_virt(addr);
+	void *bounce = ptr;
+	struct lowcore *abs_lc;
+	unsigned long size;
+	int this_cpu, cpu;
+
+	cpus_read_lock();
+	this_cpu = get_cpu();
+	if (addr >= sizeof(struct lowcore)) {
+		cpu = get_swapped_owner(addr);
+		if (cpu < 0)
+			goto out;
+	}
+	bounce = (void *)__get_free_page(GFP_ATOMIC);
+	if (!bounce)
+		goto out;
+	size = PAGE_SIZE - (addr & ~PAGE_MASK);
+	if (addr < sizeof(struct lowcore)) {
+		abs_lc = get_abs_lowcore();
+		ptr = (void *)abs_lc + addr;
+		memcpy(bounce, ptr, size);
+		put_abs_lowcore(abs_lc);
+	} else if (cpu == this_cpu) {
+		ptr = (void *)(addr - virt_to_phys(lowcore_ptr[cpu]));
+		memcpy(bounce, ptr, size);
+	} else {
+		memcpy(bounce, ptr, size);
+	}
+out:
+	put_cpu();
+	cpus_read_unlock();
+	return bounce;
+}
+
+/*
+ * Free converted buffer for /dev/mem access (if necessary)
+ */
+void unxlate_dev_mem_ptr(phys_addr_t addr, void *ptr)
+{
+	if (addr != virt_to_phys(ptr))
+		free_page((unsigned long)ptr);
+}
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
new file mode 100644
index 0000000000..fc9a7dc26c
--- /dev/null
+++ b/arch/s390/mm/mmap.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  flexible mmap layout support
+ *
+ * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
+ * All Rights Reserved.
+ *
+ * Started by Ingo Molnar <mingo@elte.hu>
+ */
+
+#include <linux/elf-randomize.h>
+#include <linux/personality.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/mm.h>
+#include <linux/random.h>
+#include <linux/compat.h>
+#include <linux/security.h>
+#include <asm/elf.h>
+
+static unsigned long stack_maxrandom_size(void)
+{
+	if (!(current->flags & PF_RANDOMIZE))
+		return 0;
+	return STACK_RND_MASK << PAGE_SHIFT;
+}
+
+static inline int mmap_is_legacy(struct rlimit *rlim_stack)
+{
+	if (current->personality & ADDR_COMPAT_LAYOUT)
+		return 1;
+	if (rlim_stack->rlim_cur == RLIM_INFINITY)
+		return 1;
+	return sysctl_legacy_va_layout;
+}
+
+unsigned long arch_mmap_rnd(void)
+{
+	return (get_random_u32() & MMAP_RND_MASK) << PAGE_SHIFT;
+}
+
+static unsigned long mmap_base_legacy(unsigned long rnd)
+{
+	return TASK_UNMAPPED_BASE + rnd;
+}
+
+static inline unsigned long mmap_base(unsigned long rnd,
+				      struct rlimit *rlim_stack)
+{
+	unsigned long gap = rlim_stack->rlim_cur;
+	unsigned long pad = stack_maxrandom_size() + stack_guard_gap;
+	unsigned long gap_min, gap_max;
+
+	/* Values close to RLIM_INFINITY can overflow. */
+	if (gap + pad > gap)
+		gap += pad;
+
+	/*
+	 * Top of mmap area (just below the process stack).
+	 * Leave at least a ~128 MB hole.
+	 */
+	gap_min = SZ_128M;
+	gap_max = (STACK_TOP / 6) * 5;
+
+	if (gap < gap_min)
+		gap = gap_min;
+	else if (gap > gap_max)
+		gap = gap_max;
+
+	return PAGE_ALIGN(STACK_TOP - gap - rnd);
+}
+
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
+				     unsigned long len, unsigned long pgoff,
+				     unsigned long flags)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	struct vm_unmapped_area_info info;
+
+	if (len > TASK_SIZE - mmap_min_addr)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED)
+		goto check_asce_limit;
+
+	if (addr) {
+		addr = PAGE_ALIGN(addr);
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+		    (!vma || addr + len <= vm_start_gap(vma)))
+			goto check_asce_limit;
+	}
+
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = mm->mmap_base;
+	info.high_limit = TASK_SIZE;
+	if (filp || (flags & MAP_SHARED))
+		info.align_mask = MMAP_ALIGN_MASK << PAGE_SHIFT;
+	else
+		info.align_mask = 0;
+	info.align_offset = pgoff << PAGE_SHIFT;
+	addr = vm_unmapped_area(&info);
+	if (offset_in_page(addr))
+		return addr;
+
+check_asce_limit:
+	return check_asce_limit(mm, addr, len);
+}
+
+unsigned long arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
+					     unsigned long len, unsigned long pgoff,
+					     unsigned long flags)
+{
+	struct vm_area_struct *vma;
+	struct mm_struct *mm = current->mm;
+	struct vm_unmapped_area_info info;
+
+	/* requested length too big for entire address space */
+	if (len > TASK_SIZE - mmap_min_addr)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED)
+		goto check_asce_limit;
+
+	/* requesting a specific address */
+	if (addr) {
+		addr = PAGE_ALIGN(addr);
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+				(!vma || addr + len <= vm_start_gap(vma)))
+			goto check_asce_limit;
+	}
+
+	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+	info.length = len;
+	info.low_limit = PAGE_SIZE;
+	info.high_limit = mm->mmap_base;
+	if (filp || (flags & MAP_SHARED))
+		info.align_mask = MMAP_ALIGN_MASK << PAGE_SHIFT;
+	else
+		info.align_mask = 0;
+	info.align_offset = pgoff << PAGE_SHIFT;
+	addr = vm_unmapped_area(&info);
+
+	/*
+	 * A failed mmap() very likely causes application failure,
+	 * so fall back to the bottom-up function here. This scenario
+	 * can happen with large stack limits and large mmap()
+	 * allocations.
+	 */
+	if (offset_in_page(addr)) {
+		VM_BUG_ON(addr != -ENOMEM);
+		info.flags = 0;
+		info.low_limit = TASK_UNMAPPED_BASE;
+		info.high_limit = TASK_SIZE;
+		addr = vm_unmapped_area(&info);
+		if (offset_in_page(addr))
+			return addr;
+	}
+
+check_asce_limit:
+	return check_asce_limit(mm, addr, len);
+}
+
+/*
+ * This function, called very early during the creation of a new
+ * process VM image, sets up which VM layout function to use:
+ */
+void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
+{
+	unsigned long random_factor = 0UL;
+
+	if (current->flags & PF_RANDOMIZE)
+		random_factor = arch_mmap_rnd();
+
+	/*
+	 * Fall back to the standard layout if the personality
+	 * bit is set, or if the expected stack growth is unlimited:
+	 */
+	if (mmap_is_legacy(rlim_stack)) {
+		mm->mmap_base = mmap_base_legacy(random_factor);
+		mm->get_unmapped_area = arch_get_unmapped_area;
+	} else {
+		mm->mmap_base = mmap_base(random_factor, rlim_stack);
+		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
+	}
+}
+
+static const pgprot_t protection_map[16] = {
+	[VM_NONE]					= PAGE_NONE,
+	[VM_READ]					= PAGE_RO,
+	[VM_WRITE]					= PAGE_RO,
+	[VM_WRITE | VM_READ]				= PAGE_RO,
+	[VM_EXEC]					= PAGE_RX,
+	[VM_EXEC | VM_READ]				= PAGE_RX,
+	[VM_EXEC | VM_WRITE]				= PAGE_RX,
+	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_RX,
+	[VM_SHARED]					= PAGE_NONE,
+	[VM_SHARED | VM_READ]				= PAGE_RO,
+	[VM_SHARED | VM_WRITE]				= PAGE_RW,
+	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_RW,
+	[VM_SHARED | VM_EXEC]				= PAGE_RX,
+	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_RX,
+	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_RWX,
+	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_RWX
+};
+DECLARE_VM_GET_PAGE_PROT
diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c
new file mode 100644
index 0000000000..79a037f49f
--- /dev/null
+++ b/arch/s390/mm/page-states.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2008
+ *
+ * Guest page hinting for unused pages.
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/memblock.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <asm/asm-extable.h>
+#include <asm/facility.h>
+#include <asm/page-states.h>
+
+static int cmma_flag = 1;
+
+static int __init cmma(char *str)
+{
+	bool enabled;
+
+	if (!kstrtobool(str, &enabled))
+		cmma_flag = enabled;
+	return 1;
+}
+__setup("cmma=", cmma);
+
+static inline int cmma_test_essa(void)
+{
+	unsigned long tmp = 0;
+	int rc = -EOPNOTSUPP;
+
+	/* test ESSA_GET_STATE */
+	asm volatile(
+		"	.insn	rrf,0xb9ab0000,%[tmp],%[tmp],%[cmd],0\n"
+		"0:     la      %[rc],0\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: [rc] "+&d" (rc), [tmp] "+&d" (tmp)
+		: [cmd] "i" (ESSA_GET_STATE));
+	return rc;
+}
+
+void __init cmma_init(void)
+{
+	if (!cmma_flag)
+		return;
+	if (cmma_test_essa()) {
+		cmma_flag = 0;
+		return;
+	}
+	if (test_facility(147))
+		cmma_flag = 2;
+}
+
+static inline void set_page_unused(struct page *page, int order)
+{
+	int i, rc;
+
+	for (i = 0; i < (1 << order); i++)
+		asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
+			     : "=&d" (rc)
+			     : "a" (page_to_phys(page + i)),
+			       "i" (ESSA_SET_UNUSED));
+}
+
+static inline void set_page_stable_dat(struct page *page, int order)
+{
+	int i, rc;
+
+	for (i = 0; i < (1 << order); i++)
+		asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
+			     : "=&d" (rc)
+			     : "a" (page_to_phys(page + i)),
+			       "i" (ESSA_SET_STABLE));
+}
+
+static inline void set_page_stable_nodat(struct page *page, int order)
+{
+	int i, rc;
+
+	for (i = 0; i < (1 << order); i++)
+		asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
+			     : "=&d" (rc)
+			     : "a" (page_to_phys(page + i)),
+			       "i" (ESSA_SET_STABLE_NODAT));
+}
+
+static void mark_kernel_pmd(pud_t *pud, unsigned long addr, unsigned long end)
+{
+	unsigned long next;
+	struct page *page;
+	pmd_t *pmd;
+
+	pmd = pmd_offset(pud, addr);
+	do {
+		next = pmd_addr_end(addr, end);
+		if (pmd_none(*pmd) || pmd_large(*pmd))
+			continue;
+		page = phys_to_page(pmd_val(*pmd));
+		set_bit(PG_arch_1, &page->flags);
+	} while (pmd++, addr = next, addr != end);
+}
+
+static void mark_kernel_pud(p4d_t *p4d, unsigned long addr, unsigned long end)
+{
+	unsigned long next;
+	struct page *page;
+	pud_t *pud;
+	int i;
+
+	pud = pud_offset(p4d, addr);
+	do {
+		next = pud_addr_end(addr, end);
+		if (pud_none(*pud) || pud_large(*pud))
+			continue;
+		if (!pud_folded(*pud)) {
+			page = phys_to_page(pud_val(*pud));
+			for (i = 0; i < 4; i++)
+				set_bit(PG_arch_1, &page[i].flags);
+		}
+		mark_kernel_pmd(pud, addr, next);
+	} while (pud++, addr = next, addr != end);
+}
+
+static void mark_kernel_p4d(pgd_t *pgd, unsigned long addr, unsigned long end)
+{
+	unsigned long next;
+	struct page *page;
+	p4d_t *p4d;
+	int i;
+
+	p4d = p4d_offset(pgd, addr);
+	do {
+		next = p4d_addr_end(addr, end);
+		if (p4d_none(*p4d))
+			continue;
+		if (!p4d_folded(*p4d)) {
+			page = phys_to_page(p4d_val(*p4d));
+			for (i = 0; i < 4; i++)
+				set_bit(PG_arch_1, &page[i].flags);
+		}
+		mark_kernel_pud(p4d, addr, next);
+	} while (p4d++, addr = next, addr != end);
+}
+
+static void mark_kernel_pgd(void)
+{
+	unsigned long addr, next;
+	struct page *page;
+	pgd_t *pgd;
+	int i;
+
+	addr = 0;
+	pgd = pgd_offset_k(addr);
+	do {
+		next = pgd_addr_end(addr, MODULES_END);
+		if (pgd_none(*pgd))
+			continue;
+		if (!pgd_folded(*pgd)) {
+			page = phys_to_page(pgd_val(*pgd));
+			for (i = 0; i < 4; i++)
+				set_bit(PG_arch_1, &page[i].flags);
+		}
+		mark_kernel_p4d(pgd, addr, next);
+	} while (pgd++, addr = next, addr != MODULES_END);
+}
+
+void __init cmma_init_nodat(void)
+{
+	struct page *page;
+	unsigned long start, end, ix;
+	int i;
+
+	if (cmma_flag < 2)
+		return;
+	/* Mark pages used in kernel page tables */
+	mark_kernel_pgd();
+	page = virt_to_page(&swapper_pg_dir);
+	for (i = 0; i < 4; i++)
+		set_bit(PG_arch_1, &page[i].flags);
+	page = virt_to_page(&invalid_pg_dir);
+	for (i = 0; i < 4; i++)
+		set_bit(PG_arch_1, &page[i].flags);
+
+	/* Set all kernel pages not used for page tables to stable/no-dat */
+	for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, NULL) {
+		page = pfn_to_page(start);
+		for (ix = start; ix < end; ix++, page++) {
+			if (__test_and_clear_bit(PG_arch_1, &page->flags))
+				continue;	/* skip page table pages */
+			if (!list_empty(&page->lru))
+				continue;	/* skip free pages */
+			set_page_stable_nodat(page, 0);
+		}
+	}
+}
+
+void arch_free_page(struct page *page, int order)
+{
+	if (!cmma_flag)
+		return;
+	set_page_unused(page, order);
+}
+
+void arch_alloc_page(struct page *page, int order)
+{
+	if (!cmma_flag)
+		return;
+	if (cmma_flag < 2)
+		set_page_stable_dat(page, order);
+	else
+		set_page_stable_nodat(page, order);
+}
+
+void arch_set_page_dat(struct page *page, int order)
+{
+	if (!cmma_flag)
+		return;
+	set_page_stable_dat(page, order);
+}
diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c
new file mode 100644
index 0000000000..b87e96c64b
--- /dev/null
+++ b/arch/s390/mm/pageattr.c
@@ -0,0 +1,452 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2011
+ * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
+ */
+#include <linux/hugetlb.h>
+#include <linux/proc_fs.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <asm/cacheflush.h>
+#include <asm/facility.h>
+#include <asm/pgalloc.h>
+#include <asm/kfence.h>
+#include <asm/page.h>
+#include <asm/set_memory.h>
+
+static inline unsigned long sske_frame(unsigned long addr, unsigned char skey)
+{
+	asm volatile(".insn rrf,0xb22b0000,%[skey],%[addr],1,0"
+		     : [addr] "+a" (addr) : [skey] "d" (skey));
+	return addr;
+}
+
+void __storage_key_init_range(unsigned long start, unsigned long end)
+{
+	unsigned long boundary, size;
+
+	while (start < end) {
+		if (MACHINE_HAS_EDAT1) {
+			/* set storage keys for a 1MB frame */
+			size = 1UL << 20;
+			boundary = (start + size) & ~(size - 1);
+			if (boundary <= end) {
+				do {
+					start = sske_frame(start, PAGE_DEFAULT_KEY);
+				} while (start < boundary);
+				continue;
+			}
+		}
+		page_set_storage_key(start, PAGE_DEFAULT_KEY, 1);
+		start += PAGE_SIZE;
+	}
+}
+
+#ifdef CONFIG_PROC_FS
+atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]);
+
+void arch_report_meminfo(struct seq_file *m)
+{
+	seq_printf(m, "DirectMap4k:    %8lu kB\n",
+		   atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_4K]) << 2);
+	seq_printf(m, "DirectMap1M:    %8lu kB\n",
+		   atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_1M]) << 10);
+	seq_printf(m, "DirectMap2G:    %8lu kB\n",
+		   atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_2G]) << 21);
+}
+#endif /* CONFIG_PROC_FS */
+
+static void pgt_set(unsigned long *old, unsigned long new, unsigned long addr,
+		    unsigned long dtt)
+{
+	unsigned long *table, mask;
+
+	mask = 0;
+	if (MACHINE_HAS_EDAT2) {
+		switch (dtt) {
+		case CRDTE_DTT_REGION3:
+			mask = ~(PTRS_PER_PUD * sizeof(pud_t) - 1);
+			break;
+		case CRDTE_DTT_SEGMENT:
+			mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
+			break;
+		case CRDTE_DTT_PAGE:
+			mask = ~(PTRS_PER_PTE * sizeof(pte_t) - 1);
+			break;
+		}
+		table = (unsigned long *)((unsigned long)old & mask);
+		crdte(*old, new, table, dtt, addr, S390_lowcore.kernel_asce);
+	} else if (MACHINE_HAS_IDTE) {
+		cspg(old, *old, new);
+	} else {
+		csp((unsigned int *)old + 1, *old, new);
+	}
+}
+
+static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
+			  unsigned long flags)
+{
+	pte_t *ptep, new;
+
+	if (flags == SET_MEMORY_4K)
+		return 0;
+	ptep = pte_offset_kernel(pmdp, addr);
+	do {
+		new = *ptep;
+		if (pte_none(new))
+			return -EINVAL;
+		if (flags & SET_MEMORY_RO)
+			new = pte_wrprotect(new);
+		else if (flags & SET_MEMORY_RW)
+			new = pte_mkwrite_novma(pte_mkdirty(new));
+		if (flags & SET_MEMORY_NX)
+			new = set_pte_bit(new, __pgprot(_PAGE_NOEXEC));
+		else if (flags & SET_MEMORY_X)
+			new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
+		if (flags & SET_MEMORY_INV) {
+			new = set_pte_bit(new, __pgprot(_PAGE_INVALID));
+		} else if (flags & SET_MEMORY_DEF) {
+			new = __pte(pte_val(new) & PAGE_MASK);
+			new = set_pte_bit(new, PAGE_KERNEL);
+			if (!MACHINE_HAS_NX)
+				new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
+		}
+		pgt_set((unsigned long *)ptep, pte_val(new), addr, CRDTE_DTT_PAGE);
+		ptep++;
+		addr += PAGE_SIZE;
+		cond_resched();
+	} while (addr < end);
+	return 0;
+}
+
+static int split_pmd_page(pmd_t *pmdp, unsigned long addr)
+{
+	unsigned long pte_addr, prot;
+	pte_t *pt_dir, *ptep;
+	pmd_t new;
+	int i, ro, nx;
+
+	pt_dir = vmem_pte_alloc();
+	if (!pt_dir)
+		return -ENOMEM;
+	pte_addr = pmd_pfn(*pmdp) << PAGE_SHIFT;
+	ro = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT);
+	nx = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_NOEXEC);
+	prot = pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
+	if (!nx)
+		prot &= ~_PAGE_NOEXEC;
+	ptep = pt_dir;
+	for (i = 0; i < PTRS_PER_PTE; i++) {
+		set_pte(ptep, __pte(pte_addr | prot));
+		pte_addr += PAGE_SIZE;
+		ptep++;
+	}
+	new = __pmd(__pa(pt_dir) | _SEGMENT_ENTRY);
+	pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
+	update_page_count(PG_DIRECT_MAP_4K, PTRS_PER_PTE);
+	update_page_count(PG_DIRECT_MAP_1M, -1);
+	return 0;
+}
+
+static void modify_pmd_page(pmd_t *pmdp, unsigned long addr,
+			    unsigned long flags)
+{
+	pmd_t new = *pmdp;
+
+	if (flags & SET_MEMORY_RO)
+		new = pmd_wrprotect(new);
+	else if (flags & SET_MEMORY_RW)
+		new = pmd_mkwrite_novma(pmd_mkdirty(new));
+	if (flags & SET_MEMORY_NX)
+		new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
+	else if (flags & SET_MEMORY_X)
+		new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
+	if (flags & SET_MEMORY_INV) {
+		new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
+	} else if (flags & SET_MEMORY_DEF) {
+		new = __pmd(pmd_val(new) & PMD_MASK);
+		new = set_pmd_bit(new, SEGMENT_KERNEL);
+		if (!MACHINE_HAS_NX)
+			new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
+	}
+	pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
+}
+
+static int walk_pmd_level(pud_t *pudp, unsigned long addr, unsigned long end,
+			  unsigned long flags)
+{
+	unsigned long next;
+	int need_split;
+	pmd_t *pmdp;
+	int rc = 0;
+
+	pmdp = pmd_offset(pudp, addr);
+	do {
+		if (pmd_none(*pmdp))
+			return -EINVAL;
+		next = pmd_addr_end(addr, end);
+		if (pmd_large(*pmdp)) {
+			need_split  = !!(flags & SET_MEMORY_4K);
+			need_split |= !!(addr & ~PMD_MASK);
+			need_split |= !!(addr + PMD_SIZE > next);
+			if (need_split) {
+				rc = split_pmd_page(pmdp, addr);
+				if (rc)
+					return rc;
+				continue;
+			}
+			modify_pmd_page(pmdp, addr, flags);
+		} else {
+			rc = walk_pte_level(pmdp, addr, next, flags);
+			if (rc)
+				return rc;
+		}
+		pmdp++;
+		addr = next;
+		cond_resched();
+	} while (addr < end);
+	return rc;
+}
+
+static int split_pud_page(pud_t *pudp, unsigned long addr)
+{
+	unsigned long pmd_addr, prot;
+	pmd_t *pm_dir, *pmdp;
+	pud_t new;
+	int i, ro, nx;
+
+	pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
+	if (!pm_dir)
+		return -ENOMEM;
+	pmd_addr = pud_pfn(*pudp) << PAGE_SHIFT;
+	ro = !!(pud_val(*pudp) & _REGION_ENTRY_PROTECT);
+	nx = !!(pud_val(*pudp) & _REGION_ENTRY_NOEXEC);
+	prot = pgprot_val(ro ? SEGMENT_KERNEL_RO : SEGMENT_KERNEL);
+	if (!nx)
+		prot &= ~_SEGMENT_ENTRY_NOEXEC;
+	pmdp = pm_dir;
+	for (i = 0; i < PTRS_PER_PMD; i++) {
+		set_pmd(pmdp, __pmd(pmd_addr | prot));
+		pmd_addr += PMD_SIZE;
+		pmdp++;
+	}
+	new = __pud(__pa(pm_dir) | _REGION3_ENTRY);
+	pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
+	update_page_count(PG_DIRECT_MAP_1M, PTRS_PER_PMD);
+	update_page_count(PG_DIRECT_MAP_2G, -1);
+	return 0;
+}
+
+static void modify_pud_page(pud_t *pudp, unsigned long addr,
+			    unsigned long flags)
+{
+	pud_t new = *pudp;
+
+	if (flags & SET_MEMORY_RO)
+		new = pud_wrprotect(new);
+	else if (flags & SET_MEMORY_RW)
+		new = pud_mkwrite(pud_mkdirty(new));
+	if (flags & SET_MEMORY_NX)
+		new = set_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
+	else if (flags & SET_MEMORY_X)
+		new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
+	if (flags & SET_MEMORY_INV) {
+		new = set_pud_bit(new, __pgprot(_REGION_ENTRY_INVALID));
+	} else if (flags & SET_MEMORY_DEF) {
+		new = __pud(pud_val(new) & PUD_MASK);
+		new = set_pud_bit(new, REGION3_KERNEL);
+		if (!MACHINE_HAS_NX)
+			new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
+	}
+	pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
+}
+
+static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end,
+			  unsigned long flags)
+{
+	unsigned long next;
+	int need_split;
+	pud_t *pudp;
+	int rc = 0;
+
+	pudp = pud_offset(p4d, addr);
+	do {
+		if (pud_none(*pudp))
+			return -EINVAL;
+		next = pud_addr_end(addr, end);
+		if (pud_large(*pudp)) {
+			need_split  = !!(flags & SET_MEMORY_4K);
+			need_split |= !!(addr & ~PUD_MASK);
+			need_split |= !!(addr + PUD_SIZE > next);
+			if (need_split) {
+				rc = split_pud_page(pudp, addr);
+				if (rc)
+					break;
+				continue;
+			}
+			modify_pud_page(pudp, addr, flags);
+		} else {
+			rc = walk_pmd_level(pudp, addr, next, flags);
+		}
+		pudp++;
+		addr = next;
+		cond_resched();
+	} while (addr < end && !rc);
+	return rc;
+}
+
+static int walk_p4d_level(pgd_t *pgd, unsigned long addr, unsigned long end,
+			  unsigned long flags)
+{
+	unsigned long next;
+	p4d_t *p4dp;
+	int rc = 0;
+
+	p4dp = p4d_offset(pgd, addr);
+	do {
+		if (p4d_none(*p4dp))
+			return -EINVAL;
+		next = p4d_addr_end(addr, end);
+		rc = walk_pud_level(p4dp, addr, next, flags);
+		p4dp++;
+		addr = next;
+		cond_resched();
+	} while (addr < end && !rc);
+	return rc;
+}
+
+DEFINE_MUTEX(cpa_mutex);
+
+static int change_page_attr(unsigned long addr, unsigned long end,
+			    unsigned long flags)
+{
+	unsigned long next;
+	int rc = -EINVAL;
+	pgd_t *pgdp;
+
+	pgdp = pgd_offset_k(addr);
+	do {
+		if (pgd_none(*pgdp))
+			break;
+		next = pgd_addr_end(addr, end);
+		rc = walk_p4d_level(pgdp, addr, next, flags);
+		if (rc)
+			break;
+		cond_resched();
+	} while (pgdp++, addr = next, addr < end && !rc);
+	return rc;
+}
+
+static int change_page_attr_alias(unsigned long addr, unsigned long end,
+				  unsigned long flags)
+{
+	unsigned long alias, offset, va_start, va_end;
+	struct vm_struct *area;
+	int rc = 0;
+
+	/*
+	 * Changes to read-only permissions on kernel VA mappings are also
+	 * applied to the kernel direct mapping. Execute permissions are
+	 * intentionally not transferred to keep all allocated pages within
+	 * the direct mapping non-executable.
+	 */
+	flags &= SET_MEMORY_RO | SET_MEMORY_RW;
+	if (!flags)
+		return 0;
+	area = NULL;
+	while (addr < end) {
+		if (!area)
+			area = find_vm_area((void *)addr);
+		if (!area || !(area->flags & VM_ALLOC))
+			return 0;
+		va_start = (unsigned long)area->addr;
+		va_end = va_start + area->nr_pages * PAGE_SIZE;
+		offset = (addr - va_start) >> PAGE_SHIFT;
+		alias = (unsigned long)page_address(area->pages[offset]);
+		rc = change_page_attr(alias, alias + PAGE_SIZE, flags);
+		if (rc)
+			break;
+		addr += PAGE_SIZE;
+		if (addr >= va_end)
+			area = NULL;
+	}
+	return rc;
+}
+
+int __set_memory(unsigned long addr, unsigned long numpages, unsigned long flags)
+{
+	unsigned long end;
+	int rc;
+
+	if (!MACHINE_HAS_NX)
+		flags &= ~(SET_MEMORY_NX | SET_MEMORY_X);
+	if (!flags)
+		return 0;
+	if (!numpages)
+		return 0;
+	addr &= PAGE_MASK;
+	end = addr + numpages * PAGE_SIZE;
+	mutex_lock(&cpa_mutex);
+	rc = change_page_attr(addr, end, flags);
+	if (rc)
+		goto out;
+	rc = change_page_attr_alias(addr, end, flags);
+out:
+	mutex_unlock(&cpa_mutex);
+	return rc;
+}
+
+int set_direct_map_invalid_noflush(struct page *page)
+{
+	return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_INV);
+}
+
+int set_direct_map_default_noflush(struct page *page)
+{
+	return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_DEF);
+}
+
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
+
+static void ipte_range(pte_t *pte, unsigned long address, int nr)
+{
+	int i;
+
+	if (test_facility(13)) {
+		__ptep_ipte_range(address, nr - 1, pte, IPTE_GLOBAL);
+		return;
+	}
+	for (i = 0; i < nr; i++) {
+		__ptep_ipte(address, pte, 0, 0, IPTE_GLOBAL);
+		address += PAGE_SIZE;
+		pte++;
+	}
+}
+
+void __kernel_map_pages(struct page *page, int numpages, int enable)
+{
+	unsigned long address;
+	pte_t *ptep, pte;
+	int nr, i, j;
+
+	for (i = 0; i < numpages;) {
+		address = (unsigned long)page_to_virt(page + i);
+		ptep = virt_to_kpte(address);
+		nr = (unsigned long)ptep >> ilog2(sizeof(long));
+		nr = PTRS_PER_PTE - (nr & (PTRS_PER_PTE - 1));
+		nr = min(numpages - i, nr);
+		if (enable) {
+			for (j = 0; j < nr; j++) {
+				pte = clear_pte_bit(*ptep, __pgprot(_PAGE_INVALID));
+				set_pte(ptep, pte);
+				address += PAGE_SIZE;
+				ptep++;
+			}
+		} else {
+			ipte_range(ptep, address, nr);
+		}
+		i += nr;
+	}
+}
+
+#endif /* CONFIG_DEBUG_PAGEALLOC */
diff --git a/arch/s390/mm/pfault.c b/arch/s390/mm/pfault.c
new file mode 100644
index 0000000000..1aac13bb8f
--- /dev/null
+++ b/arch/s390/mm/pfault.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 1999, 2023
+ */
+
+#include <linux/cpuhotplug.h>
+#include <linux/sched/task.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <asm/asm-extable.h>
+#include <asm/pfault.h>
+#include <asm/diag.h>
+
+#define __SUBCODE_MASK 0x0600
+#define __PF_RES_FIELD 0x8000000000000000UL
+
+/*
+ * 'pfault' pseudo page faults routines.
+ */
+static int pfault_disable;
+
+static int __init nopfault(char *str)
+{
+	pfault_disable = 1;
+	return 1;
+}
+early_param("nopfault", nopfault);
+
+struct pfault_refbk {
+	u16 refdiagc;
+	u16 reffcode;
+	u16 refdwlen;
+	u16 refversn;
+	u64 refgaddr;
+	u64 refselmk;
+	u64 refcmpmk;
+	u64 reserved;
+};
+
+static struct pfault_refbk pfault_init_refbk = {
+	.refdiagc = 0x258,
+	.reffcode = 0,
+	.refdwlen = 5,
+	.refversn = 2,
+	.refgaddr = __LC_LPP,
+	.refselmk = 1UL << 48,
+	.refcmpmk = 1UL << 48,
+	.reserved = __PF_RES_FIELD
+};
+
+int __pfault_init(void)
+{
+	int rc = -EOPNOTSUPP;
+
+	if (pfault_disable)
+		return rc;
+	diag_stat_inc(DIAG_STAT_X258);
+	asm volatile(
+		"	diag	%[refbk],%[rc],0x258\n"
+		"0:	nopr	%%r7\n"
+		EX_TABLE(0b, 0b)
+		: [rc] "+d" (rc)
+		: [refbk] "a" (&pfault_init_refbk), "m" (pfault_init_refbk)
+		: "cc");
+	return rc;
+}
+
+static struct pfault_refbk pfault_fini_refbk = {
+	.refdiagc = 0x258,
+	.reffcode = 1,
+	.refdwlen = 5,
+	.refversn = 2,
+};
+
+void __pfault_fini(void)
+{
+	if (pfault_disable)
+		return;
+	diag_stat_inc(DIAG_STAT_X258);
+	asm volatile(
+		"	diag	%[refbk],0,0x258\n"
+		"0:	nopr	%%r7\n"
+		EX_TABLE(0b, 0b)
+		:
+		: [refbk] "a" (&pfault_fini_refbk), "m" (pfault_fini_refbk)
+		: "cc");
+}
+
+static DEFINE_SPINLOCK(pfault_lock);
+static LIST_HEAD(pfault_list);
+
+#define PF_COMPLETE	0x0080
+
+/*
+ * The mechanism of our pfault code: if Linux is running as guest, runs a user
+ * space process and the user space process accesses a page that the host has
+ * paged out we get a pfault interrupt.
+ *
+ * This allows us, within the guest, to schedule a different process. Without
+ * this mechanism the host would have to suspend the whole virtual cpu until
+ * the page has been paged in.
+ *
+ * So when we get such an interrupt then we set the state of the current task
+ * to uninterruptible and also set the need_resched flag. Both happens within
+ * interrupt context(!). If we later on want to return to user space we
+ * recognize the need_resched flag and then call schedule().  It's not very
+ * obvious how this works...
+ *
+ * Of course we have a lot of additional fun with the completion interrupt (->
+ * host signals that a page of a process has been paged in and the process can
+ * continue to run). This interrupt can arrive on any cpu and, since we have
+ * virtual cpus, actually appear before the interrupt that signals that a page
+ * is missing.
+ */
+static void pfault_interrupt(struct ext_code ext_code,
+			     unsigned int param32, unsigned long param64)
+{
+	struct task_struct *tsk;
+	__u16 subcode;
+	pid_t pid;
+
+	/*
+	 * Get the external interruption subcode & pfault initial/completion
+	 * signal bit. VM stores this in the 'cpu address' field associated
+	 * with the external interrupt.
+	 */
+	subcode = ext_code.subcode;
+	if ((subcode & 0xff00) != __SUBCODE_MASK)
+		return;
+	inc_irq_stat(IRQEXT_PFL);
+	/* Get the token (= pid of the affected task). */
+	pid = param64 & LPP_PID_MASK;
+	rcu_read_lock();
+	tsk = find_task_by_pid_ns(pid, &init_pid_ns);
+	if (tsk)
+		get_task_struct(tsk);
+	rcu_read_unlock();
+	if (!tsk)
+		return;
+	spin_lock(&pfault_lock);
+	if (subcode & PF_COMPLETE) {
+		/* signal bit is set -> a page has been swapped in by VM */
+		if (tsk->thread.pfault_wait == 1) {
+			/*
+			 * Initial interrupt was faster than the completion
+			 * interrupt. pfault_wait is valid. Set pfault_wait
+			 * back to zero and wake up the process. This can
+			 * safely be done because the task is still sleeping
+			 * and can't produce new pfaults.
+			 */
+			tsk->thread.pfault_wait = 0;
+			list_del(&tsk->thread.list);
+			wake_up_process(tsk);
+			put_task_struct(tsk);
+		} else {
+			/*
+			 * Completion interrupt was faster than initial
+			 * interrupt. Set pfault_wait to -1 so the initial
+			 * interrupt doesn't put the task to sleep.
+			 * If the task is not running, ignore the completion
+			 * interrupt since it must be a leftover of a PFAULT
+			 * CANCEL operation which didn't remove all pending
+			 * completion interrupts.
+			 */
+			if (task_is_running(tsk))
+				tsk->thread.pfault_wait = -1;
+		}
+	} else {
+		/* signal bit not set -> a real page is missing. */
+		if (WARN_ON_ONCE(tsk != current))
+			goto out;
+		if (tsk->thread.pfault_wait == 1) {
+			/* Already on the list with a reference: put to sleep */
+			goto block;
+		} else if (tsk->thread.pfault_wait == -1) {
+			/*
+			 * Completion interrupt was faster than the initial
+			 * interrupt (pfault_wait == -1). Set pfault_wait
+			 * back to zero and exit.
+			 */
+			tsk->thread.pfault_wait = 0;
+		} else {
+			/*
+			 * Initial interrupt arrived before completion
+			 * interrupt. Let the task sleep.
+			 * An extra task reference is needed since a different
+			 * cpu may set the task state to TASK_RUNNING again
+			 * before the scheduler is reached.
+			 */
+			get_task_struct(tsk);
+			tsk->thread.pfault_wait = 1;
+			list_add(&tsk->thread.list, &pfault_list);
+block:
+			/*
+			 * Since this must be a userspace fault, there
+			 * is no kernel task state to trample. Rely on the
+			 * return to userspace schedule() to block.
+			 */
+			__set_current_state(TASK_UNINTERRUPTIBLE);
+			set_tsk_need_resched(tsk);
+			set_preempt_need_resched();
+		}
+	}
+out:
+	spin_unlock(&pfault_lock);
+	put_task_struct(tsk);
+}
+
+static int pfault_cpu_dead(unsigned int cpu)
+{
+	struct thread_struct *thread, *next;
+	struct task_struct *tsk;
+
+	spin_lock_irq(&pfault_lock);
+	list_for_each_entry_safe(thread, next, &pfault_list, list) {
+		thread->pfault_wait = 0;
+		list_del(&thread->list);
+		tsk = container_of(thread, struct task_struct, thread);
+		wake_up_process(tsk);
+		put_task_struct(tsk);
+	}
+	spin_unlock_irq(&pfault_lock);
+	return 0;
+}
+
+static int __init pfault_irq_init(void)
+{
+	int rc;
+
+	rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt);
+	if (rc)
+		goto out_extint;
+	rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP;
+	if (rc)
+		goto out_pfault;
+	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
+	cpuhp_setup_state_nocalls(CPUHP_S390_PFAULT_DEAD, "s390/pfault:dead",
+				  NULL, pfault_cpu_dead);
+	return 0;
+
+out_pfault:
+	unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt);
+out_extint:
+	pfault_disable = 1;
+	return rc;
+}
+early_initcall(pfault_irq_init);
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
new file mode 100644
index 0000000000..6396d6b06a
--- /dev/null
+++ b/arch/s390/mm/pgalloc.c
@@ -0,0 +1,757 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Page table allocation functions
+ *
+ *    Copyright IBM Corp. 2016
+ *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/sysctl.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <asm/mmu_context.h>
+#include <asm/pgalloc.h>
+#include <asm/gmap.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+
+#ifdef CONFIG_PGSTE
+
+int page_table_allocate_pgste = 0;
+EXPORT_SYMBOL(page_table_allocate_pgste);
+
+static struct ctl_table page_table_sysctl[] = {
+	{
+		.procname	= "allocate_pgste",
+		.data		= &page_table_allocate_pgste,
+		.maxlen		= sizeof(int),
+		.mode		= S_IRUGO | S_IWUSR,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{ }
+};
+
+static int __init page_table_register_sysctl(void)
+{
+	return register_sysctl("vm", page_table_sysctl) ? 0 : -ENOMEM;
+}
+__initcall(page_table_register_sysctl);
+
+#endif /* CONFIG_PGSTE */
+
+unsigned long *crst_table_alloc(struct mm_struct *mm)
+{
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL, CRST_ALLOC_ORDER);
+
+	if (!ptdesc)
+		return NULL;
+	arch_set_page_dat(ptdesc_page(ptdesc), CRST_ALLOC_ORDER);
+	return (unsigned long *) ptdesc_to_virt(ptdesc);
+}
+
+void crst_table_free(struct mm_struct *mm, unsigned long *table)
+{
+	pagetable_free(virt_to_ptdesc(table));
+}
+
+static void __crst_table_upgrade(void *arg)
+{
+	struct mm_struct *mm = arg;
+
+	/* change all active ASCEs to avoid the creation of new TLBs */
+	if (current->active_mm == mm) {
+		S390_lowcore.user_asce = mm->context.asce;
+		__ctl_load(S390_lowcore.user_asce, 7, 7);
+	}
+	__tlb_flush_local();
+}
+
+int crst_table_upgrade(struct mm_struct *mm, unsigned long end)
+{
+	unsigned long *pgd = NULL, *p4d = NULL, *__pgd;
+	unsigned long asce_limit = mm->context.asce_limit;
+
+	/* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */
+	VM_BUG_ON(asce_limit < _REGION2_SIZE);
+
+	if (end <= asce_limit)
+		return 0;
+
+	if (asce_limit == _REGION2_SIZE) {
+		p4d = crst_table_alloc(mm);
+		if (unlikely(!p4d))
+			goto err_p4d;
+		crst_table_init(p4d, _REGION2_ENTRY_EMPTY);
+	}
+	if (end > _REGION1_SIZE) {
+		pgd = crst_table_alloc(mm);
+		if (unlikely(!pgd))
+			goto err_pgd;
+		crst_table_init(pgd, _REGION1_ENTRY_EMPTY);
+	}
+
+	spin_lock_bh(&mm->page_table_lock);
+
+	/*
+	 * This routine gets called with mmap_lock lock held and there is
+	 * no reason to optimize for the case of otherwise. However, if
+	 * that would ever change, the below check will let us know.
+	 */
+	VM_BUG_ON(asce_limit != mm->context.asce_limit);
+
+	if (p4d) {
+		__pgd = (unsigned long *) mm->pgd;
+		p4d_populate(mm, (p4d_t *) p4d, (pud_t *) __pgd);
+		mm->pgd = (pgd_t *) p4d;
+		mm->context.asce_limit = _REGION1_SIZE;
+		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+			_ASCE_USER_BITS | _ASCE_TYPE_REGION2;
+		mm_inc_nr_puds(mm);
+	}
+	if (pgd) {
+		__pgd = (unsigned long *) mm->pgd;
+		pgd_populate(mm, (pgd_t *) pgd, (p4d_t *) __pgd);
+		mm->pgd = (pgd_t *) pgd;
+		mm->context.asce_limit = TASK_SIZE_MAX;
+		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+			_ASCE_USER_BITS | _ASCE_TYPE_REGION1;
+	}
+
+	spin_unlock_bh(&mm->page_table_lock);
+
+	on_each_cpu(__crst_table_upgrade, mm, 0);
+
+	return 0;
+
+err_pgd:
+	crst_table_free(mm, p4d);
+err_p4d:
+	return -ENOMEM;
+}
+
+static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
+{
+	return atomic_fetch_xor(bits, v) ^ bits;
+}
+
+#ifdef CONFIG_PGSTE
+
+struct page *page_table_alloc_pgste(struct mm_struct *mm)
+{
+	struct ptdesc *ptdesc;
+	u64 *table;
+
+	ptdesc = pagetable_alloc(GFP_KERNEL, 0);
+	if (ptdesc) {
+		table = (u64 *)ptdesc_to_virt(ptdesc);
+		arch_set_page_dat(virt_to_page(table), 0);
+		memset64(table, _PAGE_INVALID, PTRS_PER_PTE);
+		memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
+	}
+	return ptdesc_page(ptdesc);
+}
+
+void page_table_free_pgste(struct page *page)
+{
+	pagetable_free(page_ptdesc(page));
+}
+
+#endif /* CONFIG_PGSTE */
+
+/*
+ * A 2KB-pgtable is either upper or lower half of a normal page.
+ * The second half of the page may be unused or used as another
+ * 2KB-pgtable.
+ *
+ * Whenever possible the parent page for a new 2KB-pgtable is picked
+ * from the list of partially allocated pages mm_context_t::pgtable_list.
+ * In case the list is empty a new parent page is allocated and added to
+ * the list.
+ *
+ * When a parent page gets fully allocated it contains 2KB-pgtables in both
+ * upper and lower halves and is removed from mm_context_t::pgtable_list.
+ *
+ * When 2KB-pgtable is freed from to fully allocated parent page that
+ * page turns partially allocated and added to mm_context_t::pgtable_list.
+ *
+ * If 2KB-pgtable is freed from the partially allocated parent page that
+ * page turns unused and gets removed from mm_context_t::pgtable_list.
+ * Furthermore, the unused parent page is released.
+ *
+ * As follows from the above, no unallocated or fully allocated parent
+ * pages are contained in mm_context_t::pgtable_list.
+ *
+ * The upper byte (bits 24-31) of the parent page _refcount is used
+ * for tracking contained 2KB-pgtables and has the following format:
+ *
+ *   PP  AA
+ * 01234567    upper byte (bits 24-31) of struct page::_refcount
+ *   ||  ||
+ *   ||  |+--- upper 2KB-pgtable is allocated
+ *   ||  +---- lower 2KB-pgtable is allocated
+ *   |+------- upper 2KB-pgtable is pending for removal
+ *   +-------- lower 2KB-pgtable is pending for removal
+ *
+ * (See commit 620b4e903179 ("s390: use _refcount for pgtables") on why
+ * using _refcount is possible).
+ *
+ * When 2KB-pgtable is allocated the corresponding AA bit is set to 1.
+ * The parent page is either:
+ *   - added to mm_context_t::pgtable_list in case the second half of the
+ *     parent page is still unallocated;
+ *   - removed from mm_context_t::pgtable_list in case both hales of the
+ *     parent page are allocated;
+ * These operations are protected with mm_context_t::lock.
+ *
+ * When 2KB-pgtable is deallocated the corresponding AA bit is set to 0
+ * and the corresponding PP bit is set to 1 in a single atomic operation.
+ * Thus, PP and AA bits corresponding to the same 2KB-pgtable are mutually
+ * exclusive and may never be both set to 1!
+ * The parent page is either:
+ *   - added to mm_context_t::pgtable_list in case the second half of the
+ *     parent page is still allocated;
+ *   - removed from mm_context_t::pgtable_list in case the second half of
+ *     the parent page is unallocated;
+ * These operations are protected with mm_context_t::lock.
+ *
+ * It is important to understand that mm_context_t::lock only protects
+ * mm_context_t::pgtable_list and AA bits, but not the parent page itself
+ * and PP bits.
+ *
+ * Releasing the parent page happens whenever the PP bit turns from 1 to 0,
+ * while both AA bits and the second PP bit are already unset. Then the
+ * parent page does not contain any 2KB-pgtable fragment anymore, and it has
+ * also been removed from mm_context_t::pgtable_list. It is safe to release
+ * the page therefore.
+ *
+ * PGSTE memory spaces use full 4KB-pgtables and do not need most of the
+ * logic described above. Both AA bits are set to 1 to denote a 4KB-pgtable
+ * while the PP bits are never used, nor such a page is added to or removed
+ * from mm_context_t::pgtable_list.
+ *
+ * pte_free_defer() overrides those rules: it takes the page off pgtable_list,
+ * and prevents both 2K fragments from being reused. pte_free_defer() has to
+ * guarantee that its pgtable cannot be reused before the RCU grace period
+ * has elapsed (which page_table_free_rcu() does not actually guarantee).
+ * But for simplicity, because page->rcu_head overlays page->lru, and because
+ * the RCU callback might not be called before the mm_context_t has been freed,
+ * pte_free_defer() in this implementation prevents both fragments from being
+ * reused, and delays making the call to RCU until both fragments are freed.
+ */
+unsigned long *page_table_alloc(struct mm_struct *mm)
+{
+	unsigned long *table;
+	struct ptdesc *ptdesc;
+	unsigned int mask, bit;
+
+	/* Try to get a fragment of a 4K page as a 2K page table */
+	if (!mm_alloc_pgste(mm)) {
+		table = NULL;
+		spin_lock_bh(&mm->context.lock);
+		if (!list_empty(&mm->context.pgtable_list)) {
+			ptdesc = list_first_entry(&mm->context.pgtable_list,
+						struct ptdesc, pt_list);
+			mask = atomic_read(&ptdesc->_refcount) >> 24;
+			/*
+			 * The pending removal bits must also be checked.
+			 * Failure to do so might lead to an impossible
+			 * value of (i.e 0x13 or 0x23) written to _refcount.
+			 * Such values violate the assumption that pending and
+			 * allocation bits are mutually exclusive, and the rest
+			 * of the code unrails as result. That could lead to
+			 * a whole bunch of races and corruptions.
+			 */
+			mask = (mask | (mask >> 4)) & 0x03U;
+			if (mask != 0x03U) {
+				table = (unsigned long *) ptdesc_to_virt(ptdesc);
+				bit = mask & 1;		/* =1 -> second 2K */
+				if (bit)
+					table += PTRS_PER_PTE;
+				atomic_xor_bits(&ptdesc->_refcount,
+							0x01U << (bit + 24));
+				list_del_init(&ptdesc->pt_list);
+			}
+		}
+		spin_unlock_bh(&mm->context.lock);
+		if (table)
+			return table;
+	}
+	/* Allocate a fresh page */
+	ptdesc = pagetable_alloc(GFP_KERNEL, 0);
+	if (!ptdesc)
+		return NULL;
+	if (!pagetable_pte_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
+		return NULL;
+	}
+	arch_set_page_dat(ptdesc_page(ptdesc), 0);
+	/* Initialize page table */
+	table = (unsigned long *) ptdesc_to_virt(ptdesc);
+	if (mm_alloc_pgste(mm)) {
+		/* Return 4K page table with PGSTEs */
+		INIT_LIST_HEAD(&ptdesc->pt_list);
+		atomic_xor_bits(&ptdesc->_refcount, 0x03U << 24);
+		memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE);
+		memset64((u64 *)table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
+	} else {
+		/* Return the first 2K fragment of the page */
+		atomic_xor_bits(&ptdesc->_refcount, 0x01U << 24);
+		memset64((u64 *)table, _PAGE_INVALID, 2 * PTRS_PER_PTE);
+		spin_lock_bh(&mm->context.lock);
+		list_add(&ptdesc->pt_list, &mm->context.pgtable_list);
+		spin_unlock_bh(&mm->context.lock);
+	}
+	return table;
+}
+
+static void page_table_release_check(struct page *page, void *table,
+				     unsigned int half, unsigned int mask)
+{
+	char msg[128];
+
+	if (!IS_ENABLED(CONFIG_DEBUG_VM))
+		return;
+	if (!mask && list_empty(&page->lru))
+		return;
+	snprintf(msg, sizeof(msg),
+		 "Invalid pgtable %p release half 0x%02x mask 0x%02x",
+		 table, half, mask);
+	dump_page(page, msg);
+}
+
+static void pte_free_now(struct rcu_head *head)
+{
+	struct ptdesc *ptdesc;
+
+	ptdesc = container_of(head, struct ptdesc, pt_rcu_head);
+	pagetable_pte_dtor(ptdesc);
+	pagetable_free(ptdesc);
+}
+
+void page_table_free(struct mm_struct *mm, unsigned long *table)
+{
+	unsigned int mask, bit, half;
+	struct ptdesc *ptdesc = virt_to_ptdesc(table);
+
+	if (!mm_alloc_pgste(mm)) {
+		/* Free 2K page table fragment of a 4K page */
+		bit = ((unsigned long) table & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
+		spin_lock_bh(&mm->context.lock);
+		/*
+		 * Mark the page for delayed release. The actual release
+		 * will happen outside of the critical section from this
+		 * function or from __tlb_remove_table()
+		 */
+		mask = atomic_xor_bits(&ptdesc->_refcount, 0x11U << (bit + 24));
+		mask >>= 24;
+		if ((mask & 0x03U) && !folio_test_active(ptdesc_folio(ptdesc))) {
+			/*
+			 * Other half is allocated, and neither half has had
+			 * its free deferred: add page to head of list, to make
+			 * this freed half available for immediate reuse.
+			 */
+			list_add(&ptdesc->pt_list, &mm->context.pgtable_list);
+		} else {
+			/* If page is on list, now remove it. */
+			list_del_init(&ptdesc->pt_list);
+		}
+		spin_unlock_bh(&mm->context.lock);
+		mask = atomic_xor_bits(&ptdesc->_refcount, 0x10U << (bit + 24));
+		mask >>= 24;
+		if (mask != 0x00U)
+			return;
+		half = 0x01U << bit;
+	} else {
+		half = 0x03U;
+		mask = atomic_xor_bits(&ptdesc->_refcount, 0x03U << 24);
+		mask >>= 24;
+	}
+
+	page_table_release_check(ptdesc_page(ptdesc), table, half, mask);
+	if (folio_test_clear_active(ptdesc_folio(ptdesc)))
+		call_rcu(&ptdesc->pt_rcu_head, pte_free_now);
+	else
+		pte_free_now(&ptdesc->pt_rcu_head);
+}
+
+void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
+			 unsigned long vmaddr)
+{
+	struct mm_struct *mm;
+	unsigned int bit, mask;
+	struct ptdesc *ptdesc = virt_to_ptdesc(table);
+
+	mm = tlb->mm;
+	if (mm_alloc_pgste(mm)) {
+		gmap_unlink(mm, table, vmaddr);
+		table = (unsigned long *) ((unsigned long)table | 0x03U);
+		tlb_remove_ptdesc(tlb, table);
+		return;
+	}
+	bit = ((unsigned long) table & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t));
+	spin_lock_bh(&mm->context.lock);
+	/*
+	 * Mark the page for delayed release. The actual release will happen
+	 * outside of the critical section from __tlb_remove_table() or from
+	 * page_table_free()
+	 */
+	mask = atomic_xor_bits(&ptdesc->_refcount, 0x11U << (bit + 24));
+	mask >>= 24;
+	if ((mask & 0x03U) && !folio_test_active(ptdesc_folio(ptdesc))) {
+		/*
+		 * Other half is allocated, and neither half has had
+		 * its free deferred: add page to end of list, to make
+		 * this freed half available for reuse once its pending
+		 * bit has been cleared by __tlb_remove_table().
+		 */
+		list_add_tail(&ptdesc->pt_list, &mm->context.pgtable_list);
+	} else {
+		/* If page is on list, now remove it. */
+		list_del_init(&ptdesc->pt_list);
+	}
+	spin_unlock_bh(&mm->context.lock);
+	table = (unsigned long *) ((unsigned long) table | (0x01U << bit));
+	tlb_remove_table(tlb, table);
+}
+
+void __tlb_remove_table(void *_table)
+{
+	unsigned int mask = (unsigned long) _table & 0x03U, half = mask;
+	void *table = (void *)((unsigned long) _table ^ mask);
+	struct ptdesc *ptdesc = virt_to_ptdesc(table);
+
+	switch (half) {
+	case 0x00U:	/* pmd, pud, or p4d */
+		pagetable_free(ptdesc);
+		return;
+	case 0x01U:	/* lower 2K of a 4K page table */
+	case 0x02U:	/* higher 2K of a 4K page table */
+		mask = atomic_xor_bits(&ptdesc->_refcount, mask << (4 + 24));
+		mask >>= 24;
+		if (mask != 0x00U)
+			return;
+		break;
+	case 0x03U:	/* 4K page table with pgstes */
+		mask = atomic_xor_bits(&ptdesc->_refcount, 0x03U << 24);
+		mask >>= 24;
+		break;
+	}
+
+	page_table_release_check(ptdesc_page(ptdesc), table, half, mask);
+	if (folio_test_clear_active(ptdesc_folio(ptdesc)))
+		call_rcu(&ptdesc->pt_rcu_head, pte_free_now);
+	else
+		pte_free_now(&ptdesc->pt_rcu_head);
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable)
+{
+	struct page *page;
+
+	page = virt_to_page(pgtable);
+	SetPageActive(page);
+	page_table_free(mm, (unsigned long *)pgtable);
+	/*
+	 * page_table_free() does not do the pgste gmap_unlink() which
+	 * page_table_free_rcu() does: warn us if pgste ever reaches here.
+	 */
+	WARN_ON_ONCE(mm_has_pgste(mm));
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+/*
+ * Base infrastructure required to generate basic asces, region, segment,
+ * and page tables that do not make use of enhanced features like EDAT1.
+ */
+
+static struct kmem_cache *base_pgt_cache;
+
+static unsigned long *base_pgt_alloc(void)
+{
+	unsigned long *table;
+
+	table = kmem_cache_alloc(base_pgt_cache, GFP_KERNEL);
+	if (table)
+		memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE);
+	return table;
+}
+
+static void base_pgt_free(unsigned long *table)
+{
+	kmem_cache_free(base_pgt_cache, table);
+}
+
+static unsigned long *base_crst_alloc(unsigned long val)
+{
+	unsigned long *table;
+	struct ptdesc *ptdesc;
+
+	ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, CRST_ALLOC_ORDER);
+	if (!ptdesc)
+		return NULL;
+	table = ptdesc_address(ptdesc);
+
+	crst_table_init(table, val);
+	return table;
+}
+
+static void base_crst_free(unsigned long *table)
+{
+	pagetable_free(virt_to_ptdesc(table));
+}
+
+#define BASE_ADDR_END_FUNC(NAME, SIZE)					\
+static inline unsigned long base_##NAME##_addr_end(unsigned long addr,	\
+						   unsigned long end)	\
+{									\
+	unsigned long next = (addr + (SIZE)) & ~((SIZE) - 1);		\
+									\
+	return (next - 1) < (end - 1) ? next : end;			\
+}
+
+BASE_ADDR_END_FUNC(page,    _PAGE_SIZE)
+BASE_ADDR_END_FUNC(segment, _SEGMENT_SIZE)
+BASE_ADDR_END_FUNC(region3, _REGION3_SIZE)
+BASE_ADDR_END_FUNC(region2, _REGION2_SIZE)
+BASE_ADDR_END_FUNC(region1, _REGION1_SIZE)
+
+static inline unsigned long base_lra(unsigned long address)
+{
+	unsigned long real;
+
+	asm volatile(
+		"	lra	%0,0(%1)\n"
+		: "=d" (real) : "a" (address) : "cc");
+	return real;
+}
+
+static int base_page_walk(unsigned long *origin, unsigned long addr,
+			  unsigned long end, int alloc)
+{
+	unsigned long *pte, next;
+
+	if (!alloc)
+		return 0;
+	pte = origin;
+	pte += (addr & _PAGE_INDEX) >> _PAGE_SHIFT;
+	do {
+		next = base_page_addr_end(addr, end);
+		*pte = base_lra(addr);
+	} while (pte++, addr = next, addr < end);
+	return 0;
+}
+
+static int base_segment_walk(unsigned long *origin, unsigned long addr,
+			     unsigned long end, int alloc)
+{
+	unsigned long *ste, next, *table;
+	int rc;
+
+	ste = origin;
+	ste += (addr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
+	do {
+		next = base_segment_addr_end(addr, end);
+		if (*ste & _SEGMENT_ENTRY_INVALID) {
+			if (!alloc)
+				continue;
+			table = base_pgt_alloc();
+			if (!table)
+				return -ENOMEM;
+			*ste = __pa(table) | _SEGMENT_ENTRY;
+		}
+		table = __va(*ste & _SEGMENT_ENTRY_ORIGIN);
+		rc = base_page_walk(table, addr, next, alloc);
+		if (rc)
+			return rc;
+		if (!alloc)
+			base_pgt_free(table);
+		cond_resched();
+	} while (ste++, addr = next, addr < end);
+	return 0;
+}
+
+static int base_region3_walk(unsigned long *origin, unsigned long addr,
+			     unsigned long end, int alloc)
+{
+	unsigned long *rtte, next, *table;
+	int rc;
+
+	rtte = origin;
+	rtte += (addr & _REGION3_INDEX) >> _REGION3_SHIFT;
+	do {
+		next = base_region3_addr_end(addr, end);
+		if (*rtte & _REGION_ENTRY_INVALID) {
+			if (!alloc)
+				continue;
+			table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY);
+			if (!table)
+				return -ENOMEM;
+			*rtte = __pa(table) | _REGION3_ENTRY;
+		}
+		table = __va(*rtte & _REGION_ENTRY_ORIGIN);
+		rc = base_segment_walk(table, addr, next, alloc);
+		if (rc)
+			return rc;
+		if (!alloc)
+			base_crst_free(table);
+	} while (rtte++, addr = next, addr < end);
+	return 0;
+}
+
+static int base_region2_walk(unsigned long *origin, unsigned long addr,
+			     unsigned long end, int alloc)
+{
+	unsigned long *rste, next, *table;
+	int rc;
+
+	rste = origin;
+	rste += (addr & _REGION2_INDEX) >> _REGION2_SHIFT;
+	do {
+		next = base_region2_addr_end(addr, end);
+		if (*rste & _REGION_ENTRY_INVALID) {
+			if (!alloc)
+				continue;
+			table = base_crst_alloc(_REGION3_ENTRY_EMPTY);
+			if (!table)
+				return -ENOMEM;
+			*rste = __pa(table) | _REGION2_ENTRY;
+		}
+		table = __va(*rste & _REGION_ENTRY_ORIGIN);
+		rc = base_region3_walk(table, addr, next, alloc);
+		if (rc)
+			return rc;
+		if (!alloc)
+			base_crst_free(table);
+	} while (rste++, addr = next, addr < end);
+	return 0;
+}
+
+static int base_region1_walk(unsigned long *origin, unsigned long addr,
+			     unsigned long end, int alloc)
+{
+	unsigned long *rfte, next, *table;
+	int rc;
+
+	rfte = origin;
+	rfte += (addr & _REGION1_INDEX) >> _REGION1_SHIFT;
+	do {
+		next = base_region1_addr_end(addr, end);
+		if (*rfte & _REGION_ENTRY_INVALID) {
+			if (!alloc)
+				continue;
+			table = base_crst_alloc(_REGION2_ENTRY_EMPTY);
+			if (!table)
+				return -ENOMEM;
+			*rfte = __pa(table) | _REGION1_ENTRY;
+		}
+		table = __va(*rfte & _REGION_ENTRY_ORIGIN);
+		rc = base_region2_walk(table, addr, next, alloc);
+		if (rc)
+			return rc;
+		if (!alloc)
+			base_crst_free(table);
+	} while (rfte++, addr = next, addr < end);
+	return 0;
+}
+
+/**
+ * base_asce_free - free asce and tables returned from base_asce_alloc()
+ * @asce: asce to be freed
+ *
+ * Frees all region, segment, and page tables that were allocated with a
+ * corresponding base_asce_alloc() call.
+ */
+void base_asce_free(unsigned long asce)
+{
+	unsigned long *table = __va(asce & _ASCE_ORIGIN);
+
+	if (!asce)
+		return;
+	switch (asce & _ASCE_TYPE_MASK) {
+	case _ASCE_TYPE_SEGMENT:
+		base_segment_walk(table, 0, _REGION3_SIZE, 0);
+		break;
+	case _ASCE_TYPE_REGION3:
+		base_region3_walk(table, 0, _REGION2_SIZE, 0);
+		break;
+	case _ASCE_TYPE_REGION2:
+		base_region2_walk(table, 0, _REGION1_SIZE, 0);
+		break;
+	case _ASCE_TYPE_REGION1:
+		base_region1_walk(table, 0, TASK_SIZE_MAX, 0);
+		break;
+	}
+	base_crst_free(table);
+}
+
+static int base_pgt_cache_init(void)
+{
+	static DEFINE_MUTEX(base_pgt_cache_mutex);
+	unsigned long sz = _PAGE_TABLE_SIZE;
+
+	if (base_pgt_cache)
+		return 0;
+	mutex_lock(&base_pgt_cache_mutex);
+	if (!base_pgt_cache)
+		base_pgt_cache = kmem_cache_create("base_pgt", sz, sz, 0, NULL);
+	mutex_unlock(&base_pgt_cache_mutex);
+	return base_pgt_cache ? 0 : -ENOMEM;
+}
+
+/**
+ * base_asce_alloc - create kernel mapping without enhanced DAT features
+ * @addr: virtual start address of kernel mapping
+ * @num_pages: number of consecutive pages
+ *
+ * Generate an asce, including all required region, segment and page tables,
+ * that can be used to access the virtual kernel mapping. The difference is
+ * that the returned asce does not make use of any enhanced DAT features like
+ * e.g. large pages. This is required for some I/O functions that pass an
+ * asce, like e.g. some service call requests.
+ *
+ * Note: the returned asce may NEVER be attached to any cpu. It may only be
+ *	 used for I/O requests. tlb entries that might result because the
+ *	 asce was attached to a cpu won't be cleared.
+ */
+unsigned long base_asce_alloc(unsigned long addr, unsigned long num_pages)
+{
+	unsigned long asce, *table, end;
+	int rc;
+
+	if (base_pgt_cache_init())
+		return 0;
+	end = addr + num_pages * PAGE_SIZE;
+	if (end <= _REGION3_SIZE) {
+		table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY);
+		if (!table)
+			return 0;
+		rc = base_segment_walk(table, addr, end, 1);
+		asce = __pa(table) | _ASCE_TYPE_SEGMENT | _ASCE_TABLE_LENGTH;
+	} else if (end <= _REGION2_SIZE) {
+		table = base_crst_alloc(_REGION3_ENTRY_EMPTY);
+		if (!table)
+			return 0;
+		rc = base_region3_walk(table, addr, end, 1);
+		asce = __pa(table) | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
+	} else if (end <= _REGION1_SIZE) {
+		table = base_crst_alloc(_REGION2_ENTRY_EMPTY);
+		if (!table)
+			return 0;
+		rc = base_region2_walk(table, addr, end, 1);
+		asce = __pa(table) | _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
+	} else {
+		table = base_crst_alloc(_REGION1_ENTRY_EMPTY);
+		if (!table)
+			return 0;
+		rc = base_region1_walk(table, addr, end, 1);
+		asce = __pa(table) | _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH;
+	}
+	if (rc) {
+		base_asce_free(asce);
+		asce = 0;
+	}
+	return asce;
+}
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
new file mode 100644
index 0000000000..5cb9294154
--- /dev/null
+++ b/arch/s390/mm/pgtable.c
@@ -0,0 +1,1207 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Copyright IBM Corp. 2007, 2011
+ *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/gfp.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/slab.h>
+#include <linux/swapops.h>
+#include <linux/sysctl.h>
+#include <linux/ksm.h>
+#include <linux/mman.h>
+
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
+#include <asm/page-states.h>
+
+pgprot_t pgprot_writecombine(pgprot_t prot)
+{
+	/*
+	 * mio_wb_bit_mask may be set on a different CPU, but it is only set
+	 * once at init and only read afterwards.
+	 */
+	return __pgprot(pgprot_val(prot) | mio_wb_bit_mask);
+}
+EXPORT_SYMBOL_GPL(pgprot_writecombine);
+
+pgprot_t pgprot_writethrough(pgprot_t prot)
+{
+	/*
+	 * mio_wb_bit_mask may be set on a different CPU, but it is only set
+	 * once at init and only read afterwards.
+	 */
+	return __pgprot(pgprot_val(prot) & ~mio_wb_bit_mask);
+}
+EXPORT_SYMBOL_GPL(pgprot_writethrough);
+
+static inline void ptep_ipte_local(struct mm_struct *mm, unsigned long addr,
+				   pte_t *ptep, int nodat)
+{
+	unsigned long opt, asce;
+
+	if (MACHINE_HAS_TLB_GUEST) {
+		opt = 0;
+		asce = READ_ONCE(mm->context.gmap_asce);
+		if (asce == 0UL || nodat)
+			opt |= IPTE_NODAT;
+		if (asce != -1UL) {
+			asce = asce ? : mm->context.asce;
+			opt |= IPTE_GUEST_ASCE;
+		}
+		__ptep_ipte(addr, ptep, opt, asce, IPTE_LOCAL);
+	} else {
+		__ptep_ipte(addr, ptep, 0, 0, IPTE_LOCAL);
+	}
+}
+
+static inline void ptep_ipte_global(struct mm_struct *mm, unsigned long addr,
+				    pte_t *ptep, int nodat)
+{
+	unsigned long opt, asce;
+
+	if (MACHINE_HAS_TLB_GUEST) {
+		opt = 0;
+		asce = READ_ONCE(mm->context.gmap_asce);
+		if (asce == 0UL || nodat)
+			opt |= IPTE_NODAT;
+		if (asce != -1UL) {
+			asce = asce ? : mm->context.asce;
+			opt |= IPTE_GUEST_ASCE;
+		}
+		__ptep_ipte(addr, ptep, opt, asce, IPTE_GLOBAL);
+	} else {
+		__ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
+	}
+}
+
+static inline pte_t ptep_flush_direct(struct mm_struct *mm,
+				      unsigned long addr, pte_t *ptep,
+				      int nodat)
+{
+	pte_t old;
+
+	old = *ptep;
+	if (unlikely(pte_val(old) & _PAGE_INVALID))
+		return old;
+	atomic_inc(&mm->context.flush_count);
+	if (MACHINE_HAS_TLB_LC &&
+	    cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
+		ptep_ipte_local(mm, addr, ptep, nodat);
+	else
+		ptep_ipte_global(mm, addr, ptep, nodat);
+	atomic_dec(&mm->context.flush_count);
+	return old;
+}
+
+static inline pte_t ptep_flush_lazy(struct mm_struct *mm,
+				    unsigned long addr, pte_t *ptep,
+				    int nodat)
+{
+	pte_t old;
+
+	old = *ptep;
+	if (unlikely(pte_val(old) & _PAGE_INVALID))
+		return old;
+	atomic_inc(&mm->context.flush_count);
+	if (cpumask_equal(&mm->context.cpu_attach_mask,
+			  cpumask_of(smp_processor_id()))) {
+		set_pte(ptep, set_pte_bit(*ptep, __pgprot(_PAGE_INVALID)));
+		mm->context.flush_mm = 1;
+	} else
+		ptep_ipte_global(mm, addr, ptep, nodat);
+	atomic_dec(&mm->context.flush_count);
+	return old;
+}
+
+static inline pgste_t pgste_get_lock(pte_t *ptep)
+{
+	unsigned long new = 0;
+#ifdef CONFIG_PGSTE
+	unsigned long old;
+
+	asm(
+		"	lg	%0,%2\n"
+		"0:	lgr	%1,%0\n"
+		"	nihh	%0,0xff7f\n"	/* clear PCL bit in old */
+		"	oihh	%1,0x0080\n"	/* set PCL bit in new */
+		"	csg	%0,%1,%2\n"
+		"	jl	0b\n"
+		: "=&d" (old), "=&d" (new), "=Q" (ptep[PTRS_PER_PTE])
+		: "Q" (ptep[PTRS_PER_PTE]) : "cc", "memory");
+#endif
+	return __pgste(new);
+}
+
+static inline void pgste_set_unlock(pte_t *ptep, pgste_t pgste)
+{
+#ifdef CONFIG_PGSTE
+	asm(
+		"	nihh	%1,0xff7f\n"	/* clear PCL bit */
+		"	stg	%1,%0\n"
+		: "=Q" (ptep[PTRS_PER_PTE])
+		: "d" (pgste_val(pgste)), "Q" (ptep[PTRS_PER_PTE])
+		: "cc", "memory");
+#endif
+}
+
+static inline pgste_t pgste_get(pte_t *ptep)
+{
+	unsigned long pgste = 0;
+#ifdef CONFIG_PGSTE
+	pgste = *(unsigned long *)(ptep + PTRS_PER_PTE);
+#endif
+	return __pgste(pgste);
+}
+
+static inline void pgste_set(pte_t *ptep, pgste_t pgste)
+{
+#ifdef CONFIG_PGSTE
+	*(pgste_t *)(ptep + PTRS_PER_PTE) = pgste;
+#endif
+}
+
+static inline pgste_t pgste_update_all(pte_t pte, pgste_t pgste,
+				       struct mm_struct *mm)
+{
+#ifdef CONFIG_PGSTE
+	unsigned long address, bits, skey;
+
+	if (!mm_uses_skeys(mm) || pte_val(pte) & _PAGE_INVALID)
+		return pgste;
+	address = pte_val(pte) & PAGE_MASK;
+	skey = (unsigned long) page_get_storage_key(address);
+	bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
+	/* Transfer page changed & referenced bit to guest bits in pgste */
+	pgste_val(pgste) |= bits << 48;		/* GR bit & GC bit */
+	/* Copy page access key and fetch protection bit to pgste */
+	pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
+	pgste_val(pgste) |= (skey & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
+#endif
+	return pgste;
+
+}
+
+static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry,
+				 struct mm_struct *mm)
+{
+#ifdef CONFIG_PGSTE
+	unsigned long address;
+	unsigned long nkey;
+
+	if (!mm_uses_skeys(mm) || pte_val(entry) & _PAGE_INVALID)
+		return;
+	VM_BUG_ON(!(pte_val(*ptep) & _PAGE_INVALID));
+	address = pte_val(entry) & PAGE_MASK;
+	/*
+	 * Set page access key and fetch protection bit from pgste.
+	 * The guest C/R information is still in the PGSTE, set real
+	 * key C/R to 0.
+	 */
+	nkey = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
+	nkey |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
+	page_set_storage_key(address, nkey, 0);
+#endif
+}
+
+static inline pgste_t pgste_set_pte(pte_t *ptep, pgste_t pgste, pte_t entry)
+{
+#ifdef CONFIG_PGSTE
+	if ((pte_val(entry) & _PAGE_PRESENT) &&
+	    (pte_val(entry) & _PAGE_WRITE) &&
+	    !(pte_val(entry) & _PAGE_INVALID)) {
+		if (!MACHINE_HAS_ESOP) {
+			/*
+			 * Without enhanced suppression-on-protection force
+			 * the dirty bit on for all writable ptes.
+			 */
+			entry = set_pte_bit(entry, __pgprot(_PAGE_DIRTY));
+			entry = clear_pte_bit(entry, __pgprot(_PAGE_PROTECT));
+		}
+		if (!(pte_val(entry) & _PAGE_PROTECT))
+			/* This pte allows write access, set user-dirty */
+			pgste_val(pgste) |= PGSTE_UC_BIT;
+	}
+#endif
+	set_pte(ptep, entry);
+	return pgste;
+}
+
+static inline pgste_t pgste_pte_notify(struct mm_struct *mm,
+				       unsigned long addr,
+				       pte_t *ptep, pgste_t pgste)
+{
+#ifdef CONFIG_PGSTE
+	unsigned long bits;
+
+	bits = pgste_val(pgste) & (PGSTE_IN_BIT | PGSTE_VSIE_BIT);
+	if (bits) {
+		pgste_val(pgste) ^= bits;
+		ptep_notify(mm, addr, ptep, bits);
+	}
+#endif
+	return pgste;
+}
+
+static inline pgste_t ptep_xchg_start(struct mm_struct *mm,
+				      unsigned long addr, pte_t *ptep)
+{
+	pgste_t pgste = __pgste(0);
+
+	if (mm_has_pgste(mm)) {
+		pgste = pgste_get_lock(ptep);
+		pgste = pgste_pte_notify(mm, addr, ptep, pgste);
+	}
+	return pgste;
+}
+
+static inline pte_t ptep_xchg_commit(struct mm_struct *mm,
+				    unsigned long addr, pte_t *ptep,
+				    pgste_t pgste, pte_t old, pte_t new)
+{
+	if (mm_has_pgste(mm)) {
+		if (pte_val(old) & _PAGE_INVALID)
+			pgste_set_key(ptep, pgste, new, mm);
+		if (pte_val(new) & _PAGE_INVALID) {
+			pgste = pgste_update_all(old, pgste, mm);
+			if ((pgste_val(pgste) & _PGSTE_GPS_USAGE_MASK) ==
+			    _PGSTE_GPS_USAGE_UNUSED)
+				old = set_pte_bit(old, __pgprot(_PAGE_UNUSED));
+		}
+		pgste = pgste_set_pte(ptep, pgste, new);
+		pgste_set_unlock(ptep, pgste);
+	} else {
+		set_pte(ptep, new);
+	}
+	return old;
+}
+
+pte_t ptep_xchg_direct(struct mm_struct *mm, unsigned long addr,
+		       pte_t *ptep, pte_t new)
+{
+	pgste_t pgste;
+	pte_t old;
+	int nodat;
+
+	preempt_disable();
+	pgste = ptep_xchg_start(mm, addr, ptep);
+	nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
+	old = ptep_flush_direct(mm, addr, ptep, nodat);
+	old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
+	preempt_enable();
+	return old;
+}
+EXPORT_SYMBOL(ptep_xchg_direct);
+
+/*
+ * Caller must check that new PTE only differs in _PAGE_PROTECT HW bit, so that
+ * RDP can be used instead of IPTE. See also comments at pte_allow_rdp().
+ */
+void ptep_reset_dat_prot(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
+			 pte_t new)
+{
+	preempt_disable();
+	atomic_inc(&mm->context.flush_count);
+	if (cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
+		__ptep_rdp(addr, ptep, 0, 0, 1);
+	else
+		__ptep_rdp(addr, ptep, 0, 0, 0);
+	/*
+	 * PTE is not invalidated by RDP, only _PAGE_PROTECT is cleared. That
+	 * means it is still valid and active, and must not be changed according
+	 * to the architecture. But writing a new value that only differs in SW
+	 * bits is allowed.
+	 */
+	set_pte(ptep, new);
+	atomic_dec(&mm->context.flush_count);
+	preempt_enable();
+}
+EXPORT_SYMBOL(ptep_reset_dat_prot);
+
+pte_t ptep_xchg_lazy(struct mm_struct *mm, unsigned long addr,
+		     pte_t *ptep, pte_t new)
+{
+	pgste_t pgste;
+	pte_t old;
+	int nodat;
+
+	preempt_disable();
+	pgste = ptep_xchg_start(mm, addr, ptep);
+	nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
+	old = ptep_flush_lazy(mm, addr, ptep, nodat);
+	old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
+	preempt_enable();
+	return old;
+}
+EXPORT_SYMBOL(ptep_xchg_lazy);
+
+pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr,
+			     pte_t *ptep)
+{
+	pgste_t pgste;
+	pte_t old;
+	int nodat;
+	struct mm_struct *mm = vma->vm_mm;
+
+	preempt_disable();
+	pgste = ptep_xchg_start(mm, addr, ptep);
+	nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
+	old = ptep_flush_lazy(mm, addr, ptep, nodat);
+	if (mm_has_pgste(mm)) {
+		pgste = pgste_update_all(old, pgste, mm);
+		pgste_set(ptep, pgste);
+	}
+	return old;
+}
+
+void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
+			     pte_t *ptep, pte_t old_pte, pte_t pte)
+{
+	pgste_t pgste;
+	struct mm_struct *mm = vma->vm_mm;
+
+	if (!MACHINE_HAS_NX)
+		pte = clear_pte_bit(pte, __pgprot(_PAGE_NOEXEC));
+	if (mm_has_pgste(mm)) {
+		pgste = pgste_get(ptep);
+		pgste_set_key(ptep, pgste, pte, mm);
+		pgste = pgste_set_pte(ptep, pgste, pte);
+		pgste_set_unlock(ptep, pgste);
+	} else {
+		set_pte(ptep, pte);
+	}
+	preempt_enable();
+}
+
+static inline void pmdp_idte_local(struct mm_struct *mm,
+				   unsigned long addr, pmd_t *pmdp)
+{
+	if (MACHINE_HAS_TLB_GUEST)
+		__pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
+			    mm->context.asce, IDTE_LOCAL);
+	else
+		__pmdp_idte(addr, pmdp, 0, 0, IDTE_LOCAL);
+	if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
+		gmap_pmdp_idte_local(mm, addr);
+}
+
+static inline void pmdp_idte_global(struct mm_struct *mm,
+				    unsigned long addr, pmd_t *pmdp)
+{
+	if (MACHINE_HAS_TLB_GUEST) {
+		__pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
+			    mm->context.asce, IDTE_GLOBAL);
+		if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
+			gmap_pmdp_idte_global(mm, addr);
+	} else if (MACHINE_HAS_IDTE) {
+		__pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);
+		if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
+			gmap_pmdp_idte_global(mm, addr);
+	} else {
+		__pmdp_csp(pmdp);
+		if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
+			gmap_pmdp_csp(mm, addr);
+	}
+}
+
+static inline pmd_t pmdp_flush_direct(struct mm_struct *mm,
+				      unsigned long addr, pmd_t *pmdp)
+{
+	pmd_t old;
+
+	old = *pmdp;
+	if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
+		return old;
+	atomic_inc(&mm->context.flush_count);
+	if (MACHINE_HAS_TLB_LC &&
+	    cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
+		pmdp_idte_local(mm, addr, pmdp);
+	else
+		pmdp_idte_global(mm, addr, pmdp);
+	atomic_dec(&mm->context.flush_count);
+	return old;
+}
+
+static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
+				    unsigned long addr, pmd_t *pmdp)
+{
+	pmd_t old;
+
+	old = *pmdp;
+	if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
+		return old;
+	atomic_inc(&mm->context.flush_count);
+	if (cpumask_equal(&mm->context.cpu_attach_mask,
+			  cpumask_of(smp_processor_id()))) {
+		set_pmd(pmdp, set_pmd_bit(*pmdp, __pgprot(_SEGMENT_ENTRY_INVALID)));
+		mm->context.flush_mm = 1;
+		if (mm_has_pgste(mm))
+			gmap_pmdp_invalidate(mm, addr);
+	} else {
+		pmdp_idte_global(mm, addr, pmdp);
+	}
+	atomic_dec(&mm->context.flush_count);
+	return old;
+}
+
+#ifdef CONFIG_PGSTE
+static int pmd_lookup(struct mm_struct *mm, unsigned long addr, pmd_t **pmdp)
+{
+	struct vm_area_struct *vma;
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+
+	/* We need a valid VMA, otherwise this is clearly a fault. */
+	vma = vma_lookup(mm, addr);
+	if (!vma)
+		return -EFAULT;
+
+	pgd = pgd_offset(mm, addr);
+	if (!pgd_present(*pgd))
+		return -ENOENT;
+
+	p4d = p4d_offset(pgd, addr);
+	if (!p4d_present(*p4d))
+		return -ENOENT;
+
+	pud = pud_offset(p4d, addr);
+	if (!pud_present(*pud))
+		return -ENOENT;
+
+	/* Large PUDs are not supported yet. */
+	if (pud_large(*pud))
+		return -EFAULT;
+
+	*pmdp = pmd_offset(pud, addr);
+	return 0;
+}
+#endif
+
+pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
+		       pmd_t *pmdp, pmd_t new)
+{
+	pmd_t old;
+
+	preempt_disable();
+	old = pmdp_flush_direct(mm, addr, pmdp);
+	set_pmd(pmdp, new);
+	preempt_enable();
+	return old;
+}
+EXPORT_SYMBOL(pmdp_xchg_direct);
+
+pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
+		     pmd_t *pmdp, pmd_t new)
+{
+	pmd_t old;
+
+	preempt_disable();
+	old = pmdp_flush_lazy(mm, addr, pmdp);
+	set_pmd(pmdp, new);
+	preempt_enable();
+	return old;
+}
+EXPORT_SYMBOL(pmdp_xchg_lazy);
+
+static inline void pudp_idte_local(struct mm_struct *mm,
+				   unsigned long addr, pud_t *pudp)
+{
+	if (MACHINE_HAS_TLB_GUEST)
+		__pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
+			    mm->context.asce, IDTE_LOCAL);
+	else
+		__pudp_idte(addr, pudp, 0, 0, IDTE_LOCAL);
+}
+
+static inline void pudp_idte_global(struct mm_struct *mm,
+				    unsigned long addr, pud_t *pudp)
+{
+	if (MACHINE_HAS_TLB_GUEST)
+		__pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
+			    mm->context.asce, IDTE_GLOBAL);
+	else if (MACHINE_HAS_IDTE)
+		__pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
+	else
+		/*
+		 * Invalid bit position is the same for pmd and pud, so we can
+		 * re-use _pmd_csp() here
+		 */
+		__pmdp_csp((pmd_t *) pudp);
+}
+
+static inline pud_t pudp_flush_direct(struct mm_struct *mm,
+				      unsigned long addr, pud_t *pudp)
+{
+	pud_t old;
+
+	old = *pudp;
+	if (pud_val(old) & _REGION_ENTRY_INVALID)
+		return old;
+	atomic_inc(&mm->context.flush_count);
+	if (MACHINE_HAS_TLB_LC &&
+	    cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
+		pudp_idte_local(mm, addr, pudp);
+	else
+		pudp_idte_global(mm, addr, pudp);
+	atomic_dec(&mm->context.flush_count);
+	return old;
+}
+
+pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
+		       pud_t *pudp, pud_t new)
+{
+	pud_t old;
+
+	preempt_disable();
+	old = pudp_flush_direct(mm, addr, pudp);
+	set_pud(pudp, new);
+	preempt_enable();
+	return old;
+}
+EXPORT_SYMBOL(pudp_xchg_direct);
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				pgtable_t pgtable)
+{
+	struct list_head *lh = (struct list_head *) pgtable;
+
+	assert_spin_locked(pmd_lockptr(mm, pmdp));
+
+	/* FIFO */
+	if (!pmd_huge_pte(mm, pmdp))
+		INIT_LIST_HEAD(lh);
+	else
+		list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
+	pmd_huge_pte(mm, pmdp) = pgtable;
+}
+
+pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
+{
+	struct list_head *lh;
+	pgtable_t pgtable;
+	pte_t *ptep;
+
+	assert_spin_locked(pmd_lockptr(mm, pmdp));
+
+	/* FIFO */
+	pgtable = pmd_huge_pte(mm, pmdp);
+	lh = (struct list_head *) pgtable;
+	if (list_empty(lh))
+		pmd_huge_pte(mm, pmdp) = NULL;
+	else {
+		pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
+		list_del(lh);
+	}
+	ptep = (pte_t *) pgtable;
+	set_pte(ptep, __pte(_PAGE_INVALID));
+	ptep++;
+	set_pte(ptep, __pte(_PAGE_INVALID));
+	return pgtable;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+#ifdef CONFIG_PGSTE
+void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
+		     pte_t *ptep, pte_t entry)
+{
+	pgste_t pgste;
+
+	/* the mm_has_pgste() check is done in set_pte_at() */
+	preempt_disable();
+	pgste = pgste_get_lock(ptep);
+	pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
+	pgste_set_key(ptep, pgste, entry, mm);
+	pgste = pgste_set_pte(ptep, pgste, entry);
+	pgste_set_unlock(ptep, pgste);
+	preempt_enable();
+}
+
+void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+	pgste_t pgste;
+
+	preempt_disable();
+	pgste = pgste_get_lock(ptep);
+	pgste_val(pgste) |= PGSTE_IN_BIT;
+	pgste_set_unlock(ptep, pgste);
+	preempt_enable();
+}
+
+/**
+ * ptep_force_prot - change access rights of a locked pte
+ * @mm: pointer to the process mm_struct
+ * @addr: virtual address in the guest address space
+ * @ptep: pointer to the page table entry
+ * @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
+ * @bit: pgste bit to set (e.g. for notification)
+ *
+ * Returns 0 if the access rights were changed and -EAGAIN if the current
+ * and requested access rights are incompatible.
+ */
+int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
+		    pte_t *ptep, int prot, unsigned long bit)
+{
+	pte_t entry;
+	pgste_t pgste;
+	int pte_i, pte_p, nodat;
+
+	pgste = pgste_get_lock(ptep);
+	entry = *ptep;
+	/* Check pte entry after all locks have been acquired */
+	pte_i = pte_val(entry) & _PAGE_INVALID;
+	pte_p = pte_val(entry) & _PAGE_PROTECT;
+	if ((pte_i && (prot != PROT_NONE)) ||
+	    (pte_p && (prot & PROT_WRITE))) {
+		pgste_set_unlock(ptep, pgste);
+		return -EAGAIN;
+	}
+	/* Change access rights and set pgste bit */
+	nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
+	if (prot == PROT_NONE && !pte_i) {
+		ptep_flush_direct(mm, addr, ptep, nodat);
+		pgste = pgste_update_all(entry, pgste, mm);
+		entry = set_pte_bit(entry, __pgprot(_PAGE_INVALID));
+	}
+	if (prot == PROT_READ && !pte_p) {
+		ptep_flush_direct(mm, addr, ptep, nodat);
+		entry = clear_pte_bit(entry, __pgprot(_PAGE_INVALID));
+		entry = set_pte_bit(entry, __pgprot(_PAGE_PROTECT));
+	}
+	pgste_val(pgste) |= bit;
+	pgste = pgste_set_pte(ptep, pgste, entry);
+	pgste_set_unlock(ptep, pgste);
+	return 0;
+}
+
+int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
+		    pte_t *sptep, pte_t *tptep, pte_t pte)
+{
+	pgste_t spgste, tpgste;
+	pte_t spte, tpte;
+	int rc = -EAGAIN;
+
+	if (!(pte_val(*tptep) & _PAGE_INVALID))
+		return 0;	/* already shadowed */
+	spgste = pgste_get_lock(sptep);
+	spte = *sptep;
+	if (!(pte_val(spte) & _PAGE_INVALID) &&
+	    !((pte_val(spte) & _PAGE_PROTECT) &&
+	      !(pte_val(pte) & _PAGE_PROTECT))) {
+		pgste_val(spgste) |= PGSTE_VSIE_BIT;
+		tpgste = pgste_get_lock(tptep);
+		tpte = __pte((pte_val(spte) & PAGE_MASK) |
+			     (pte_val(pte) & _PAGE_PROTECT));
+		/* don't touch the storage key - it belongs to parent pgste */
+		tpgste = pgste_set_pte(tptep, tpgste, tpte);
+		pgste_set_unlock(tptep, tpgste);
+		rc = 1;
+	}
+	pgste_set_unlock(sptep, spgste);
+	return rc;
+}
+
+void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
+{
+	pgste_t pgste;
+	int nodat;
+
+	pgste = pgste_get_lock(ptep);
+	/* notifier is called by the caller */
+	nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
+	ptep_flush_direct(mm, saddr, ptep, nodat);
+	/* don't touch the storage key - it belongs to parent pgste */
+	pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
+	pgste_set_unlock(ptep, pgste);
+}
+
+static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
+{
+	if (!non_swap_entry(entry))
+		dec_mm_counter(mm, MM_SWAPENTS);
+	else if (is_migration_entry(entry)) {
+		struct page *page = pfn_swap_entry_to_page(entry);
+
+		dec_mm_counter(mm, mm_counter(page));
+	}
+	free_swap_and_cache(entry);
+}
+
+void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
+		     pte_t *ptep, int reset)
+{
+	unsigned long pgstev;
+	pgste_t pgste;
+	pte_t pte;
+
+	/* Zap unused and logically-zero pages */
+	preempt_disable();
+	pgste = pgste_get_lock(ptep);
+	pgstev = pgste_val(pgste);
+	pte = *ptep;
+	if (!reset && pte_swap(pte) &&
+	    ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
+	     (pgstev & _PGSTE_GPS_ZERO))) {
+		ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
+		pte_clear(mm, addr, ptep);
+	}
+	if (reset)
+		pgste_val(pgste) &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
+	pgste_set_unlock(ptep, pgste);
+	preempt_enable();
+}
+
+void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+	unsigned long ptev;
+	pgste_t pgste;
+
+	/* Clear storage key ACC and F, but set R/C */
+	preempt_disable();
+	pgste = pgste_get_lock(ptep);
+	pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
+	pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT;
+	ptev = pte_val(*ptep);
+	if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
+		page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 0);
+	pgste_set_unlock(ptep, pgste);
+	preempt_enable();
+}
+
+/*
+ * Test and reset if a guest page is dirty
+ */
+bool ptep_test_and_clear_uc(struct mm_struct *mm, unsigned long addr,
+		       pte_t *ptep)
+{
+	pgste_t pgste;
+	pte_t pte;
+	bool dirty;
+	int nodat;
+
+	pgste = pgste_get_lock(ptep);
+	dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
+	pgste_val(pgste) &= ~PGSTE_UC_BIT;
+	pte = *ptep;
+	if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
+		pgste = pgste_pte_notify(mm, addr, ptep, pgste);
+		nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
+		ptep_ipte_global(mm, addr, ptep, nodat);
+		if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
+			pte = set_pte_bit(pte, __pgprot(_PAGE_PROTECT));
+		else
+			pte = set_pte_bit(pte, __pgprot(_PAGE_INVALID));
+		set_pte(ptep, pte);
+	}
+	pgste_set_unlock(ptep, pgste);
+	return dirty;
+}
+EXPORT_SYMBOL_GPL(ptep_test_and_clear_uc);
+
+int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
+			  unsigned char key, bool nq)
+{
+	unsigned long keyul, paddr;
+	spinlock_t *ptl;
+	pgste_t old, new;
+	pmd_t *pmdp;
+	pte_t *ptep;
+
+	/*
+	 * If we don't have a PTE table and if there is no huge page mapped,
+	 * we can ignore attempts to set the key to 0, because it already is 0.
+	 */
+	switch (pmd_lookup(mm, addr, &pmdp)) {
+	case -ENOENT:
+		return key ? -EFAULT : 0;
+	case 0:
+		break;
+	default:
+		return -EFAULT;
+	}
+again:
+	ptl = pmd_lock(mm, pmdp);
+	if (!pmd_present(*pmdp)) {
+		spin_unlock(ptl);
+		return key ? -EFAULT : 0;
+	}
+
+	if (pmd_large(*pmdp)) {
+		paddr = pmd_val(*pmdp) & HPAGE_MASK;
+		paddr |= addr & ~HPAGE_MASK;
+		/*
+		 * Huge pmds need quiescing operations, they are
+		 * always mapped.
+		 */
+		page_set_storage_key(paddr, key, 1);
+		spin_unlock(ptl);
+		return 0;
+	}
+	spin_unlock(ptl);
+
+	ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
+	if (!ptep)
+		goto again;
+	new = old = pgste_get_lock(ptep);
+	pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
+			    PGSTE_ACC_BITS | PGSTE_FP_BIT);
+	keyul = (unsigned long) key;
+	pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
+	pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
+	if (!(pte_val(*ptep) & _PAGE_INVALID)) {
+		unsigned long bits, skey;
+
+		paddr = pte_val(*ptep) & PAGE_MASK;
+		skey = (unsigned long) page_get_storage_key(paddr);
+		bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
+		skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
+		/* Set storage key ACC and FP */
+		page_set_storage_key(paddr, skey, !nq);
+		/* Merge host changed & referenced into pgste  */
+		pgste_val(new) |= bits << 52;
+	}
+	/* changing the guest storage key is considered a change of the page */
+	if ((pgste_val(new) ^ pgste_val(old)) &
+	    (PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
+		pgste_val(new) |= PGSTE_UC_BIT;
+
+	pgste_set_unlock(ptep, new);
+	pte_unmap_unlock(ptep, ptl);
+	return 0;
+}
+EXPORT_SYMBOL(set_guest_storage_key);
+
+/*
+ * Conditionally set a guest storage key (handling csske).
+ * oldkey will be updated when either mr or mc is set and a pointer is given.
+ *
+ * Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
+ * storage key was updated and -EFAULT on access errors.
+ */
+int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
+			       unsigned char key, unsigned char *oldkey,
+			       bool nq, bool mr, bool mc)
+{
+	unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
+	int rc;
+
+	/* we can drop the pgste lock between getting and setting the key */
+	if (mr | mc) {
+		rc = get_guest_storage_key(current->mm, addr, &tmp);
+		if (rc)
+			return rc;
+		if (oldkey)
+			*oldkey = tmp;
+		if (!mr)
+			mask |= _PAGE_REFERENCED;
+		if (!mc)
+			mask |= _PAGE_CHANGED;
+		if (!((tmp ^ key) & mask))
+			return 0;
+	}
+	rc = set_guest_storage_key(current->mm, addr, key, nq);
+	return rc < 0 ? rc : 1;
+}
+EXPORT_SYMBOL(cond_set_guest_storage_key);
+
+/*
+ * Reset a guest reference bit (rrbe), returning the reference and changed bit.
+ *
+ * Returns < 0 in case of error, otherwise the cc to be reported to the guest.
+ */
+int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
+{
+	spinlock_t *ptl;
+	unsigned long paddr;
+	pgste_t old, new;
+	pmd_t *pmdp;
+	pte_t *ptep;
+	int cc = 0;
+
+	/*
+	 * If we don't have a PTE table and if there is no huge page mapped,
+	 * the storage key is 0 and there is nothing for us to do.
+	 */
+	switch (pmd_lookup(mm, addr, &pmdp)) {
+	case -ENOENT:
+		return 0;
+	case 0:
+		break;
+	default:
+		return -EFAULT;
+	}
+again:
+	ptl = pmd_lock(mm, pmdp);
+	if (!pmd_present(*pmdp)) {
+		spin_unlock(ptl);
+		return 0;
+	}
+
+	if (pmd_large(*pmdp)) {
+		paddr = pmd_val(*pmdp) & HPAGE_MASK;
+		paddr |= addr & ~HPAGE_MASK;
+		cc = page_reset_referenced(paddr);
+		spin_unlock(ptl);
+		return cc;
+	}
+	spin_unlock(ptl);
+
+	ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
+	if (!ptep)
+		goto again;
+	new = old = pgste_get_lock(ptep);
+	/* Reset guest reference bit only */
+	pgste_val(new) &= ~PGSTE_GR_BIT;
+
+	if (!(pte_val(*ptep) & _PAGE_INVALID)) {
+		paddr = pte_val(*ptep) & PAGE_MASK;
+		cc = page_reset_referenced(paddr);
+		/* Merge real referenced bit into host-set */
+		pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
+	}
+	/* Reflect guest's logical view, not physical */
+	cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
+	/* Changing the guest storage key is considered a change of the page */
+	if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
+		pgste_val(new) |= PGSTE_UC_BIT;
+
+	pgste_set_unlock(ptep, new);
+	pte_unmap_unlock(ptep, ptl);
+	return cc;
+}
+EXPORT_SYMBOL(reset_guest_reference_bit);
+
+int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
+			  unsigned char *key)
+{
+	unsigned long paddr;
+	spinlock_t *ptl;
+	pgste_t pgste;
+	pmd_t *pmdp;
+	pte_t *ptep;
+
+	/*
+	 * If we don't have a PTE table and if there is no huge page mapped,
+	 * the storage key is 0.
+	 */
+	*key = 0;
+
+	switch (pmd_lookup(mm, addr, &pmdp)) {
+	case -ENOENT:
+		return 0;
+	case 0:
+		break;
+	default:
+		return -EFAULT;
+	}
+again:
+	ptl = pmd_lock(mm, pmdp);
+	if (!pmd_present(*pmdp)) {
+		spin_unlock(ptl);
+		return 0;
+	}
+
+	if (pmd_large(*pmdp)) {
+		paddr = pmd_val(*pmdp) & HPAGE_MASK;
+		paddr |= addr & ~HPAGE_MASK;
+		*key = page_get_storage_key(paddr);
+		spin_unlock(ptl);
+		return 0;
+	}
+	spin_unlock(ptl);
+
+	ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
+	if (!ptep)
+		goto again;
+	pgste = pgste_get_lock(ptep);
+	*key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
+	paddr = pte_val(*ptep) & PAGE_MASK;
+	if (!(pte_val(*ptep) & _PAGE_INVALID))
+		*key = page_get_storage_key(paddr);
+	/* Reflect guest's logical view, not physical */
+	*key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
+	pgste_set_unlock(ptep, pgste);
+	pte_unmap_unlock(ptep, ptl);
+	return 0;
+}
+EXPORT_SYMBOL(get_guest_storage_key);
+
+/**
+ * pgste_perform_essa - perform ESSA actions on the PGSTE.
+ * @mm: the memory context. It must have PGSTEs, no check is performed here!
+ * @hva: the host virtual address of the page whose PGSTE is to be processed
+ * @orc: the specific action to perform, see the ESSA_SET_* macros.
+ * @oldpte: the PTE will be saved there if the pointer is not NULL.
+ * @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
+ *
+ * Return: 1 if the page is to be added to the CBRL, otherwise 0,
+ *	   or < 0 in case of error. -EINVAL is returned for invalid values
+ *	   of orc, -EFAULT for invalid addresses.
+ */
+int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
+			unsigned long *oldpte, unsigned long *oldpgste)
+{
+	struct vm_area_struct *vma;
+	unsigned long pgstev;
+	spinlock_t *ptl;
+	pgste_t pgste;
+	pte_t *ptep;
+	int res = 0;
+
+	WARN_ON_ONCE(orc > ESSA_MAX);
+	if (unlikely(orc > ESSA_MAX))
+		return -EINVAL;
+
+	vma = vma_lookup(mm, hva);
+	if (!vma || is_vm_hugetlb_page(vma))
+		return -EFAULT;
+	ptep = get_locked_pte(mm, hva, &ptl);
+	if (unlikely(!ptep))
+		return -EFAULT;
+	pgste = pgste_get_lock(ptep);
+	pgstev = pgste_val(pgste);
+	if (oldpte)
+		*oldpte = pte_val(*ptep);
+	if (oldpgste)
+		*oldpgste = pgstev;
+
+	switch (orc) {
+	case ESSA_GET_STATE:
+		break;
+	case ESSA_SET_STABLE:
+		pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
+		pgstev |= _PGSTE_GPS_USAGE_STABLE;
+		break;
+	case ESSA_SET_UNUSED:
+		pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+		pgstev |= _PGSTE_GPS_USAGE_UNUSED;
+		if (pte_val(*ptep) & _PAGE_INVALID)
+			res = 1;
+		break;
+	case ESSA_SET_VOLATILE:
+		pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+		pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
+		if (pte_val(*ptep) & _PAGE_INVALID)
+			res = 1;
+		break;
+	case ESSA_SET_POT_VOLATILE:
+		pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+		if (!(pte_val(*ptep) & _PAGE_INVALID)) {
+			pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
+			break;
+		}
+		if (pgstev & _PGSTE_GPS_ZERO) {
+			pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
+			break;
+		}
+		if (!(pgstev & PGSTE_GC_BIT)) {
+			pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
+			res = 1;
+			break;
+		}
+		break;
+	case ESSA_SET_STABLE_RESIDENT:
+		pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+		pgstev |= _PGSTE_GPS_USAGE_STABLE;
+		/*
+		 * Since the resident state can go away any time after this
+		 * call, we will not make this page resident. We can revisit
+		 * this decision if a guest will ever start using this.
+		 */
+		break;
+	case ESSA_SET_STABLE_IF_RESIDENT:
+		if (!(pte_val(*ptep) & _PAGE_INVALID)) {
+			pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+			pgstev |= _PGSTE_GPS_USAGE_STABLE;
+		}
+		break;
+	case ESSA_SET_STABLE_NODAT:
+		pgstev &= ~_PGSTE_GPS_USAGE_MASK;
+		pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
+		break;
+	default:
+		/* we should never get here! */
+		break;
+	}
+	/* If we are discarding a page, set it to logical zero */
+	if (res)
+		pgstev |= _PGSTE_GPS_ZERO;
+
+	pgste_val(pgste) = pgstev;
+	pgste_set_unlock(ptep, pgste);
+	pte_unmap_unlock(ptep, ptl);
+	return res;
+}
+EXPORT_SYMBOL(pgste_perform_essa);
+
+/**
+ * set_pgste_bits - set specific PGSTE bits.
+ * @mm: the memory context. It must have PGSTEs, no check is performed here!
+ * @hva: the host virtual address of the page whose PGSTE is to be processed
+ * @bits: a bitmask representing the bits that will be touched
+ * @value: the values of the bits to be written. Only the bits in the mask
+ *	   will be written.
+ *
+ * Return: 0 on success, < 0 in case of error.
+ */
+int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
+			unsigned long bits, unsigned long value)
+{
+	struct vm_area_struct *vma;
+	spinlock_t *ptl;
+	pgste_t new;
+	pte_t *ptep;
+
+	vma = vma_lookup(mm, hva);
+	if (!vma || is_vm_hugetlb_page(vma))
+		return -EFAULT;
+	ptep = get_locked_pte(mm, hva, &ptl);
+	if (unlikely(!ptep))
+		return -EFAULT;
+	new = pgste_get_lock(ptep);
+
+	pgste_val(new) &= ~bits;
+	pgste_val(new) |= value & bits;
+
+	pgste_set_unlock(ptep, new);
+	pte_unmap_unlock(ptep, ptl);
+	return 0;
+}
+EXPORT_SYMBOL(set_pgste_bits);
+
+/**
+ * get_pgste - get the current PGSTE for the given address.
+ * @mm: the memory context. It must have PGSTEs, no check is performed here!
+ * @hva: the host virtual address of the page whose PGSTE is to be processed
+ * @pgstep: will be written with the current PGSTE for the given address.
+ *
+ * Return: 0 on success, < 0 in case of error.
+ */
+int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
+{
+	struct vm_area_struct *vma;
+	spinlock_t *ptl;
+	pte_t *ptep;
+
+	vma = vma_lookup(mm, hva);
+	if (!vma || is_vm_hugetlb_page(vma))
+		return -EFAULT;
+	ptep = get_locked_pte(mm, hva, &ptl);
+	if (unlikely(!ptep))
+		return -EFAULT;
+	*pgstep = pgste_val(pgste_get(ptep));
+	pte_unmap_unlock(ptep, ptl);
+	return 0;
+}
+EXPORT_SYMBOL(get_pgste);
+#endif
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
new file mode 100644
index 0000000000..6d276103c6
--- /dev/null
+++ b/arch/s390/mm/vmem.c
@@ -0,0 +1,669 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Copyright IBM Corp. 2006
+ */
+
+#include <linux/memory_hotplug.h>
+#include <linux/memblock.h>
+#include <linux/pfn.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/hugetlb.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <asm/page-states.h>
+#include <asm/cacheflush.h>
+#include <asm/nospec-branch.h>
+#include <asm/pgalloc.h>
+#include <asm/setup.h>
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+#include <asm/set_memory.h>
+
+static DEFINE_MUTEX(vmem_mutex);
+
+static void __ref *vmem_alloc_pages(unsigned int order)
+{
+	unsigned long size = PAGE_SIZE << order;
+
+	if (slab_is_available())
+		return (void *)__get_free_pages(GFP_KERNEL, order);
+	return memblock_alloc(size, size);
+}
+
+static void vmem_free_pages(unsigned long addr, int order)
+{
+	/* We don't expect boot memory to be removed ever. */
+	if (!slab_is_available() ||
+	    WARN_ON_ONCE(PageReserved(virt_to_page((void *)addr))))
+		return;
+	free_pages(addr, order);
+}
+
+void *vmem_crst_alloc(unsigned long val)
+{
+	unsigned long *table;
+
+	table = vmem_alloc_pages(CRST_ALLOC_ORDER);
+	if (!table)
+		return NULL;
+	crst_table_init(table, val);
+	if (slab_is_available())
+		arch_set_page_dat(virt_to_page(table), CRST_ALLOC_ORDER);
+	return table;
+}
+
+pte_t __ref *vmem_pte_alloc(void)
+{
+	unsigned long size = PTRS_PER_PTE * sizeof(pte_t);
+	pte_t *pte;
+
+	if (slab_is_available())
+		pte = (pte_t *) page_table_alloc(&init_mm);
+	else
+		pte = (pte_t *) memblock_alloc(size, size);
+	if (!pte)
+		return NULL;
+	memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
+	return pte;
+}
+
+static void vmem_pte_free(unsigned long *table)
+{
+	/* We don't expect boot memory to be removed ever. */
+	if (!slab_is_available() ||
+	    WARN_ON_ONCE(PageReserved(virt_to_page(table))))
+		return;
+	page_table_free(&init_mm, table);
+}
+
+#define PAGE_UNUSED 0xFD
+
+/*
+ * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges
+ * from unused_sub_pmd_start to next PMD_SIZE boundary.
+ */
+static unsigned long unused_sub_pmd_start;
+
+static void vmemmap_flush_unused_sub_pmd(void)
+{
+	if (!unused_sub_pmd_start)
+		return;
+	memset((void *)unused_sub_pmd_start, PAGE_UNUSED,
+	       ALIGN(unused_sub_pmd_start, PMD_SIZE) - unused_sub_pmd_start);
+	unused_sub_pmd_start = 0;
+}
+
+static void vmemmap_mark_sub_pmd_used(unsigned long start, unsigned long end)
+{
+	/*
+	 * As we expect to add in the same granularity as we remove, it's
+	 * sufficient to mark only some piece used to block the memmap page from
+	 * getting removed (just in case the memmap never gets initialized,
+	 * e.g., because the memory block never gets onlined).
+	 */
+	memset((void *)start, 0, sizeof(struct page));
+}
+
+static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end)
+{
+	/*
+	 * We only optimize if the new used range directly follows the
+	 * previously unused range (esp., when populating consecutive sections).
+	 */
+	if (unused_sub_pmd_start == start) {
+		unused_sub_pmd_start = end;
+		if (likely(IS_ALIGNED(unused_sub_pmd_start, PMD_SIZE)))
+			unused_sub_pmd_start = 0;
+		return;
+	}
+	vmemmap_flush_unused_sub_pmd();
+	vmemmap_mark_sub_pmd_used(start, end);
+}
+
+static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end)
+{
+	unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
+
+	vmemmap_flush_unused_sub_pmd();
+
+	/* Could be our memmap page is filled with PAGE_UNUSED already ... */
+	vmemmap_mark_sub_pmd_used(start, end);
+
+	/* Mark the unused parts of the new memmap page PAGE_UNUSED. */
+	if (!IS_ALIGNED(start, PMD_SIZE))
+		memset((void *)page, PAGE_UNUSED, start - page);
+	/*
+	 * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of
+	 * consecutive sections. Remember for the last added PMD the last
+	 * unused range in the populated PMD.
+	 */
+	if (!IS_ALIGNED(end, PMD_SIZE))
+		unused_sub_pmd_start = end;
+}
+
+/* Returns true if the PMD is completely unused and can be freed. */
+static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end)
+{
+	unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
+
+	vmemmap_flush_unused_sub_pmd();
+	memset((void *)start, PAGE_UNUSED, end - start);
+	return !memchr_inv((void *)page, PAGE_UNUSED, PMD_SIZE);
+}
+
+/* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
+static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr,
+				  unsigned long end, bool add, bool direct)
+{
+	unsigned long prot, pages = 0;
+	int ret = -ENOMEM;
+	pte_t *pte;
+
+	prot = pgprot_val(PAGE_KERNEL);
+	if (!MACHINE_HAS_NX)
+		prot &= ~_PAGE_NOEXEC;
+
+	pte = pte_offset_kernel(pmd, addr);
+	for (; addr < end; addr += PAGE_SIZE, pte++) {
+		if (!add) {
+			if (pte_none(*pte))
+				continue;
+			if (!direct)
+				vmem_free_pages((unsigned long) pfn_to_virt(pte_pfn(*pte)), 0);
+			pte_clear(&init_mm, addr, pte);
+		} else if (pte_none(*pte)) {
+			if (!direct) {
+				void *new_page = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
+
+				if (!new_page)
+					goto out;
+				set_pte(pte, __pte(__pa(new_page) | prot));
+			} else {
+				set_pte(pte, __pte(__pa(addr) | prot));
+			}
+		} else {
+			continue;
+		}
+		pages++;
+	}
+	ret = 0;
+out:
+	if (direct)
+		update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages);
+	return ret;
+}
+
+static void try_free_pte_table(pmd_t *pmd, unsigned long start)
+{
+	pte_t *pte;
+	int i;
+
+	/* We can safely assume this is fully in 1:1 mapping & vmemmap area */
+	pte = pte_offset_kernel(pmd, start);
+	for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
+		if (!pte_none(*pte))
+			return;
+	}
+	vmem_pte_free((unsigned long *) pmd_deref(*pmd));
+	pmd_clear(pmd);
+}
+
+/* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
+static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
+				  unsigned long end, bool add, bool direct)
+{
+	unsigned long next, prot, pages = 0;
+	int ret = -ENOMEM;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	prot = pgprot_val(SEGMENT_KERNEL);
+	if (!MACHINE_HAS_NX)
+		prot &= ~_SEGMENT_ENTRY_NOEXEC;
+
+	pmd = pmd_offset(pud, addr);
+	for (; addr < end; addr = next, pmd++) {
+		next = pmd_addr_end(addr, end);
+		if (!add) {
+			if (pmd_none(*pmd))
+				continue;
+			if (pmd_large(*pmd)) {
+				if (IS_ALIGNED(addr, PMD_SIZE) &&
+				    IS_ALIGNED(next, PMD_SIZE)) {
+					if (!direct)
+						vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
+					pmd_clear(pmd);
+					pages++;
+				} else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) {
+					vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
+					pmd_clear(pmd);
+				}
+				continue;
+			}
+		} else if (pmd_none(*pmd)) {
+			if (IS_ALIGNED(addr, PMD_SIZE) &&
+			    IS_ALIGNED(next, PMD_SIZE) &&
+			    MACHINE_HAS_EDAT1 && direct &&
+			    !debug_pagealloc_enabled()) {
+				set_pmd(pmd, __pmd(__pa(addr) | prot));
+				pages++;
+				continue;
+			} else if (!direct && MACHINE_HAS_EDAT1) {
+				void *new_page;
+
+				/*
+				 * Use 1MB frames for vmemmap if available. We
+				 * always use large frames even if they are only
+				 * partially used. Otherwise we would have also
+				 * page tables since vmemmap_populate gets
+				 * called for each section separately.
+				 */
+				new_page = vmemmap_alloc_block(PMD_SIZE, NUMA_NO_NODE);
+				if (new_page) {
+					set_pmd(pmd, __pmd(__pa(new_page) | prot));
+					if (!IS_ALIGNED(addr, PMD_SIZE) ||
+					    !IS_ALIGNED(next, PMD_SIZE)) {
+						vmemmap_use_new_sub_pmd(addr, next);
+					}
+					continue;
+				}
+			}
+			pte = vmem_pte_alloc();
+			if (!pte)
+				goto out;
+			pmd_populate(&init_mm, pmd, pte);
+		} else if (pmd_large(*pmd)) {
+			if (!direct)
+				vmemmap_use_sub_pmd(addr, next);
+			continue;
+		}
+		ret = modify_pte_table(pmd, addr, next, add, direct);
+		if (ret)
+			goto out;
+		if (!add)
+			try_free_pte_table(pmd, addr & PMD_MASK);
+	}
+	ret = 0;
+out:
+	if (direct)
+		update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages);
+	return ret;
+}
+
+static void try_free_pmd_table(pud_t *pud, unsigned long start)
+{
+	pmd_t *pmd;
+	int i;
+
+	pmd = pmd_offset(pud, start);
+	for (i = 0; i < PTRS_PER_PMD; i++, pmd++)
+		if (!pmd_none(*pmd))
+			return;
+	vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER);
+	pud_clear(pud);
+}
+
+static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
+			    bool add, bool direct)
+{
+	unsigned long next, prot, pages = 0;
+	int ret = -ENOMEM;
+	pud_t *pud;
+	pmd_t *pmd;
+
+	prot = pgprot_val(REGION3_KERNEL);
+	if (!MACHINE_HAS_NX)
+		prot &= ~_REGION_ENTRY_NOEXEC;
+	pud = pud_offset(p4d, addr);
+	for (; addr < end; addr = next, pud++) {
+		next = pud_addr_end(addr, end);
+		if (!add) {
+			if (pud_none(*pud))
+				continue;
+			if (pud_large(*pud)) {
+				if (IS_ALIGNED(addr, PUD_SIZE) &&
+				    IS_ALIGNED(next, PUD_SIZE)) {
+					pud_clear(pud);
+					pages++;
+				}
+				continue;
+			}
+		} else if (pud_none(*pud)) {
+			if (IS_ALIGNED(addr, PUD_SIZE) &&
+			    IS_ALIGNED(next, PUD_SIZE) &&
+			    MACHINE_HAS_EDAT2 && direct &&
+			    !debug_pagealloc_enabled()) {
+				set_pud(pud, __pud(__pa(addr) | prot));
+				pages++;
+				continue;
+			}
+			pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
+			if (!pmd)
+				goto out;
+			pud_populate(&init_mm, pud, pmd);
+		} else if (pud_large(*pud)) {
+			continue;
+		}
+		ret = modify_pmd_table(pud, addr, next, add, direct);
+		if (ret)
+			goto out;
+		if (!add)
+			try_free_pmd_table(pud, addr & PUD_MASK);
+	}
+	ret = 0;
+out:
+	if (direct)
+		update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages);
+	return ret;
+}
+
+static void try_free_pud_table(p4d_t *p4d, unsigned long start)
+{
+	pud_t *pud;
+	int i;
+
+	pud = pud_offset(p4d, start);
+	for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
+		if (!pud_none(*pud))
+			return;
+	}
+	vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER);
+	p4d_clear(p4d);
+}
+
+static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
+			    bool add, bool direct)
+{
+	unsigned long next;
+	int ret = -ENOMEM;
+	p4d_t *p4d;
+	pud_t *pud;
+
+	p4d = p4d_offset(pgd, addr);
+	for (; addr < end; addr = next, p4d++) {
+		next = p4d_addr_end(addr, end);
+		if (!add) {
+			if (p4d_none(*p4d))
+				continue;
+		} else if (p4d_none(*p4d)) {
+			pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
+			if (!pud)
+				goto out;
+			p4d_populate(&init_mm, p4d, pud);
+		}
+		ret = modify_pud_table(p4d, addr, next, add, direct);
+		if (ret)
+			goto out;
+		if (!add)
+			try_free_pud_table(p4d, addr & P4D_MASK);
+	}
+	ret = 0;
+out:
+	return ret;
+}
+
+static void try_free_p4d_table(pgd_t *pgd, unsigned long start)
+{
+	p4d_t *p4d;
+	int i;
+
+	p4d = p4d_offset(pgd, start);
+	for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
+		if (!p4d_none(*p4d))
+			return;
+	}
+	vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER);
+	pgd_clear(pgd);
+}
+
+static int modify_pagetable(unsigned long start, unsigned long end, bool add,
+			    bool direct)
+{
+	unsigned long addr, next;
+	int ret = -ENOMEM;
+	pgd_t *pgd;
+	p4d_t *p4d;
+
+	if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end)))
+		return -EINVAL;
+	/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
+	if (WARN_ON_ONCE(end > VMALLOC_START))
+		return -EINVAL;
+	for (addr = start; addr < end; addr = next) {
+		next = pgd_addr_end(addr, end);
+		pgd = pgd_offset_k(addr);
+
+		if (!add) {
+			if (pgd_none(*pgd))
+				continue;
+		} else if (pgd_none(*pgd)) {
+			p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
+			if (!p4d)
+				goto out;
+			pgd_populate(&init_mm, pgd, p4d);
+		}
+		ret = modify_p4d_table(pgd, addr, next, add, direct);
+		if (ret)
+			goto out;
+		if (!add)
+			try_free_p4d_table(pgd, addr & PGDIR_MASK);
+	}
+	ret = 0;
+out:
+	if (!add)
+		flush_tlb_kernel_range(start, end);
+	return ret;
+}
+
+static int add_pagetable(unsigned long start, unsigned long end, bool direct)
+{
+	return modify_pagetable(start, end, true, direct);
+}
+
+static int remove_pagetable(unsigned long start, unsigned long end, bool direct)
+{
+	return modify_pagetable(start, end, false, direct);
+}
+
+/*
+ * Add a physical memory range to the 1:1 mapping.
+ */
+static int vmem_add_range(unsigned long start, unsigned long size)
+{
+	start = (unsigned long)__va(start);
+	return add_pagetable(start, start + size, true);
+}
+
+/*
+ * Remove a physical memory range from the 1:1 mapping.
+ */
+static void vmem_remove_range(unsigned long start, unsigned long size)
+{
+	start = (unsigned long)__va(start);
+	remove_pagetable(start, start + size, true);
+}
+
+/*
+ * Add a backed mem_map array to the virtual mem_map array.
+ */
+int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
+			       struct vmem_altmap *altmap)
+{
+	int ret;
+
+	mutex_lock(&vmem_mutex);
+	/* We don't care about the node, just use NUMA_NO_NODE on allocations */
+	ret = add_pagetable(start, end, false);
+	if (ret)
+		remove_pagetable(start, end, false);
+	mutex_unlock(&vmem_mutex);
+	return ret;
+}
+
+void vmemmap_free(unsigned long start, unsigned long end,
+		  struct vmem_altmap *altmap)
+{
+	mutex_lock(&vmem_mutex);
+	remove_pagetable(start, end, false);
+	mutex_unlock(&vmem_mutex);
+}
+
+void vmem_remove_mapping(unsigned long start, unsigned long size)
+{
+	mutex_lock(&vmem_mutex);
+	vmem_remove_range(start, size);
+	mutex_unlock(&vmem_mutex);
+}
+
+struct range arch_get_mappable_range(void)
+{
+	struct range mhp_range;
+
+	mhp_range.start = 0;
+	mhp_range.end = max_mappable - 1;
+	return mhp_range;
+}
+
+int vmem_add_mapping(unsigned long start, unsigned long size)
+{
+	struct range range = arch_get_mappable_range();
+	int ret;
+
+	if (start < range.start ||
+	    start + size > range.end + 1 ||
+	    start + size < start)
+		return -ERANGE;
+
+	mutex_lock(&vmem_mutex);
+	ret = vmem_add_range(start, size);
+	if (ret)
+		vmem_remove_range(start, size);
+	mutex_unlock(&vmem_mutex);
+	return ret;
+}
+
+/*
+ * Allocate new or return existing page-table entry, but do not map it
+ * to any physical address. If missing, allocate segment- and region-
+ * table entries along. Meeting a large segment- or region-table entry
+ * while traversing is an error, since the function is expected to be
+ * called against virtual regions reserved for 4KB mappings only.
+ */
+pte_t *vmem_get_alloc_pte(unsigned long addr, bool alloc)
+{
+	pte_t *ptep = NULL;
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	pgd = pgd_offset_k(addr);
+	if (pgd_none(*pgd)) {
+		if (!alloc)
+			goto out;
+		p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
+		if (!p4d)
+			goto out;
+		pgd_populate(&init_mm, pgd, p4d);
+	}
+	p4d = p4d_offset(pgd, addr);
+	if (p4d_none(*p4d)) {
+		if (!alloc)
+			goto out;
+		pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
+		if (!pud)
+			goto out;
+		p4d_populate(&init_mm, p4d, pud);
+	}
+	pud = pud_offset(p4d, addr);
+	if (pud_none(*pud)) {
+		if (!alloc)
+			goto out;
+		pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
+		if (!pmd)
+			goto out;
+		pud_populate(&init_mm, pud, pmd);
+	} else if (WARN_ON_ONCE(pud_large(*pud))) {
+		goto out;
+	}
+	pmd = pmd_offset(pud, addr);
+	if (pmd_none(*pmd)) {
+		if (!alloc)
+			goto out;
+		pte = vmem_pte_alloc();
+		if (!pte)
+			goto out;
+		pmd_populate(&init_mm, pmd, pte);
+	} else if (WARN_ON_ONCE(pmd_large(*pmd))) {
+		goto out;
+	}
+	ptep = pte_offset_kernel(pmd, addr);
+out:
+	return ptep;
+}
+
+int __vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot, bool alloc)
+{
+	pte_t *ptep, pte;
+
+	if (!IS_ALIGNED(addr, PAGE_SIZE))
+		return -EINVAL;
+	ptep = vmem_get_alloc_pte(addr, alloc);
+	if (!ptep)
+		return -ENOMEM;
+	__ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
+	pte = mk_pte_phys(phys, prot);
+	set_pte(ptep, pte);
+	return 0;
+}
+
+int vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot)
+{
+	int rc;
+
+	mutex_lock(&vmem_mutex);
+	rc = __vmem_map_4k_page(addr, phys, prot, true);
+	mutex_unlock(&vmem_mutex);
+	return rc;
+}
+
+void vmem_unmap_4k_page(unsigned long addr)
+{
+	pte_t *ptep;
+
+	mutex_lock(&vmem_mutex);
+	ptep = virt_to_kpte(addr);
+	__ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
+	pte_clear(&init_mm, addr, ptep);
+	mutex_unlock(&vmem_mutex);
+}
+
+void __init vmem_map_init(void)
+{
+	__set_memory_rox(_stext, _etext);
+	__set_memory_ro(_etext, __end_rodata);
+	__set_memory_rox(_sinittext, _einittext);
+	__set_memory_rox(__stext_amode31, __etext_amode31);
+	/*
+	 * If the BEAR-enhancement facility is not installed the first
+	 * prefix page is used to return to the previous context with
+	 * an LPSWE instruction and therefore must be executable.
+	 */
+	if (!static_key_enabled(&cpu_has_bear))
+		set_memory_x(0, 1);
+	if (debug_pagealloc_enabled()) {
+		/*
+		 * Use RELOC_HIDE() as long as __va(0) translates to NULL,
+		 * since performing pointer arithmetic on a NULL pointer
+		 * has undefined behavior and generates compiler warnings.
+		 */
+		__set_memory_4k(__va(0), RELOC_HIDE(__va(0), ident_map_size));
+	}
+	if (MACHINE_HAS_NX)
+		ctl_set_bit(0, 20);
+	pr_info("Write protected kernel read-only data: %luk\n",
+		(unsigned long)(__end_rodata - _stext) >> 10);
+}