1 files changed, 281 insertions, 0 deletions
diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c
new file mode 100644
index 000000000..dc3cede7f
--- /dev/null
+++ b/arch/s390/mm/page-states.c
@@ -0,0 +1,281 @@
+// 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/facility.h>
+#include <asm/page-states.h>
+
+static int cmma_flag = 1;
+
+static int __init cmma(char *str)
+{
+	char *parm;
+
+	parm = strstrip(str);
+	if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {
+		cmma_flag = 1;
+		return 1;
+	}
+	cmma_flag = 0;
+	if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)
+		return 1;
+	return 0;
+}
+__setup("cmma=", cmma);
+
+static inline int cmma_test_essa(void)
+{
+	register unsigned long tmp asm("0") = 0;
+	register int rc asm("1");
+
+	/* test ESSA_GET_STATE */
+	asm volatile(
+		"	.insn	rrf,0xb9ab0000,%1,%1,%2,0\n"
+		"0:     la      %0,0\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "=&d" (rc), "+&d" (tmp)
+		: "i" (ESSA_GET_STATE), "0" (-EOPNOTSUPP));
+	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 unsigned char get_page_state(struct page *page)
+{
+	unsigned char state;
+
+	asm volatile("	.insn	rrf,0xb9ab0000,%0,%1,%2,0"
+		     : "=&d" (state)
+		     : "a" (page_to_phys(page)),
+		       "i" (ESSA_GET_STATE));
+	return state & 0x3f;
+}
+
+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 = virt_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 = virt_to_page(pud_val(*pud));
+			for (i = 0; i < 3; 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 = virt_to_page(p4d_val(*p4d));
+			for (i = 0; i < 3; 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 = virt_to_page(pgd_val(*pgd));
+			for (i = 0; i < 3; 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 memblock_region *reg;
+	struct page *page;
+	unsigned long start, end, ix;
+
+	if (cmma_flag < 2)
+		return;
+	/* Mark pages used in kernel page tables */
+	mark_kernel_pgd();
+
+	/* Set all kernel pages not used for page tables to stable/no-dat */
+	for_each_memblock(memory, reg) {
+		start = memblock_region_memory_base_pfn(reg);
+		end = memblock_region_memory_end_pfn(reg);
+		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);
+}
+
+void arch_set_page_nodat(struct page *page, int order)
+{
+	if (cmma_flag < 2)
+		return;
+	set_page_stable_nodat(page, order);
+}
+
+int arch_test_page_nodat(struct page *page)
+{
+	unsigned char state;
+
+	if (cmma_flag < 2)
+		return 0;
+	state = get_page_state(page);
+	return !!(state & 0x20);
+}
+
+void arch_set_page_states(int make_stable)
+{
+	unsigned long flags, order, t;
+	struct list_head *l;
+	struct page *page;
+	struct zone *zone;
+
+	if (!cmma_flag)
+		return;
+	if (make_stable)
+		drain_local_pages(NULL);
+	for_each_populated_zone(zone) {
+		spin_lock_irqsave(&zone->lock, flags);
+		for_each_migratetype_order(order, t) {
+			list_for_each(l, &zone->free_area[order].free_list[t]) {
+				page = list_entry(l, struct page, lru);
+				if (make_stable)
+					set_page_stable_dat(page, order);
+				else
+					set_page_unused(page, order);
+			}
+		}
+		spin_unlock_irqrestore(&zone->lock, flags);
+	}
+}