1 files changed, 477 insertions, 0 deletions
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
new file mode 100644
index 0000000000..02870beb27
--- /dev/null
+++ b/arch/arm64/kernel/hibernate.c
@@ -0,0 +1,477 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*:
+ * Hibernate support specific for ARM64
+ *
+ * Derived from work on ARM hibernation support by:
+ *
+ * Ubuntu project, hibernation support for mach-dove
+ * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu)
+ * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.)
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ */
+#define pr_fmt(x) "hibernate: " x
+#include <linux/cpu.h>
+#include <linux/kvm_host.h>
+#include <linux/pm.h>
+#include <linux/sched.h>
+#include <linux/suspend.h>
+#include <linux/utsname.h>
+
+#include <asm/barrier.h>
+#include <asm/cacheflush.h>
+#include <asm/cputype.h>
+#include <asm/daifflags.h>
+#include <asm/irqflags.h>
+#include <asm/kexec.h>
+#include <asm/memory.h>
+#include <asm/mmu_context.h>
+#include <asm/mte.h>
+#include <asm/sections.h>
+#include <asm/smp.h>
+#include <asm/smp_plat.h>
+#include <asm/suspend.h>
+#include <asm/sysreg.h>
+#include <asm/trans_pgd.h>
+#include <asm/virt.h>
+
+/*
+ * Hibernate core relies on this value being 0 on resume, and marks it
+ * __nosavedata assuming it will keep the resume kernel's '0' value. This
+ * doesn't happen with either KASLR.
+ *
+ * defined as "__visible int in_suspend __nosavedata" in
+ * kernel/power/hibernate.c
+ */
+extern int in_suspend;
+
+/* Do we need to reset el2? */
+#define el2_reset_needed() (is_hyp_nvhe())
+
+/* hyp-stub vectors, used to restore el2 during resume from hibernate. */
+extern char __hyp_stub_vectors[];
+
+/*
+ * The logical cpu number we should resume on, initialised to a non-cpu
+ * number.
+ */
+static int sleep_cpu = -EINVAL;
+
+/*
+ * Values that may not change over hibernate/resume. We put the build number
+ * and date in here so that we guarantee not to resume with a different
+ * kernel.
+ */
+struct arch_hibernate_hdr_invariants {
+	char		uts_version[__NEW_UTS_LEN + 1];
+};
+
+/* These values need to be know across a hibernate/restore. */
+static struct arch_hibernate_hdr {
+	struct arch_hibernate_hdr_invariants invariants;
+
+	/* These are needed to find the relocated kernel if built with kaslr */
+	phys_addr_t	ttbr1_el1;
+	void		(*reenter_kernel)(void);
+
+	/*
+	 * We need to know where the __hyp_stub_vectors are after restore to
+	 * re-configure el2.
+	 */
+	phys_addr_t	__hyp_stub_vectors;
+
+	u64		sleep_cpu_mpidr;
+} resume_hdr;
+
+static inline void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i)
+{
+	memset(i, 0, sizeof(*i));
+	memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version));
+}
+
+int pfn_is_nosave(unsigned long pfn)
+{
+	unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin);
+	unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1);
+
+	return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn)) ||
+		crash_is_nosave(pfn);
+}
+
+void notrace save_processor_state(void)
+{
+}
+
+void notrace restore_processor_state(void)
+{
+}
+
+int arch_hibernation_header_save(void *addr, unsigned int max_size)
+{
+	struct arch_hibernate_hdr *hdr = addr;
+
+	if (max_size < sizeof(*hdr))
+		return -EOVERFLOW;
+
+	arch_hdr_invariants(&hdr->invariants);
+	hdr->ttbr1_el1		= __pa_symbol(swapper_pg_dir);
+	hdr->reenter_kernel	= _cpu_resume;
+
+	/* We can't use __hyp_get_vectors() because kvm may still be loaded */
+	if (el2_reset_needed())
+		hdr->__hyp_stub_vectors = __pa_symbol(__hyp_stub_vectors);
+	else
+		hdr->__hyp_stub_vectors = 0;
+
+	/* Save the mpidr of the cpu we called cpu_suspend() on... */
+	if (sleep_cpu < 0) {
+		pr_err("Failing to hibernate on an unknown CPU.\n");
+		return -ENODEV;
+	}
+	hdr->sleep_cpu_mpidr = cpu_logical_map(sleep_cpu);
+	pr_info("Hibernating on CPU %d [mpidr:0x%llx]\n", sleep_cpu,
+		hdr->sleep_cpu_mpidr);
+
+	return 0;
+}
+EXPORT_SYMBOL(arch_hibernation_header_save);
+
+int arch_hibernation_header_restore(void *addr)
+{
+	int ret;
+	struct arch_hibernate_hdr_invariants invariants;
+	struct arch_hibernate_hdr *hdr = addr;
+
+	arch_hdr_invariants(&invariants);
+	if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) {
+		pr_crit("Hibernate image not generated by this kernel!\n");
+		return -EINVAL;
+	}
+
+	sleep_cpu = get_logical_index(hdr->sleep_cpu_mpidr);
+	pr_info("Hibernated on CPU %d [mpidr:0x%llx]\n", sleep_cpu,
+		hdr->sleep_cpu_mpidr);
+	if (sleep_cpu < 0) {
+		pr_crit("Hibernated on a CPU not known to this kernel!\n");
+		sleep_cpu = -EINVAL;
+		return -EINVAL;
+	}
+
+	ret = bringup_hibernate_cpu(sleep_cpu);
+	if (ret) {
+		sleep_cpu = -EINVAL;
+		return ret;
+	}
+
+	resume_hdr = *hdr;
+
+	return 0;
+}
+EXPORT_SYMBOL(arch_hibernation_header_restore);
+
+static void *hibernate_page_alloc(void *arg)
+{
+	return (void *)get_safe_page((__force gfp_t)(unsigned long)arg);
+}
+
+/*
+ * Copies length bytes, starting at src_start into an new page,
+ * perform cache maintenance, then maps it at the specified address low
+ * address as executable.
+ *
+ * This is used by hibernate to copy the code it needs to execute when
+ * overwriting the kernel text. This function generates a new set of page
+ * tables, which it loads into ttbr0.
+ *
+ * Length is provided as we probably only want 4K of data, even on a 64K
+ * page system.
+ */
+static int create_safe_exec_page(void *src_start, size_t length,
+				 phys_addr_t *phys_dst_addr)
+{
+	struct trans_pgd_info trans_info = {
+		.trans_alloc_page	= hibernate_page_alloc,
+		.trans_alloc_arg	= (__force void *)GFP_ATOMIC,
+	};
+
+	void *page = (void *)get_safe_page(GFP_ATOMIC);
+	phys_addr_t trans_ttbr0;
+	unsigned long t0sz;
+	int rc;
+
+	if (!page)
+		return -ENOMEM;
+
+	memcpy(page, src_start, length);
+	caches_clean_inval_pou((unsigned long)page, (unsigned long)page + length);
+	rc = trans_pgd_idmap_page(&trans_info, &trans_ttbr0, &t0sz, page);
+	if (rc)
+		return rc;
+
+	cpu_install_ttbr0(trans_ttbr0, t0sz);
+	*phys_dst_addr = virt_to_phys(page);
+
+	return 0;
+}
+
+#ifdef CONFIG_ARM64_MTE
+
+static DEFINE_XARRAY(mte_pages);
+
+static int save_tags(struct page *page, unsigned long pfn)
+{
+	void *tag_storage, *ret;
+
+	tag_storage = mte_allocate_tag_storage();
+	if (!tag_storage)
+		return -ENOMEM;
+
+	mte_save_page_tags(page_address(page), tag_storage);
+
+	ret = xa_store(&mte_pages, pfn, tag_storage, GFP_KERNEL);
+	if (WARN(xa_is_err(ret), "Failed to store MTE tags")) {
+		mte_free_tag_storage(tag_storage);
+		return xa_err(ret);
+	} else if (WARN(ret, "swsusp: %s: Duplicate entry", __func__)) {
+		mte_free_tag_storage(ret);
+	}
+
+	return 0;
+}
+
+static void swsusp_mte_free_storage(void)
+{
+	XA_STATE(xa_state, &mte_pages, 0);
+	void *tags;
+
+	xa_lock(&mte_pages);
+	xas_for_each(&xa_state, tags, ULONG_MAX) {
+		mte_free_tag_storage(tags);
+	}
+	xa_unlock(&mte_pages);
+
+	xa_destroy(&mte_pages);
+}
+
+static int swsusp_mte_save_tags(void)
+{
+	struct zone *zone;
+	unsigned long pfn, max_zone_pfn;
+	int ret = 0;
+	int n = 0;
+
+	if (!system_supports_mte())
+		return 0;
+
+	for_each_populated_zone(zone) {
+		max_zone_pfn = zone_end_pfn(zone);
+		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) {
+			struct page *page = pfn_to_online_page(pfn);
+
+			if (!page)
+				continue;
+
+			if (!page_mte_tagged(page))
+				continue;
+
+			ret = save_tags(page, pfn);
+			if (ret) {
+				swsusp_mte_free_storage();
+				goto out;
+			}
+
+			n++;
+		}
+	}
+	pr_info("Saved %d MTE pages\n", n);
+
+out:
+	return ret;
+}
+
+static void swsusp_mte_restore_tags(void)
+{
+	XA_STATE(xa_state, &mte_pages, 0);
+	int n = 0;
+	void *tags;
+
+	xa_lock(&mte_pages);
+	xas_for_each(&xa_state, tags, ULONG_MAX) {
+		unsigned long pfn = xa_state.xa_index;
+		struct page *page = pfn_to_online_page(pfn);
+
+		mte_restore_page_tags(page_address(page), tags);
+
+		mte_free_tag_storage(tags);
+		n++;
+	}
+	xa_unlock(&mte_pages);
+
+	pr_info("Restored %d MTE pages\n", n);
+
+	xa_destroy(&mte_pages);
+}
+
+#else	/* CONFIG_ARM64_MTE */
+
+static int swsusp_mte_save_tags(void)
+{
+	return 0;
+}
+
+static void swsusp_mte_restore_tags(void)
+{
+}
+
+#endif	/* CONFIG_ARM64_MTE */
+
+int swsusp_arch_suspend(void)
+{
+	int ret = 0;
+	unsigned long flags;
+	struct sleep_stack_data state;
+
+	if (cpus_are_stuck_in_kernel()) {
+		pr_err("Can't hibernate: no mechanism to offline secondary CPUs.\n");
+		return -EBUSY;
+	}
+
+	flags = local_daif_save();
+
+	if (__cpu_suspend_enter(&state)) {
+		/* make the crash dump kernel image visible/saveable */
+		crash_prepare_suspend();
+
+		ret = swsusp_mte_save_tags();
+		if (ret)
+			return ret;
+
+		sleep_cpu = smp_processor_id();
+		ret = swsusp_save();
+	} else {
+		/* Clean kernel core startup/idle code to PoC*/
+		dcache_clean_inval_poc((unsigned long)__mmuoff_data_start,
+				    (unsigned long)__mmuoff_data_end);
+		dcache_clean_inval_poc((unsigned long)__idmap_text_start,
+				    (unsigned long)__idmap_text_end);
+
+		/* Clean kvm setup code to PoC? */
+		if (el2_reset_needed()) {
+			dcache_clean_inval_poc(
+				(unsigned long)__hyp_idmap_text_start,
+				(unsigned long)__hyp_idmap_text_end);
+			dcache_clean_inval_poc((unsigned long)__hyp_text_start,
+					    (unsigned long)__hyp_text_end);
+		}
+
+		swsusp_mte_restore_tags();
+
+		/* make the crash dump kernel image protected again */
+		crash_post_resume();
+
+		/*
+		 * Tell the hibernation core that we've just restored
+		 * the memory
+		 */
+		in_suspend = 0;
+
+		sleep_cpu = -EINVAL;
+		__cpu_suspend_exit();
+
+		/*
+		 * Just in case the boot kernel did turn the SSBD
+		 * mitigation off behind our back, let's set the state
+		 * to what we expect it to be.
+		 */
+		spectre_v4_enable_mitigation(NULL);
+	}
+
+	local_daif_restore(flags);
+
+	return ret;
+}
+
+/*
+ * Setup then Resume from the hibernate image using swsusp_arch_suspend_exit().
+ *
+ * Memory allocated by get_safe_page() will be dealt with by the hibernate code,
+ * we don't need to free it here.
+ */
+int swsusp_arch_resume(void)
+{
+	int rc;
+	void *zero_page;
+	size_t exit_size;
+	pgd_t *tmp_pg_dir;
+	phys_addr_t el2_vectors;
+	void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *,
+					  void *, phys_addr_t, phys_addr_t);
+	struct trans_pgd_info trans_info = {
+		.trans_alloc_page	= hibernate_page_alloc,
+		.trans_alloc_arg	= (void *)GFP_ATOMIC,
+	};
+
+	/*
+	 * Restoring the memory image will overwrite the ttbr1 page tables.
+	 * Create a second copy of just the linear map, and use this when
+	 * restoring.
+	 */
+	rc = trans_pgd_create_copy(&trans_info, &tmp_pg_dir, PAGE_OFFSET,
+				   PAGE_END);
+	if (rc)
+		return rc;
+
+	/*
+	 * We need a zero page that is zero before & after resume in order
+	 * to break before make on the ttbr1 page tables.
+	 */
+	zero_page = (void *)get_safe_page(GFP_ATOMIC);
+	if (!zero_page) {
+		pr_err("Failed to allocate zero page.\n");
+		return -ENOMEM;
+	}
+
+	if (el2_reset_needed()) {
+		rc = trans_pgd_copy_el2_vectors(&trans_info, &el2_vectors);
+		if (rc) {
+			pr_err("Failed to setup el2 vectors\n");
+			return rc;
+		}
+	}
+
+	exit_size = __hibernate_exit_text_end - __hibernate_exit_text_start;
+	/*
+	 * Copy swsusp_arch_suspend_exit() to a safe page. This will generate
+	 * a new set of ttbr0 page tables and load them.
+	 */
+	rc = create_safe_exec_page(__hibernate_exit_text_start, exit_size,
+				   (phys_addr_t *)&hibernate_exit);
+	if (rc) {
+		pr_err("Failed to create safe executable page for hibernate_exit code.\n");
+		return rc;
+	}
+
+	/*
+	 * KASLR will cause the el2 vectors to be in a different location in
+	 * the resumed kernel. Load hibernate's temporary copy into el2.
+	 *
+	 * We can skip this step if we booted at EL1, or are running with VHE.
+	 */
+	if (el2_reset_needed())
+		__hyp_set_vectors(el2_vectors);
+
+	hibernate_exit(virt_to_phys(tmp_pg_dir), resume_hdr.ttbr1_el1,
+		       resume_hdr.reenter_kernel, restore_pblist,
+		       resume_hdr.__hyp_stub_vectors, virt_to_phys(zero_page));
+
+	return 0;
+}
+
+int hibernate_resume_nonboot_cpu_disable(void)
+{
+	if (sleep_cpu < 0) {
+		pr_err("Failing to resume from hibernate on an unknown CPU.\n");
+		return -ENODEV;
+	}
+
+	return freeze_secondary_cpus(sleep_cpu);
+}