summaryrefslogtreecommitdiff
path: root/arch/arm64/kernel/hibernate.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm64/kernel/hibernate.c')
-rw-r--r--arch/arm64/kernel/hibernate.c461
1 files changed, 461 insertions, 0 deletions
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
new file mode 100644
index 000000000000..7e16fb327644
--- /dev/null
+++ b/arch/arm64/kernel/hibernate.c
@@ -0,0 +1,461 @@
+/*:
+ * 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.)
+ * https://lkml.org/lkml/2010/6/18/4
+ * https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html
+ * https://patchwork.kernel.org/patch/96442/
+ *
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ */
+#define pr_fmt(x) "hibernate: " x
+#include <linux/kvm_host.h>
+#include <linux/mm.h>
+#include <linux/pm.h>
+#include <linux/sched.h>
+#include <linux/suspend.h>
+#include <linux/utsname.h>
+#include <linux/version.h>
+
+#include <asm/barrier.h>
+#include <asm/cacheflush.h>
+#include <asm/irqflags.h>
+#include <asm/memory.h>
+#include <asm/mmu_context.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/pgtable-hwdef.h>
+#include <asm/sections.h>
+#include <asm/suspend.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;
+
+/* Find a symbols alias in the linear map */
+#define LMADDR(x) phys_to_virt(virt_to_phys(x))
+
+/* Do we need to reset el2? */
+#define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode())
+
+/*
+ * Start/end of the hibernate exit code, this must be copied to a 'safe'
+ * location in memory, and executed from there.
+ */
+extern char __hibernate_exit_text_start[], __hibernate_exit_text_end[];
+
+/* temporary el2 vectors in the __hibernate_exit_text section. */
+extern char hibernate_el2_vectors[];
+
+/* hyp-stub vectors, used to restore el2 during resume from hibernate. */
+extern char __hyp_stub_vectors[];
+
+/*
+ * 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;
+} 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 = virt_to_pfn(&__nosave_begin);
+ unsigned long nosave_end_pfn = virt_to_pfn(&__nosave_end - 1);
+
+ return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn);
+}
+
+void notrace save_processor_state(void)
+{
+ WARN_ON(num_online_cpus() != 1);
+}
+
+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 = virt_to_phys(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 = virt_to_phys(__hyp_stub_vectors);
+ else
+ hdr->__hyp_stub_vectors = 0;
+
+ return 0;
+}
+EXPORT_SYMBOL(arch_hibernation_header_save);
+
+int arch_hibernation_header_restore(void *addr)
+{
+ 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;
+ }
+
+ resume_hdr = *hdr;
+
+ return 0;
+}
+EXPORT_SYMBOL(arch_hibernation_header_restore);
+
+/*
+ * Copies length bytes, starting at src_start into an new page,
+ * perform cache maintentance, 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,
+ unsigned long dst_addr,
+ phys_addr_t *phys_dst_addr,
+ void *(*allocator)(gfp_t mask),
+ gfp_t mask)
+{
+ int rc = 0;
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned long dst = (unsigned long)allocator(mask);
+
+ if (!dst) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ memcpy((void *)dst, src_start, length);
+ flush_icache_range(dst, dst + length);
+
+ pgd = pgd_offset_raw(allocator(mask), dst_addr);
+ if (pgd_none(*pgd)) {
+ pud = allocator(mask);
+ if (!pud) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ pgd_populate(&init_mm, pgd, pud);
+ }
+
+ pud = pud_offset(pgd, dst_addr);
+ if (pud_none(*pud)) {
+ pmd = allocator(mask);
+ if (!pmd) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ pud_populate(&init_mm, pud, pmd);
+ }
+
+ pmd = pmd_offset(pud, dst_addr);
+ if (pmd_none(*pmd)) {
+ pte = allocator(mask);
+ if (!pte) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ pmd_populate_kernel(&init_mm, pmd, pte);
+ }
+
+ pte = pte_offset_kernel(pmd, dst_addr);
+ set_pte(pte, __pte(virt_to_phys((void *)dst) |
+ pgprot_val(PAGE_KERNEL_EXEC)));
+
+ /* Load our new page tables */
+ asm volatile("msr ttbr0_el1, %0;"
+ "isb;"
+ "tlbi vmalle1is;"
+ "dsb ish;"
+ "isb" : : "r"(virt_to_phys(pgd)));
+
+ *phys_dst_addr = virt_to_phys((void *)dst);
+
+out:
+ return rc;
+}
+
+
+int swsusp_arch_suspend(void)
+{
+ int ret = 0;
+ unsigned long flags;
+ struct sleep_stack_data state;
+
+ local_dbg_save(flags);
+
+ if (__cpu_suspend_enter(&state)) {
+ ret = swsusp_save();
+ } else {
+ /* Clean kernel to PoC for secondary core startup */
+ __flush_dcache_area(LMADDR(KERNEL_START), KERNEL_END - KERNEL_START);
+
+ /*
+ * Tell the hibernation core that we've just restored
+ * the memory
+ */
+ in_suspend = 0;
+
+ __cpu_suspend_exit();
+ }
+
+ local_dbg_restore(flags);
+
+ return ret;
+}
+
+static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start,
+ unsigned long end)
+{
+ pte_t *src_pte;
+ pte_t *dst_pte;
+ unsigned long addr = start;
+
+ dst_pte = (pte_t *)get_safe_page(GFP_ATOMIC);
+ if (!dst_pte)
+ return -ENOMEM;
+ pmd_populate_kernel(&init_mm, dst_pmd, dst_pte);
+ dst_pte = pte_offset_kernel(dst_pmd, start);
+
+ src_pte = pte_offset_kernel(src_pmd, start);
+ do {
+ if (!pte_none(*src_pte))
+ /*
+ * Resume will overwrite areas that may be marked
+ * read only (code, rodata). Clear the RDONLY bit from
+ * the temporary mappings we use during restore.
+ */
+ set_pte(dst_pte, __pte(pte_val(*src_pte) & ~PTE_RDONLY));
+ } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
+
+ return 0;
+}
+
+static int copy_pmd(pud_t *dst_pud, pud_t *src_pud, unsigned long start,
+ unsigned long end)
+{
+ pmd_t *src_pmd;
+ pmd_t *dst_pmd;
+ unsigned long next;
+ unsigned long addr = start;
+
+ if (pud_none(*dst_pud)) {
+ dst_pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
+ if (!dst_pmd)
+ return -ENOMEM;
+ pud_populate(&init_mm, dst_pud, dst_pmd);
+ }
+ dst_pmd = pmd_offset(dst_pud, start);
+
+ src_pmd = pmd_offset(src_pud, start);
+ do {
+ next = pmd_addr_end(addr, end);
+ if (pmd_none(*src_pmd))
+ continue;
+ if (pmd_table(*src_pmd)) {
+ if (copy_pte(dst_pmd, src_pmd, addr, next))
+ return -ENOMEM;
+ } else {
+ set_pmd(dst_pmd,
+ __pmd(pmd_val(*src_pmd) & ~PMD_SECT_RDONLY));
+ }
+ } while (dst_pmd++, src_pmd++, addr = next, addr != end);
+
+ return 0;
+}
+
+static int copy_pud(pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long start,
+ unsigned long end)
+{
+ pud_t *dst_pud;
+ pud_t *src_pud;
+ unsigned long next;
+ unsigned long addr = start;
+
+ if (pgd_none(*dst_pgd)) {
+ dst_pud = (pud_t *)get_safe_page(GFP_ATOMIC);
+ if (!dst_pud)
+ return -ENOMEM;
+ pgd_populate(&init_mm, dst_pgd, dst_pud);
+ }
+ dst_pud = pud_offset(dst_pgd, start);
+
+ src_pud = pud_offset(src_pgd, start);
+ do {
+ next = pud_addr_end(addr, end);
+ if (pud_none(*src_pud))
+ continue;
+ if (pud_table(*(src_pud))) {
+ if (copy_pmd(dst_pud, src_pud, addr, next))
+ return -ENOMEM;
+ } else {
+ set_pud(dst_pud,
+ __pud(pud_val(*src_pud) & ~PMD_SECT_RDONLY));
+ }
+ } while (dst_pud++, src_pud++, addr = next, addr != end);
+
+ return 0;
+}
+
+static int copy_page_tables(pgd_t *dst_pgd, unsigned long start,
+ unsigned long end)
+{
+ unsigned long next;
+ unsigned long addr = start;
+ pgd_t *src_pgd = pgd_offset_k(start);
+
+ dst_pgd = pgd_offset_raw(dst_pgd, start);
+ do {
+ next = pgd_addr_end(addr, end);
+ if (pgd_none(*src_pgd))
+ continue;
+ if (copy_pud(dst_pgd, src_pgd, addr, next))
+ return -ENOMEM;
+ } while (dst_pgd++, src_pgd++, addr = next, addr != end);
+
+ return 0;
+}
+
+/*
+ * 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 = 0;
+ void *zero_page;
+ size_t exit_size;
+ pgd_t *tmp_pg_dir;
+ void *lm_restore_pblist;
+ phys_addr_t phys_hibernate_exit;
+ void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *,
+ void *, phys_addr_t, phys_addr_t);
+
+ /*
+ * Locate the exit code in the bottom-but-one page, so that *NULL
+ * still has disastrous affects.
+ */
+ hibernate_exit = (void *)PAGE_SIZE;
+ 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,
+ (unsigned long)hibernate_exit,
+ &phys_hibernate_exit,
+ (void *)get_safe_page, GFP_ATOMIC);
+ if (rc) {
+ pr_err("Failed to create safe executable page for hibernate_exit code.");
+ goto out;
+ }
+
+ /*
+ * The hibernate exit text contains a set of el2 vectors, that will
+ * be executed at el2 with the mmu off in order to reload hyp-stub.
+ */
+ __flush_dcache_area(hibernate_exit, exit_size);
+
+ /*
+ * Restoring the memory image will overwrite the ttbr1 page tables.
+ * Create a second copy of just the linear map, and use this when
+ * restoring.
+ */
+ tmp_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
+ if (!tmp_pg_dir) {
+ pr_err("Failed to allocate memory for temporary page tables.");
+ rc = -ENOMEM;
+ goto out;
+ }
+ rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, 0);
+ if (rc)
+ goto out;
+
+ /*
+ * Since we only copied the linear map, we need to find restore_pblist's
+ * linear map address.
+ */
+ lm_restore_pblist = LMADDR(restore_pblist);
+
+ /*
+ * 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()) {
+ phys_addr_t el2_vectors = phys_hibernate_exit; /* base */
+ el2_vectors += hibernate_el2_vectors -
+ __hibernate_exit_text_start; /* offset */
+
+ __hyp_set_vectors(el2_vectors);
+ }
+
+ /*
+ * We need a zero page that is zero before & after resume in order to
+ * to break before make on the ttbr1 page tables.
+ */
+ zero_page = (void *)get_safe_page(GFP_ATOMIC);
+
+ hibernate_exit(virt_to_phys(tmp_pg_dir), resume_hdr.ttbr1_el1,
+ resume_hdr.reenter_kernel, lm_restore_pblist,
+ resume_hdr.__hyp_stub_vectors, virt_to_phys(zero_page));
+
+out:
+ return rc;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-05 02:46:06 +0000