diff options
Diffstat (limited to 'arch/arm64/kernel/hibernate.c')
| -rw-r--r-- | arch/arm64/kernel/hibernate.c | 511 |
1 files changed, 511 insertions, 0 deletions
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c new file mode 100644 index 000000000000..35a33d705536 --- /dev/null +++ b/arch/arm64/kernel/hibernate.c @@ -0,0 +1,511 @@ +/*: + * 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/notifier.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/kexec.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/sysreg.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)) || + crash_is_nosave(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. A strict BBM approach requires that we + * ensure that TLBs are free of any entries that may overlap with the + * global mappings we are about to install. + * + * For a real hibernate/resume cycle TTBR0 currently points to a zero + * page, but TLBs may contain stale ASID-tagged entries (e.g. for EFI + * runtime services), while for a userspace-driven test_resume cycle it + * points to userspace page tables (and we must point it at a zero page + * ourselves). Elsewhere we only (un)install the idmap with preemption + * disabled, so T0SZ should be as required regardless. + */ + cpu_set_reserved_ttbr0(); + local_flush_tlb_all(); + write_sysreg(virt_to_phys(pgd), ttbr0_el1); + isb(); + + *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)) { + /* make the crash dump kernel image visible/saveable */ + crash_prepare_suspend(); + + ret = swsusp_save(); + } else { + /* Clean kernel to PoC for secondary core startup */ + __flush_dcache_area(LMADDR(KERNEL_START), KERNEL_END - KERNEL_START); + + /* 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; + + __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); + + /* + * 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); + + /* + * 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); + if (!zero_page) { + pr_err("Failed to allocate zero page."); + rc = -ENOMEM; + goto out; + } + + /* + * 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); + + /* + * 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); + } + + 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; +} + +static int check_boot_cpu_online_pm_callback(struct notifier_block *nb, + unsigned long action, void *ptr) +{ + if (action == PM_HIBERNATION_PREPARE && + cpumask_first(cpu_online_mask) != 0) { + pr_warn("CPU0 is offline.\n"); + return notifier_from_errno(-ENODEV); + } + + return NOTIFY_OK; +} + +static int __init check_boot_cpu_online_init(void) +{ + /* + * Set this pm_notifier callback with a lower priority than + * cpu_hotplug_pm_callback, so that cpu_hotplug_pm_callback will be + * called earlier to disable cpu hotplug before the cpu online check. + */ + pm_notifier(check_boot_cpu_online_pm_callback, -INT_MAX); + + return 0; +} +core_initcall(check_boot_cpu_online_init); |