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Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/kernel/hibernate.c | 478 |
1 files changed, 478 insertions, 0 deletions
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c new file mode 100644 index 000000000..788597a6b --- /dev/null +++ b/arch/arm64/kernel/hibernate.c @@ -0,0 +1,478 @@ +// 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) +{ + 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 = __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); +} |