// 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.)
* 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>
*/
#define pr_fmt(x) "hibernate: " x
#include <linux/cpu.h>
#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/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/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/pgtable-hwdef.h>
#include <asm/sections.h>
#include <asm/smp.h>
#include <asm/smp_plat.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;
/* Do we need to reset el2? */
#define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode())
/* 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[];
/*
* 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;
}
if (!cpu_online(sleep_cpu)) {
pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n");
ret = cpu_up(sleep_cpu);
if (ret) {
pr_err("Failed to bring hibernate-CPU up!\n");
sleep_cpu = -EINVAL;
return ret;
}
}
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 *pgdp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
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);
pgdp = pgd_offset_raw(allocator(mask), dst_addr);
if (pgd_none(READ_ONCE(*pgdp))) {
pudp = allocator(mask);
if (!pudp) {
rc = -ENOMEM;
goto out;
}
pgd_populate(&init_mm, pgdp, pudp);
}
pudp = pud_offset(pgdp, dst_addr);
if (pud_none(READ_ONCE(*pudp))) {
pmdp = allocator(mask);
if (!pmdp) {
rc = -ENOMEM;
goto out;
}
pud_populate(&init_mm, pudp, pmdp);
}
pmdp = pmd_offset(pudp, dst_addr);
if (pmd_none(READ_ONCE(*pmdp))) {
ptep = allocator(mask);
if (!ptep) {
rc = -ENOMEM;
goto out;
}
pmd_populate_kernel(&init_mm, pmdp, ptep);
}
ptep = pte_offset_kernel(pmdp, dst_addr);
set_pte(ptep, pfn_pte(virt_to_pfn(dst), 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(phys_to_ttbr(virt_to_phys(pgdp)), ttbr0_el1);
isb();
*phys_dst_addr = virt_to_phys((void *)dst);
out:
return rc;
}
#define dcache_clean_range(start, end) __flush_dcache_area(start, (end - start))
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();
sleep_cpu = smp_processor_id();
ret = swsusp_save();
} else {
/* Clean kernel core startup/idle code to PoC*/
dcache_clean_range(__mmuoff_data_start, __mmuoff_data_end);
dcache_clean_range(__idmap_text_start, __idmap_text_end);
/* Clean kvm setup code to PoC? */
if (el2_reset_needed()) {
dcache_clean_range(__hyp_idmap_text_start, __hyp_idmap_text_end);
dcache_clean_range(__hyp_text_start, __hyp_text_end);
}
/* 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.
*/
switch (arm64_get_ssbd_state()) {
case ARM64_SSBD_FORCE_ENABLE:
case ARM64_SSBD_KERNEL:
arm64_set_ssbd_mitigation(true);
}
}
local_daif_restore(flags);
return ret;
}
static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr)
{
pte_t pte = READ_ONCE(*src_ptep);
if (pte_valid(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_ptep, pte_mkwrite(pte));
} else if (debug_pagealloc_enabled() && !pte_none(pte)) {
/*
* debug_pagealloc will removed the PTE_VALID bit if
* the page isn't in use by the resume kernel. It may have
* been in use by the original kernel, in which case we need
* to put it back in our copy to do the restore.
*
* Before marking this entry valid, check the pfn should
* be mapped.
*/
BUG_ON(!pfn_valid(pte_pfn(pte)));
set_pte(dst_ptep, pte_mkpresent(pte_mkwrite(pte)));
}
}
static int copy_pte(pmd_t *dst_pmdp, pmd_t *src_pmdp, unsigned long start,
unsigned long end)
{
pte_t *src_ptep;
pte_t *dst_ptep;
unsigned long addr = start;
dst_ptep = (pte_t *)get_safe_page(GFP_ATOMIC);
if (!dst_ptep)
return -ENOMEM;
pmd_populate_kernel(&init_mm, dst_pmdp, dst_ptep);
dst_ptep = pte_offset_kernel(dst_pmdp, start);
src_ptep = pte_offset_kernel(src_pmdp, start);
do {
_copy_pte(dst_ptep, src_ptep, addr);
} while (dst_ptep++, src_ptep++, addr += PAGE_SIZE, addr != end);
return 0;
}
static int copy_pmd(pud_t *dst_pudp, pud_t *src_pudp, unsigned long start,
unsigned long end)
{
pmd_t *src_pmdp;
pmd_t *dst_pmdp;
unsigned long next;
unsigned long addr = start;
if (pud_none(READ_ONCE(*dst_pudp))) {
dst_pmdp = (pmd_t *)get_safe_page(GFP_ATOMIC);
if (!dst_pmdp)
return -ENOMEM;
pud_populate(&init_mm, dst_pudp, dst_pmdp);
}
dst_pmdp = pmd_offset(dst_pudp, start);
src_pmdp = pmd_offset(src_pudp, start);
do {
pmd_t pmd = READ_ONCE(*src_pmdp);
next = pmd_addr_end(addr, end);
if (pmd_none(pmd))
continue;
if (pmd_table(pmd)) {
if (copy_pte(dst_pmdp, src_pmdp, addr, next))
return -ENOMEM;
} else {
set_pmd(dst_pmdp,
__pmd(pmd_val(pmd) & ~PMD_SECT_RDONLY));
}
} while (dst_pmdp++, src_pmdp++, addr = next, addr != end);
return 0;
}
static int copy_pud(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,
unsigned long end)
{
pud_t *dst_pudp;
pud_t *src_pudp;
unsigned long next;
unsigned long addr = start;
if (pgd_none(READ_ONCE(*dst_pgdp))) {
dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC);
if (!dst_pudp)
return -ENOMEM;
pgd_populate(&init_mm, dst_pgdp, dst_pudp);
}
dst_pudp = pud_offset(dst_pgdp, start);
src_pudp = pud_offset(src_pgdp, start);
do {
pud_t pud = READ_ONCE(*src_pudp);
next = pud_addr_end(addr, end);
if (pud_none(pud))
continue;
if (pud_table(pud)) {
if (copy_pmd(dst_pudp, src_pudp, addr, next))
return -ENOMEM;
} else {
set_pud(dst_pudp,
__pud(pud_val(pud) & ~PMD_SECT_RDONLY));
}
} while (dst_pudp++, src_pudp++, addr = next, addr != end);
return 0;
}
static int copy_page_tables(pgd_t *dst_pgdp, unsigned long start,
unsigned long end)
{
unsigned long next;
unsigned long addr = start;
pgd_t *src_pgdp = pgd_offset_k(start);
dst_pgdp = pgd_offset_raw(dst_pgdp, start);
do {
next = pgd_addr_end(addr, end);
if (pgd_none(READ_ONCE(*src_pgdp)))
continue;
if (copy_pud(dst_pgdp, src_pgdp, addr, next))
return -ENOMEM;
} while (dst_pgdp++, src_pgdp++, 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;
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.\n");
rc = -ENOMEM;
goto out;
}
rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, 0);
if (rc)
goto out;
/*
* 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.\n");
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.\n");
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, restore_pblist,
resume_hdr.__hyp_stub_vectors, virt_to_phys(zero_page));
out:
return rc;
}
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);
}
