/*:
* 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/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/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/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;
/* 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())
/* 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 = 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;
/* 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 *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;
}
#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;
}
local_dbg_save(flags);
if (__cpu_suspend_enter(&state)) {
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);
/*
* Tell the hibernation core that we've just restored
* the memory
*/
in_suspend = 0;
sleep_cpu = -EINVAL;
__cpu_suspend_exit();
}
local_dbg_restore(flags);
return ret;
}
static void _copy_pte(pte_t *dst_pte, pte_t *src_pte, unsigned long addr)
{
pte_t pte = *src_pte;
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_pte, pte_clear_rdonly(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_pte, pte_mkpresent(pte_clear_rdonly(pte)));
}
}
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 {
_copy_pte(dst_pte, src_pte, addr);
} 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;
}
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);
}
