![Laura Abbott](/assets/img/avatar_default.png)
__pa_symbol is technically the marcro that should be used for kernel symbols. Switch to this as a pre-requisite for DEBUG_VIRTUAL which will do bounds checking. Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
546 lines
14 KiB
C
546 lines
14 KiB
C
/*:
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* Hibernate support specific for ARM64
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*
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* Derived from work on ARM hibernation support by:
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*
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* Ubuntu project, hibernation support for mach-dove
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* Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu)
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* Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.)
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* https://lkml.org/lkml/2010/6/18/4
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* https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html
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* https://patchwork.kernel.org/patch/96442/
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*
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* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
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*
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* License terms: GNU General Public License (GPL) version 2
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*/
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#define pr_fmt(x) "hibernate: " x
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#include <linux/cpu.h>
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#include <linux/kvm_host.h>
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#include <linux/mm.h>
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#include <linux/pm.h>
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#include <linux/sched.h>
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#include <linux/suspend.h>
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#include <linux/utsname.h>
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#include <linux/version.h>
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#include <asm/barrier.h>
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#include <asm/cacheflush.h>
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#include <asm/cputype.h>
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#include <asm/irqflags.h>
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#include <asm/memory.h>
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#include <asm/mmu_context.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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#include <asm/pgtable-hwdef.h>
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#include <asm/sections.h>
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#include <asm/smp.h>
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#include <asm/smp_plat.h>
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#include <asm/suspend.h>
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#include <asm/sysreg.h>
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#include <asm/virt.h>
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/*
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* Hibernate core relies on this value being 0 on resume, and marks it
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* __nosavedata assuming it will keep the resume kernel's '0' value. This
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* doesn't happen with either KASLR.
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*
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* defined as "__visible int in_suspend __nosavedata" in
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* kernel/power/hibernate.c
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*/
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extern int in_suspend;
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/* Do we need to reset el2? */
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#define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode())
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/* temporary el2 vectors in the __hibernate_exit_text section. */
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extern char hibernate_el2_vectors[];
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/* hyp-stub vectors, used to restore el2 during resume from hibernate. */
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extern char __hyp_stub_vectors[];
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/*
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* The logical cpu number we should resume on, initialised to a non-cpu
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* number.
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*/
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static int sleep_cpu = -EINVAL;
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/*
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* Values that may not change over hibernate/resume. We put the build number
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* and date in here so that we guarantee not to resume with a different
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* kernel.
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*/
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struct arch_hibernate_hdr_invariants {
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char uts_version[__NEW_UTS_LEN + 1];
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};
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/* These values need to be know across a hibernate/restore. */
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static struct arch_hibernate_hdr {
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struct arch_hibernate_hdr_invariants invariants;
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/* These are needed to find the relocated kernel if built with kaslr */
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phys_addr_t ttbr1_el1;
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void (*reenter_kernel)(void);
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/*
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* We need to know where the __hyp_stub_vectors are after restore to
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* re-configure el2.
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*/
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phys_addr_t __hyp_stub_vectors;
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u64 sleep_cpu_mpidr;
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} resume_hdr;
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static inline void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i)
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{
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memset(i, 0, sizeof(*i));
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memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version));
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}
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int pfn_is_nosave(unsigned long pfn)
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{
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unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin);
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unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1);
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return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn);
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}
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void notrace save_processor_state(void)
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{
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WARN_ON(num_online_cpus() != 1);
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}
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void notrace restore_processor_state(void)
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{
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}
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int arch_hibernation_header_save(void *addr, unsigned int max_size)
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{
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struct arch_hibernate_hdr *hdr = addr;
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if (max_size < sizeof(*hdr))
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return -EOVERFLOW;
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arch_hdr_invariants(&hdr->invariants);
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hdr->ttbr1_el1 = __pa_symbol(swapper_pg_dir);
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hdr->reenter_kernel = _cpu_resume;
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/* We can't use __hyp_get_vectors() because kvm may still be loaded */
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if (el2_reset_needed())
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hdr->__hyp_stub_vectors = __pa_symbol(__hyp_stub_vectors);
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else
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hdr->__hyp_stub_vectors = 0;
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/* Save the mpidr of the cpu we called cpu_suspend() on... */
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if (sleep_cpu < 0) {
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pr_err("Failing to hibernate on an unknown CPU.\n");
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return -ENODEV;
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}
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hdr->sleep_cpu_mpidr = cpu_logical_map(sleep_cpu);
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pr_info("Hibernating on CPU %d [mpidr:0x%llx]\n", sleep_cpu,
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hdr->sleep_cpu_mpidr);
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return 0;
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}
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EXPORT_SYMBOL(arch_hibernation_header_save);
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int arch_hibernation_header_restore(void *addr)
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{
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int ret;
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struct arch_hibernate_hdr_invariants invariants;
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struct arch_hibernate_hdr *hdr = addr;
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arch_hdr_invariants(&invariants);
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if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) {
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pr_crit("Hibernate image not generated by this kernel!\n");
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return -EINVAL;
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}
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sleep_cpu = get_logical_index(hdr->sleep_cpu_mpidr);
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pr_info("Hibernated on CPU %d [mpidr:0x%llx]\n", sleep_cpu,
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hdr->sleep_cpu_mpidr);
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if (sleep_cpu < 0) {
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pr_crit("Hibernated on a CPU not known to this kernel!\n");
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sleep_cpu = -EINVAL;
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return -EINVAL;
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}
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if (!cpu_online(sleep_cpu)) {
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pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n");
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ret = cpu_up(sleep_cpu);
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if (ret) {
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pr_err("Failed to bring hibernate-CPU up!\n");
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sleep_cpu = -EINVAL;
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return ret;
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}
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}
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resume_hdr = *hdr;
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return 0;
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}
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EXPORT_SYMBOL(arch_hibernation_header_restore);
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/*
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* Copies length bytes, starting at src_start into an new page,
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* perform cache maintentance, then maps it at the specified address low
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* address as executable.
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*
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* This is used by hibernate to copy the code it needs to execute when
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* overwriting the kernel text. This function generates a new set of page
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* tables, which it loads into ttbr0.
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*
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* Length is provided as we probably only want 4K of data, even on a 64K
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* page system.
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*/
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static int create_safe_exec_page(void *src_start, size_t length,
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unsigned long dst_addr,
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phys_addr_t *phys_dst_addr,
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void *(*allocator)(gfp_t mask),
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gfp_t mask)
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{
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int rc = 0;
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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unsigned long dst = (unsigned long)allocator(mask);
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if (!dst) {
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rc = -ENOMEM;
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goto out;
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}
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memcpy((void *)dst, src_start, length);
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flush_icache_range(dst, dst + length);
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pgd = pgd_offset_raw(allocator(mask), dst_addr);
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if (pgd_none(*pgd)) {
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pud = allocator(mask);
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if (!pud) {
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rc = -ENOMEM;
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goto out;
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}
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pgd_populate(&init_mm, pgd, pud);
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}
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pud = pud_offset(pgd, dst_addr);
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if (pud_none(*pud)) {
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pmd = allocator(mask);
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if (!pmd) {
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rc = -ENOMEM;
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goto out;
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}
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pud_populate(&init_mm, pud, pmd);
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}
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pmd = pmd_offset(pud, dst_addr);
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if (pmd_none(*pmd)) {
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pte = allocator(mask);
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if (!pte) {
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rc = -ENOMEM;
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goto out;
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}
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pmd_populate_kernel(&init_mm, pmd, pte);
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}
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pte = pte_offset_kernel(pmd, dst_addr);
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set_pte(pte, __pte(virt_to_phys((void *)dst) |
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pgprot_val(PAGE_KERNEL_EXEC)));
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/*
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* Load our new page tables. A strict BBM approach requires that we
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* ensure that TLBs are free of any entries that may overlap with the
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* global mappings we are about to install.
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*
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* For a real hibernate/resume cycle TTBR0 currently points to a zero
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* page, but TLBs may contain stale ASID-tagged entries (e.g. for EFI
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* runtime services), while for a userspace-driven test_resume cycle it
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* points to userspace page tables (and we must point it at a zero page
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* ourselves). Elsewhere we only (un)install the idmap with preemption
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* disabled, so T0SZ should be as required regardless.
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*/
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cpu_set_reserved_ttbr0();
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local_flush_tlb_all();
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write_sysreg(virt_to_phys(pgd), ttbr0_el1);
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isb();
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*phys_dst_addr = virt_to_phys((void *)dst);
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out:
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return rc;
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}
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#define dcache_clean_range(start, end) __flush_dcache_area(start, (end - start))
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int swsusp_arch_suspend(void)
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{
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int ret = 0;
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unsigned long flags;
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struct sleep_stack_data state;
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if (cpus_are_stuck_in_kernel()) {
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pr_err("Can't hibernate: no mechanism to offline secondary CPUs.\n");
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return -EBUSY;
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}
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local_dbg_save(flags);
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if (__cpu_suspend_enter(&state)) {
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sleep_cpu = smp_processor_id();
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ret = swsusp_save();
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} else {
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/* Clean kernel core startup/idle code to PoC*/
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dcache_clean_range(__mmuoff_data_start, __mmuoff_data_end);
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dcache_clean_range(__idmap_text_start, __idmap_text_end);
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/* Clean kvm setup code to PoC? */
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if (el2_reset_needed())
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dcache_clean_range(__hyp_idmap_text_start, __hyp_idmap_text_end);
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/*
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* Tell the hibernation core that we've just restored
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* the memory
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*/
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in_suspend = 0;
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sleep_cpu = -EINVAL;
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__cpu_suspend_exit();
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}
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local_dbg_restore(flags);
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return ret;
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}
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static void _copy_pte(pte_t *dst_pte, pte_t *src_pte, unsigned long addr)
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{
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pte_t pte = *src_pte;
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if (pte_valid(pte)) {
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/*
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* Resume will overwrite areas that may be marked
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* read only (code, rodata). Clear the RDONLY bit from
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* the temporary mappings we use during restore.
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*/
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set_pte(dst_pte, pte_clear_rdonly(pte));
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} else if (debug_pagealloc_enabled() && !pte_none(pte)) {
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/*
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* debug_pagealloc will removed the PTE_VALID bit if
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* the page isn't in use by the resume kernel. It may have
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* been in use by the original kernel, in which case we need
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* to put it back in our copy to do the restore.
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*
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* Before marking this entry valid, check the pfn should
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* be mapped.
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*/
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BUG_ON(!pfn_valid(pte_pfn(pte)));
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set_pte(dst_pte, pte_mkpresent(pte_clear_rdonly(pte)));
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}
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}
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static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start,
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unsigned long end)
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{
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pte_t *src_pte;
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pte_t *dst_pte;
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unsigned long addr = start;
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dst_pte = (pte_t *)get_safe_page(GFP_ATOMIC);
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if (!dst_pte)
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return -ENOMEM;
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pmd_populate_kernel(&init_mm, dst_pmd, dst_pte);
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dst_pte = pte_offset_kernel(dst_pmd, start);
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src_pte = pte_offset_kernel(src_pmd, start);
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do {
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_copy_pte(dst_pte, src_pte, addr);
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} while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
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return 0;
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}
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static int copy_pmd(pud_t *dst_pud, pud_t *src_pud, unsigned long start,
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unsigned long end)
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{
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pmd_t *src_pmd;
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pmd_t *dst_pmd;
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unsigned long next;
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unsigned long addr = start;
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if (pud_none(*dst_pud)) {
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dst_pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
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if (!dst_pmd)
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return -ENOMEM;
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pud_populate(&init_mm, dst_pud, dst_pmd);
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}
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dst_pmd = pmd_offset(dst_pud, start);
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src_pmd = pmd_offset(src_pud, start);
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do {
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next = pmd_addr_end(addr, end);
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if (pmd_none(*src_pmd))
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continue;
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if (pmd_table(*src_pmd)) {
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if (copy_pte(dst_pmd, src_pmd, addr, next))
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return -ENOMEM;
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} else {
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set_pmd(dst_pmd,
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__pmd(pmd_val(*src_pmd) & ~PMD_SECT_RDONLY));
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}
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} while (dst_pmd++, src_pmd++, addr = next, addr != end);
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return 0;
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}
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static int copy_pud(pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long start,
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unsigned long end)
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{
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pud_t *dst_pud;
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pud_t *src_pud;
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unsigned long next;
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unsigned long addr = start;
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if (pgd_none(*dst_pgd)) {
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dst_pud = (pud_t *)get_safe_page(GFP_ATOMIC);
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if (!dst_pud)
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return -ENOMEM;
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pgd_populate(&init_mm, dst_pgd, dst_pud);
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}
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dst_pud = pud_offset(dst_pgd, start);
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src_pud = pud_offset(src_pgd, start);
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do {
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next = pud_addr_end(addr, end);
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if (pud_none(*src_pud))
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continue;
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if (pud_table(*(src_pud))) {
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if (copy_pmd(dst_pud, src_pud, addr, next))
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return -ENOMEM;
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} else {
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set_pud(dst_pud,
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__pud(pud_val(*src_pud) & ~PMD_SECT_RDONLY));
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}
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} while (dst_pud++, src_pud++, addr = next, addr != end);
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return 0;
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}
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static int copy_page_tables(pgd_t *dst_pgd, unsigned long start,
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unsigned long end)
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{
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unsigned long next;
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unsigned long addr = start;
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pgd_t *src_pgd = pgd_offset_k(start);
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dst_pgd = pgd_offset_raw(dst_pgd, start);
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do {
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next = pgd_addr_end(addr, end);
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if (pgd_none(*src_pgd))
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continue;
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if (copy_pud(dst_pgd, src_pgd, addr, next))
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return -ENOMEM;
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} while (dst_pgd++, src_pgd++, addr = next, addr != end);
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return 0;
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}
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/*
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* Setup then Resume from the hibernate image using swsusp_arch_suspend_exit().
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*
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* Memory allocated by get_safe_page() will be dealt with by the hibernate code,
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* we don't need to free it here.
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*/
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int swsusp_arch_resume(void)
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{
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int rc = 0;
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void *zero_page;
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size_t exit_size;
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pgd_t *tmp_pg_dir;
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phys_addr_t phys_hibernate_exit;
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void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *,
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void *, phys_addr_t, phys_addr_t);
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/*
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* Restoring the memory image will overwrite the ttbr1 page tables.
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* Create a second copy of just the linear map, and use this when
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* restoring.
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*/
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tmp_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
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if (!tmp_pg_dir) {
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pr_err("Failed to allocate memory for temporary page tables.\n");
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rc = -ENOMEM;
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goto out;
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}
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rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, 0);
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if (rc)
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goto out;
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/*
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* We need a zero page that is zero before & after resume in order to
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* to break before make on the ttbr1 page tables.
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*/
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zero_page = (void *)get_safe_page(GFP_ATOMIC);
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if (!zero_page) {
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pr_err("Failed to allocate zero page.\n");
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rc = -ENOMEM;
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goto out;
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}
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/*
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* Locate the exit code in the bottom-but-one page, so that *NULL
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* still has disastrous affects.
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*/
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hibernate_exit = (void *)PAGE_SIZE;
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exit_size = __hibernate_exit_text_end - __hibernate_exit_text_start;
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/*
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* 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);
|
|
}
|