arch/arm64/kernel/hibernate.c - third_party/kernel - Git at Google

 /*:
  * 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/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 *trans_pgd;
 	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);

 	trans_pgd = allocator(mask);
 	if (!trans_pgd) {
 		rc = -ENOMEM;
 		goto out;
 	}

 	pgdp = pgd_offset_raw(trans_pgd, 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);
 }
	/*:
	* 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/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 *trans_pgd;
	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);

	trans_pgd = allocator(mask);
	if (!trans_pgd) {
	rc = -ENOMEM;
	goto out;
	}

	pgdp = pgd_offset_raw(trans_pgd, 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);
	}