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e4630fdd47
The low-level resume-from-hibernation code on x86-64 uses kernel_ident_mapping_init() to create the temoprary identity mapping, but that function assumes that the offset between kernel virtual addresses and physical addresses is aligned on the PGD level. However, with a randomized identity mapping base, it may be aligned on the PUD level and if that happens, the temporary identity mapping created by set_up_temporary_mappings() will not reflect the actual kernel identity mapping and the image restoration will fail as a result (leading to a kernel panic most of the time). To fix this problem, rework kernel_ident_mapping_init() to support unaligned offsets between KVA and PA up to the PMD level and make set_up_temporary_mappings() use it as approprtiate. Reported-and-tested-by: Thomas Garnier <thgarnie@google.com> Reported-by: Borislav Petkov <bp@suse.de> Suggested-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Yinghai Lu <yinghai@kernel.org>
221 lines
5.6 KiB
C
221 lines
5.6 KiB
C
/*
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* Hibernation support for x86-64
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*
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* Distribute under GPLv2
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*
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* Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
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* Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
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* Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
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*/
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#include <linux/gfp.h>
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#include <linux/smp.h>
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#include <linux/suspend.h>
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#include <asm/init.h>
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#include <asm/proto.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/mtrr.h>
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#include <asm/sections.h>
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#include <asm/suspend.h>
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#include <asm/tlbflush.h>
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/* Defined in hibernate_asm_64.S */
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extern asmlinkage __visible int restore_image(void);
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/*
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* Address to jump to in the last phase of restore in order to get to the image
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* kernel's text (this value is passed in the image header).
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*/
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unsigned long restore_jump_address __visible;
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unsigned long jump_address_phys;
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/*
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* Value of the cr3 register from before the hibernation (this value is passed
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* in the image header).
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*/
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unsigned long restore_cr3 __visible;
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unsigned long temp_level4_pgt __visible;
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unsigned long relocated_restore_code __visible;
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static int set_up_temporary_text_mapping(pgd_t *pgd)
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{
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pmd_t *pmd;
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pud_t *pud;
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/*
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* The new mapping only has to cover the page containing the image
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* kernel's entry point (jump_address_phys), because the switch over to
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* it is carried out by relocated code running from a page allocated
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* specifically for this purpose and covered by the identity mapping, so
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* the temporary kernel text mapping is only needed for the final jump.
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* Moreover, in that mapping the virtual address of the image kernel's
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* entry point must be the same as its virtual address in the image
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* kernel (restore_jump_address), so the image kernel's
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* restore_registers() code doesn't find itself in a different area of
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* the virtual address space after switching over to the original page
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* tables used by the image kernel.
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*/
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pud = (pud_t *)get_safe_page(GFP_ATOMIC);
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if (!pud)
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return -ENOMEM;
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pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
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if (!pmd)
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return -ENOMEM;
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set_pmd(pmd + pmd_index(restore_jump_address),
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__pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC));
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set_pud(pud + pud_index(restore_jump_address),
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__pud(__pa(pmd) | _KERNPG_TABLE));
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set_pgd(pgd + pgd_index(restore_jump_address),
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__pgd(__pa(pud) | _KERNPG_TABLE));
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return 0;
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}
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static void *alloc_pgt_page(void *context)
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{
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return (void *)get_safe_page(GFP_ATOMIC);
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}
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static int set_up_temporary_mappings(void)
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{
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struct x86_mapping_info info = {
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.alloc_pgt_page = alloc_pgt_page,
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.pmd_flag = __PAGE_KERNEL_LARGE_EXEC,
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.offset = __PAGE_OFFSET,
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};
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unsigned long mstart, mend;
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pgd_t *pgd;
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int result;
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int i;
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pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
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if (!pgd)
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return -ENOMEM;
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/* Prepare a temporary mapping for the kernel text */
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result = set_up_temporary_text_mapping(pgd);
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if (result)
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return result;
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/* Set up the direct mapping from scratch */
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for (i = 0; i < nr_pfn_mapped; i++) {
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mstart = pfn_mapped[i].start << PAGE_SHIFT;
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mend = pfn_mapped[i].end << PAGE_SHIFT;
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result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
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if (result)
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return result;
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}
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temp_level4_pgt = (unsigned long)pgd - __PAGE_OFFSET;
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return 0;
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}
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static int relocate_restore_code(void)
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{
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pgd_t *pgd;
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pud_t *pud;
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relocated_restore_code = get_safe_page(GFP_ATOMIC);
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if (!relocated_restore_code)
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return -ENOMEM;
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memcpy((void *)relocated_restore_code, &core_restore_code, PAGE_SIZE);
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/* Make the page containing the relocated code executable */
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pgd = (pgd_t *)__va(read_cr3()) + pgd_index(relocated_restore_code);
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pud = pud_offset(pgd, relocated_restore_code);
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if (pud_large(*pud)) {
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set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
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} else {
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pmd_t *pmd = pmd_offset(pud, relocated_restore_code);
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if (pmd_large(*pmd)) {
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set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
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} else {
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pte_t *pte = pte_offset_kernel(pmd, relocated_restore_code);
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set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
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}
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}
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__flush_tlb_all();
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return 0;
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}
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int swsusp_arch_resume(void)
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{
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int error;
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/* We have got enough memory and from now on we cannot recover */
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error = set_up_temporary_mappings();
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if (error)
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return error;
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error = relocate_restore_code();
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if (error)
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return error;
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restore_image();
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return 0;
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}
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/*
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* pfn_is_nosave - check if given pfn is in the 'nosave' section
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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 = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
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unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
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return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
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}
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struct restore_data_record {
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unsigned long jump_address;
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unsigned long jump_address_phys;
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unsigned long cr3;
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unsigned long magic;
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};
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#define RESTORE_MAGIC 0x123456789ABCDEF0UL
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/**
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* arch_hibernation_header_save - populate the architecture specific part
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* of a hibernation image header
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* @addr: address to save the data at
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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 restore_data_record *rdr = addr;
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if (max_size < sizeof(struct restore_data_record))
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return -EOVERFLOW;
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rdr->jump_address = (unsigned long)&restore_registers;
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rdr->jump_address_phys = __pa_symbol(&restore_registers);
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rdr->cr3 = restore_cr3;
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rdr->magic = RESTORE_MAGIC;
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return 0;
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}
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/**
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* arch_hibernation_header_restore - read the architecture specific data
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* from the hibernation image header
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* @addr: address to read the data from
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*/
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int arch_hibernation_header_restore(void *addr)
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{
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struct restore_data_record *rdr = addr;
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restore_jump_address = rdr->jump_address;
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jump_address_phys = rdr->jump_address_phys;
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restore_cr3 = rdr->cr3;
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return (rdr->magic == RESTORE_MAGIC) ? 0 : -EINVAL;
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}
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