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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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66aad4fdf2
Kernel identity mappings on x86-64 kernels are created in two ways: by the early x86 boot code, or by kernel_ident_mapping_init(). Native kernels (which is the dominant usecase) use the former, but the kexec and the hibernation code uses kernel_ident_mapping_init(). There's a subtle difference between these two ways of how identity mappings are created, the current kernel_ident_mapping_init() code creates identity mappings always using 2MB page(PMD level) - while the native kernel boot path also utilizes gbpages where available. This difference is suboptimal both for performance and for memory usage: kernel_ident_mapping_init() needs to allocate pages for the page tables when creating the new identity mappings. This patch adds 1GB page(PUD level) support to kernel_ident_mapping_init() to address these concerns. The primary advantage would be better TLB coverage/performance, because we'd utilize 1GB TLBs instead of 2MB ones. It is also useful for machines with large number of memory to save paging structure allocations(around 4MB/TB using 2MB page) when setting identity mappings for all the memory, after using 1GB page it will consume only 8KB/TB. ( Note that this change alone does not activate gbpages in kexec, we are doing that in a separate patch. ) Signed-off-by: Xunlei Pang <xlpang@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Cc: akpm@linux-foundation.org Cc: kexec@lists.infradead.org Link: http://lkml.kernel.org/r/1493862171-8799-1-git-send-email-xlpang@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
330 lines
8.1 KiB
C
330 lines
8.1 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 <linux/scatterlist.h>
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#include <linux/kdebug.h>
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#include <crypto/hash.h>
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#include <asm/e820/api.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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p4d_t *p4d;
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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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if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
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p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
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if (!p4d)
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return -ENOMEM;
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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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if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
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set_p4d(p4d + p4d_index(restore_jump_address), __p4d(__pa(pud) | _KERNPG_TABLE));
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set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(p4d) | _KERNPG_TABLE));
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} else {
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/* No p4d for 4-level paging: point the pgd to the pud page table */
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set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(pud) | _KERNPG_TABLE));
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}
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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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.page_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 = __pa(pgd);
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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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p4d_t *p4d;
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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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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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p4d = p4d_offset(pgd, relocated_restore_code);
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if (p4d_large(*p4d)) {
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set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX));
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goto out;
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}
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pud = pud_offset(p4d, 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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goto out;
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}
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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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goto out;
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}
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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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out:
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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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#define MD5_DIGEST_SIZE 16
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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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u8 e820_digest[MD5_DIGEST_SIZE];
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};
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#define RESTORE_MAGIC 0x23456789ABCDEF01UL
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#if IS_BUILTIN(CONFIG_CRYPTO_MD5)
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/**
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* get_e820_md5 - calculate md5 according to given e820 table
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*
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* @table: the e820 table to be calculated
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* @buf: the md5 result to be stored to
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*/
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static int get_e820_md5(struct e820_table *table, void *buf)
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{
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struct scatterlist sg;
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struct crypto_ahash *tfm;
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int size;
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int ret = 0;
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tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(tfm))
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return -ENOMEM;
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{
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AHASH_REQUEST_ON_STACK(req, tfm);
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size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry) * table->nr_entries;
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ahash_request_set_tfm(req, tfm);
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sg_init_one(&sg, (u8 *)table, size);
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ahash_request_set_callback(req, 0, NULL, NULL);
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ahash_request_set_crypt(req, &sg, buf, size);
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if (crypto_ahash_digest(req))
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ret = -EINVAL;
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ahash_request_zero(req);
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}
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crypto_free_ahash(tfm);
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return ret;
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}
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static void hibernation_e820_save(void *buf)
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{
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get_e820_md5(e820_table_firmware, buf);
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}
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static bool hibernation_e820_mismatch(void *buf)
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{
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int ret;
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u8 result[MD5_DIGEST_SIZE];
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memset(result, 0, MD5_DIGEST_SIZE);
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/* If there is no digest in suspend kernel, let it go. */
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if (!memcmp(result, buf, MD5_DIGEST_SIZE))
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return false;
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ret = get_e820_md5(e820_table_firmware, result);
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if (ret)
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return true;
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return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false;
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}
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#else
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static void hibernation_e820_save(void *buf)
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{
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}
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static bool hibernation_e820_mismatch(void *buf)
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{
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/* If md5 is not builtin for restore kernel, let it go. */
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return false;
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}
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#endif
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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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hibernation_e820_save(rdr->e820_digest);
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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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if (rdr->magic != RESTORE_MAGIC) {
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pr_crit("Unrecognized hibernate image header format!\n");
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return -EINVAL;
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}
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if (hibernation_e820_mismatch(rdr->e820_digest)) {
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pr_crit("Hibernate inconsistent memory map detected!\n");
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return -ENODEV;
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}
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return 0;
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}
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