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https://github.com/edk2-porting/linux-next.git
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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>
83 lines
1.9 KiB
C
83 lines
1.9 KiB
C
/*
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* Helper routines for building identity mapping page tables. This is
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* included by both the compressed kernel and the regular kernel.
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*/
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static void ident_pmd_init(struct x86_mapping_info *info, pmd_t *pmd_page,
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unsigned long addr, unsigned long end)
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{
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addr &= PMD_MASK;
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for (; addr < end; addr += PMD_SIZE) {
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pmd_t *pmd = pmd_page + pmd_index(addr);
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if (pmd_present(*pmd))
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continue;
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set_pmd(pmd, __pmd((addr - info->offset) | info->pmd_flag));
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}
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}
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static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page,
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unsigned long addr, unsigned long end)
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{
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unsigned long next;
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for (; addr < end; addr = next) {
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pud_t *pud = pud_page + pud_index(addr);
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pmd_t *pmd;
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next = (addr & PUD_MASK) + PUD_SIZE;
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if (next > end)
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next = end;
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if (pud_present(*pud)) {
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pmd = pmd_offset(pud, 0);
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ident_pmd_init(info, pmd, addr, next);
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continue;
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}
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pmd = (pmd_t *)info->alloc_pgt_page(info->context);
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if (!pmd)
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return -ENOMEM;
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ident_pmd_init(info, pmd, addr, next);
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set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
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}
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return 0;
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}
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int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
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unsigned long pstart, unsigned long pend)
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{
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unsigned long addr = pstart + info->offset;
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unsigned long end = pend + info->offset;
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unsigned long next;
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int result;
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for (; addr < end; addr = next) {
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pgd_t *pgd = pgd_page + pgd_index(addr);
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pud_t *pud;
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next = (addr & PGDIR_MASK) + PGDIR_SIZE;
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if (next > end)
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next = end;
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if (pgd_present(*pgd)) {
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pud = pud_offset(pgd, 0);
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result = ident_pud_init(info, pud, addr, next);
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if (result)
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return result;
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continue;
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}
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pud = (pud_t *)info->alloc_pgt_page(info->context);
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if (!pud)
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return -ENOMEM;
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result = ident_pud_init(info, pud, addr, next);
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if (result)
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return result;
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set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
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}
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return 0;
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}
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