From 0a9fe8ca844d43f3f547f0e166122b6048121c8f Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 4 Dec 2018 13:37:21 -0800 Subject: x86/mm: Validate kernel_physical_mapping_init() PTE population The usage of __flush_tlb_all() in the kernel_physical_mapping_init() path is not necessary. In general flushing the TLB is not required when updating an entry from the !present state. However, to give confidence in the future removal of TLB flushing in this path, use the new set_pte_safe() family of helpers to assert that the !present assumption is true in this path. [ mingo: Minor readability edits. ] Suggested-by: Peter Zijlstra Suggested-by: Dave Hansen Signed-off-by: Dan Williams Acked-by: Kirill A. Shutemov Acked-by: Peter Zijlstra (Intel) Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Rik van Riel Cc: Sebastian Andrzej Siewior Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/154395944177.32119.8524957429632012270.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/pgalloc.h | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'arch/x86/include/asm/pgalloc.h') diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h index ec7f43327033..1ea41aaef68b 100644 --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -80,6 +80,13 @@ static inline void pmd_populate_kernel(struct mm_struct *mm, set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE)); } +static inline void pmd_populate_kernel_safe(struct mm_struct *mm, + pmd_t *pmd, pte_t *pte) +{ + paravirt_alloc_pte(mm, __pa(pte) >> PAGE_SHIFT); + set_pmd_safe(pmd, __pmd(__pa(pte) | _PAGE_TABLE)); +} + static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, struct page *pte) { @@ -132,6 +139,12 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT); set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd))); } + +static inline void pud_populate_safe(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) +{ + paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT); + set_pud_safe(pud, __pud(_PAGE_TABLE | __pa(pmd))); +} #endif /* CONFIG_X86_PAE */ #if CONFIG_PGTABLE_LEVELS > 3 @@ -141,6 +154,12 @@ static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud) set_p4d(p4d, __p4d(_PAGE_TABLE | __pa(pud))); } +static inline void p4d_populate_safe(struct mm_struct *mm, p4d_t *p4d, pud_t *pud) +{ + paravirt_alloc_pud(mm, __pa(pud) >> PAGE_SHIFT); + set_p4d_safe(p4d, __p4d(_PAGE_TABLE | __pa(pud))); +} + static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr) { gfp_t gfp = GFP_KERNEL_ACCOUNT; @@ -173,6 +192,14 @@ static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, p4d_t *p4d) set_pgd(pgd, __pgd(_PAGE_TABLE | __pa(p4d))); } +static inline void pgd_populate_safe(struct mm_struct *mm, pgd_t *pgd, p4d_t *p4d) +{ + if (!pgtable_l5_enabled()) + return; + paravirt_alloc_p4d(mm, __pa(p4d) >> PAGE_SHIFT); + set_pgd_safe(pgd, __pgd(_PAGE_TABLE | __pa(p4d))); +} + static inline p4d_t *p4d_alloc_one(struct mm_struct *mm, unsigned long addr) { gfp_t gfp = GFP_KERNEL_ACCOUNT; -- cgit v1.2.3