From 5ebf3f8d5b56412973ca3f2363dae52f795c6700 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 7 Aug 2018 15:09:37 -0700 Subject: [PATCH] x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert commit 0768f91530ff46683e0b372df14fd79fe8d156e5 upstream Some cases in THP like: - MADV_FREE - mprotect - split mark the PMD non present for temporarily to prevent races. The window for an L1TF attack in these contexts is very small, but it wants to be fixed for correctness sake. Use the proper low level functions for pmd/pud_mknotpresent() to address this. Signed-off-by: Andi Kleen Signed-off-by: Thomas Gleixner Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/pgtable.h | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 4e06358..47b37af 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -350,11 +350,6 @@ static inline pmd_t pmd_mkwrite(pmd_t pmd) return pmd_set_flags(pmd, _PAGE_RW); } -static inline pmd_t pmd_mknotpresent(pmd_t pmd) -{ - return pmd_clear_flags(pmd, _PAGE_PRESENT | _PAGE_PROTNONE); -} - #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY static inline int pte_soft_dirty(pte_t pte) { @@ -418,6 +413,12 @@ static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot) return __pmd(pfn | massage_pgprot(pgprot)); } +static inline pmd_t pmd_mknotpresent(pmd_t pmd) +{ + return pfn_pmd(pmd_pfn(pmd), + __pgprot(pmd_flags(pmd) & ~(_PAGE_PRESENT|_PAGE_PROTNONE))); +} + static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask); static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) -- 2.7.4