From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yu-cheng Yu Subject: [RFC PATCH v2 11/27] x86/mm: Modify ptep_set_wrprotect and pmdp_set_wrprotect for _PAGE_DIRTY_SW Date: Tue, 10 Jul 2018 15:26:23 -0700 Message-ID: <20180710222639.8241-12-yu-cheng.yu@intel.com> References: <20180710222639.8241-1-yu-cheng.yu@intel.com> Return-path: In-Reply-To: <20180710222639.8241-1-yu-cheng.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek Peter Cc: Yu-cheng Yu List-Id: linux-api@vger.kernel.org Update ptep_set_wrprotect() and pmdp_set_wrprotect() for _PAGE_DIRTY_SW. Signed-off-by: Yu-cheng Yu --- arch/x86/include/asm/pgtable.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index ecbd3539a864..456a864aa605 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -1170,7 +1170,18 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { + pte_t pte; + clear_bit(_PAGE_BIT_RW, (unsigned long *)&ptep->pte); + pte = *ptep; + + /* + * On platforms before CET, other threads could race to + * create a RO and _PAGE_DIRTY_HW PTE again. However, + * on CET platforms, this is safe without a TLB flush. + */ + pte = pte_move_flags(pte, _PAGE_DIRTY_HW, _PAGE_DIRTY_SW); + set_pte_at(mm, addr, ptep, pte); } #define flush_tlb_fix_spurious_fault(vma, address) do { } while (0) @@ -1220,7 +1231,18 @@ static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm, static inline void pmdp_set_wrprotect(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp) { + pmd_t pmd; + clear_bit(_PAGE_BIT_RW, (unsigned long *)pmdp); + pmd = *pmdp; + + /* + * On platforms before CET, other threads could race to + * create a RO and _PAGE_DIRTY_HW PMD again. However, + * on CET platforms, this is safe without a TLB flush. + */ + pmd = pmd_move_flags(pmd, _PAGE_DIRTY_HW, _PAGE_DIRTY_SW); + set_pmd_at(mm, addr, pmdp, pmd); } #define pud_write pud_write -- 2.17.1