From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yu-cheng Yu Subject: [RFC PATCH v9 10/27] x86/mm: Update pte_modify, pmd_modify, and _PAGE_CHG_MASK for _PAGE_DIRTY_SW Date: Wed, 5 Feb 2020 10:19:18 -0800 Message-ID: <20200205181935.3712-11-yu-cheng.yu@intel.com> References: <20200205181935.3712-1-yu-cheng.yu@intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200205181935.3712-1-yu-cheng.yu@intel.com> Sender: linux-doc-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 , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit Cc: Yu-cheng Yu List-Id: linux-api@vger.kernel.org After the introduction of _PAGE_DIRTY_SW, pte_modify and pmd_modify need to set the Dirty bit accordingly: if Shadow Stack is enabled and _PAGE_RW is cleared, use _PAGE_DIRTY_SW; otherwise _PAGE_DIRTY_HW. Since the Dirty bit is modify by pte_modify(), remove _PAGE_DIRTY_HW from PAGE_CHG_MASK. Signed-off-by: Yu-cheng Yu --- arch/x86/include/asm/pgtable.h | 16 ++++++++++++++++ arch/x86/include/asm/pgtable_types.h | 4 ++-- 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 62aeb118bc36..2733e7ec16b3 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -702,6 +702,14 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) val &= _PAGE_CHG_MASK; val |= check_pgprot(newprot) & ~_PAGE_CHG_MASK; val = flip_protnone_guard(oldval, val, PTE_PFN_MASK); + + if (pte_dirty(pte)) { + if (static_cpu_has(X86_FEATURE_SHSTK) && !(val & _PAGE_RW)) + val |= _PAGE_DIRTY_SW; + else + val |= _PAGE_DIRTY_HW; + } + return __pte(val); } @@ -712,6 +720,14 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) val &= _HPAGE_CHG_MASK; val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK; val = flip_protnone_guard(oldval, val, PHYSICAL_PMD_PAGE_MASK); + + if (pmd_dirty(pmd)) { + if (static_cpu_has(X86_FEATURE_SHSTK) && !(val & _PAGE_RW)) + val |= _PAGE_DIRTY_SW; + else + val |= _PAGE_DIRTY_HW; + } + return __pmd(val); } diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 826823df917f..e7e28bf7e919 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -150,8 +150,8 @@ * instance, and is *not* included in this mask since * pte_modify() does modify it. */ -#define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ - _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY_HW | \ +#define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ + _PAGE_SPECIAL | _PAGE_ACCESSED | \ _PAGE_SOFT_DIRTY | _PAGE_DEVMAP) #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE) -- 2.21.0