[RFC PATCH v9 10/27] x86/mm: Update pte_modify, pmd_modify, and _PAGE_CHG_MASK for _PAGE_DIRTY_SW
From: Yu-cheng Yu <hidden>
Date: 2020-02-05 18:22:23
Also in:
linux-arch, linux-doc, linux-mm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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 <redacted> --- 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