From: Anshuman Khandual Date: Thu, 13 Jul 2023 07:15:18 +0000 (+0530) Subject: arm64/mm: Set only the PTE_DIRTY bit while preserving the HW dirty state X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6477c3886ae101367aae2e808caf71f7b0fcc18e;p=linux.git arm64/mm: Set only the PTE_DIRTY bit while preserving the HW dirty state pte_mkdirty() creates dirty states both in SW and HW bits, which is really not required, either in pte_wrprotect() or pte_modify() for preserving the HW dirty state. Because pte_mkdirty() sets PTE_DIRTY and clears PTE_RDONLY as pte_write() always evaluates to be true - otherwise pte_hw_dirty() will not test out in the first place. Clearing PTE_RDONLY again is not required here because the pte is already in pte_hw_dirty() but might soon loose its dirty state thus requiring preservation in SW dirty bit i.e PTE_DIRTY. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual Reviewed-by: David Hildenbrand Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20230713071518.628440-1-anshuman.khandual@arm.com Signed-off-by: Will Deacon --- diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 02b7abcf1f9fc..72c2e84313606 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -213,7 +213,7 @@ static inline pte_t pte_wrprotect(pte_t pte) * clear), set the PTE_DIRTY bit. */ if (pte_hw_dirty(pte)) - pte = pte_mkdirty(pte); + pte = set_pte_bit(pte, __pgprot(PTE_DIRTY)); pte = clear_pte_bit(pte, __pgprot(PTE_WRITE)); pte = set_pte_bit(pte, __pgprot(PTE_RDONLY)); @@ -824,7 +824,8 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) PTE_ATTRINDX_MASK; /* preserve the hardware dirty information */ if (pte_hw_dirty(pte)) - pte = pte_mkdirty(pte); + pte = set_pte_bit(pte, __pgprot(PTE_DIRTY)); + pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask); return pte; }