From 7c929ad0b3167e980a3963e03403a761138a4350 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 25 Sep 2023 20:31:27 +0200 Subject: [PATCH] powerpc/nohash: Refactor checking of no-change in pte_update() On nohash/64, a few callers of pte_update() check if there is really a change in order to avoid an unnecessary write. Refactor that inside pte_update(). Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/076563e611c2b51036686a8d378bfd5ef1726341.1695659959.git.christophe.leroy@csgroup.eu --- arch/powerpc/include/asm/nohash/64/pgtable.h | 9 --------- arch/powerpc/include/asm/nohash/pgtable.h | 3 +++ 2 files changed, 3 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h index b149a39f26853e..cba08a62c52cd5 100644 --- a/arch/powerpc/include/asm/nohash/64/pgtable.h +++ b/arch/powerpc/include/asm/nohash/64/pgtable.h @@ -181,8 +181,6 @@ static inline int __ptep_test_and_clear_young(struct mm_struct *mm, { unsigned long old; - if (!pte_young(*ptep)) - return 0; old = pte_update(mm, addr, ptep, _PAGE_ACCESSED, 0, 0); return (old & _PAGE_ACCESSED) != 0; } @@ -198,10 +196,6 @@ static inline int __ptep_test_and_clear_young(struct mm_struct *mm, static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - - if ((pte_val(*ptep) & _PAGE_RW) == 0) - return; - pte_update(mm, addr, ptep, _PAGE_RW, 0, 0); } @@ -209,9 +203,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, static inline void huge_ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - if ((pte_val(*ptep) & _PAGE_RW) == 0) - return; - pte_update(mm, addr, ptep, _PAGE_RW, 0, 1); } diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h index bd5c3a4baabd05..8adaacbbdd1d66 100644 --- a/arch/powerpc/include/asm/nohash/pgtable.h +++ b/arch/powerpc/include/asm/nohash/pgtable.h @@ -47,6 +47,9 @@ static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, p pte_basic_t old = pte_val(*p); pte_basic_t new = (old & ~(pte_basic_t)clr) | set; + if (new == old) + return old; + *p = __pte(new); if (IS_ENABLED(CONFIG_44x) && (old & _PAGE_USER) && (old & _PAGE_EXEC))