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powerpc/nohash: Refactor checking of no-change in pte_update()

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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 <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/076563e611c2b51036686a8d378bfd5ef1726341.1695659959.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2023-09-25 20:31:27 +02:00 committed by Michael Ellerman
parent 42a2722319
commit 7c929ad0b3
2 changed files with 3 additions and 9 deletions
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9
arch/powerpc/include/asm/nohash/64/pgtable.h
View File

@ -181,8 +181,6 @@ static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
{ {
unsigned long old; unsigned long old;
if (!pte_young(*ptep))
return 0;
old = pte_update(mm, addr, ptep, _PAGE_ACCESSED, 0, 0); old = pte_update(mm, addr, ptep, _PAGE_ACCESSED, 0, 0);
return (old & _PAGE_ACCESSED) != 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, static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
pte_t *ptep) pte_t *ptep)
{ {
if ((pte_val(*ptep) & _PAGE_RW) == 0)
return;
pte_update(mm, addr, ptep, _PAGE_RW, 0, 0); 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, static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
unsigned long addr, pte_t *ptep) unsigned long addr, pte_t *ptep)
{ {
if ((pte_val(*ptep) & _PAGE_RW) == 0)
return;
pte_update(mm, addr, ptep, _PAGE_RW, 0, 1); pte_update(mm, addr, ptep, _PAGE_RW, 0, 1);
} }

3
arch/powerpc/include/asm/nohash/pgtable.h
View File

@ -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 old = pte_val(*p);
pte_basic_t new = (old & ~(pte_basic_t)clr) | set; pte_basic_t new = (old & ~(pte_basic_t)clr) | set;
if (new == old)
return old;
*p = __pte(new); *p = __pte(new);
if (IS_ENABLED(CONFIG_44x) && (old & _PAGE_USER) && (old & _PAGE_EXEC)) if (IS_ENABLED(CONFIG_44x) && (old & _PAGE_USER) && (old & _PAGE_EXEC))