From e2aaae2d3677563c1bb6cd15fbddd701381823be Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 10 Feb 2022 16:08:29 +0100 Subject: s390/mm: add set_pXd()/set_pte() helper functions Add set_pXd()/set_pte() helper functions which must be used to update page table entries. The new helpers use WRITE_ONCE() to make sure that a page table entry is written to only once. Without this the compiler could otherwise generate code which writes several times to a page table entry when updating its contents from invalid to valid, which could lead to surprising results especially for multithreaded processes... Reviewed-by: Claudio Imbrenda Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik --- arch/s390/include/asm/pgtable.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'arch/s390/include/asm/pgtable.h') diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 008a6c856fa4..2aa8057c7ef8 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -881,6 +881,31 @@ static inline pgprot_t pte_pgprot(pte_t pte) * pgd/pmd/pte modification functions */ +static inline void set_pgd(pgd_t *pgdp, pgd_t pgd) +{ + WRITE_ONCE(*pgdp, pgd); +} + +static inline void set_p4d(p4d_t *p4dp, p4d_t p4d) +{ + WRITE_ONCE(*p4dp, p4d); +} + +static inline void set_pud(pud_t *pudp, pud_t pud) +{ + WRITE_ONCE(*pudp, pud); +} + +static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) +{ + WRITE_ONCE(*pmdp, pmd); +} + +static inline void set_pte(pte_t *ptep, pte_t pte) +{ + WRITE_ONCE(*ptep, pte); +} + static inline void pgd_clear(pgd_t *pgd) { if ((pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R1) -- cgit v1.2.3-59-g8ed1b