From 481e980a7c199c5a4634fd7ea308067dd4ba75fa Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 15 Jun 2020 12:57:58 +0000 Subject: mm: Allow arches to provide ptep_get() Since commit 9e343b467c70 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses") it is not possible anymore to use READ_ONCE() to access complex page table entries like the one defined for powerpc 8xx with 16k size pages. Define a ptep_get() helper that architectures can override instead of performing a READ_ONCE() on the page table entry pointer. Fixes: 9e343b467c70 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses") Signed-off-by: Christophe Leroy Acked-by: Will Deacon Acked-by: Peter Zijlstra (Intel) Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/087fa12b6e920e32315136b998aa834f99242695.1592225558.git.christophe.leroy@csgroup.eu --- mm/gup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/gup.c b/mm/gup.c index 761df4944ef5..6f47697f8fb0 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2196,7 +2196,7 @@ static inline pte_t gup_get_pte(pte_t *ptep) */ static inline pte_t gup_get_pte(pte_t *ptep) { - return READ_ONCE(*ptep); + return ptep_get(ptep); } #endif /* CONFIG_GUP_GET_PTE_LOW_HIGH */ -- cgit v1.2.3-59-g8ed1b