From be51e3fde5c10f269c065fdca2caf28e4708e21e Mon Sep 17 00:00:00 2001 From: Anshuman Khandual Date: Wed, 3 Jun 2020 16:00:56 -0700 Subject: arm64/mm: drop __HAVE_ARCH_HUGE_PTEP_GET Patch series "mm/hugetlb: Add some new generic fallbacks", v3. This series adds the following new generic fallbacks. Before that it drops __HAVE_ARCH_HUGE_PTEP_GET from arm64 platform. 1. is_hugepage_only_range() 2. arch_clear_hugepage_flags() After this arm (32 bit) remains the sole platform defining it's own huge_ptep_get() via __HAVE_ARCH_HUGE_PTEP_GET. This patch (of 3): Platform specific huge_ptep_get() is required only when fetching the huge PTE involves more than just dereferencing the page table pointer. This is not the case on arm64 platform. Hence huge_ptep_pte() can be dropped along with it's __HAVE_ARCH_HUGE_PTEP_GET subscription. Before that, it updates the generic huge_ptep_get() with READ_ONCE() which will prevent known page table issues with THP on arm64. Signed-off-by: Anshuman Khandual Signed-off-by: Andrew Morton Acked-by: Mike Kravetz Cc: Catalin Marinas Cc: Will Deacon Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Christian Borntraeger Cc: "David S. Miller" Cc: Fenghua Yu Cc: Heiko Carstens Cc: Helge Deller Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: "James E.J. Bottomley" Cc: Michael Ellerman Cc: Palmer Dabbelt Cc: Paul Mackerras Cc: Paul Walmsley Cc: Rich Felker Cc: Russell King Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Tony Luck Cc: Vasily Gorbik Cc: Yoshinori Sato Link: http://lkml.kernel.org/r/1588907271-11920-1-git-send-email-anshuman.khandual@arm.com Link: http://lkml.kernel.org/r//1506527369-19535-1-git-send-email-will.deacon@arm.com/ Link: http://lkml.kernel.org/r/1588907271-11920-2-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds --- include/asm-generic/hugetlb.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h index 822f433ac95c..40f85decc2ee 100644 --- a/include/asm-generic/hugetlb.h +++ b/include/asm-generic/hugetlb.h @@ -122,7 +122,7 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma, #ifndef __HAVE_ARCH_HUGE_PTEP_GET static inline pte_t huge_ptep_get(pte_t *ptep) { - return *ptep; + return READ_ONCE(*ptep); } #endif -- cgit v1.2.3-59-g8ed1b