From: Anshuman Khandual <anshuman.khandual@xxxxxxx> 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. Link: http://lkml.kernel.org/r/1588907271-11920-1-git-send-email-anshuman.khandual@xxxxxxx Link: http://lkml.kernel.org/r//1506527369-19535-1-git-send-email-will.deacon@xxxxxxx/ Link: http://lkml.kernel.org/r/1588907271-11920-2-git-send-email-anshuman.khandual@xxxxxxx Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> Acked-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: Helge Deller <deller@xxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx> Cc: Rich Felker <dalias@xxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm64/include/asm/hugetlb.h | 6 ------ include/asm-generic/hugetlb.h | 2 +- 2 files changed, 1 insertion(+), 7 deletions(-) --- a/arch/arm64/include/asm/hugetlb.h~arm64-mm-drop-__have_arch_huge_ptep_get +++ a/arch/arm64/include/asm/hugetlb.h @@ -17,12 +17,6 @@ extern bool arch_hugetlb_migration_supported(struct hstate *h); #endif -#define __HAVE_ARCH_HUGE_PTEP_GET -static inline pte_t huge_ptep_get(pte_t *ptep) -{ - return READ_ONCE(*ptep); -} - static inline int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr, unsigned long len) { --- a/include/asm-generic/hugetlb.h~arm64-mm-drop-__have_arch_huge_ptep_get +++ a/include/asm-generic/hugetlb.h @@ -122,7 +122,7 @@ static inline int huge_ptep_set_access_f #ifndef __HAVE_ARCH_HUGE_PTEP_GET static inline pte_t huge_ptep_get(pte_t *ptep) { - return *ptep; + return READ_ONCE(*ptep); } #endif _
