From: Alexandre Ghiti Date: Thu, 14 Aug 2025 12:06:14 +0000 (+0000) Subject: riscv: use an atomic xchg in pudp_huge_get_and_clear() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=668208b161a0b679427e7d0f34c0a65fd7d23979;p=users%2Fhch%2Fmisc.git riscv: use an atomic xchg in pudp_huge_get_and_clear() Make sure we return the right pud value and not a value that could have been overwritten in between by a different core. Link: https://lkml.kernel.org/r/20250814-dev-alex-thp_pud_xchg-v1-1-b4704dfae206@rivosinc.com Fixes: c3cc2a4a3a23 ("riscv: Add support for PUD THP") Signed-off-by: Alexandre Ghiti Cc: Andrew Donnellan Cc: Signed-off-by: Andrew Morton --- diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 91697fbf1f90..e69346307e78 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -942,6 +942,17 @@ static inline int pudp_test_and_clear_young(struct vm_area_struct *vma, return ptep_test_and_clear_young(vma, address, (pte_t *)pudp); } +#define __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR +static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm, + unsigned long address, pud_t *pudp) +{ + pud_t pud = __pud(atomic_long_xchg((atomic_long_t *)pudp, 0)); + + page_table_check_pud_clear(mm, pud); + + return pud; +} + static inline int pud_young(pud_t pud) { return pte_young(pud_pte(pud));