6.16-stable review patch. If anyone has any objections, please let me know.
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From: Alexandre Ghiti alexghiti@rivosinc.com
commit 546e42c8c6d9498d5eac14bf2aca0383a11b145a upstream.
Make sure we return the right pud value and not a value that could have been overwritten in between by a different core.
Fixes: c3cc2a4a3a23 ("riscv: Add support for PUD THP") Cc: stable@vger.kernel.org Signed-off-by: Alexandre Ghiti alexghiti@rivosinc.com Link: https://lore.kernel.org/r/20250814-dev-alex-thp_pud_xchg-v1-1-b4704dfae206@r... [pjw@kernel.org: use xchg rather than atomic_long_xchg; avoid atomic op for !CONFIG_SMP like x86] Signed-off-by: Paul Walmsley pjw@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/include/asm/pgtable.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
--- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -964,6 +964,23 @@ static inline int pudp_test_and_clear_yo 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) +{ +#ifdef CONFIG_SMP + pud_t pud = __pud(xchg(&pudp->pud, 0)); +#else + pud_t pud = *pudp; + + pud_clear(pudp); +#endif + + page_table_check_pud_clear(mm, pud); + + return pud; +} + static inline int pud_young(pud_t pud) { return pte_young(pud_pte(pud));