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[141.95.202.232]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3232f8c8e4bsm923478a91.2.2025.08.14.05.06.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Aug 2025 05:06:50 -0700 (PDT) From: Alexandre Ghiti Date: Thu, 14 Aug 2025 12:06:14 +0000 Subject: [PATCH] riscv: Use an atomic xchg in pudp_huge_get_and_clear() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250814-dev-alex-thp_pud_xchg-v1-1-b4704dfae206@rivosinc.com> X-B4-Tracking: v=1; b=H4sIADXRnWgC/x3MQQqAIBBA0avErBvI1KiuEhGhUw5EiVYI0d2Tl m/x/wORAlOEvngg0M2Rjz1DlAUYN+8rIdtsqKtaV61QaOnGeaOEp/OTv+yUjFuxFVoaKaTtVAO 59YEWTv93GN/3A4nQqbBnAAAA X-Change-ID: 20250814-dev-alex-thp_pud_xchg-8153c313d946 To: Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Alexandre Ghiti X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=1490; i=alexghiti@rivosinc.com; h=from:subject:message-id; bh=wiB//OFp2BrFQuwN6BZWO5CNv4TW0Uuh2XVDxdHzt2g=; b=owGbwMvMwCGWYr9pz6TW912Mp9WSGDLmXvT/2sjZzsLpbla9zt1RuuD5t94w2cMrAiYbPNs49 c9vRsYXHaUsDGIcDLJiiiwK5gldLfZn62f/ufQeZg4rE8gQBi5OAZjIyyMM//1mHIl5e/635P6/ pQ/FNQKfHZd/Ja4ac2j/y6McX6b1rhFkZJhk8vpp7+FXXZc0rvpcrXQS7NPLM3TaFGYw/3j4Sov 1HpwA X-Developer-Key: i=alexghiti@rivosinc.com; a=openpgp; fpr=DC049C97114ED82152FE79A783E4BA75438E93E3 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 --- Note that this will conflict with https://lore.kernel.org/linux-riscv/20250625063753.77511-1-ajd@linux.ibm.co= m/ if applied after 6.17. --- arch/riscv/include/asm/pgtable.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgta= ble.h index 91697fbf1f9013005800f713797e4b6b1fc8d312..e69346307e78608dd98d8b7a77b= 7063c333448ee 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); } =20 +#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 =3D __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)); --- base-commit: 62950c35a515743739e3d863eac25c20a5bd1613 change-id: 20250814-dev-alex-thp_pud_xchg-8153c313d946 Best regards, --=20 Alexandre Ghiti