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Wed, 03 Jun 2026 09:11:20 -0700 (PDT) Date: Wed, 3 Jun 2026 18:09:52 +0200 In-Reply-To: <20260603160949.3372482-6-ardb+git@google.com> Mime-Version: 1.0 References: <20260603160949.3372482-6-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=2222; i=ardb@kernel.org; h=from:subject; bh=klTYuM9nrZaRSnTcs7Uaq38kYQvUy5mIsHZz1sf0jcw=; b=owGbwMvMwCVmkMcZplerG8N4Wi2JIUsh8KL6g/daO9pnK2+X3DhXPXKbsllExfMJs+ocW2KSW Y0fh0zoKGVhEONikBVTZBGY/ffdztMTpWqdZ8nCzGFlAhnCwMUpABOximD4p7Hz1NRnV46F1Zft DDxXyWkZcXf2ml3G5jNyAwOueKik6zAyHJklGVT4TXPNy8qLuzxbxG89qbH06y1pzigNu5+XEP2 THQA= X-Mailer: git-send-email 2.54.0.1013.g208068f2d8-goog Message-ID: <20260603160949.3372482-8-ardb+git@google.com> Subject: [PATCH 2/4] arm64: Avoid double evaluation of __ptep_get() From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, maz@kernel.org, Ard Biesheuvel , Kevin Brodsky , Mark Brown Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260603_091123_367345_95350DDE X-CRM114-Status: GOOD ( 13.82 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Ard Biesheuvel Sashiko warns that the new pte_valid_noncont() macro is used in a manner where the argument (which performs a READ_ONCE() of the descriptor) is evaluated twice. Drop the macro that we just added, and move the check into the newly added users. Signed-off-by: Ard Biesheuvel --- arch/arm64/include/asm/pgtable.h | 4 ---- arch/arm64/mm/mmu.c | 14 ++++++++++---- 2 files changed, 10 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 491ba0a6492d..c9e4e00a9af2 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -181,10 +181,6 @@ static inline pteval_t __phys_to_pte_val(phys_addr_t phys) * Returns true if the pte is valid and has the contiguous bit set. */ #define pte_valid_cont(pte) (pte_valid(pte) && pte_cont(pte)) -/* - * Returns true if the pte is valid and has the contiguous bit cleared. - */ -#define pte_valid_noncont(pte) (pte_valid(pte) && !pte_cont(pte)) /* * Could the pte be present in the TLB? We must check mm_tlb_flush_pending * so that we don't erroneously return false for pages that have been diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index be51f6cac86f..d68e691c093a 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -186,9 +186,12 @@ static void init_pte(pte_t *ptep, unsigned long addr, unsigned long end, static bool pte_range_has_valid_noncont(pte_t *ptep) { - for (int i = 0; i < CONT_PTES; i++) - if (pte_valid_noncont(__ptep_get(&ptep[i]))) + for (int i = 0; i < CONT_PTES; i++) { + pte_t pte = __ptep_get(&ptep[i]); + + if (pte_valid(pte) && !pte_cont(pte)) return true; + } return false; } @@ -291,9 +294,12 @@ static int init_pmd(pmd_t *pmdp, unsigned long addr, unsigned long end, static bool pmd_range_has_valid_noncont(pmd_t *pmdp) { - for (int i = 0; i < CONT_PMDS; i++) - if (pte_valid_noncont(pmd_pte(READ_ONCE(pmdp[i])))) + for (int i = 0; i < CONT_PMDS; i++) { + pte_t pte = pmd_pte(READ_ONCE(pmdp[i])); + + if (pte_valid(pte) && !pte_cont(pte)) return true; + } return false; } -- 2.54.0.1013.g208068f2d8-goog