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Mon, 27 Apr 2026 08:35:41 -0700 (PDT) Date: Mon, 27 Apr 2026 17:34:24 +0200 In-Reply-To: <20260427153416.2103979-17-ardb+git@google.com> Mime-Version: 1.0 References: <20260427153416.2103979-17-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=918; i=ardb@kernel.org; h=from:subject; bh=2M+2R/xfGuHti5Wurk6r5E9xqbGluJyDsIl7VYMOsyI=; b=owGbwMvMwCVmkMcZplerG8N4Wi2JIfN9E8tUw49az8LPeSafvHDx3bajk3bfqxCf4/ElO9n+i EqbmadXRykLgxgXg6yYIovA7L/vdp6eKFXrPEsWZg4rE8gQBi5OAZhIxHGGf2rT5kc6JZw8EfTc dtq0B6b/C6uZdnxyULeaKj/79Ou3L1gZGd7fr5d6L8ZyoL7vypL3Bx1P/wzxNdu7JOz5R5H7c65 9f80EAA== X-Mailer: git-send-email 2.54.0.rc2.544.gc7ae2d5bb8-goog Message-ID: <20260427153416.2103979-24-ardb+git@google.com> Subject: [PATCH v4 07/15] arm64: mm: Permit contiguous descriptors to be rewritten From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, Ard Biesheuvel , Ryan Roberts , Anshuman Khandual , Liz Prucka , Seth Jenkins , Kees Cook , Mike Rapoport , David Hildenbrand , Andrew Morton , linux-mm@kvack.org, linux-hardening@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260427_083547_320595_C1708274 X-CRM114-Status: GOOD ( 12.47 ) 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 Currently, pgattr_change_is_safe() is overly pedantic when it comes to descriptors with the contiguous hint attribute set, as it rejects assignments even if the old and the new value are the same. So relax the check to allow that. Signed-off-by: Ard Biesheuvel --- arch/arm64/mm/mmu.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 9610dd2d7bd9..bfb2f1cae724 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -134,10 +134,6 @@ bool pgattr_change_is_safe(pteval_t old, pteval_t new) if (pte_pfn(__pte(old)) != pte_pfn(__pte(new))) return false; - /* live contiguous mappings may not be manipulated at all */ - if ((old | new) & PTE_CONT) - return false; - /* Transitioning from Non-Global to Global is unsafe */ if (old & ~new & PTE_NG) return false; -- 2.54.0.rc2.544.gc7ae2d5bb8-goog