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AFNElJ/kh6hHDueAI25pGGdt3pf2NA+gClTVkEmNX6iPMe4svK2xhHX2IbIbOCg5qr0/mlDiv+dnycF9vU5SrwEJeL0=@vger.kernel.org X-Gm-Message-State: AOJu0YxlRZ4T3OwLUGQC7ieCFnz1WX+sx6LvVQav/PS9NmKVkXM90gGl 1lMLd2YD+gv6khHEV6kY6321VLvr3X+Vv+PRm3G2ZcBMbxhSOMBJ5d9sw09SKUYKQ5hV/7N08w= = X-Received: from wrjb13.prod.google.com ([2002:adf:e30d:0:b0:45b:cad1:2df1]) (user=ardb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:2c06:b0:45d:4fc0:fe0a with SMTP id ffacd0b85a97d-45e5c5dd346mr33349921f8f.32.1779203905296; Tue, 19 May 2026 08:18:25 -0700 (PDT) Date: Tue, 19 May 2026 17:16:24 +0200 In-Reply-To: <20260519151616.2557018-15-ardb+git@google.com> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260519151616.2557018-15-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=914; i=ardb@kernel.org; h=from:subject; bh=DzlMi7mku98t808/4L/IevsaqNhHNBA7ZPaOWGTKp3M=; b=owGbwMvMwCVmkMcZplerG8N4Wi2JIYun7ozjx5JHO2c9Tvz2bbb1UYGuFVGxfyOk/Lcl39l/K H2HsKVMRykLgxgXg6yYIovA7L/vdp6eKFXrPEsWZg4rE8gQBi5OAZjI0z2MDCcD0w4yfjZVbdjI l/1mdYzWeoF7uf/65CXWOutIPTyn6s7wz/CboZoY8yGh2dyvFDVyd1ef1EtQfpqkvm298dz7pw+ +ZwAA X-Mailer: git-send-email 2.54.0.563.g4f69b47b94-goog Message-ID: <20260519151616.2557018-22-ardb+git@google.com> Subject: [PATCH v5 07/13] 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 , Jann Horn , linux-mm@kvack.org, linux-hardening@vger.kernel.org Content-Type: text/plain; charset="UTF-8" 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 0405fac18959..7cecd25aa83b 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; -- 2.54.0.563.g4f69b47b94-goog