From patchwork Wed Aug 28 23:27:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13782137 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6EB99161319; Wed, 28 Aug 2024 23:30:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724887815; cv=none; b=EW1GGha69p3cS/EfVwlnZqL+91BNmMWYGg0kjAtKbgv4+z0XJE2FU3xxh2PLIPI8gEs/DuE5POSP4t/ALrdS1it2HOh9HDWqehJiCO5W/8Z3sP3ktj6pc/kGLbVq3TYJ5ZRUiYpwjRLMfoIcq0sPzWEXNeqamJYiI1eHTd703Ag= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724887815; c=relaxed/simple; bh=q8jtVg186GFJVIbjl1JCrkiZnz/oBLnR/HtHUgXvMfA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=PU3wOJ2qJk6wI1DEGGkMQGk0KELRgrXXcKPC1rxNNm7O308zSN5TbrKXXqGAuN2frhnr3nUKDeCSmDbbstQIQZJ+Bg9DEQKEPv3TCBema3bEVzvxqzd06gSlH4HuMdPxfPMI0wbP2uJt1Bt/szlatZ3s9xRXsK7uyQfEHpcUvQI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=csXIYlPb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="csXIYlPb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E576DC4CEC5; Wed, 28 Aug 2024 23:30:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1724887815; bh=q8jtVg186GFJVIbjl1JCrkiZnz/oBLnR/HtHUgXvMfA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=csXIYlPbjsq0/jESzviJXGLS5PVUMwFyPcl9Xf8tCAU3CGgzUzcSXEOOGrzJGOi4n +LVpTfKWkimkyH2gkwgyYFLAqrNxMfByqvcuy0VRXO4vSBMDQDGRLkHTzLYPfpeOy2 AyEWc7lOsYqAfbBDM8Bc6mJym3P1TCGwFH6JYwLsXtYbilIWgJGJBuUIWwEF4ruBzk Irzl16KGJZap13BwqZWYzbzXWP+4eyR9laKqpNp69phFVR0DOgEfIDlzw09zIlvjZg aqd4HA+U9jzpvZJm3UVCJjQd5uoKjF5Q0gQa5Ttxa0UAOtqwlc/QdBtfEypp/Uxek/ Eb/XXqGaqeeCg== From: Mark Brown Date: Thu, 29 Aug 2024 00:27:30 +0100 Subject: [PATCH v12 14/39] arm64/mm: Map pages for guarded control stack Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240829-arm64-gcs-v12-14-42fec947436a@kernel.org> References: <20240829-arm64-gcs-v12-0-42fec947436a@kernel.org> In-Reply-To: <20240829-arm64-gcs-v12-0-42fec947436a@kernel.org> To: Catalin Marinas , Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , Kees Cook Cc: "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Thiago Jung Bauermann , Ross Burton , Yury Khrustalev , Wilco Dijkstra , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Mark Brown X-Mailer: b4 0.15-dev-37811 X-Developer-Signature: v=1; a=openpgp-sha256; l=1824; i=broonie@kernel.org; h=from:subject:message-id; bh=q8jtVg186GFJVIbjl1JCrkiZnz/oBLnR/HtHUgXvMfA=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmz7KDz+A8JTqcELz4cAJ592v00no+g1aVltB8BmzS YLVlld6JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZs+ygwAKCRAk1otyXVSH0GfJB/ 49HQhF+L8EiPWM7v3hZ36OyfEAtuZYOAa7yxbdtNlpOsOKuJCieWaGUjCl4V7oMxDUXRoMqIYkJ2Y7 0UjpPJ2A/OzEmFWXJzvSlVo9eCTfasoJ4KB8k9tuDNt/wmQ2GuY7C+9u0ds83AmngnuKcfDeqVE0VW 8xDc5pxqMmvZE+kh51h7AXaa+kMQTlm7Dnb4gtNI554joq08SMIgk7fZKptpoJne0VPkT1C7gUBfTG r3ZYOx8kpQ6ZA2hstniXP3cfObhdDaqIBtvnccak5YaFOo4qP9sUvzJOoHVrguVBLRswG/5kNuET2U 0gXB7BzsUfSt94B6y9IbRGc5knJOAA X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Map pages flagged as being part of a GCS as such rather than using the full set of generic VM flags. This is done using a conditional rather than extending the size of protection_map since that would make for a very sparse array. Reviewed-by: Thiago Jung Bauermann Reviewed-by: Catalin Marinas Signed-off-by: Mark Brown --- arch/arm64/include/asm/mman.h | 9 +++++++++ arch/arm64/mm/mmap.c | 9 ++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index c21849ffdd88..37dfd2882f04 100644 --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -61,6 +61,15 @@ static inline bool arch_validate_flags(unsigned long vm_flags) return false; } + if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { + /* An executable GCS isn't a good idea. */ + if (vm_flags & VM_EXEC) + return false; + + /* The memory management core should prevent this */ + VM_WARN_ON(vm_flags & VM_SHARED); + } + return true; } diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 642bdf908b22..5943898f366b 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -83,8 +83,15 @@ arch_initcall(adjust_protection_map); pgprot_t vm_get_page_prot(unsigned long vm_flags) { - pteval_t prot = pgprot_val(protection_map[vm_flags & + pteval_t prot; + + /* Short circuit GCS to avoid bloating the table. */ + if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { + prot = _PAGE_GCS_RO; + } else { + prot = pgprot_val(protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]); + } if (vm_flags & VM_ARM64_BTI) prot |= PTE_GP;