From patchwork Sat Feb 3 12:25:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13544082 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 DF7DD15E5B5; Sat, 3 Feb 2024 12:31:01 +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=1706963462; cv=none; b=nCrG6Vm0Ko9TjB+2IiIHI7X+dvT2Ei8ZFAkTTENIMuLtpv9rZaVAWmqj72mgdFBdZPpZCUVtgKnSkprVMo6eiTZOceEBxT6miW791YMmuJ+BLiZaK984C4wV6lfw0KOdfAA/f8c6xv4c2m4XtvZVfQ6Pd/Nm/uQg1cFZ6Q7afQg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706963462; c=relaxed/simple; bh=s6bCn957vl7MWPN5faZZH74vr8xHhA9oW4MYYSSC+7I=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=J08+BL8Qg/G8JvQnD12caSqrxT+w7T51OxCQxJrXgEGzhw3L7Od9xNsDHSEENJZ9XQUSPJwM8JMYXAeAoEpsQAvBwkoiwcgUUrZiQXcHW7gRp8STAsLk1gDMkHIqtk/1RJRTK2Ga9ocXIAHJHYmHix25VaEMvY7UDduBaYgNksE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cXOJ77sc; 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="cXOJ77sc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F7B3C43390; Sat, 3 Feb 2024 12:30:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706963461; bh=s6bCn957vl7MWPN5faZZH74vr8xHhA9oW4MYYSSC+7I=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=cXOJ77sc3cQAIYTgI4yLYEpIC37f03fcaibYvuInwn8di/O4yIt+bHnqL//pUPxDo hYEsFtkP6kQ89PQKm8oK7Wa9WxYQxdLqg+otrN5iczV2csW4rN1aMx8vigCUbn8kDd bmsybYB2hCWtaAxNkqcsA7w7EhpTS+iu98v+OGoXKYYdspFjQn6SR05CQaI5eZRZfT 4Yfc+cN/cWZF8hS+rJhDfqi8J7ujnzpTykA1gdfYbQTXJmJLh9EySsLIC7gaxOoXOc Fc1D2QtP4kY4lu1FgkM5ScscVf9rbilxymkFNDtZTdM+1+0v+4XyIa1x9LC7C0S0sP GlrafKo2iJ7Bg== From: Mark Brown Date: Sat, 03 Feb 2024 12:25:38 +0000 Subject: [PATCH v8 12/38] arm64/mm: Map pages for guarded control stack Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240203-arm64-gcs-v8-12-c9fec77673ef@kernel.org> References: <20240203-arm64-gcs-v8-0-c9fec77673ef@kernel.org> In-Reply-To: <20240203-arm64-gcs-v8-0-c9fec77673ef@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 , Kees Cook , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy Cc: "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Thiago Jung Bauermann , 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 0.13-dev-a684c X-Developer-Signature: v=1; a=openpgp-sha256; l=1837; i=broonie@kernel.org; h=from:subject:message-id; bh=s6bCn957vl7MWPN5faZZH74vr8xHhA9oW4MYYSSC+7I=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBlvjDaHwr5wrOWEW/xel9E3S7jsHXGClztspo/AIxO WVUvGMiJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZb4w2gAKCRAk1otyXVSH0DmCB/ 95KF+JXdMxHAx9xnGeVA7yTyp0+fMAu3TeB7kS7DtuBsLE4OtsXKtaSYZVp0Hm5moimwKXZTN8sLaR TkcMryVwyRFPeF/KBSacACnQi7Bt9HFPmo9H0eBNRCZuAv9vxu1NFrua3FD7vN0xbAuzCYRC+d53+k 61m3z2A9musH8F9maMwFmrdAW1+mROuXbvvK/LNIGA8xEkvqwNMm7hXoiXIRNdFzWTDBENITY28+dB RAddUPCMDR3nm/ogfYadyteOSUiumCbk85Ejb+ZT+4B6IyxeUQasBjqo+/eSMQVa6Ke6EvIKHHrOQY mUUz2tdyO/wb4T5iv2uYIYRZSrxs8I 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. Signed-off-by: Mark Brown --- arch/arm64/include/asm/mman.h | 9 +++++++++ arch/arm64/mm/mmap.c | 13 ++++++++++++- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index c21849ffdd88..6d3fe6433a62 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, and the mm + * core can't cope with a shared GCS. + */ + if (vm_flags & (VM_EXEC | VM_ARM64_BTI | VM_SHARED)) + return false; + } + return true; } diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 645fe60d000f..e44ce6fcfad9 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -79,9 +79,20 @@ 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; + + /* If this is a GCS then only interpret VM_WRITE. */ + if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { + if (vm_flags & VM_WRITE) + prot = _PAGE_GCS; + else + prot = _PAGE_GCS_RO; + } else { + prot = pgprot_val(protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]); + } + /* VM_ARM64_BTI on a GCS is rejected in arch_validate_flags() */ if (vm_flags & VM_ARM64_BTI) prot |= PTE_GP;