From patchwork Thu Aug 1 12:06:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13750355 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 31BA91A721D; Thu, 1 Aug 2024 12:58:48 +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=1722517129; cv=none; b=pXvD64hBDa2Xz7mQxz/LwpNmTXVPf+fSyoIFgiQZ71sJd8+FrDGCGgen1/MWOXoDy1X//EQ0EvPIE1l4GtMqHXMJjW8lHVobi0U0JQLdS9SQUCDIULhHSvOacdHu1IMbTXz1Trzu99XmDPTlNJAMdnGFnNk58dj9uAm+ib25ZI8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722517129; c=relaxed/simple; bh=iKC2Iasck77jV+Uk+oAXshC4xI2+EzWFpjmjkamUboo=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=OPf6moYe9zX/WRfXG1Ke4wwjHfebFfVrwtzBV/m/GcOx+y9sRq2FuNrBH0e29jxeTbAIFUlqSA07ojm4mY3Wa4lTpoPr3JAbhEd97rnz5J/uU8/EgQ+y37Vekoq9nHWol9Z/V2JmvsUCSfDSG73y4nAyRDscy4HD3WiSRGRStVo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dyQayV0f; 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="dyQayV0f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5CF41C4AF0B; Thu, 1 Aug 2024 12:58:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722517128; bh=iKC2Iasck77jV+Uk+oAXshC4xI2+EzWFpjmjkamUboo=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=dyQayV0fQPSZH8iBt3r920gWMR8PRqUKHxVxDgPQjyeJut555M3l4cDwsz+/L5qQS As1Fxhi/6bCXuwjr9NdjvBX6wDqf/Fxi3a8wGAE/qWUiZL5LYBhtTcPbxCWz/QML29 60npbjduYtAn0JzFHAUE8zwm6Q1kOxEoiKce7sC4wvjTflnDQ0DF9MalXGTrLYgS8F gXhhRz+nBXf6sqzaCfAlsMkL7do3RzBVthp97yDax4qvCcZ3OHQ8g2VY2PSqMAZLNd IxRDzjVoRVEX+F42dHQhDdgLvph86KDdI1LnkW1mniZkz3+zak2yx9Ro6Xt7xlGQRb XzXuKvipxoNHQ== From: Mark Brown Date: Thu, 01 Aug 2024 13:06:40 +0100 Subject: [PATCH v10 13/40] 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: <20240801-arm64-gcs-v10-13-699e2bd2190b@kernel.org> References: <20240801-arm64-gcs-v10-0-699e2bd2190b@kernel.org> In-Reply-To: <20240801-arm64-gcs-v10-0-699e2bd2190b@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 , 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=1838; i=broonie@kernel.org; h=from:subject:message-id; bh=iKC2Iasck77jV+Uk+oAXshC4xI2+EzWFpjmjkamUboo=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmq4YQi3D2wTTUJjuQQY3F7F1CBBVgw8rRNdzwjqNE tB9JpyaJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZquGEAAKCRAk1otyXVSH0LglB/ 9TWv0MHUp/MwJEjSWgKUaa9AI9T9ei3Yo/iBGwhTkm2lo8TZTWMdtH0ztI+7/sV7Bv2+cOXKDxO8Wn xdLbDBsr/gw3zkkssfqjmj3brMAAxPZsleH+Lznr+NV+/0NRHmSZxbVAVa0JsJVu2db+gWre42Wu2T lPKPmT9WC8gLVXsjaY6dzYqMNV662wcZ41nyv8oPea28bIjpwZZNSJspMdUGqpSQdGnjZp/yxu68w5 Y//Qbhz9rxsr1xOKKwh14tKc+nbFMdl2zKPVWbv5yGUS5EZEVUxqENG9eNNKup/HT0n8dZcq3Yep9V Z6RDFNJfx4fCy4UAAQiNxjCf+kO5rX 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 Signed-off-by: Mark Brown --- arch/arm64/include/asm/mman.h | 9 +++++++++ arch/arm64/mm/mmap.c | 10 +++++++++- 2 files changed, 18 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 642bdf908b22..3ed63fc8cd0a 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -83,9 +83,17 @@ 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)]); + } + /* VM_ARM64_BTI on a GCS is rejected in arch_validate_flags() */ if (vm_flags & VM_ARM64_BTI) prot |= PTE_GP;