From patchwork Mon Oct 9 12:08:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13413495 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8114E95A9A for ; Mon, 9 Oct 2023 12:13:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346671AbjJIMNc (ORCPT ); Mon, 9 Oct 2023 08:13:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376306AbjJIMMu (ORCPT ); Mon, 9 Oct 2023 08:12:50 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5DD76136; Mon, 9 Oct 2023 05:12:07 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17B99C433C8; Mon, 9 Oct 2023 12:11:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696853527; bh=nFe19RrcDm61i+JVIJSNKwCFAGBQlI1oN8c03/2+1zo=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=cZGxWSXvQ9p+yKwDzwrWzB8K+WHJgYHI1Erz8lZPQZUjIVKP+bVL6Xl9GUFpktBxe hxdvoPWujKNy0cokSw4VRdpvpwrCR38nw0uDO8tdhtSCc2Gf3hqYoN5AVuGG+dtFXl B0oqdGcPg90/Pll34H0J2fLgA8jEabIHpRHztOFrhc8NklEPwg2oOIPH+N8m486WUw 4lTIaRy++XwgJJdJGGOxXbGqck3GBhTXmKln9du8EN9QggrY+v5LSuXXJ9JPUe35OL 9A2hH/x+I3R/FaCj1jk9DBSfuO83Q9lo++fe4hpLmO6s62YW1iuQmdEM1f7jfEcvxY DFhl7UE1FYSYw== From: Mark Brown Date: Mon, 09 Oct 2023 13:08:47 +0100 Subject: [PATCH v6 13/38] arm64/mm: Map pages for guarded control stack MIME-Version: 1.0 Message-Id: <20231009-arm64-gcs-v6-13-78e55deaa4dd@kernel.org> References: <20231009-arm64-gcs-v6-0-78e55deaa4dd@kernel.org> In-Reply-To: <20231009-arm64-gcs-v6-0-78e55deaa4dd@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 , 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-0438c X-Developer-Signature: v=1; a=openpgp-sha256; l=1837; i=broonie@kernel.org; h=from:subject:message-id; bh=nFe19RrcDm61i+JVIJSNKwCFAGBQlI1oN8c03/2+1zo=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBlI+2bTh8bFfyd2r4ErvGH3ueKxYkR2qokJvrjYIHe d3kV+mSJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZSPtmwAKCRAk1otyXVSH0GQlB/ 9cpjBNO3Hkf17J4ctj7mZ/0x9xYzjeURnc3L7chNJsl7kVZCHJwsK3oGMSJuzBGHmA8bm5zbKxGdHv cIzNzCvwKKPP+GpZ4iV98ewuyU2DUhLI68aHjVxzw1a5ilduYukZQVlSaOEhzaMWfa3JrWfON37j17 U0ypx1Dn/X62XIv6vRrnZn0kGsmi1oyQ8xGTxxuW9KankfsQ68FXGsqRGt62v5teQZoIs5VHY3mdD2 MyBLR7qTYazUymR623R0tIYIiOqlfKTrt8pcRb2punJmcVyjApsuS5jnzIRiB2CsNrWsSAbIJO2Jug J/T3ncAFQKv5EOKNpQTGTowHJvMb4F X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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 8f5b7ce857ed..e6fc7ef83ea1 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_valdiate_flags() */ if (vm_flags & VM_ARM64_BTI) prot |= PTE_GP;