From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F18B3C54FD0 for ; Mon, 27 Apr 2020 06:25:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D63FB206B6 for ; Mon, 27 Apr 2020 06:25:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726593AbgD0GZQ (ORCPT ); Mon, 27 Apr 2020 02:25:16 -0400 Received: from foss.arm.com ([217.140.110.172]:57178 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726237AbgD0GZP (ORCPT ); Mon, 27 Apr 2020 02:25:15 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6999931B; Sun, 26 Apr 2020 23:25:15 -0700 (PDT) Received: from a075553-lin.blr.arm.com (a075553-lin.blr.arm.com [10.162.17.24]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id A1AF13F73D; Sun, 26 Apr 2020 23:25:12 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Bhupesh Sharma , Vincenzo Frascino , James Morse , Amit Daniel Kachhap , Mark Rutland Subject: [PATCH v2 1/2] arm64/crash_core: Export KERNELPACMASK in vmcoreinfo Date: Mon, 27 Apr 2020 11:55:01 +0530 Message-Id: <1587968702-19996-1-git-send-email-amit.kachhap@arm.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Recently arm64 linux kernel added support for Armv8.3-A Pointer Authentication feature. If this feature is enabled in the kernel and the hardware supports address authentication then the return addresses are signed and stored in the stack to prevent ROP kind of attack. Kdump tool will now dump the kernel with signed lr values in the stack. Any user analysis tool for this kernel dump may need the kernel pac mask information in vmcoreinfo to generate the correct return address for stacktrace purpose as well as to resolve the symbol name. This patch is similar to commit ec6e822d1a22d0eef ("arm64: expose user PAC bit positions via ptrace") which exposes pac mask information via ptrace interfaces. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Signed-off-by: Amit Daniel Kachhap --- Changes since v1: * Rebased to kernel 5.7-rc3. * commit log change. An implementation of this new KERNELPACMASK vmcoreinfo field used by crash tool can be found here[1]. This change is accepted by crash utility maintainer [2]. [1]: https://www.redhat.com/archives/crash-utility/2020-April/msg00095.html [2]: https://www.redhat.com/archives/crash-utility/2020-April/msg00099.html arch/arm64/include/asm/compiler.h | 3 +++ arch/arm64/kernel/crash_core.c | 4 ++++ 2 files changed, 7 insertions(+) diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h index eece20d..32d5900 100644 --- a/arch/arm64/include/asm/compiler.h +++ b/arch/arm64/include/asm/compiler.h @@ -19,6 +19,9 @@ #define __builtin_return_address(val) \ (void *)(ptrauth_clear_pac((unsigned long)__builtin_return_address(val))) +#else /* !CONFIG_ARM64_PTR_AUTH */ +#define ptrauth_user_pac_mask() 0ULL +#define ptrauth_kernel_pac_mask() 0ULL #endif /* CONFIG_ARM64_PTR_AUTH */ #endif /* __ASM_COMPILER_H */ diff --git a/arch/arm64/kernel/crash_core.c b/arch/arm64/kernel/crash_core.c index ca4c3e1..25cf2ce 100644 --- a/arch/arm64/kernel/crash_core.c +++ b/arch/arm64/kernel/crash_core.c @@ -6,6 +6,7 @@ #include #include +#include void arch_crash_save_vmcoreinfo(void) { @@ -16,4 +17,7 @@ void arch_crash_save_vmcoreinfo(void) vmcoreinfo_append_str("NUMBER(PHYS_OFFSET)=0x%llx\n", PHYS_OFFSET); vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); + vmcoreinfo_append_str("NUMBER(KERNELPACMASK)=0x%llx\n", + system_supports_address_auth() ? + ptrauth_kernel_pac_mask() : 0); } -- 2.7.4