From patchwork Fri Oct 5 08:47:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kristina Martsenko X-Patchwork-Id: 10627679 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 12E7815A6 for ; Fri, 5 Oct 2018 08:55:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E96AE2923A for ; Fri, 5 Oct 2018 08:55:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DACC029157; Fri, 5 Oct 2018 08:55:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 5B4B629157 for ; Fri, 5 Oct 2018 08:55:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=jAsdSbWQvsyvf0cm8Cdks2tKVzAnsIZgFzFqwfylKTY=; b=eY580j4pGh/SRwV8xxs/dxQOQH 70j38YtX+Y+k/76fdxfTooRzx/LUM0Mlk4G6dvrdLvz/VukoScmWVTBWF0K63D0EJgBtP+vugDy1M 0kf04VlMHkU2/LBTS/dCtBn3V/4a076FRPu+c2g+lrzmOV99cYmKekh+xa+YGCSmFl3P+K9Go9AU6 PjWvWNy4cIi3HOfWURchLc6aiHC1UDZhN1QtyyevIOlkBDelewkf+3iOci9OvxSX/XVTQE0Dz9RS7 2moHL9nsHrB9VfA801HGTAqHCuNUBgUksmRYG6Wq0bKMFSWaW3XKXzqejF6hWSRqv6ixTZNPJ98td a+LR4OFw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1g8Lti-00049t-P7; Fri, 05 Oct 2018 08:55:46 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1g8LoU-0008GD-KD for linux-arm-kernel@lists.infradead.org; Fri, 05 Oct 2018 08:51:44 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8F6F2ED1; Fri, 5 Oct 2018 01:50:20 -0700 (PDT) Received: from moonbear.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5A9CB3F5B3; Fri, 5 Oct 2018 01:50:17 -0700 (PDT) From: Kristina Martsenko To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 09/17] arm64: perf: strip PAC when unwinding userspace Date: Fri, 5 Oct 2018 09:47:46 +0100 Message-Id: <20181005084754.20950-10-kristina.martsenko@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20181005084754.20950-1-kristina.martsenko@arm.com> References: <20181005084754.20950-1-kristina.martsenko@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181005_015023_207476_20C07021 X-CRM114-Status: GOOD ( 16.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , linux-arch@vger.kernel.org, Andrew Jones , Jacob Bramley , Arnd Bergmann , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Adam Wallis , "Suzuki K . Poulose" , Will Deacon , Christoffer Dall , kvmarm@lists.cs.columbia.edu, Ramana Radhakrishnan , Amit Kachhap , Dave P Martin , linux-kernel@vger.kernel.org, Kees Cook MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Mark Rutland When the kernel is unwinding userspace callchains, we can't expect that the userspace consumer of these callchains has the data necessary to strip the PAC from the stored LR. This patch has the kernel strip the PAC from user stackframes when the in-kernel unwinder is used. This only affects the LR value, and not the FP. This only affects the in-kernel unwinder. When userspace performs unwinding, it is up to userspace to strip PACs as necessary (which can be determined from DWARF information). Signed-off-by: Mark Rutland [kristina: add pointer_auth.h #include] Signed-off-by: Kristina Martsenko Cc: Catalin Marinas Cc: Ramana Radhakrishnan Cc: Will Deacon --- arch/arm64/include/asm/pointer_auth.h | 7 +++++++ arch/arm64/kernel/perf_callchain.c | 6 +++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h index 15486079e9ec..f5a4b075be65 100644 --- a/arch/arm64/include/asm/pointer_auth.h +++ b/arch/arm64/include/asm/pointer_auth.h @@ -57,6 +57,12 @@ static inline void ptrauth_keys_switch(struct ptrauth_keys *keys) */ #define ptrauth_pac_mask() GENMASK(54, VA_BITS) +/* Only valid for EL0 TTBR0 instruction pointers */ +static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr) +{ + return ptr & ~ptrauth_pac_mask(); +} + #define mm_ctx_ptrauth_init(ctx) \ ptrauth_keys_init(&(ctx)->ptrauth_keys) @@ -64,6 +70,7 @@ static inline void ptrauth_keys_switch(struct ptrauth_keys *keys) ptrauth_keys_switch(&(ctx)->ptrauth_keys) #else /* CONFIG_ARM64_PTR_AUTH */ +#define ptrauth_strip_insn_pac(lr) (lr) #define mm_ctx_ptrauth_init(ctx) #define mm_ctx_ptrauth_switch(ctx) #endif /* CONFIG_ARM64_PTR_AUTH */ diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c index bcafd7dcfe8b..94754f07f67a 100644 --- a/arch/arm64/kernel/perf_callchain.c +++ b/arch/arm64/kernel/perf_callchain.c @@ -18,6 +18,7 @@ #include #include +#include #include struct frame_tail { @@ -35,6 +36,7 @@ user_backtrace(struct frame_tail __user *tail, { struct frame_tail buftail; unsigned long err; + unsigned long lr; /* Also check accessibility of one struct frame_tail beyond */ if (!access_ok(VERIFY_READ, tail, sizeof(buftail))) @@ -47,7 +49,9 @@ user_backtrace(struct frame_tail __user *tail, if (err) return NULL; - perf_callchain_store(entry, buftail.lr); + lr = ptrauth_strip_insn_pac(buftail.lr); + + perf_callchain_store(entry, lr); /* * Frame pointers should strictly progress back up the stack