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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 20ABEC2BA17 for ; Mon, 6 Apr 2020 16:41:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7ABD24971 for ; Mon, 6 Apr 2020 16:41:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="sZgUXhLM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729625AbgDFQlv (ORCPT ); Mon, 6 Apr 2020 12:41:51 -0400 Received: from mail-pg1-f202.google.com ([209.85.215.202]:54096 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729608AbgDFQlu (ORCPT ); Mon, 6 Apr 2020 12:41:50 -0400 Received: by mail-pg1-f202.google.com with SMTP id c33so13486889pgl.20 for ; Mon, 06 Apr 2020 09:41:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=FvIJZaGomfz5bQTqJN2U0Xo4/dMI8mtkhTC7egpm8RA=; b=sZgUXhLMxuUZHoqYFcqJQyMtRrVeB4vbIJgZfI8vPE3ap9A/9BT16xYBgEZfJZwzHb p/Xb5EGHwP5/CHALYTdDgmSLbcPrGZxAna83nSg6gIywsrUh7VegvbRlWKSidmTZaduL JkIi3FLIB3RLFCMs8/R2AIvOjODoY4FM+pu6UiLLtsoUZ4FIpMSRZZd/sl1DrxuOHLRs qsTLwGT7TZOTmsB4zwdErv1k7eKdBWOhQ0UgfSaLWeBzdHI/14RLXcoxTbmTmzGS4PJz S1BSe2jfOXJpexnv2HjTJdH928LuWNUeCfCevn3GUQ3kWhph4qWJWBu706wq7G4VUNsy Vq+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=FvIJZaGomfz5bQTqJN2U0Xo4/dMI8mtkhTC7egpm8RA=; b=cN5tWGVY8kOFKYR8tlnmW54ey4apofauGwxs/7St61HK+m8J/0I5JLUHKzRyVYQ22s dCOMoBroUst+iNldv8MunZlC2al8zVN4wG/doFyxzAlg/1D7Gp1rarpScvaBSYXtW1mj tA86x1fCiemfxf9sNYAdIJFPOhOGZp7dxfX7PUHqvtVvfmWJvj2yYUpgBLCE1GxFrW52 /BwncSRmlB0lr/vcpR5k4lTeELKytxH54XC8frrZEV46qtkdzFKmPSdfe+qZb77C9FZN LV7Ofk+wqVF47RNKXB6qPbqSgBL6EgLRneHz6RDlks9JF9vV3laaK0q2H6XOd4KzN1D0 fYCQ== X-Gm-Message-State: AGi0PualSK482Cjr9pxzeZt5S9rvtFl7Vrwfh2bnGuFaTTYLf9yKKFpm W2PmVx76j1nm3YlTvIPtKoBDNRYdcvciIgG2+ZY= X-Google-Smtp-Source: APiQypIFwmNrjKh1lQZCso9eQPW5DK0TW2vYCZpfEPndLBGmeeUElj0RyNkfI+/Jw0+mhfmcbtmfQfN+X3LYM4MOsRg= X-Received: by 2002:a63:9550:: with SMTP id t16mr19437932pgn.300.1586191308872; Mon, 06 Apr 2020 09:41:48 -0700 (PDT) Date: Mon, 6 Apr 2020 09:41:15 -0700 In-Reply-To: <20200406164121.154322-1-samitolvanen@google.com> Message-Id: <20200406164121.154322-7-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20200406164121.154322-1-samitolvanen@google.com> X-Mailer: git-send-email 2.26.0.292.g33ef6b2f38-goog Subject: [PATCH v10 06/12] arm64: preserve x18 when CPU is suspended From: Sami Tolvanen To: Will Deacon , Catalin Marinas , James Morse , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland Cc: Dave Martin , Kees Cook , Laura Abbott , Marc Zyngier , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Don't lose the current task's shadow stack when the CPU is suspended. Signed-off-by: Sami Tolvanen Reviewed-by: Nick Desaulniers Reviewed-by: Kees Cook Reviewed-by: Mark Rutland Acked-by: Will Deacon --- arch/arm64/include/asm/suspend.h | 2 +- arch/arm64/mm/proc.S | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/suspend.h b/arch/arm64/include/asm/suspend.h index 8939c87c4dce..0cde2f473971 100644 --- a/arch/arm64/include/asm/suspend.h +++ b/arch/arm64/include/asm/suspend.h @@ -2,7 +2,7 @@ #ifndef __ASM_SUSPEND_H #define __ASM_SUSPEND_H -#define NR_CTX_REGS 12 +#define NR_CTX_REGS 13 #define NR_CALLEE_SAVED_REGS 12 /* diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 197a9ba2d5ea..ed15be0f8103 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -58,6 +58,8 @@ * cpu_do_suspend - save CPU registers context * * x0: virtual address of context pointer + * + * This must be kept in sync with struct cpu_suspend_ctx in . */ SYM_FUNC_START(cpu_do_suspend) mrs x2, tpidr_el0 @@ -82,6 +84,11 @@ alternative_endif stp x8, x9, [x0, #48] stp x10, x11, [x0, #64] stp x12, x13, [x0, #80] + /* + * Save x18 as it may be used as a platform register, e.g. by shadow + * call stack. + */ + str x18, [x0, #96] ret SYM_FUNC_END(cpu_do_suspend) @@ -98,6 +105,13 @@ SYM_FUNC_START(cpu_do_resume) ldp x9, x10, [x0, #48] ldp x11, x12, [x0, #64] ldp x13, x14, [x0, #80] + /* + * Restore x18, as it may be used as a platform register, and clear + * the buffer to minimize the risk of exposure when used for shadow + * call stack. + */ + ldr x18, [x0, #96] + str xzr, [x0, #96] msr tpidr_el0, x2 msr tpidrro_el0, x3 msr contextidr_el1, x4 -- 2.26.0.292.g33ef6b2f38-goog 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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,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 B6036C2BA1E for ; Mon, 6 Apr 2020 16:43:21 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8859624987 for ; Mon, 6 Apr 2020 16:43:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="sdFoHScl"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="sZgUXhLM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8859624987 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:From:Subject:References:Mime-Version :Message-Id:In-Reply-To:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ce6IEjEzvGlbVuM56iizHyiDRs3WJrCTuY9wIrztmBQ=; b=sdFoHSclSQKz7S pIJ/DYHyzYkXDN5D9yxPaI6cBvyKAsl3hu1eTpIWZ8ZITWO7y1uoyJEIPa1UbCAt/Gdgq8DHkwrBO 2RPgZzGjglSBJs0VbA6HizQ/vXd1Nmd1ItIIh3h+2DlV1rHE9CZz7zc85FntaC79nwjd+w+bbuUGv sAPeECX9+8eHa2LCeGs0/YztQmlME4ojpx8QbIBZwM6o5Xt774eB6P7NJoP/0lVt7hQPTXu40ekuA VCV3b0qPxoorG7kV412/FObKjBON1itrBPA+l8/JeRxHPXVfSfA9B/Jf5gZ1NIvLl7OXBUctVgiW4 NQ3FMgBYTft9sw+acF9g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jLUqG-0005W5-TO; Mon, 06 Apr 2020 16:43:20 +0000 Received: from mail-pg1-x54a.google.com ([2607:f8b0:4864:20::54a]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jLUoo-000494-Kw for linux-arm-kernel@lists.infradead.org; Mon, 06 Apr 2020 16:41:52 +0000 Received: by mail-pg1-x54a.google.com with SMTP id o18so3729144pgh.9 for ; Mon, 06 Apr 2020 09:41:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=FvIJZaGomfz5bQTqJN2U0Xo4/dMI8mtkhTC7egpm8RA=; b=sZgUXhLMxuUZHoqYFcqJQyMtRrVeB4vbIJgZfI8vPE3ap9A/9BT16xYBgEZfJZwzHb p/Xb5EGHwP5/CHALYTdDgmSLbcPrGZxAna83nSg6gIywsrUh7VegvbRlWKSidmTZaduL JkIi3FLIB3RLFCMs8/R2AIvOjODoY4FM+pu6UiLLtsoUZ4FIpMSRZZd/sl1DrxuOHLRs qsTLwGT7TZOTmsB4zwdErv1k7eKdBWOhQ0UgfSaLWeBzdHI/14RLXcoxTbmTmzGS4PJz S1BSe2jfOXJpexnv2HjTJdH928LuWNUeCfCevn3GUQ3kWhph4qWJWBu706wq7G4VUNsy Vq+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=FvIJZaGomfz5bQTqJN2U0Xo4/dMI8mtkhTC7egpm8RA=; b=Pt+UUa+hJcTq6IQ6W42CEpPnO/Fm6E78T3vV1J9NtbLCSFoQJGkN8HpLTMshKYwVr7 dzgtra2v3qiX2nub5UPstBqLwXNKq2oETn6ZEhnFDf1oJtlmwBxNbyHJ9zyyfbSHPgn1 S6X1LjZF9noTsyMVjnhV36r66G6bUeTlidah0z3LyuahpWpSMVZtxkkuXSuxNl5xDprk aW50ef6I9yo6YPnsavEFsflJCl+ArTK9UePAp1FvelRR2A28gQcmusp73LtvlOWmZblX fxRun3cVxfDZHOU6OP16dHfl3LIWkY7mkqqc3vMZCdGNOq0t0MXu1yyAiPN0yH7Mscwd Gbhg== X-Gm-Message-State: AGi0PuanIKUXVLXi1NNOA2mHjtmFdU1D3iFlf69ppEzWAoHnGc6OrCPi Ye3ccGWuxS0/J+FcWL+SrUSNeJU1eb+v7vf220M= X-Google-Smtp-Source: APiQypIFwmNrjKh1lQZCso9eQPW5DK0TW2vYCZpfEPndLBGmeeUElj0RyNkfI+/Jw0+mhfmcbtmfQfN+X3LYM4MOsRg= X-Received: by 2002:a63:9550:: with SMTP id t16mr19437932pgn.300.1586191308872; Mon, 06 Apr 2020 09:41:48 -0700 (PDT) Date: Mon, 6 Apr 2020 09:41:15 -0700 In-Reply-To: <20200406164121.154322-1-samitolvanen@google.com> Message-Id: <20200406164121.154322-7-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20200406164121.154322-1-samitolvanen@google.com> X-Mailer: git-send-email 2.26.0.292.g33ef6b2f38-goog Subject: [PATCH v10 06/12] arm64: preserve x18 when CPU is suspended From: Sami Tolvanen To: Will Deacon , Catalin Marinas , James Morse , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200406_094150_716222_0E280BD1 X-CRM114-Status: GOOD ( 10.80 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kees Cook , Jann Horn , Masahiro Yamada , Marc Zyngier , kernel-hardening@lists.openwall.com, Nick Desaulniers , linux-kernel@vger.kernel.org, Miguel Ojeda , clang-built-linux@googlegroups.com, Sami Tolvanen , Laura Abbott , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Don't lose the current task's shadow stack when the CPU is suspended. Signed-off-by: Sami Tolvanen Reviewed-by: Nick Desaulniers Reviewed-by: Kees Cook Reviewed-by: Mark Rutland Acked-by: Will Deacon --- arch/arm64/include/asm/suspend.h | 2 +- arch/arm64/mm/proc.S | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/suspend.h b/arch/arm64/include/asm/suspend.h index 8939c87c4dce..0cde2f473971 100644 --- a/arch/arm64/include/asm/suspend.h +++ b/arch/arm64/include/asm/suspend.h @@ -2,7 +2,7 @@ #ifndef __ASM_SUSPEND_H #define __ASM_SUSPEND_H -#define NR_CTX_REGS 12 +#define NR_CTX_REGS 13 #define NR_CALLEE_SAVED_REGS 12 /* diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 197a9ba2d5ea..ed15be0f8103 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -58,6 +58,8 @@ * cpu_do_suspend - save CPU registers context * * x0: virtual address of context pointer + * + * This must be kept in sync with struct cpu_suspend_ctx in . */ SYM_FUNC_START(cpu_do_suspend) mrs x2, tpidr_el0 @@ -82,6 +84,11 @@ alternative_endif stp x8, x9, [x0, #48] stp x10, x11, [x0, #64] stp x12, x13, [x0, #80] + /* + * Save x18 as it may be used as a platform register, e.g. by shadow + * call stack. + */ + str x18, [x0, #96] ret SYM_FUNC_END(cpu_do_suspend) @@ -98,6 +105,13 @@ SYM_FUNC_START(cpu_do_resume) ldp x9, x10, [x0, #48] ldp x11, x12, [x0, #64] ldp x13, x14, [x0, #80] + /* + * Restore x18, as it may be used as a platform register, and clear + * the buffer to minimize the risk of exposure when used for shadow + * call stack. + */ + ldr x18, [x0, #96] + str xzr, [x0, #96] msr tpidr_el0, x2 msr tpidrro_el0, x3 msr contextidr_el1, x4 -- 2.26.0.292.g33ef6b2f38-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 AE2EAC2BA17 for ; Mon, 6 Apr 2020 16:42:54 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 0B2232496D for ; Mon, 6 Apr 2020 16:42:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="sZgUXhLM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B2232496D Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-18436-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 25896 invoked by uid 550); 6 Apr 2020 16:42:01 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 25826 invoked from network); 6 Apr 2020 16:42:01 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=FvIJZaGomfz5bQTqJN2U0Xo4/dMI8mtkhTC7egpm8RA=; b=sZgUXhLMxuUZHoqYFcqJQyMtRrVeB4vbIJgZfI8vPE3ap9A/9BT16xYBgEZfJZwzHb p/Xb5EGHwP5/CHALYTdDgmSLbcPrGZxAna83nSg6gIywsrUh7VegvbRlWKSidmTZaduL JkIi3FLIB3RLFCMs8/R2AIvOjODoY4FM+pu6UiLLtsoUZ4FIpMSRZZd/sl1DrxuOHLRs qsTLwGT7TZOTmsB4zwdErv1k7eKdBWOhQ0UgfSaLWeBzdHI/14RLXcoxTbmTmzGS4PJz S1BSe2jfOXJpexnv2HjTJdH928LuWNUeCfCevn3GUQ3kWhph4qWJWBu706wq7G4VUNsy Vq+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=FvIJZaGomfz5bQTqJN2U0Xo4/dMI8mtkhTC7egpm8RA=; b=Ugc1VW9mSBYHW2dpA02pSZ9NVohpPFm66iLLNcUnPs0Pv5dQl81OYI8cjJv7JicdnH Dt11rHRMI5ruJsq8NI9U2nrx34sKyUcQGcIO0cmC6jT1mqE/+UooQcW5gwOGPSoJKHmB UDEl1Qmobclpbn6hFwl8/fKurRINUHIUU1W/YNEA0tK7wGaOvumGk1jmFYX0k5CRu3rR jBMlVbBwz/S1VYyUYDG54OE5RzSyydCz7uxxnEDf1m+Xr+VW8a4Ub/t5Qzv0aA/Raiug lT0vUGlhbHUDQUPDtCfKF7iIB0JojIx4ICcvSTSVxl+qLFsn3ShczJFIfDcWttHaesWF t1IA== X-Gm-Message-State: AGi0PubulWemkvLZcb0bOox2K9jeO5ruuIss2ZOCX04d4pq3nF+UePEJ 06U1uPgUOootmMNtt88OUAdu6o3bP70AHaqOHPE= X-Google-Smtp-Source: APiQypIFwmNrjKh1lQZCso9eQPW5DK0TW2vYCZpfEPndLBGmeeUElj0RyNkfI+/Jw0+mhfmcbtmfQfN+X3LYM4MOsRg= X-Received: by 2002:a63:9550:: with SMTP id t16mr19437932pgn.300.1586191308872; Mon, 06 Apr 2020 09:41:48 -0700 (PDT) Date: Mon, 6 Apr 2020 09:41:15 -0700 In-Reply-To: <20200406164121.154322-1-samitolvanen@google.com> Message-Id: <20200406164121.154322-7-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20200406164121.154322-1-samitolvanen@google.com> X-Mailer: git-send-email 2.26.0.292.g33ef6b2f38-goog Subject: [PATCH v10 06/12] arm64: preserve x18 when CPU is suspended From: Sami Tolvanen To: Will Deacon , Catalin Marinas , James Morse , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland Cc: Dave Martin , Kees Cook , Laura Abbott , Marc Zyngier , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Don't lose the current task's shadow stack when the CPU is suspended. Signed-off-by: Sami Tolvanen Reviewed-by: Nick Desaulniers Reviewed-by: Kees Cook Reviewed-by: Mark Rutland Acked-by: Will Deacon --- arch/arm64/include/asm/suspend.h | 2 +- arch/arm64/mm/proc.S | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/suspend.h b/arch/arm64/include/asm/suspend.h index 8939c87c4dce..0cde2f473971 100644 --- a/arch/arm64/include/asm/suspend.h +++ b/arch/arm64/include/asm/suspend.h @@ -2,7 +2,7 @@ #ifndef __ASM_SUSPEND_H #define __ASM_SUSPEND_H -#define NR_CTX_REGS 12 +#define NR_CTX_REGS 13 #define NR_CALLEE_SAVED_REGS 12 /* diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 197a9ba2d5ea..ed15be0f8103 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -58,6 +58,8 @@ * cpu_do_suspend - save CPU registers context * * x0: virtual address of context pointer + * + * This must be kept in sync with struct cpu_suspend_ctx in . */ SYM_FUNC_START(cpu_do_suspend) mrs x2, tpidr_el0 @@ -82,6 +84,11 @@ alternative_endif stp x8, x9, [x0, #48] stp x10, x11, [x0, #64] stp x12, x13, [x0, #80] + /* + * Save x18 as it may be used as a platform register, e.g. by shadow + * call stack. + */ + str x18, [x0, #96] ret SYM_FUNC_END(cpu_do_suspend) @@ -98,6 +105,13 @@ SYM_FUNC_START(cpu_do_resume) ldp x9, x10, [x0, #48] ldp x11, x12, [x0, #64] ldp x13, x14, [x0, #80] + /* + * Restore x18, as it may be used as a platform register, and clear + * the buffer to minimize the risk of exposure when used for shadow + * call stack. + */ + ldr x18, [x0, #96] + str xzr, [x0, #96] msr tpidr_el0, x2 msr tpidrro_el0, x3 msr contextidr_el1, x4 -- 2.26.0.292.g33ef6b2f38-goog