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,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 E2E0AC54FD0 for ; Mon, 27 Apr 2020 16:00:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC494205C9 for ; Mon, 27 Apr 2020 16:00:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZfWmmWWe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728579AbgD0QAs (ORCPT ); Mon, 27 Apr 2020 12:00:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1728517AbgD0QAq (ORCPT ); Mon, 27 Apr 2020 12:00:46 -0400 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23B04C0610D5 for ; Mon, 27 Apr 2020 09:00:46 -0700 (PDT) Received: by mail-qk1-x749.google.com with SMTP id a18so18789662qkl.0 for ; Mon, 27 Apr 2020 09:00:46 -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=aDem5II6XtVFnIoK0CnL/HzpdSNcG3sRMln2VgftrwU=; b=ZfWmmWWeg8Xv5CC2meB1osNUPG8RstNTWpr4cI8ESrfdKMVwQ7dxJXztTGQFimsM+Q CNvseJXVkYZoisMem4nRmxocSgBUZWRX2WM22kEjc8yGFWBw+H2CgMCAGJRvh5nA4tpL psKwxJzZBPKnH8RZhpmunbTEeHw7mqoGl1Chyd7YQFp1F8NuL79hZl5YpbN3INQoxV+B bs2zi3POqfqPXq6HRcKeb0fQ5M+8KRlgMPb3DVTPJden1T0c6jIaMjOnnX/iCef8UIHH 0wTi0R/2zRQc9P2Tgoryc+izyibMdoy6SFeJchSyHM1zbcKBR0WBctCIMUrRhaOOp1KA baSQ== 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=aDem5II6XtVFnIoK0CnL/HzpdSNcG3sRMln2VgftrwU=; b=IeNa4+Ah1UzyTYGKobibE1zbYgX6HA+hviFlgEYTwjHieXGXhEPjFsDG1LG4h5Rj3t QMgUqoF7Sxygs/UIAvKnb9lFnPEVQVpSUWTnQFOGBwW32/AoxrQk7S/4LQwLSUy2Z5Y5 cEos1srZulpFDkmCnh1ewXSc6C4ugKdbRoIFHvrDTljPXboLYnKY5vKSNBW49jQq6Gxw 8LcD5s9fVFtg1GquMP9aLbswcTmnLucJSIKdoAiJVjIG8Sjgzxna7g4566yanoR76CDr Vqn/JXG/RQ06g0A3rZIPVkPf3CQwdVQm20ISP12UxGL41uthYckJ9h+uoBBGJSXAYSwq sciQ== X-Gm-Message-State: AGi0PuYrQZClHYdQ2dzq+9CsL6scEQhWRyT5V6NbwfLtPihEAWR66D98 w0mnZhNa7pYKi9ib7WkKW2Uj0bfhoAzIHfvVe20= X-Google-Smtp-Source: APiQypJO4M2N3eKFmynDymgRKzs8tsPGJgj0wNazOuUIlfBTsE5WgPC/94hr99zCwp1irzlSc77dDJj+XxgS7YX4+qA= X-Received: by 2002:a0c:8262:: with SMTP id h89mr21907606qva.173.1588003245161; Mon, 27 Apr 2020 09:00:45 -0700 (PDT) Date: Mon, 27 Apr 2020 09:00:12 -0700 In-Reply-To: <20200427160018.243569-1-samitolvanen@google.com> Message-Id: <20200427160018.243569-7-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20200427160018.243569-1-samitolvanen@google.com> X-Mailer: git-send-email 2.26.2.303.gf8c07b1a785-goog Subject: [PATCH v13 06/12] arm64: preserve x18 when CPU is suspended From: Sami Tolvanen To: Will Deacon , Catalin Marinas , James Morse , Steven Rostedt , Ard Biesheuvel , Mark Rutland , Masahiro Yamada , Michal Marek , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot Cc: Dave Martin , Kees Cook , Laura Abbott , Marc Zyngier , Masami Hiramatsu , Nick Desaulniers , Jann Horn , Miguel Ojeda , 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 -- 2.26.2.303.gf8c07b1a785-goog