From patchwork Mon Apr 27 16:00:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11512947 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CBC7014B4 for ; Mon, 27 Apr 2020 16:02:28 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 325CB205C9 for ; Mon, 27 Apr 2020 16:02:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZfWmmWWe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 325CB205C9 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-18643-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 13880 invoked by uid 550); 27 Apr 2020 16:01:04 -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: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 13805 invoked from network); 27 Apr 2020 16:01:02 -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=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=LBuUiL10Wjs5O+hiZIAfePFSjwXhzkLH2IiuW7mdnNOpZCrHIl0doQTWWPCRZkNxod n06P/InUcjQhkgh4kTWilgrxtEQuoQrjS67pA667SU9NFRGjPiH93QqRj2MHb3n6plJ3 7bXUocn5vKuN92yqRrCpDucyJkGgREbrSy77UJTfyMQ/rcJs0eYePLaJGJtEi5qwn57X Xsf+mUIlbU2owhkogITMVuRVm5gYWs/7MhPN4aKTUz/3ApHNBsqRV7L3C4IsQ2HdUONk VZ1ut+fTf41w/YEnxPH+sCRsETQqwO6AjtSmJYwRdSRojbsoqiuPUfJA9LaxoCqAr/aA /uGQ== X-Gm-Message-State: AGi0PubaJMafeNRKdrYQNzhZ1fJceSjc9GinwajwP+fjThBAaL+O3hPt e5xSbCuQ5PducGA3FDt9hpdy2js0s/sA2cUJKWo= 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 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