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 57F34C35E01 for ; Tue, 25 Feb 2020 17:40:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F0B32176D for ; Tue, 25 Feb 2020 17:40:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="t2cjymvo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728065AbgBYRkI (ORCPT ); Tue, 25 Feb 2020 12:40:08 -0500 Received: from mail-pj1-f73.google.com ([209.85.216.73]:35611 "EHLO mail-pj1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731080AbgBYRkE (ORCPT ); Tue, 25 Feb 2020 12:40:04 -0500 Received: by mail-pj1-f73.google.com with SMTP id d3so56980pjl.0 for ; Tue, 25 Feb 2020 09:40:04 -0800 (PST) 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=tR8HWR8eyR6LK2Q8Pau54PB7Q0F7v08515rGGzIGLyo=; b=t2cjymvoAu3LNnY2V+9fr1UqF1UTZQ7oaKDZV95hsccbo+Wem9ObhjTRot2oxcbV5s JfHwf3EV7LvbpaOCXbv6b6KpquhcRc0DyfxTbmG8xfI0XgwDdCaXq1SsCwfJFidfJNH0 /1lyLaxQdfo98V3WIDBrRZyBcNTKLXgCD4k/O7fm5khTgVNWgLamopl3Y0pvahPUzGES f28q5lH+lgtKGXo6iAptbVXigkwOR4L5+NG1VNse0XvPI6kiA+OwQCXooeRip2W1h5N+ n5U5kzyS0lZfpanYDv8d/3XVs1lgSeb9v4a97K9YEiQO+OqzbCqn5MKxr0OMervjTlWG lsGg== 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=tR8HWR8eyR6LK2Q8Pau54PB7Q0F7v08515rGGzIGLyo=; b=bUDAR19vWr0z6av7voMzT9j+io304heYOEYWNHqkXeLwj4XVZNf5gUYQTPr1CKjfU1 0ZRGBJNaMhWMv4ntUmCAj3ecBV8x4QA8QdZSpgqatGUP8EvN39wB5f5+YF/VRAanEJJi zjISLF8JAV5/A2ewT4ZoaXPuhqfo6BXCQ51HrLqSE240/XK0QVPAjcIXdNVDU6ddki6Z fscMgTitM5rwFzWZ0B4cs0MfNUe/3bAvdm4Axa4oIQ2t7a+VWbgY9AYLElHd/B0OgnLB V6WePvMm8U/18AFqK49q895EKWkJrggZ8AEP3KuJ+1z8iZ1M9hTXOdZhBzvw0p8HRZCn 63vg== X-Gm-Message-State: APjAAAVogAi95gaRHi4gYbUTpgQkoFAdt2ZP5Vj3qv8vHQ+DaLoO9b0D +V0oiczWWX+yCpb13spR1j6TBTWpKMktOi4uLe8= X-Google-Smtp-Source: APXvYqzUk4s2BxWsI4JfB/KPQ9dbRtIv21dR3HjtRTMHFyoCRyFREYlh9Gc57x5jkFPGsRhM08FL9vGs5N7u7TLsbsw= X-Received: by 2002:a63:691:: with SMTP id 139mr62220302pgg.325.1582652403730; Tue, 25 Feb 2020 09:40:03 -0800 (PST) Date: Tue, 25 Feb 2020 09:39:27 -0800 In-Reply-To: <20200225173933.74818-1-samitolvanen@google.com> Message-Id: <20200225173933.74818-7-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20200225173933.74818-1-samitolvanen@google.com> X-Mailer: git-send-email 2.25.0.265.gbab2e86ba0-goog Subject: [PATCH v9 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 aafed6902411..7d37e3c70ff5 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -56,6 +56,8 @@ * 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 @@ -80,6 +82,11 @@ 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) @@ -96,6 +103,13 @@ 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 -- 2.25.0.265.gbab2e86ba0-goog