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 B1A75C5DF60 for ; Tue, 5 Nov 2019 23:56:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 572CC21A49 for ; Tue, 5 Nov 2019 23:56:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="jWGQrW7g" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387599AbfKEX4s (ORCPT ); Tue, 5 Nov 2019 18:56:48 -0500 Received: from mail-pg1-f202.google.com ([209.85.215.202]:34558 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387560AbfKEX4o (ORCPT ); Tue, 5 Nov 2019 18:56:44 -0500 Received: by mail-pg1-f202.google.com with SMTP id w9so16295906pgl.1 for ; Tue, 05 Nov 2019 15:56:43 -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=uzQ8cGBP/iiy1dmy29qxsrkA2y8A3VyyoGWk/X1qxUc=; b=jWGQrW7gYc6D9nJteHiWYUXaoKd47FGvgCnUcq1RN0FNUvS12DXoQv/Qs2ZSsEmdsr KIrZA7BzUYt42AyztGMVcz/QumFEYK2cJY5/FcPWOE01nPlBEr1XYQMmzvlCuOtePFHy BrO2pUitDMPbbMwQ+djW4zvLYrFatsGxSZFpwthI0l0tEUjCd15qBB7CofGFXzjONnIJ qdmdd/w16M48KK0143WbpUnJCYAPG0RUwEwhRL4ts3yhMXpE4SQA62x4WivBRaT/AZDF 1NajHEvW01XhI1VvxrXdeiyPREGJ54AL4BUaLlFQCeTXTsDjryTGcoQgi5Pmte9ZuS+r +4hw== 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=uzQ8cGBP/iiy1dmy29qxsrkA2y8A3VyyoGWk/X1qxUc=; b=l4qJpNwxURUWQ2hoBsQapY/6+n3aYqEtVmUXxmCJ0ZsjC6B6lVzq9AJ2jTU6H8c106 A37Y/wYD0An65H5x7Z/fJwAurOjU1DqO1HsMppqX1mM/inUcX23x8iycmPj8+5bR94WG qjPRxf+nAPlKKnU5YalkVvwkAXio6zt3wNCjQmeRl67woU2EM8McNaeFqSbAmn/N8Kdc BQ7xYcXbznrf41pSBXYKvWeSaFbN5Auqzwr6LQw9r8yDlso3MRgo27zjVpD0kkUi0oNv +mZ40naLCffdIgVG0ju5xxedbm/RGopLrs74JfUNDs4osIPP9CJjOUmFJbVxkK7VFd7R cWqg== X-Gm-Message-State: APjAAAVDAi8172fudrjg3kvIRBunM1AKA4m8SLJbjgu6gKz/x/wfD+9K svGk/iX5ogYSg5HOIXV0A6K+VkSM+SuxwqqSMvc= X-Google-Smtp-Source: APXvYqzhnl/od1+4wqmG+HB56zcHmEodlg2M4/tt0l0rrKjOHl/n60b0sUyw2UaMRpO3OuPN2c7IjdKlcyCGNq68Qz4= X-Received: by 2002:a65:5382:: with SMTP id x2mr1469482pgq.420.1572998202872; Tue, 05 Nov 2019 15:56:42 -0800 (PST) Date: Tue, 5 Nov 2019 15:56:04 -0800 In-Reply-To: <20191105235608.107702-1-samitolvanen@google.com> Message-Id: <20191105235608.107702-11-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191105235608.107702-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v5 10/14] arm64: preserve x18 when CPU is suspended From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel Cc: Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , 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 --- 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 fdabf40a83c8..5c8219c55948 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -49,6 +49,8 @@ * 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 . */ ENTRY(cpu_do_suspend) mrs x2, tpidr_el0 @@ -73,6 +75,11 @@ 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 ENDPROC(cpu_do_suspend) @@ -89,6 +96,13 @@ ENTRY(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 -- 2.24.0.rc1.363.gb1bccd3e3d-goog