From patchwork Tue Feb 25 17:39:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11404351 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 78C0013A4 for ; Tue, 25 Feb 2020 17:40:50 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id D452320658 for ; Tue, 25 Feb 2020 17:40:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="t2cjymvo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D452320658 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-17911-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 1978 invoked by uid 550); 25 Feb 2020 17:40:16 -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 1910 invoked from network); 25 Feb 2020 17:40:16 -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=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=k5rQqj0IjMo/4ltWMVFRIyXMlF+yro1+fkAzbCvdt/uipHUD33VpCYP/9os0fNQtO8 e0NY6bqrxD68VFkteVt7x9KJD3+AWXFSTX7LT1We/5LvOEo6ssBnW/Bdt4kdv5pXb2aE Rk6Oxigcu0kFO2L20W28ubbeVl7BIQ9+55KuJp9fw9sDF8bm1spCJ437htdj0BC3o9AA H4A08XFhnjgJWH5+lHkSHnd/oBzPP5xEWkkqaS4R6Fz/8IDnWyaQCcz/lDaKvP1P+SEo nBTC1eNvb5PpC4GwFy49ByhrvfVVxq2b82yiNwQucuE8JpIVfN27v85eLsl5lFcvO3Ql IdIQ== X-Gm-Message-State: APjAAAVmaMkI6xnLQ7aXNRRVo6WhhTZCrXwUBM/sKg/eUQYnikodkzOp 6CFn87lLtl3/KEi4hOUz39JN75zwPjAeFgHv3k0= 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 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