From patchwork Wed Feb 19 00:08:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11390087 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 768A2924 for ; Wed, 19 Feb 2020 00:09:22 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id D31F822B48 for ; Wed, 19 Feb 2020 00:09:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="b5n4a+qz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D31F822B48 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-17832-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 32144 invoked by uid 550); 19 Feb 2020 00:09:00 -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 32042 invoked from network); 19 Feb 2020 00:09:00 -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=b5n4a+qzRVoc9p1sMaGcT/avtJg0p34XcrSWSeo6yE4SNClAhGvDWJAoBExyHPO3/M PugrHM1VkHW3JMcUgboaltvnYlevaK0mhr2LWRqBIjWKqlzzLgwrVNQ3WddvYgyZ590f EhOJfkNAkqMLFx8slzXRty6uvqQquUIPBM/qiVSwThzajXQpK2du4fa3QUrFH6uSuwiw w0rKl/E1ibiFUvV8qBI2200bkOB5w3Pa6/gAJnn7yIMSbqnGEL5kL5QKEghpUKm+Uin5 /fxQ/rvydrg0/k7tj3penT6Yk7Wsvz1o47oE7V6wluUfG2Bz66AXSiCps8hDwWSTAkqK OklQ== 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=DIeh5hmOrv+6xersbis5pojiyTH/ZiWOune5k1hD4v3htR9sE7t2HyqRATIdlPGE2O MC2VHSFQyW/YvAUu2RTYxgTLtKtVJo2sm9bMAX1M7oPTm8gAv3V2+KfOmBMO50P2uTLD +s+blzGUNX0d5d3u2ZrwUvb+I2q6c58W95JFGqZ2EKaGIkY/KU1tOUiRllYKJsuFoH+c LRFSl+gp1TJJxTn4WG3/x8Z19PArIOpYVqi386kERwkP2C6brlLG020o1cFmmd4ykAnb c4NRO5NB8tH3Aw7HN3vqdoaUvazuk+C9jg0M164KfnrS5s6BZYJgIA3rnv8nJNL4VaBc wpog== X-Gm-Message-State: APjAAAWdeRyicD9JKYVhoy24mjFnGZyPFmVifFjFFe/j0gZv1EfVTykS wT8Gf71yxuPsyUJQGKO2hjaAa0yuNs2hl8VcScU= X-Google-Smtp-Source: APXvYqxOXrqP7Hvugsa8IU49Lr4UDLSOLYebYtchIFGNM9hOXl0Twc3BrDAcc+jG4ELWfvylhcvwGTzbahuYoyApHyM= X-Received: by 2002:a63:3d44:: with SMTP id k65mr4554387pga.349.1582070928011; Tue, 18 Feb 2020 16:08:48 -0800 (PST) Date: Tue, 18 Feb 2020 16:08:11 -0800 In-Reply-To: <20200219000817.195049-1-samitolvanen@google.com> Message-Id: <20200219000817.195049-7-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20200219000817.195049-1-samitolvanen@google.com> X-Mailer: git-send-email 2.25.0.265.gbab2e86ba0-goog Subject: [PATCH v8 06/12] arm64: preserve x18 when CPU is suspended From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland , james.morse@arm.com 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