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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 8F358C04AAF for ; Thu, 16 May 2019 15:59:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E8B220848 for ; Thu, 16 May 2019 15:59:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727638AbfEPP7y (ORCPT ); Thu, 16 May 2019 11:59:54 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43402 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727172AbfEPP6v (ORCPT ); Thu, 16 May 2019 11:58:51 -0400 Received: from [167.98.27.226] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hRImM-0006zE-R1; Thu, 16 May 2019 16:58:47 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hRImD-0001Pq-Qz; Thu, 16 May 2019 16:58:37 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Peter Zijlstra" , "Jiri Kosina" , "Kees Cook" , "Thomas Gleixner" , "David Woodhouse" , "Asit Mallick" , "Andi Kleen" , "Ingo Molnar" , "Dave Hansen" , "Andrea Arcangeli" , "Arjan van de Ven" , "Dave Stewart" , "Jon Masters" , "Linus Torvalds" , "Waiman Long" , "Casey Schaufler" , "Tim Chen" , "Andy Lutomirski" , "Tom Lendacky" , "Greg KH" , "Josh Poimboeuf" Date: Thu, 16 May 2019 16:55:33 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 44/86] x86/speculation: Reorder the spec_v2 code In-Reply-To: X-SA-Exim-Connect-IP: 167.98.27.226 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.68-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner commit 15d6b7aab0793b2de8a05d8a828777dd24db424e upstream. Reorder the code so it is better grouped. No functional change. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Cc: Peter Zijlstra Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Jiri Kosina Cc: Tom Lendacky Cc: Josh Poimboeuf Cc: Andrea Arcangeli Cc: David Woodhouse Cc: Tim Chen Cc: Andi Kleen Cc: Dave Hansen Cc: Casey Schaufler Cc: Asit Mallick Cc: Arjan van de Ven Cc: Jon Masters Cc: Waiman Long Cc: Greg KH Cc: Dave Stewart Cc: Kees Cook Link: https://lkml.kernel.org/r/20181125185004.707122879@linutronix.de [bwh: Backported to 3.16: - We still have the minimal mitigation modes - Adjust context] Signed-off-by: Ben Hutchings --- --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -178,30 +178,6 @@ void __init check_bugs(void) #endif } -/* The kernel command line selection */ -enum spectre_v2_mitigation_cmd { - SPECTRE_V2_CMD_NONE, - SPECTRE_V2_CMD_AUTO, - SPECTRE_V2_CMD_FORCE, - SPECTRE_V2_CMD_RETPOLINE, - SPECTRE_V2_CMD_RETPOLINE_GENERIC, - SPECTRE_V2_CMD_RETPOLINE_AMD, -}; - -static const char *spectre_v2_strings[] = { - [SPECTRE_V2_NONE] = "Vulnerable", - [SPECTRE_V2_RETPOLINE_MINIMAL] = "Vulnerable: Minimal generic ASM retpoline", - [SPECTRE_V2_RETPOLINE_MINIMAL_AMD] = "Vulnerable: Minimal AMD ASM retpoline", - [SPECTRE_V2_RETPOLINE_GENERIC] = "Mitigation: Full generic retpoline", - [SPECTRE_V2_RETPOLINE_AMD] = "Mitigation: Full AMD retpoline", - [SPECTRE_V2_IBRS_ENHANCED] = "Mitigation: Enhanced IBRS", -}; - -#undef pr_fmt -#define pr_fmt(fmt) "Spectre V2 : " fmt - -static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE; - void x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest) { @@ -271,6 +247,11 @@ static void x86_amd_ssb_disable(void) wrmsrl(MSR_AMD64_LS_CFG, msrval); } +#undef pr_fmt +#define pr_fmt(fmt) "Spectre V2 : " fmt + +static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE; + #ifdef RETPOLINE static bool spectre_v2_bad_module; @@ -292,6 +273,45 @@ static inline const char *spectre_v2_mod static inline const char *spectre_v2_module_string(void) { return ""; } #endif +static inline bool match_option(const char *arg, int arglen, const char *opt) +{ + int len = strlen(opt); + + return len == arglen && !strncmp(arg, opt, len); +} + +/* The kernel command line selection for spectre v2 */ +enum spectre_v2_mitigation_cmd { + SPECTRE_V2_CMD_NONE, + SPECTRE_V2_CMD_AUTO, + SPECTRE_V2_CMD_FORCE, + SPECTRE_V2_CMD_RETPOLINE, + SPECTRE_V2_CMD_RETPOLINE_GENERIC, + SPECTRE_V2_CMD_RETPOLINE_AMD, +}; + +static const char *spectre_v2_strings[] = { + [SPECTRE_V2_NONE] = "Vulnerable", + [SPECTRE_V2_RETPOLINE_MINIMAL] = "Vulnerable: Minimal generic ASM retpoline", + [SPECTRE_V2_RETPOLINE_MINIMAL_AMD] = "Vulnerable: Minimal AMD ASM retpoline", + [SPECTRE_V2_RETPOLINE_GENERIC] = "Mitigation: Full generic retpoline", + [SPECTRE_V2_RETPOLINE_AMD] = "Mitigation: Full AMD retpoline", + [SPECTRE_V2_IBRS_ENHANCED] = "Mitigation: Enhanced IBRS", +}; + +static const struct { + const char *option; + enum spectre_v2_mitigation_cmd cmd; + bool secure; +} mitigation_options[] = { + { "off", SPECTRE_V2_CMD_NONE, false }, + { "on", SPECTRE_V2_CMD_FORCE, true }, + { "retpoline", SPECTRE_V2_CMD_RETPOLINE, false }, + { "retpoline,amd", SPECTRE_V2_CMD_RETPOLINE_AMD, false }, + { "retpoline,generic", SPECTRE_V2_CMD_RETPOLINE_GENERIC, false }, + { "auto", SPECTRE_V2_CMD_AUTO, false }, +}; + static void __init spec2_print_if_insecure(const char *reason) { if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) @@ -309,31 +329,11 @@ static inline bool retp_compiler(void) return __is_defined(RETPOLINE); } -static inline bool match_option(const char *arg, int arglen, const char *opt) -{ - int len = strlen(opt); - - return len == arglen && !strncmp(arg, opt, len); -} - -static const struct { - const char *option; - enum spectre_v2_mitigation_cmd cmd; - bool secure; -} mitigation_options[] = { - { "off", SPECTRE_V2_CMD_NONE, false }, - { "on", SPECTRE_V2_CMD_FORCE, true }, - { "retpoline", SPECTRE_V2_CMD_RETPOLINE, false }, - { "retpoline,amd", SPECTRE_V2_CMD_RETPOLINE_AMD, false }, - { "retpoline,generic", SPECTRE_V2_CMD_RETPOLINE_GENERIC, false }, - { "auto", SPECTRE_V2_CMD_AUTO, false }, -}; - static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) { + enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO; char arg[20]; int ret, i; - enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO; if (cmdline_find_option_bool(boot_command_line, "nospectre_v2")) return SPECTRE_V2_CMD_NONE; @@ -376,48 +376,6 @@ static enum spectre_v2_mitigation_cmd __ return cmd; } -static bool stibp_needed(void) -{ - if (spectre_v2_enabled == SPECTRE_V2_NONE) - return false; - - /* Enhanced IBRS makes using STIBP unnecessary. */ - if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED) - return false; - - if (!boot_cpu_has(X86_FEATURE_STIBP)) - return false; - - return true; -} - -static void update_stibp_msr(void *info) -{ - wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); -} - -void arch_smt_update(void) -{ - u64 mask; - - if (!stibp_needed()) - return; - - mutex_lock(&spec_ctrl_mutex); - - mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP; - if (sched_smt_active()) - mask |= SPEC_CTRL_STIBP; - - if (mask != x86_spec_ctrl_base) { - pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n", - mask & SPEC_CTRL_STIBP ? "Enabling" : "Disabling"); - x86_spec_ctrl_base = mask; - on_each_cpu(update_stibp_msr, NULL, 1); - } - mutex_unlock(&spec_ctrl_mutex); -} - static void __init spectre_v2_select_mitigation(void) { enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline(); @@ -522,6 +480,48 @@ specv2_set_mode: arch_smt_update(); } +static bool stibp_needed(void) +{ + if (spectre_v2_enabled == SPECTRE_V2_NONE) + return false; + + /* Enhanced IBRS makes using STIBP unnecessary. */ + if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED) + return false; + + if (!boot_cpu_has(X86_FEATURE_STIBP)) + return false; + + return true; +} + +static void update_stibp_msr(void *info) +{ + wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); +} + +void arch_smt_update(void) +{ + u64 mask; + + if (!stibp_needed()) + return; + + mutex_lock(&spec_ctrl_mutex); + + mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP; + if (sched_smt_active()) + mask |= SPEC_CTRL_STIBP; + + if (mask != x86_spec_ctrl_base) { + pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n", + mask & SPEC_CTRL_STIBP ? "Enabling" : "Disabling"); + x86_spec_ctrl_base = mask; + on_each_cpu(update_stibp_msr, NULL, 1); + } + mutex_unlock(&spec_ctrl_mutex); +} + #undef pr_fmt #define pr_fmt(fmt) "Speculative Store Bypass: " fmt