From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226oARUxEebGiB+yVOgvbMXBXTdzrEM6I0VR41fsOLykf3rgewnoTiZ/2UwMiX7WkDLM0grA ARC-Seal: i=1; a=rsa-sha256; t=1519217794; cv=none; d=google.com; s=arc-20160816; b=ksZPSYkUAjOTrZmlvpFEw++lrkD0tau2jhc/xxjVlhGxxzs9VjGOpk86tcUOY0gLeN wNhh0XpDHGwVgFJYZKpBJIKcicHQG6/m6nWaKpN670Rv7ak1AGA6NF7h3Wh6FDK/h/Go JSxEcjrvuBQJJwqwTj4PyJ+sWlDj7Fjk3xIrFQRWXizZ4lw//iTDJFLeIF3PNO2Ri6yS YrLgG3Bv5Mi6zSkuJoI08xfL+UatlzaS6lZj22jTVdyCoVUCIX6lvDGCaNFySCwy1lh2 NV/w8VCEqk1Xb0OOlJ+bAm9b1pthnZJ55733z4kuL2gbyf/4YVi4M1esQ9bnyDt1uOZT VDDQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=6MdcRUcwWqKbOQmF725ABrbD8S7td8dsUX7YOg2JONA=; b=PV9kv5MtakyDjIbP4RHA8QrQqQ6CHVT0QYHv219hFjZvv7musFITxU9N996Y4oUI5L CnDlH0J5Ye6QZYl7b1sHorEzF+2qDcX4hTq8HdAhF7rqcuMILvjIGAB63zSO17oxQaXd LYsxHdsBAH3Cmr2ZEzp86G8Qtkqb3FbKaHZCV4R3tMXh4sFBAyomF+qk+ev0fgvOaYRw fdiZ+gzeV6xc/fuICICls4VE1mp5Cax5l2YZ6bXwi+6g9lHrLR+N3m2EvnlWeh+S/OH8 E+i9uepejVzARf20gcFBK+OtdjEyV2BW2Zbuua03J5F/kqsmFYPIbFcKG1Ayenk1xVk7 sSSA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Woodhouse , Andy Lutomirski , Arjan van de Ven , Borislav Petkov , Dan Williams , Dave Hansen , David Woodhouse , Josh Poimboeuf , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.9 56/77] x86/speculation: Clean up various Spectre related details Date: Wed, 21 Feb 2018 13:49:05 +0100 Message-Id: <20180221124434.575054820@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180221124432.172390020@linuxfoundation.org> References: <20180221124432.172390020@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1593015317807560579?= X-GMAIL-MSGID: =?utf-8?q?1593015317807560579?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ingo Molnar commit 21e433bdb95bdf3aa48226fd3d33af608437f293 upstream. Harmonize all the Spectre messages so that a: dmesg | grep -i spectre ... gives us most Spectre related kernel boot messages. Also fix a few other details: - clarify a comment about firmware speculation control - s/KPTI/PTI - remove various line-breaks that made the code uglier Acked-by: David Woodhouse Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/bugs.c | 28 +++++++++++----------------- 1 file changed, 11 insertions(+), 17 deletions(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -161,8 +161,7 @@ static enum spectre_v2_mitigation_cmd __ if (cmdline_find_option_bool(boot_command_line, "nospectre_v2")) return SPECTRE_V2_CMD_NONE; else { - ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, - sizeof(arg)); + ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, sizeof(arg)); if (ret < 0) return SPECTRE_V2_CMD_AUTO; @@ -174,8 +173,7 @@ static enum spectre_v2_mitigation_cmd __ } if (i >= ARRAY_SIZE(mitigation_options)) { - pr_err("unknown option (%s). Switching to AUTO select\n", - mitigation_options[i].option); + pr_err("unknown option (%s). Switching to AUTO select\n", mitigation_options[i].option); return SPECTRE_V2_CMD_AUTO; } } @@ -184,8 +182,7 @@ static enum spectre_v2_mitigation_cmd __ cmd == SPECTRE_V2_CMD_RETPOLINE_AMD || cmd == SPECTRE_V2_CMD_RETPOLINE_GENERIC) && !IS_ENABLED(CONFIG_RETPOLINE)) { - pr_err("%s selected but not compiled in. Switching to AUTO select\n", - mitigation_options[i].option); + pr_err("%s selected but not compiled in. Switching to AUTO select\n", mitigation_options[i].option); return SPECTRE_V2_CMD_AUTO; } @@ -255,14 +252,14 @@ static void __init spectre_v2_select_mit goto retpoline_auto; break; } - pr_err("kernel not compiled with retpoline; no mitigation available!"); + pr_err("Spectre mitigation: kernel not compiled with retpoline; no mitigation available!"); return; retpoline_auto: if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) { retpoline_amd: if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { - pr_err("LFENCE not serializing. Switching to generic retpoline\n"); + pr_err("Spectre mitigation: LFENCE not serializing, switching to generic retpoline\n"); goto retpoline_generic; } mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_AMD : @@ -280,7 +277,7 @@ retpoline_auto: pr_info("%s\n", spectre_v2_strings[mode]); /* - * If neither SMEP or KPTI are available, there is a risk of + * If neither SMEP nor PTI are available, there is a risk of * hitting userspace addresses in the RSB after a context switch * from a shallow call stack to a deeper one. To prevent this fill * the entire RSB, even when using IBRS. @@ -294,21 +291,20 @@ retpoline_auto: if ((!boot_cpu_has(X86_FEATURE_KAISER) && !boot_cpu_has(X86_FEATURE_SMEP)) || is_skylake_era()) { setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW); - pr_info("Filling RSB on context switch\n"); + pr_info("Spectre v2 mitigation: Filling RSB on context switch\n"); } /* Initialize Indirect Branch Prediction Barrier if supported */ if (boot_cpu_has(X86_FEATURE_IBPB)) { setup_force_cpu_cap(X86_FEATURE_USE_IBPB); - pr_info("Enabling Indirect Branch Prediction Barrier\n"); + pr_info("Spectre v2 mitigation: Enabling Indirect Branch Prediction Barrier\n"); } } #undef pr_fmt #ifdef CONFIG_SYSFS -ssize_t cpu_show_meltdown(struct device *dev, - struct device_attribute *attr, char *buf) +ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) { if (!boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN)) return sprintf(buf, "Not affected\n"); @@ -317,16 +313,14 @@ ssize_t cpu_show_meltdown(struct device return sprintf(buf, "Vulnerable\n"); } -ssize_t cpu_show_spectre_v1(struct device *dev, - struct device_attribute *attr, char *buf) +ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf) { if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V1)) return sprintf(buf, "Not affected\n"); return sprintf(buf, "Mitigation: __user pointer sanitization\n"); } -ssize_t cpu_show_spectre_v2(struct device *dev, - struct device_attribute *attr, char *buf) +ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf) { if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) return sprintf(buf, "Not affected\n");