From nobody Sun Dec 14 06:19:10 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2324FC433FE for ; Wed, 5 Oct 2022 11:33:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229907AbiJELdq (ORCPT ); Wed, 5 Oct 2022 07:33:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229875AbiJELdW (ORCPT ); Wed, 5 Oct 2022 07:33:22 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26515733F3; Wed, 5 Oct 2022 04:33:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id EB65561644; Wed, 5 Oct 2022 11:33:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0649DC433C1; Wed, 5 Oct 2022 11:33:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1664969593; bh=qq3RoIDloIilSZvKPjVCt/4T8Vzd7BWbega5B7xoWdY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cDfSULf5igADRzTSv+q3I1O1M5MX7L2OL1jUNrgt8cgzOyCAUS6hS+JW4LbivSiEF QzDcMnm6zhHfIbstbZ8G2xLSMARvriJTIpOfyc9SrYkK2WDRA5OGg90KmmK6AKCIkr BD/hEzwQvUOBrbCfN1Zq/E6gsJokyXJRnLbbyoAw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Kim Phillips , Alexandre Chartre , "Peter Zijlstra (Intel)" , Borislav Petkov , Josh Poimboeuf , Thadeu Lima de Souza Cascardo Subject: [PATCH 5.4 08/51] x86/bugs: Report AMD retbleed vulnerability Date: Wed, 5 Oct 2022 13:31:56 +0200 Message-Id: <20221005113210.647100502@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221005113210.255710920@linuxfoundation.org> References: <20221005113210.255710920@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Alexandre Chartre commit 6b80b59b3555706508008f1f127b5412c89c7fd8 upstream. Report that AMD x86 CPUs are vulnerable to the RETBleed (Arbitrary Speculative Code Execution with Return Instructions) attack. [peterz: add hygon] [kim: invert parity; fam15h] Co-developed-by: Kim Phillips Signed-off-by: Kim Phillips Signed-off-by: Alexandre Chartre Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Josh Poimboeuf Signed-off-by: Borislav Petkov [cascardo: adjusted BUG numbers to match upstream] Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/cpufeatures.h | 3 ++- arch/x86/kernel/cpu/bugs.c | 13 +++++++++++++ arch/x86/kernel/cpu/common.c | 19 +++++++++++++++++++ drivers/base/cpu.c | 8 ++++++++ include/linux/cpu.h | 2 ++ 5 files changed, 44 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -408,6 +408,7 @@ #define X86_BUG_ITLB_MULTIHIT X86_BUG(23) /* CPU may incur MCE during cer= tain page attribute changes */ #define X86_BUG_SRBDS X86_BUG(24) /* CPU may leak RNG bits if not mitiga= ted */ #define X86_BUG_MMIO_STALE_DATA X86_BUG(25) /* CPU is affected by Process= or MMIO Stale Data vulnerabilities */ -#define X86_BUG_MMIO_UNKNOWN X86_BUG(26) /* CPU is too old and its MMIO S= tale Data status is unknown */ +#define X86_BUG_RETBLEED X86_BUG(26) /* CPU is affected by RETBleed */ +#define X86_BUG_MMIO_UNKNOWN X86_BUG(28) /* CPU is too old and its MMIO S= tale Data status is unknown */ =20 #endif /* _ASM_X86_CPUFEATURES_H */ --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1911,6 +1911,11 @@ static ssize_t srbds_show_state(char *bu return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]); } =20 +static ssize_t retbleed_show_state(char *buf) +{ + return sprintf(buf, "Vulnerable\n"); +} + static ssize_t cpu_show_common(struct device *dev, struct device_attribute= *attr, char *buf, unsigned int bug) { @@ -1957,6 +1962,9 @@ static ssize_t cpu_show_common(struct de case X86_BUG_MMIO_UNKNOWN: return mmio_stale_data_show_state(buf); =20 + case X86_BUG_RETBLEED: + return retbleed_show_state(buf); + default: break; } @@ -2016,4 +2024,9 @@ ssize_t cpu_show_mmio_stale_data(struct else return cpu_show_common(dev, attr, buf, X86_BUG_MMIO_STALE_DATA); } + +ssize_t cpu_show_retbleed(struct device *dev, struct device_attribute *att= r, char *buf) +{ + return cpu_show_common(dev, attr, buf, X86_BUG_RETBLEED); +} #endif --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1099,16 +1099,27 @@ static const __initconst struct x86_cpu_ {} }; =20 +#define VULNBL(vendor, family, model, blacklist) \ + X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, blacklist) + #define VULNBL_INTEL_STEPPINGS(model, steppings, issues) \ X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(INTEL, 6, \ INTEL_FAM6_##model, steppings, \ X86_FEATURE_ANY, issues) =20 +#define VULNBL_AMD(family, blacklist) \ + VULNBL(AMD, family, X86_MODEL_ANY, blacklist) + +#define VULNBL_HYGON(family, blacklist) \ + VULNBL(HYGON, family, X86_MODEL_ANY, blacklist) + #define SRBDS BIT(0) /* CPU is affected by X86_BUG_MMIO_STALE_DATA */ #define MMIO BIT(1) /* CPU is affected by Shared Buffers Data Sampling (SBDS), a variant of X8= 6_BUG_MMIO_STALE_DATA */ #define MMIO_SBDS BIT(2) +/* CPU is affected by RETbleed, speculating where you would not expect it = */ +#define RETBLEED BIT(3) =20 static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst =3D { VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS), @@ -1141,6 +1152,11 @@ static const struct x86_cpu_id cpu_vuln_ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO= _SBDS), VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_D, X86_STEPPING_ANY, MMIO), VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO | MM= IO_SBDS), + + VULNBL_AMD(0x15, RETBLEED), + VULNBL_AMD(0x16, RETBLEED), + VULNBL_AMD(0x17, RETBLEED), + VULNBL_HYGON(0x18, RETBLEED), {} }; =20 @@ -1248,6 +1264,9 @@ static void __init cpu_set_bug_bits(stru setup_force_cpu_bug(X86_BUG_MMIO_UNKNOWN); } =20 + if (cpu_matches(cpu_vuln_blacklist, RETBLEED)) + setup_force_cpu_bug(X86_BUG_RETBLEED); + if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN)) return; =20 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -574,6 +574,12 @@ ssize_t __weak cpu_show_mmio_stale_data( return sysfs_emit(buf, "Not affected\n"); } =20 +ssize_t __weak cpu_show_retbleed(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "Not affected\n"); +} + static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL); static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL); static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL); @@ -584,6 +590,7 @@ static DEVICE_ATTR(tsx_async_abort, 0444 static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL); static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL); static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL); +static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL); =20 static struct attribute *cpu_root_vulnerabilities_attrs[] =3D { &dev_attr_meltdown.attr, @@ -596,6 +603,7 @@ static struct attribute *cpu_root_vulner &dev_attr_itlb_multihit.attr, &dev_attr_srbds.attr, &dev_attr_mmio_stale_data.attr, + &dev_attr_retbleed.attr, NULL }; =20 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -68,6 +68,8 @@ extern ssize_t cpu_show_srbds(struct dev extern ssize_t cpu_show_mmio_stale_data(struct device *dev, struct device_attribute *attr, char *buf); +extern ssize_t cpu_show_retbleed(struct device *dev, + struct device_attribute *attr, char *buf); =20 extern __printf(4, 5) struct device *cpu_device_create(struct device *parent, void *drvdata,