x86/bugs: Report AMD retbleed vulnerability

stable inclusion
from stable-v5.10.133
commit 876750cca4f043bd626a3ac760ce887dda3b6ec7
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5PTAS
CVE: CVE-2022-29900,CVE-2022-23816,CVE-2022-29901

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=876750cca4f043bd626a3ac760ce887dda3b6ec7

--------------------------------

commit 6b80b59b 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: NKim Phillips <kim.phillips@amd.com>
Signed-off-by: NKim Phillips <kim.phillips@amd.com>
Signed-off-by: NAlexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NLin Yujun <linyujun809@huawei.com>
Reviewed-by: NZhang Jianhua <chris.zjh@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/x86/include/asm/cpufeatures.h

@@ -432,5 +432,6 @@
 #define X86_BUG_ITLB_MULTIHIT		X86_BUG(23) /* CPU may incur MCE during certain page attribute changes */
 #define X86_BUG_SRBDS			X86_BUG(24) /* CPU may leak RNG bits if not mitigated */
 #define X86_BUG_MMIO_STALE_DATA		X86_BUG(25) /* CPU is affected by Processor MMIO Stale Data vulnerabilities */
+#define X86_BUG_RETBLEED		X86_BUG(26) /* CPU is affected by RETBleed */
 
 #endif /* _ASM_X86_CPUFEATURES_H */

arch/x86/kernel/cpu/bugs.c

@@ -1917,6 +1917,11 @@ static ssize_t srbds_show_state(char *buf)
 	return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]);
 }
 
+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)
 {
@@ -1962,6 +1967,9 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
 	case X86_BUG_MMIO_STALE_DATA:
 		return mmio_stale_data_show_state(buf);
 
+	case X86_BUG_RETBLEED:
+		return retbleed_show_state(buf);
+
 	default:
 		break;
 	}
@@ -2018,4 +2026,9 @@ ssize_t cpu_show_mmio_stale_data(struct device *dev, struct device_attribute *at
 {
 	return cpu_show_common(dev, attr, buf, X86_BUG_MMIO_STALE_DATA);
 }
+
+ssize_t cpu_show_retbleed(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return cpu_show_common(dev, attr, buf, X86_BUG_RETBLEED);
+}
 #endif

arch/x86/kernel/cpu/common.c

@@ -1092,16 +1092,27 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
 	{}
 };
 
+#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)
 
+#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 X86_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)
 
 static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
 	VULNBL_INTEL_STEPPINGS(IVYBRIDGE,	X86_STEPPING_ANY,		SRBDS),
@@ -1134,6 +1145,11 @@ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
 	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 | MMIO_SBDS),
+
+	VULNBL_AMD(0x15, RETBLEED),
+	VULNBL_AMD(0x16, RETBLEED),
+	VULNBL_AMD(0x17, RETBLEED),
+	VULNBL_HYGON(0x18, RETBLEED),
 	{}
 };
 
@@ -1235,6 +1251,9 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
 	    !arch_cap_mmio_immune(ia32_cap))
 		setup_force_cpu_bug(X86_BUG_MMIO_STALE_DATA);
 
+	if (cpu_matches(cpu_vuln_blacklist, RETBLEED))
+		setup_force_cpu_bug(X86_BUG_RETBLEED);
+
 	if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
 		return;
 

drivers/base/cpu.c

@@ -572,6 +572,12 @@ ssize_t __weak cpu_show_mmio_stale_data(struct device *dev,
 	return sysfs_emit(buf, "Not affected\n");
 }
 
+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);
@@ -582,6 +588,7 @@ static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
 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);
 
 static struct attribute *cpu_root_vulnerabilities_attrs[] = {
 	&dev_attr_meltdown.attr,
@@ -594,6 +601,7 @@ static struct attribute *cpu_root_vulnerabilities_attrs[] = {
 	&dev_attr_itlb_multihit.attr,
 	&dev_attr_srbds.attr,
 	&dev_attr_mmio_stale_data.attr,
+	&dev_attr_retbleed.attr,
 	NULL
 };
 

include/linux/cpu.h

@@ -68,6 +68,8 @@ extern ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr,
 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);
 
 extern __printf(4, 5)
 struct device *cpu_device_create(struct device *parent, void *drvdata,