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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2018-04-26 05:04:20 +0300
committerThomas Gleixner <tglx@linutronix.de>2018-05-03 14:55:47 +0300
commitc456442cd3a59eeb1d60293c26cbe2ff2c4e42cf (patch)
tree63cd94bd9d6e72db8798c3dad115a04f64c962b9
parent5cf687548705412da47c9cec342fd952d71ed3d5 (diff)
downloadlinux-c456442cd3a59eeb1d60293c26cbe2ff2c4e42cf.tar.xz
x86/bugs: Expose /sys/../spec_store_bypass
Add the sysfs file for the new vulerability. It does not do much except show the words 'Vulnerable' for recent x86 cores. Intel cores prior to family 6 are known not to be vulnerable, and so are some Atoms and some Xeon Phi. It assumes that older Cyrix, Centaur, etc. cores are immune. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--Documentation/ABI/testing/sysfs-devices-system-cpu1
-rw-r--r--arch/x86/include/asm/cpufeatures.h1
-rw-r--r--arch/x86/kernel/cpu/bugs.c5
-rw-r--r--arch/x86/kernel/cpu/common.c23
-rw-r--r--drivers/base/cpu.c8
-rw-r--r--include/linux/cpu.h2
6 files changed, 40 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 025b7cf3768d..bd4975e132d3 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -478,6 +478,7 @@ What: /sys/devices/system/cpu/vulnerabilities
/sys/devices/system/cpu/vulnerabilities/meltdown
/sys/devices/system/cpu/vulnerabilities/spectre_v1
/sys/devices/system/cpu/vulnerabilities/spectre_v2
+ /sys/devices/system/cpu/vulnerabilities/spec_store_bypass
Date: January 2018
Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
Description: Information about CPU vulnerabilities
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 578793e97431..3493b58ef2cc 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -363,5 +363,6 @@
#define X86_BUG_CPU_MELTDOWN X86_BUG(14) /* CPU is affected by meltdown attack and needs kernel page table isolation */
#define X86_BUG_SPECTRE_V1 X86_BUG(15) /* CPU is affected by Spectre variant 1 attack with conditional branches */
#define X86_BUG_SPECTRE_V2 X86_BUG(16) /* CPU is affected by Spectre variant 2 attack with indirect branches */
+#define X86_BUG_SPEC_STORE_BYPASS X86_BUG(17) /* CPU is affected by speculative store bypass attack */
#endif /* _ASM_X86_CPUFEATURES_H */
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 38a8626c894c..59a9f3aa9f7a 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -404,4 +404,9 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, c
{
return cpu_show_common(dev, attr, buf, X86_BUG_SPECTRE_V2);
}
+
+ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return cpu_show_common(dev, attr, buf, X86_BUG_SPEC_STORE_BYPASS);
+}
#endif
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 9ed0a18ff6f6..6ff0cc441a59 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -927,10 +927,33 @@ static const __initconst struct x86_cpu_id cpu_no_meltdown[] = {
{}
};
+static const __initconst struct x86_cpu_id cpu_no_spec_store_bypass[] = {
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PINEVIEW },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_LINCROFT },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PENWELL },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CLOVERVIEW },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CEDARVIEW },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT1 },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT2 },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_MERRIFIELD },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_CORE_YONAH },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNL },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNM },
+ { X86_VENDOR_CENTAUR, 5, },
+ { X86_VENDOR_INTEL, 5, },
+ { X86_VENDOR_NSC, 5, },
+ { X86_VENDOR_ANY, 4, },
+ {}
+};
+
static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
{
u64 ia32_cap = 0;
+ if (!x86_match_cpu(cpu_no_spec_store_bypass))
+ setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS);
+
if (x86_match_cpu(cpu_no_speculation))
return;
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 2da998baa75c..30cc9c877ebb 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -534,14 +534,22 @@ ssize_t __weak cpu_show_spectre_v2(struct device *dev,
return sprintf(buf, "Not affected\n");
}
+ssize_t __weak cpu_show_spec_store_bypass(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(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);
+static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
static struct attribute *cpu_root_vulnerabilities_attrs[] = {
&dev_attr_meltdown.attr,
&dev_attr_spectre_v1.attr,
&dev_attr_spectre_v2.attr,
+ &dev_attr_spec_store_bypass.attr,
NULL
};
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 7b01bc11c692..a97a63eef59f 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -53,6 +53,8 @@ extern ssize_t cpu_show_spectre_v1(struct device *dev,
struct device_attribute *attr, char *buf);
extern ssize_t cpu_show_spectre_v2(struct device *dev,
struct device_attribute *attr, char *buf);
+extern ssize_t cpu_show_spec_store_bypass(struct device *dev,
+ struct device_attribute *attr, char *buf);
extern __printf(4, 5)
struct device *cpu_device_create(struct device *parent, void *drvdata,