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From a24af5ff013ee664d221b6b4d4933f8317f4facb Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Wed, 25 Apr 2018 22:04:20 -0400
Subject: [PATCH 27/93] x86/bugs: Expose /sys/../spec_store_bypass
commit c456442cd3a59eeb1d60293c26cbe2ff2c4e42cf upstream
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>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/ABI/testing/sysfs-devices-system-cpu | 1 +
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kernel/cpu/bugs.c | 5 +++++
arch/x86/kernel/cpu/common.c | 23 ++++++++++++++++++++++
drivers/base/cpu.c | 8 ++++++++
include/linux/cpu.h | 2 ++
6 files changed, 40 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index dfd56ec..6d75a9c 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -355,6 +355,7 @@ 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 a248531..a688adb 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -335,5 +335,6 @@
#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 f5cad2f..64e17a9 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -403,4 +403,9 @@ 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 357c589..4f1050a 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -879,10 +879,33 @@ 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 56b6c85..cbb1cc6 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -519,14 +519,22 @@ 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 2f475ad..917829b 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -50,6 +50,8 @@ 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,
--
2.7.4
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