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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-14 09:51:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-14 09:51:25 -0800
commit40548c6b6c134275c750eb372dc2cf8ee1bbc3d4 (patch)
tree3bfc6943c3b43f1e345ddb7c88996e7b2f121fcd /drivers/base
parent2c1cfa49901839136e578ca516a7e230182da024 (diff)
parent99a9dc98ba52267ce5e062b52de88ea1f1b2a7d8 (diff)
Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 pti updates from Thomas Gleixner: "This contains: - a PTI bugfix to avoid setting reserved CR3 bits when PCID is disabled. This seems to cause issues on a virtual machine at least and is incorrect according to the AMD manual. - a PTI bugfix which disables the perf BTS facility if PTI is enabled. The BTS AUX buffer is not globally visible and causes the CPU to fault when the mapping disappears on switching CR3 to user space. A full fix which restores BTS on PTI is non trivial and will be worked on. - PTI bugfixes for EFI and trusted boot which make sure that the user space visible page table entries have the NX bit cleared - removal of dead code in the PTI pagetable setup functions - add PTI documentation - add a selftest for vsyscall to verify that the kernel actually implements what it advertises. - a sysfs interface to expose vulnerability and mitigation information so there is a coherent way for users to retrieve the status. - the initial spectre_v2 mitigations, aka retpoline: + The necessary ASM thunk and compiler support + The ASM variants of retpoline and the conversion of affected ASM code + Make LFENCE serializing on AMD so it can be used as speculation trap + The RSB fill after vmexit - initial objtool support for retpoline As I said in the status mail this is the most of the set of patches which should go into 4.15 except two straight forward patches still on hold: - the retpoline add on of LFENCE which waits for ACKs - the RSB fill after context switch Both should be ready to go early next week and with that we'll have covered the major holes of spectre_v2 and go back to normality" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits) x86,perf: Disable intel_bts when PTI security/Kconfig: Correct the Documentation reference for PTI x86/pti: Fix !PCID and sanitize defines selftests/x86: Add test_vsyscall x86/retpoline: Fill return stack buffer on vmexit x86/retpoline/irq32: Convert assembler indirect jumps x86/retpoline/checksum32: Convert assembler indirect jumps x86/retpoline/xen: Convert Xen hypercall indirect jumps x86/retpoline/hyperv: Convert assembler indirect jumps x86/retpoline/ftrace: Convert ftrace assembler indirect jumps x86/retpoline/entry: Convert entry assembler indirect jumps x86/retpoline/crypto: Convert crypto assembler indirect jumps x86/spectre: Add boot time option to select Spectre v2 mitigation x86/retpoline: Add initial retpoline support objtool: Allow alternatives to be ignored objtool: Detect jumps to retpoline thunks x86/pti: Make unpoison of pgd for trusted boot work for real x86/alternatives: Fix optimize_nops() checking sysfs/cpu: Fix typos in vulnerability documentation x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC ...
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/Kconfig3
-rw-r--r--drivers/base/cpu.c48
2 files changed, 51 insertions, 0 deletions
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index bdc87907d6a1..2415ad9f6dd4 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -236,6 +236,9 @@ config GENERIC_CPU_DEVICES
config GENERIC_CPU_AUTOPROBE
bool
+config GENERIC_CPU_VULNERABILITIES
+ bool
+
config SOC_BUS
bool
select GLOB
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 58a9b608d821..d99038487a0d 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -511,10 +511,58 @@ static void __init cpu_dev_register_generic(void)
#endif
}
+#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
+
+ssize_t __weak cpu_show_meltdown(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "Not affected\n");
+}
+
+ssize_t __weak cpu_show_spectre_v1(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "Not affected\n");
+}
+
+ssize_t __weak cpu_show_spectre_v2(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 struct attribute *cpu_root_vulnerabilities_attrs[] = {
+ &dev_attr_meltdown.attr,
+ &dev_attr_spectre_v1.attr,
+ &dev_attr_spectre_v2.attr,
+ NULL
+};
+
+static const struct attribute_group cpu_root_vulnerabilities_group = {
+ .name = "vulnerabilities",
+ .attrs = cpu_root_vulnerabilities_attrs,
+};
+
+static void __init cpu_register_vulnerabilities(void)
+{
+ if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
+ &cpu_root_vulnerabilities_group))
+ pr_err("Unable to register CPU vulnerabilities\n");
+}
+
+#else
+static inline void cpu_register_vulnerabilities(void) { }
+#endif
+
void __init cpu_dev_init(void)
{
if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
panic("Failed to register CPU subsystem");
cpu_dev_register_generic();
+ cpu_register_vulnerabilities();
}

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