[PATCH 3.16 003/131] x86/bugs: Concentrate bug reporting into a separate function

From: Ben Hutchings
Date: Sat Sep 29 2018 - 18:00:44 EST


3.16.59-rc1 review patch. If anyone has any objections, please let me know.

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

From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

commit d1059518b4789cabe34bb4b714d07e6089c82ca1 upstream.

Those SysFS functions have a similar preamble, as such make common
code to handle them.

Suggested-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
[bwh: Backported to 3.16: s/X86_FEATURE_PTI/X86_FEATURE_KAISER/]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/bugs.c | 46 ++++++++++++++++++++++++++------------
1 file changed, 32 insertions(+), 14 deletions(-)

--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -352,30 +352,48 @@ retpoline_auto:
#undef pr_fmt

#ifdef CONFIG_SYSFS
-ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
+
+ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr,
+ char *buf, unsigned int bug)
{
- if (!boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN))
+ if (!boot_cpu_has_bug(bug))
return sprintf(buf, "Not affected\n");
- if (boot_cpu_has(X86_FEATURE_KAISER))
- return sprintf(buf, "Mitigation: PTI\n");
+
+ switch (bug) {
+ case X86_BUG_CPU_MELTDOWN:
+ if (boot_cpu_has(X86_FEATURE_KAISER))
+ return sprintf(buf, "Mitigation: PTI\n");
+
+ break;
+
+ case X86_BUG_SPECTRE_V1:
+ return sprintf(buf, "Mitigation: __user pointer sanitization\n");
+
+ case X86_BUG_SPECTRE_V2:
+ return sprintf(buf, "%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
+ boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "",
+ boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
+ spectre_v2_module_string());
+
+ default:
+ break;
+ }
+
return sprintf(buf, "Vulnerable\n");
}

+ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return cpu_show_common(dev, attr, buf, X86_BUG_CPU_MELTDOWN);
+}
+
ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
{
- if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V1))
- return sprintf(buf, "Not affected\n");
- return sprintf(buf, "Mitigation: __user pointer sanitization\n");
+ return cpu_show_common(dev, attr, buf, X86_BUG_SPECTRE_V1);
}

ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)
{
- if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
- return sprintf(buf, "Not affected\n");
-
- return sprintf(buf, "%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
- boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "",
- boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
- spectre_v2_module_string());
+ return cpu_show_common(dev, attr, buf, X86_BUG_SPECTRE_V2);
}
#endif