x86/bugs: Concentrate bug reporting into a separate function

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

Suggested-by: Borislav Petkov <bp@suse.de>
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>

arch/x86/kernel/cpu/bugs.c

@@ -314,30 +314,48 @@ 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_PTI))
-		return sprintf(buf, "Mitigation: PTI\n");
+
+	switch (bug) {
+	case X86_BUG_CPU_MELTDOWN:
+		if (boot_cpu_has(X86_FEATURE_PTI))
+			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