[patch RFC 2/5] x86/spectre: Simplify spectre code a bit

[Thomas Gleixner]

Make the sysfs print use a string array, use __defined(RETPOLINE) instead
of the ugly ifdefs.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/bugs.c |   31 +++++++++++++------------------
 1 file changed, 13 insertions(+), 18 deletions(-)

--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -78,10 +78,18 @@ enum spectre_v2_mitigation {
 	SPECTRE_V2_RETPOLINE_AMD,
 };
 
+static const char *spectre_v2_strings[] = {
+	[SPECTRE_V2_NONE]			= "Vulnerable",
+	[SPECTRE_V2_RETPOLINE_MINIMAL]		= "Mitigation: Minimal generic ASM retpoline",
+	[SPECTRE_V2_RETPOLINE_MINIMAL_AMD]	= "Mitigation: Minimal AMD ASM retpoline",
+	[SPECTRE_V2_RETPOLINE_GENERIC]		= "Mitigation: Full generic retpoline",
+	[SPECTRE_V2_RETPOLINE_AMD]		= "Mitigation: Full AMD retpoline",
+};
+
 #undef pr_fmt
 #define pr_fmt(fmt)     "Spectre V2 mitigation: " fmt
 
-static int spectre_v2_enabled = SPECTRE_V2_NONE;
+static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE;
 
 static void __init spec2_print_if_insecure(const char *reason)
 {
@@ -97,11 +105,7 @@ static void __init spec2_print_if_secure
 
 static inline bool retp_compiler(void)
 {
-#ifdef RETPOLINE
-	return true;
-#else
-	return false;
-#endif
+	return __is_defined(RETPOLINE);
 }
 
 static inline bool match_option(const char *arg, int arglen, const char *opt)
@@ -182,6 +186,8 @@ static void __init spectre_v2_check_boot
 	return;
 }
 
+#undef pr_fmt
+
 #ifdef CONFIG_SYSFS
 ssize_t cpu_show_meltdown(struct device *dev,
 			  struct device_attribute *attr, char *buf)
@@ -207,17 +213,6 @@ ssize_t cpu_show_spectre_v2(struct devic
 	if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
 		return sprintf(buf, "Not affected\n");
 
-	switch (spectre_v2_enabled) {
-	case SPECTRE_V2_RETPOLINE_MINIMAL:
-		return sprintf(buf, "Mitigation: Minimal generic ASM retpoline\n");
-	case SPECTRE_V2_RETPOLINE_MINIMAL_AMD:
-		return sprintf(buf, "Mitigation: Minimal AMD ASM retpoline\n");
-	case SPECTRE_V2_RETPOLINE_GENERIC:
-		return sprintf(buf, "Mitigation: Full generic retpoline\n");
-	case SPECTRE_V2_RETPOLINE_AMD:
-		return sprintf(buf, "Mitigation: Full AMD retpoline\n");
-	default:
-		return sprintf(buf, "Vulnerable\n");
-	}
+	return sprintf(buf, "%s\n", spectre_v2_strings[spectre_v2_enabled]);
 }
 #endif