[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 <t...@linutronix.de>
---
 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