[PATCH 3.2 080/104] x86/cpu/bugs: Make retpoline module warning conditional

[Ben Hutchings]

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

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

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

commit e383095c7fe8d218e00ec0f83e4b95ed4e627b02 upstream.

If sysfs is disabled and RETPOLINE not defined:

arch/x86/kernel/cpu/bugs.c:97:13: warning: âspectre_v2_bad_moduleâ defined but not used
[-Wunused-variable]
 static bool spectre_v2_bad_module;

Hide it.

Fixes: caf7501a1b4e ("module/retpoline: Warn about missing retpoline in module")
Reported-by: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/bugs.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -236,9 +236,10 @@ static const char *spectre_v2_strings[]
 #define pr_fmt(fmt)     "Spectre V2 : " fmt
 
 static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE;
-static bool spectre_v2_bad_module;
 
 #ifdef RETPOLINE
+static bool spectre_v2_bad_module;
+
 bool retpoline_module_ok(bool has_retpoline)
 {
 	if (spectre_v2_enabled == SPECTRE_V2_NONE || has_retpoline)
@@ -248,6 +249,13 @@ bool retpoline_module_ok(bool has_retpol
 	spectre_v2_bad_module = true;
 	return false;
 }
+
+static inline const char *spectre_v2_module_string(void)
+{
+	return spectre_v2_bad_module ? " - vulnerable module loaded" : "";
+}
+#else
+static inline const char *spectre_v2_module_string(void) { return ""; }
 #endif
 
 static void __init spec2_print_if_insecure(const char *reason)
@@ -435,6 +443,6 @@ ssize_t cpu_show_spectre_v2(struct sysde
 		return sprintf(buf, "Not affected\n");
 
 	return sprintf(buf, "%s%s\n", spectre_v2_strings[spectre_v2_enabled],
-		       spectre_v2_bad_module ? " - vulnerable module loaded" : "");
+		       spectre_v2_module_string());
 }
 #endif