4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Dou Liyang <douly.f...@cn.fujitsu.com>

(cherry picked from commit 9471eee9186a46893726e22ebb54cade3f9bc043)

The spectre_v2 option 'auto' does not check whether CONFIG_RETPOLINE is
enabled. As a consequence it fails to emit the appropriate warning and sets
feature flags which have no effect at all.

Add the missing IS_ENABLED() check.

Fixes: da285121560e ("x86/spectre: Add boot time option to select Spectre v2 
mitigation")
Signed-off-by: Dou Liyang <douly.f...@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Cc: a...@linux.intel.com
Cc: pet...@infradead.org
Cc: Tomohiro <misono.tomoh...@jp.fujitsu.com>
Cc: dave.han...@intel.com
Cc: b...@alien8.de
Cc: ar...@linux.intel.com
Cc: d...@amazon.co.uk
Cc: sta...@vger.kernel.org
Link: 
https://lkml.kernel.org/r/f5892721-7528-3647-08fb-f8d10e65a...@cn.fujitsu.com
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
[jwang: cherry-pick to 4.4]
Signed-off-by: Jack Wang <jinpu.w...@profitbricks.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 arch/x86/kernel/cpu/bugs.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -213,10 +213,10 @@ static void __init spectre_v2_select_mit
                return;
 
        case SPECTRE_V2_CMD_FORCE:
-               /* FALLTRHU */
        case SPECTRE_V2_CMD_AUTO:
-               goto retpoline_auto;
-
+               if (IS_ENABLED(CONFIG_RETPOLINE))
+                       goto retpoline_auto;
+               break;
        case SPECTRE_V2_CMD_RETPOLINE_AMD:
                if (IS_ENABLED(CONFIG_RETPOLINE))
                        goto retpoline_amd;


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