Patch "x86/spectre: Check CONFIG_RETPOLINE in command line parser" has been added to the 4.9-stable tree

Patch "x86/spectre: Check CONFIG_RETPOLINE in command line parser" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    x86/spectre: Check CONFIG_RETPOLINE in command line parser

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-spectre-check-config_retpoline-in-command-line-parser.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Feb  8 03:30:27 CET 2018
From: Dou Liyang <douly.fnst@cn.fujitsu.com>
Date: Tue, 30 Jan 2018 14:13:50 +0800
Subject: x86/spectre: Check CONFIG_RETPOLINE in command line parser

From: Dou Liyang <douly.fnst@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.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ak@linux.intel.com
Cc: peterz@infradead.org
Cc: Tomohiro" <misono.tomohiro@jp.fujitsu.com>
Cc: dave.hansen@intel.com
Cc: bp@alien8.de
Cc: arjan@linux.intel.com
Cc: dwmw@amazon.co.uk
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/f5892721-7528-3647-08fb-f8d10e65ad87@cn.fujitsu.com
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@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
@@ -212,10 +212,10 @@ 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;


Patches currently in stable-queue which might be from douly.fnst@cn.fujitsu.com are

queue-4.9/x86-spectre-check-config_retpoline-in-command-line-parser.patch