[PATCH] x86: fux duplicated X86_BUG(9) macro

From: Dave Hansen
Date: Fri Jun 17 2016 - 20:12:12 EST



From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>

cpufeatures.h currently defines X86_BUG(9) twice on 32-bit:

#define X86_BUG_NULL_SEG X86_BUG(9) /* Nulling a selector preserves the base */
...
#ifdef CONFIG_X86_32
#define X86_BUG_ESPFIX X86_BUG(9) /* "" IRET to 16-bit SS corrupts ESP/RSP high bits */
#endif

I think what happened was that this added the X86_BUG_ESPFIX, but
in an #ifdef below most of the bugs:

[58a5aac5] x86/entry/32: Introduce and use X86_BUG_ESPFIX instead of paravirt_enabled

Then this came along and added X86_BUG_NULL_SEG, but collided
with the earlier one that did the bug below the main block
defining all the X86_BUG()s.

[7a5d6704] x86/cpu: Probe the behavior of nulling out a segment at boot time

Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxx
---

b/arch/x86/include/asm/cpufeatures.h | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff -puN arch/x86/include/asm/cpufeatures.h~fix-x86-bugs-macros arch/x86/include/asm/cpufeatures.h
--- a/arch/x86/include/asm/cpufeatures.h~fix-x86-bugs-macros 2016-06-17 17:10:30.978602807 -0700
+++ b/arch/x86/include/asm/cpufeatures.h 2016-06-17 17:10:30.982602989 -0700
@@ -301,10 +301,6 @@
#define X86_BUG_FXSAVE_LEAK X86_BUG(6) /* FXSAVE leaks FOP/FIP/FOP */
#define X86_BUG_CLFLUSH_MONITOR X86_BUG(7) /* AAI65, CLFLUSH required before MONITOR */
#define X86_BUG_SYSRET_SS_ATTRS X86_BUG(8) /* SYSRET doesn't fix up SS attrs */
-#define X86_BUG_NULL_SEG X86_BUG(9) /* Nulling a selector preserves the base */
-#define X86_BUG_SWAPGS_FENCE X86_BUG(10) /* SWAPGS without input dep on GS */
-
-
#ifdef CONFIG_X86_32
/*
* 64-bit kernels don't use X86_BUG_ESPFIX. Make the define conditional
@@ -312,5 +308,7 @@
*/
#define X86_BUG_ESPFIX X86_BUG(9) /* "" IRET to 16-bit SS corrupts ESP/RSP high bits */
#endif
+#define X86_BUG_NULL_SEG X86_BUG(10) /* Nulling a selector preserves the base */
+#define X86_BUG_SWAPGS_FENCE X86_BUG(11) /* SWAPGS without input dep on GS */

#endif /* _ASM_X86_CPUFEATURES_H */
_