From: Dave Hansen <dave.han...@linux.intel.com>
epufeatures.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.han...@linux.intel.com>
Acked-by: Andy Lutomirski <l...@kernel.org>
Cc: sta...@vger.kernel.org
---
b/arch/x86/include/asm/cpufeatures.h | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff -puN arch/x86/include/asm/cpufeatures.h~knl-leak-10-fix-x86-bugs-macros
arch/x86/include/asm/cpufeatures.h
--- a/arch/x86/include/asm/cpufeatures.h~knl-leak-10-fix-x86-bugs-macros
2016-06-30 17:10:41.215185869 -0700
+++ b/arch/x86/include/asm/cpufeatures.h 2016-06-30 17:10:41.218186005
-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 */
_
