diff options
| author | Andy Lutomirski <[email protected]> | 2016-04-26 12:23:27 -0700 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2016-04-29 11:56:41 +0200 |
| commit | b038c842b385f1470f991078e71b7c5b084a7341 (patch) | |
| tree | 01b851aac2b3fd9d83a39cdfe8673bd0015f0b04 | |
| parent | 45e876f794e8e566bf827c25ef0791875081724f (diff) | |
x86/segments/64: When load_gs_index fails, clear the base
On AMD CPUs, a failed load_gs_base currently may not clear the FS
base. Fix it.
Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/1a6c4d3a8a4e7be79ba448b42685e0321d50c14c.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>
| -rw-r--r-- | arch/x86/entry/entry_64.S | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 1693c17dbf81..6344629ae1ce 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -794,6 +794,12 @@ END(native_load_gs_index) /* running with kernelgs */ bad_gs: SWAPGS /* switch back to user gs */ +.macro ZAP_GS + /* This can't be a string because the preprocessor needs to see it. */ + movl $__USER_DS, %eax + movl %eax, %gs +.endm + ALTERNATIVE "", "ZAP_GS", X86_BUG_NULL_SEG xorl %eax, %eax movl %eax, %gs jmp 2b |