Commit-ID: b038c842b385f1470f991078e71b7c5b084a7341 Gitweb: http://git.kernel.org/tip/b038c842b385f1470f991078e71b7c5b084a7341 Author: Andy Lutomirski <[email protected]> AuthorDate: Tue, 26 Apr 2016 12:23:27 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 29 Apr 2016 11:56:41 +0200
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.l...@kernel.org Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/entry/entry_64.S | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 1693c17..6344629 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
