Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [PATCH 4/8] x86/segments/64: When load_gs_index fails, clear the base | Date | Tue, 26 Apr 2016 12:23:27 -0700 |
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On AMD CPUs, a failed load_gs_base currently may not clear the FS base. Fix it.
Signed-off-by: Andy Lutomirski <luto@kernel.org> --- 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 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 -- 2.5.5
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