Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [RFC/INCOMPLETE 07/13] x86/entry/64: Really create an error-entry-from-usermode code path | Date | Tue, 16 Jun 2015 13:16:53 -0700 |
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In 539f51136500 ("x86/asm/entry/64: Disentangle error_entry/exit gsbase/ebx/usermode code"), I arranged the code slightly wrong -- IRET faults would skip the code path that was intended to execute on all error entries from user mode. Fix it up.
This does not fix a bug, but we'll need it, and it slightly shrinks the code.
Signed-off-by: Andy Lutomirski <luto@kernel.org> --- arch/x86/entry/entry_64.S | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 3bb2c4302df1..33acc3dcc281 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1145,7 +1145,11 @@ ENTRY(error_entry) testb $3, CS+8(%rsp) jz error_kernelspace - /* We entered from user mode */ +error_entry_from_usermode: + /* + * We entered from user mode or we're pretending to have entered + * from user mode due to an IRET fault. + */ SWAPGS error_entry_done: @@ -1174,8 +1178,7 @@ error_kernelspace: * gsbase and proceed. We'll fix up the exception and land in * gs_change's error handler with kernel gsbase. */ - SWAPGS - jmp error_entry_done + jmp error_entry_from_usermode bstep_iret: /* Fix truncated RIP */ -- 2.4.3
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