Messages in this thread | | | Date | Thu, 2 Jul 2015 12:25:20 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v4 10/17] x86/entry/64: Really create an error-entry-from-usermode code path |
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On Mon, Jun 29, 2015 at 12:33:42PM -0700, Andy Lutomirski wrote: > 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 | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S > index 141a5d49dddc..cd9cbc62159c 100644 > --- a/arch/x86/entry/entry_64.S > +++ b/arch/x86/entry/entry_64.S > @@ -1145,9 +1145,14 @@ ENTRY(error_entry) > testb $3, CS+8(%rsp) > jz error_kernelspace > > - /* We entered from user mode */ > +error_entry_from_usermode_swapgs: > + /* > + * We entered from user mode or we're pretending to have entered > + * from user mode due to an IRET fault. > + */ > SWAPGS > > +error_entry_from_usermode_after_swapgs: > error_entry_done:
Why the second label?
Also, please make all those labels local by prefixing them with .L because they appear unnecesasrily in objdump output as global symbols.
$ objdump -d vmlinux | grep -E "^[0-9a-f]+ <(error_entry_\w*|error_kernelspace|bstep_iret|error_bad_iret)" ffffffff8167a4a8 <error_entry_from_usermode_swapgs>: ffffffff8167a4ab <error_entry_done>: ffffffff8167a4b1 <error_kernelspace>: ffffffff8167a4e0 <bstep_iret>: ffffffff8167a4e8 <error_bad_iret>:
Oh, and shorter please :)
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply. --
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