Re: [PATCH 9/9] x86/asm/entry/64: Remove GET_THREAD_INFO in ret_from_fork

From: Andy Lutomirski
Date: Thu Apr 02 2015 - 15:02:43 EST


On Thu, Apr 2, 2015 at 7:36 AM, Denys Vlasenko <dvlasenk@xxxxxxxxxx> wrote:
> It used to be used to check for _TIF_IA32, but the check has been removed.
>
> Remove GET_THREAD_INFO too.
>
> Run-tested.

Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>

Anyone know what the eflags reset code just above it is for? Is it
because we used to allow NT in kernel eflags?

--Andy

>
> Signed-off-by: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
> CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> CC: Steven Rostedt <rostedt@xxxxxxxxxxx>
> CC: Ingo Molnar <mingo@xxxxxxxxxx>
> CC: Borislav Petkov <bp@xxxxxxxxx>
> CC: "H. Peter Anvin" <hpa@xxxxxxxxx>
> CC: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> CC: Oleg Nesterov <oleg@xxxxxxxxxx>
> CC: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> CC: Alexei Starovoitov <ast@xxxxxxxxxxxx>
> CC: Will Drewry <wad@xxxxxxxxxxxx>
> CC: Kees Cook <keescook@xxxxxxxxxxxx>
> CC: x86@xxxxxxxxxx
> CC: linux-kernel@xxxxxxxxxxxxxxx
> ---
> arch/x86/kernel/entry_64.S | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index 0124f6f..7bc097a 100644
> --- a/arch/x86/kernel/entry_64.S
> +++ b/arch/x86/kernel/entry_64.S
> @@ -507,8 +507,6 @@ ENTRY(ret_from_fork)
>
> call schedule_tail # rdi: 'prev' task parameter
>
> - GET_THREAD_INFO(%rcx)
> -
> RESTORE_EXTRA_REGS
>
> testl $3,CS(%rsp) # from kernel_thread?
> --
> 1.8.1.4
>



--
Andy Lutomirski
AMA Capital Management, LLC
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