Re: [PATCH v2] x86/asm/entry/64: 32-bit execve stubs are identical to x32 ones, merge them.

[Brian Gerst]

On Tue, Apr 21, 2015 at 12:03 PM, Denys Vlasenko <dvlasenk@xxxxxxxxxx> wrote:
> Siggested by Brian Gerst.

Suggested

>
> Run-tested.
>
> 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
> ---
>
> Changes in v2: fixed "suggested by", I remebered it wrongly.
>
>  arch/x86/kernel/entry_64.S | 23 +++++------------------
>  1 file changed, 5 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index c7b2384..3bdfdcd 100644
> --- a/arch/x86/kernel/entry_64.S
> +++ b/arch/x86/kernel/entry_64.S
> @@ -524,40 +524,27 @@ GLOBAL(stub_execveat)
>         CFI_ENDPROC
>  END(stub_execveat)
>
> -#ifdef CONFIG_X86_X32_ABI
> +#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
>         .align  8
>  GLOBAL(stub_x32_execve)
> +GLOBAL(stub32_execve)
>         CFI_STARTPROC
>         DEFAULT_FRAME 0, 8
>         call    compat_sys_execve
>         jmp     return_from_execve
>         CFI_ENDPROC
> +END(stub32_execve)
>  END(stub_x32_execve)
>         .align  8
>  GLOBAL(stub_x32_execveat)
> -       CFI_STARTPROC
> -       DEFAULT_FRAME 0, 8
> -       call    compat_sys_execveat
> -       jmp     return_from_execve
> -       CFI_ENDPROC
> -END(stub_x32_execveat)
> -#endif
> -
> -#ifdef CONFIG_IA32_EMULATION
> -       .align  8
> -GLOBAL(stub32_execve)
> -       CFI_STARTPROC
> -       call    compat_sys_execve
> -       jmp     return_from_execve
> -       CFI_ENDPROC
> -END(stub32_execve)
> -       .align  8
>  GLOBAL(stub32_execveat)
>         CFI_STARTPROC
> +       DEFAULT_FRAME 0, 8
>         call    compat_sys_execveat
>         jmp     return_from_execve
>         CFI_ENDPROC
>  END(stub32_execveat)
> +END(stub_x32_execveat)
>  #endif
>
>  /*

I don't think it's necessary to keep both labels.  Just use one and
change the syscall tables accordingly.  Otherwise, looks good.

--
Brian Gerst
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