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SubjectRe: [PATCH v2] x86/asm/entry/64: 32-bit execve stubs are identical to x32 ones, merge them.
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On Tue, Apr 21, 2015 at 12:03 PM, Denys Vlasenko <dvlasenk@redhat.com> wrote:
> Siggested by Brian Gerst.

Suggested

>
> Run-tested.
>
> Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
> CC: Linus Torvalds <torvalds@linux-foundation.org>
> CC: Steven Rostedt <rostedt@goodmis.org>
> CC: Ingo Molnar <mingo@kernel.org>
> CC: Borislav Petkov <bp@alien8.de>
> CC: "H. Peter Anvin" <hpa@zytor.com>
> CC: Andy Lutomirski <luto@amacapital.net>
> CC: Oleg Nesterov <oleg@redhat.com>
> CC: Frederic Weisbecker <fweisbec@gmail.com>
> CC: Alexei Starovoitov <ast@plumgrid.com>
> CC: Will Drewry <wad@chromium.org>
> CC: Kees Cook <keescook@chromium.org>
> CC: x86@kernel.org
> CC: linux-kernel@vger.kernel.org
> ---
>
> 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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