Re: [PATCH] MIPS: use 32-bit wrapper for compat_sys_futex

[Yong Zhang <yong.zhang@windriver.com>]

On Wed, Aug 17, 2011 at 10:17:52AM -0700, David Daney wrote:
> >diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
> >index 46c4763..f48b18e 100644
> >--- a/arch/mips/kernel/scall64-o32.S
> >+++ b/arch/mips/kernel/scall64-o32.S
> >@@ -441,7 +441,7 @@ sys_call_table:
> >     PTR     sys_fremovexattr                /* 4235 */
> >     PTR     sys_tkill
> >     PTR     sys_sendfile64
> >-    PTR     compat_sys_futex
> >+    PTR     sys_32_futex
> 
> This change is redundant, scall64-o32.S already does the right thing

My first virsion(not sent out) doesn't include scall64-o32.S either.

> so additional zero extending is not needed and is just extra
> instructions to execute for no reason.

Why I'm adding it here is for:
1)code consistent, otherwise we must move SYSCALL_DEFINE6(32_futex,...)
  under CONFIG_MIPS32_N32;
2)I'm afraid there may be some other way to touch the high 32-bit of a
  register, so touching scall64-o32.S is also for safety(due to unknown
  reason, fix me if I'm wrong).

Thanks,
Yong