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

From: Yong Zhang
Date: Wed Aug 17 2011 - 22:33:33 EST


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
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