From: David Daney <david.daney@cavium.com>
To: Yong Zhang <yong.zhang@windriver.com>
Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org,
Ralf Baechle <ralf@linux-mips.org>
Subject: Re: [PATCH] MIPS: use 32-bit wrapper for compat_sys_futex
Date: Thu, 18 Aug 2011 09:23:41 -0700 [thread overview]
Message-ID: <4E4D3C8D.1040707@cavium.com> (raw)
In-Reply-To: <20110818023247.GA3750@windriver.com>
On 08/17/2011 07:32 PM, Yong Zhang wrote:
> 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;
No, you don't have to move it. Just don't call it.
> 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).
OK: You are mistaken. You claim you don't understand what the code
does. That is really a poor justification for modifying it.
David Daney
next prev parent reply other threads:[~2011-08-18 16:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-17 1:54 [PATCH] MIPS: use 32-bit wrapper for compat_sys_futex Yong Zhang
2011-08-17 12:43 ` Ralf Baechle
2011-08-17 17:17 ` David Daney
2011-08-18 2:32 ` Yong Zhang
2011-08-18 16:23 ` David Daney [this message]
2011-08-19 1:56 ` Yong Zhang
2011-08-18 2:44 ` Yong Zhang
2011-08-18 20:19 ` Ralf Baechle
2011-08-19 3:49 ` How to trace compat syscalls? [Was Re: [PATCH] MIPS: use 32-bit wrapper for compat_sys_futex] Yong Zhang
2011-08-19 4:15 ` Yong Zhang
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