RE: A bug about system call on ARM

From: Wang, Yalin
Date: Mon Jun 03 2013 - 01:25:38 EST


Hi Will,

I have a question about this patch .

If the user space is thumb mode,
The PC should be rewind by 2 bytes,
So the fix_up code should be

Sub lr, lr, #2 .


Am I right ?


Thanks for your help .

-----Original Message-----
From: Wang, Yalin
Sent: Friday, May 31, 2013 7:31 PM
To: 'Will Deacon'
Cc: 'richard -rw- weinberger'; 'linux-arch@xxxxxxxxxxxxxxx'; 'linux-kernel@xxxxxxxxxxxxxxx'; 'linux-arm-kernel@xxxxxxxxxxxxxxxxxxx'
Subject: RE: A bug about system call on ARM

Hi Will,

I see,
I will make one more test .

Thanks for your clarification .

-----Original Message-----
From: Will Deacon [mailto:will.deacon@xxxxxxx]
Sent: Friday, May 31, 2013 7:13 PM
To: Wang, Yalin
Cc: 'richard -rw- weinberger'; 'linux-arch@xxxxxxxxxxxxxxx'; 'linux-kernel@xxxxxxxxxxxxxxx'; 'linux-arm-kernel@xxxxxxxxxxxxxxxxxxx'
Subject: Re: A bug about system call on ARM

On Fri, May 31, 2013 at 12:02:49PM +0100, Wang, Yalin wrote:
> Hi Will,
>
> I have merge your code ,
> But there is a different ,
>
> +
> + ct_user_exit

I thought you didn't have ct_user_exit? In which case, just delete this line.

> +#ifdef CONFIG_ALIGNMENT_TRAP
> + ldr ip, __cr_alignment
> + ldr ip, [ip]
> + mcr p15, 0, ip, c1, c0 @ update control register
> +#endif
>
> + enable_irq
> + get_thread_info tsk

Hard to tell without context. You can take a look at my git tree if you like (I fixed it up based on Nico's comment):

https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/commit/?h=misc-patches

Will
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/