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From: Richard Henderson <rth@twiddle.net>
To: "Aneesh Kumar K.V" <aneesh.kumar@digital.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [Alpha/Linux ] Stack layout/and register values for ret_from_sys_call
Date: Fri, 28 Dec 2001 16:07:00 -0800	[thread overview]
Message-ID: <20011228160700.B30611@twiddle.net> (raw)
In-Reply-To: <1008613257.22228.3.camel@satan.xko.dec.com>
In-Reply-To: <1008613257.22228.3.camel@satan.xko.dec.com>; from aneesh.kumar@digital.com on Mon, Dec 17, 2001 at 11:50:57PM +0530

On Mon, Dec 17, 2001 at 11:50:57PM +0530, Aneesh Kumar K.V wrote:
>  Can someone explain me what should be the stack layout and register
> value( if there is any restriction ) before calling ret_from_syscall for
> Alpha.

Top of stack should contain a struct pt_regs.  See asm/ptrace.h.

>   lda     $8,0x3fff
>   bic     $30,$8,$8
> 
> If someone can expain what happens in the above two assembly statement
> it will be really helpful.

This computes the value for "current".  The stack plus task structure
is aligned on a two-page boundary.  See task_union in linux/sched.h.


r~

      reply	other threads:[~2001-12-29  0:07 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-12-17 18:20 [Alpha/Linux ] Stack layout/and register values for ret_from_sys_call Aneesh Kumar K.V
2001-12-29  0:07 ` Richard Henderson [this message]

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