From mboxrd@z Thu Jan  1 00:00:00 1970
From: Fenghua Yu <fenghua.yu@intel.com>
Date: Mon, 15 Oct 2007 23:26:52 +0000
Subject: Re: [RFC patch] use thread.on_ustack to determine if on user stack
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To: linux-ia64@vger.kernel.org

On Mon, Oct 15, 2007 at 12:28:05PM +0800, Luming Yu wrote:
> So my problem is I don't know if it is  true that pUStk =
> thread.on_ustack in fsys mode. And I didn't locate the code that the
> thread.on_ustack is cleared to 0 during fsys mode.
> So please help.

In fsys call, pUStk is never equal to thread.on_ustack. Here is the code in
fsys_bubble_down() in fsys.S.

....
        st1 [r16]=r0                            // M2|3 clear current->thread.on_ustack flag
....
        cmp.ne pKStk,pUStk=r0,r0                // A    set pKStk <- 0, pUStk <- 1
....

The code shows that thread.on_ustack=0 and pUStk=1 during fsys setup phase. The
two should be equal in other cases than fsys. Seems the two similar names cause
confusion.

Thanks.

-Fenghua