From: Al Viro <viro@ZenIV.linux.org.uk>
To: H?vard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>,
Matthias Brugger <matthias.bgg@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
David Howells <dhowells@redhat.com>,
Dave Jones <davej@redhat.com>, Will Deacon <will.deacon@arm.com>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] arch: avr32: add dummy syscalls
Date: Mon, 4 Feb 2013 15:39:02 +0000 [thread overview]
Message-ID: <20130204153902.GC4503@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CACiLriSguKWSfFfFGK99q1h+GLrfCSyh55xW8o67kOao3g5sWg@mail.gmail.com>
On Sun, Feb 03, 2013 at 09:35:39PM -0800, H?vard Skinnemoen wrote:
> Right.
>
> > But yes, 32bit/32bit/64bit/32bit is another interesting case -
> > fanotify_mark is 32/32/64/32/32. From what ABI says it would seem to
> > be r12/r11/r8:r9/r10/stack, but if I understand you correctly, we'll
> > end up wanting *two* arguments on stack...
>
> Yes, I think there may be a difference between the IAR and gcc ABI
> here. But I could be wrong.
Umm... avr32_function_arg() in atmel 4.4.3 patch:
if (arg_rsize == 8)
{
/* use r11:r10 or r9:r8. */
if (!(GET_USED_INDEX (cum, 1) || GET_USED_INDEX (cum, 2)))
index = 1;
else if ((last_reg_index == 4) &&
!(GET_USED_INDEX (cum, 3) || GET_USED_INDEX (cum, 4)))
index = 3;
else
index = -1;
}
else if (arg_rsize == 4)
{ /* Use first available register */
index = 0;
while (index <= last_reg_index && GET_USED_INDEX (cum, index))
index++;
if (index > last_reg_index)
index = -1;
}
So it will use the gap in case of 32/32/64/32; the first two calls will
take index 0 and 1 (r12 and r11 resp.), the third will take 3 and 4
(r9:r8) and the fourth will take 2 (r10). Relevant part of
avr32_function_arg_advance():
/* Mark the used registers as "used". */
if (GET_REG_INDEX (cum) >= 0)
{
SET_USED_INDEX (cum, GET_REG_INDEX (cum));
if (arg_rsize == 8)
{
SET_USED_INDEX (cum, (GET_REG_INDEX (cum) + 1));
}
}
i.e. the third argument will only stomp on 3 and 4, leaving 2 unused.
And as far as I can see, their 4.3.3 patch does the same thing...
next prev parent reply other threads:[~2013-02-04 15:39 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-27 12:50 [PATCH] arch: avr32: add dummy syscalls Matthias Brugger
2013-01-27 19:57 ` Hans-Christian Egtvedt
2013-01-27 20:30 ` Al Viro
2013-01-27 20:39 ` Hans-Christian Egtvedt
2013-02-04 0:10 ` Al Viro
2013-02-04 0:30 ` Al Viro
2013-02-04 1:31 ` Al Viro
2013-02-04 3:02 ` Al Viro
2013-02-04 4:52 ` Håvard Skinnemoen
2013-02-04 5:05 ` Al Viro
2013-02-04 5:35 ` Håvard Skinnemoen
2013-02-04 15:39 ` Al Viro [this message]
2013-02-04 16:34 ` Håvard Skinnemoen
2013-02-04 22:53 ` Al Viro
2013-02-05 8:06 ` Hans-Christian Egtvedt
2013-02-04 3:21 ` H. Peter Anvin
2013-01-28 2:45 ` Håvard Skinnemoen
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