From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from Barracuda.deltatau.com (barracuda.deltatau.com [76.79.246.10]) by ozlabs.org (Postfix) with ESMTP id 552CD2C00BF for ; Tue, 20 Aug 2013 05:00:40 +1000 (EST) From: "Henry Bausley" To: "Benjamin Herrenschmidt" , "Kumar Gala" Subject: Re: Critical Interrupt Input Date: Mon, 19 Aug 2013 12:00:25 -0700 Message-ID: <63d2635a$648939a4$b3aeac8$@deltatau.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_59684433.2E39B445" Cc: linuxppc-dev@lists.ozlabs.org Reply-To: hbausley@deltatau.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is a multipart message in MIME format. ------=_NextPart_000_0001_59684433.2E39B445 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Support does appear to be present but there is a problem returning back to user space I suspect. What fails is it causes Linux user space programs to get Segmentation errors. Issuing a simple ls causes a segmentation fault sometimes. The shell gets terminated and you cannot log back in. INIT: Id "T0" respawning too fast: disabled for 5 minutes pops up. However, the critical interrupt handler keeps running. I know this by adding the reading of a physical I/O location in the handler and can see it is being read on the scope. The only code in the handler is below. void critintr_handler(void *dev) { critintrcount++; // increment a variable iodata = *piom; // read an I/O location mtdcr(0x0c0, 0x00002000); // clear critical interrupt } Below is a log of the type of crashes that occur: root@10.34.9.213:/opt/ppmac/ktest# ls Segmentation fault root@10.34.9.213:/opt/ppmac/ktest# ls Segmentation fault root@10.34.9.213:/opt/ppmac/ktest# ls Makefile ktest.c ktest.ko ktest.mod.o modules.order Module.symvers ktest.cbp ktest.mod.c ktest.o root@10.34.9.213:/opt/ppmac/ktest# ls Debian GNU/Linux 7 powerpmac ttyS0 powerpmac login: root Debian GNU/Linux 7 powerpmac ttyS0 powerpmac login: root Debian GNU/Linux 7 powerpmac ttyS0 powerpmac login: root Debian GNU/Linux 7 powerpmac ttyS0 powerpmac login: root Password: Last login: Thu Nov 30 20:42:16 UTC 1933 on ttyS0 Linux powerpmac 3.2.21-aspen_2.01.09 #10 Mon Aug 19 08:49:12 PDT 2013 ppc The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. INIT: Id "T0" respawning too fast: disabled for 5 minutes ---------------------------------------- From: "Benjamin Herrenschmidt" Sent: Saturday, August 17, 2013 3:05 PM To: "Kumar Gala" Cc: linuxppc-dev@lists.ozlabs.org, hbausley@deltatau.com Subject: Re: Critical Interrupt Input On Fri, 2013-08-16 at 06:04 -0500, Kumar Gala wrote: > The 44x low level code needs to handle exception stacks properly for > this to work. Since its possible to have a critical exception occur > while in a normal exception level, you have to have proper saving of > additional register state and a stack frame for the critical > exception, etc. I'm not sure if that was ever done for 44x. Don't 44x and FSL BookE share the same macros ? I would think 44x does indeed implement the same crit support as e500... What does the crash look like ? Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev Outbound scan for Spam or Virus by Barracuda at Delta Tau ------=_NextPart_000_0001_59684433.2E39B445 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Support does appear to be present but there is a problem returning back t= o user space I suspect.

What fails is it causes Linux user space pro= grams to get Segmentation errors.
Issuing a simple ls causes a segmentat= ion fault sometimes.  The shell gets terminated
and you cannot log= back in.  INIT: Id "T0" respawning too fast: disabled for 5 minutes p= ops up.

However, the critical interrupt handler keeps running. = I know this by adding the reading
of a physical I/O location in the ha= ndler and can see it is being read on the scope.


The only code i= n the handler is below.

void critintr_handler(void *dev)
{
&nb= sp; critintrcount++;          = // increment a variable
  iodata =3D *piom;    =        // read an I/O location
  mtd= cr(0x0c0, 0x00002000); // clear critical interrupt
}


Below is= a log of the type of crashes that occur:

root@10.34.9.213:/opt/ppma= c/ktest# ls
Segmentation fault
root@10.34.9.213:/opt/ppmac/ktest# ls
Segmentation fault
root@10.34.9= .213:/opt/ppmac/ktest# ls
Makefile      &n= bsp; ktest.c    ktest.ko     ktest.mod.o=   modules.order
Module.symvers  ktest.cbp  ktest.mod.c&nb= sp; ktest.o
root@10.34.9.213:/opt/ppmac/ktest# ls

Debian GNU/Linu= x 7 powerpmac ttyS0

powerpmac login: root

Debian GNU/Linux 7 = powerpmac ttyS0

powerpmac login: root

Debian GNU/Linux 7 powe= rpmac ttyS0

powerpmac login: root

Debian GNU/Linux 7 powerpma= c ttyS0

powerpmac login: root
Password:
Last login: Thu Nov 3= 0 20:42:16 UTC 1933 on ttyS0
Linux powerpmac 3.2.21-aspen_2.01.09 #10 Mo= n Aug 19 08:49:12 PDT 2013 ppc

The programs included with the Debian= GNU/Linux system are free software;
the exact distribution terms for ea= ch program are described in the
individual files in /usr/share/doc/*/cop= yright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the e= xtent
permitted by applicable law.
INIT: Id "T0" respawning too fast:= disabled for 5 minutes

<= b>From: "Benjamin Herrenschmidt" <benh@kernel.crashing.org>
Sent: Saturday, August 17, 2013 3:05 PM
To: "Kumar Gala" <= ;galak@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org,= hbausley@deltatau.com
Subject: Re: Critical Interrupt Input

On Fri, 2013-08-16 at 06:04 -0500, Kumar Gala wrote:
> The = 44x low level code needs to handle exception stacks properly for
> th= is to work. Since its possible to have a critical exception occur
> = while in a normal exception level, you have to have proper saving of
>= ; additional register state and a stack frame for the critical
> exce= ption, etc. I'm not sure if that was ever done for 44x.

Don't 44x a= nd FSL BookE share the same macros ? I would think 44x does
indeed imple= ment the same crit support as e500...

What does the crash look like = ?

Ben.


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