Subject: 24K malta

From: Greg Weeks <[email-masked]>
Date: Wed, 10 Aug 2005 09:40:36 -0400

I'm seeing something strange on a 24K malta and I'm wondering if anyone 
else has ran into something like it.

This is a 2.6.12 based kernel. I've not had a chance to try the current 
CVS yet. The last time I checked the current CVS didn't boot as is on a 
4Kc malta so I've not been keeping current with CVS.

When I try a simple

strace ls

I either hang or seg fault on a 24Kc or 24Kec processor, but a 4Kc or 
4Kec works. If I turn off the cache on the 24K it works as well. Without 
cache it's unbearably slow of course. This is the same exact build of 
the kernel and root file system for all boards.

Greg Weeks

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From: Ralf Baechle <[email-masked]>
Date: Wed, 10 Aug 2005 15:02:43 +0100

> the kernel and root file system for all boards.

I cannot reproduce this problem on 24KEc Malta, sorry.

  Ralf

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From: Greg Weeks <[email-masked]>
Date: Wed, 10 Aug 2005 10:13:50 -0400

>I cannot reproduce this problem on 24KEc Malta, sorry.
Good. That means it's something in my old tree.

Thanks.

Greg Weeks

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From: Greg Weeks <[email-masked]>
Date: Wed, 10 Aug 2005 10:45:37 -0400

Current CVS fails to build the malta_defconfig with:

scripts/kconfig/mconf arch/mips/Kconfig
arch/mips/Kconfig:690: can't open file "arch/mips/tx4938/Kconfig"
make[1]: *** [menuconfig] Error 1
make: *** [menuconfig] Error 2

Greg Weeks

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From: Ralf Baechle <[email-masked]>
Date: Wed, 10 Aug 2005 15:49:47 +0100

> make: *** [menuconfig] Error 2

CVS pilot error.  cvs -q update -d -P and don't forget to bitch about it ;)

  Ralf

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From: Greg Weeks <[email-masked]>
Date: Wed, 10 Aug 2005 11:00:40 -0400

>CVS pilot error.  cvs -q update -d -P and don't forget to bitch about it ;)
Would bitching about it do any good? I expect I'd just get told to stick 
it in my .cvsrc which is what I just did.

Now I get this:

  AS      arch/mips/kernel/r4k_switch.o
  CC      arch/mips/kernel/vpe.o
{standard input}: Assembler messages:
{standard input}:1329: Error: unrecognized opcode `mftc0 $7,$2,4'
{standard input}:1333: Error: unrecognized opcode `mftc0 $6,$2,1'

Greg Weeks

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From: Thiemo Seufer <[email-masked]>
Date: Wed, 10 Aug 2005 17:02:30 +0200

> CVS pilot error.  cvs -q update -d -P and don't forget to bitch about it ;)

The CVS authors should have made some sane global defaults. I use this
~/.cvsrc to make it less annoying:

hattusa:~$ cat .cvsrc
cvs -qz9
diff -upNR
rdiff -uR
update -dPR
checkout -P

Thiemo

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From: Ralf Baechle <[email-masked]>
Date: Wed, 10 Aug 2005 16:09:34 +0100

> {standard input}:1333: Error: unrecognized opcode `mftc0 $6,$2,1'

You have CONFIG_MT enabled but your binutils don't support these new
instructions yet.  Since you're using 4K and 24K CPUs only ATM I think
you should simply disable CONFIG_MT for now.

  Ralf

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From: Greg Weeks <[email-masked]>
Date: Wed, 10 Aug 2005 11:14:07 -0400

>you should simply disable CONFIG_MT for now.
Just turning off the vpe loading support got me past this one. I don't 
think I have CONFIG_MT set.

[gweeks@tanith linux-8-10-05]$ grep CONFIG_MT .config
# CONFIG_MTD is not set
[gweeks@tanith linux-8-10-05]$ cd arch/mips/configs/
[gweeks@tanith configs]$ grep CONFIG_MT malta_defconfig
# CONFIG_MTD is not set
[gweeks@tanith configs]$

Greg Weeks

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From: Ralf Baechle <[email-masked]>
Date: Wed, 10 Aug 2005 16:15:39 +0100

> think I have CONFIG_MT set.

Sorry, I meant CONFIG_MIPS_MT.

  Ralf

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From: Greg Weeks <[email-masked]>
Date: Wed, 10 Aug 2005 14:00:02 -0400

Greg Weeks wrote:

> I'm seeing something strange on a 24K malta and I'm wondering if 
> anyone else has ran into something like it.
>
> This is a 2.6.12 based kernel. I've not had a chance to try the 
> current CVS yet. The last time I checked the current CVS didn't boot 
> as is on a 4Kc malta so I've not been keeping current with CVS.
>
> When I try a simple
>
> strace ls
>
> 4Kec works. If I turn off the cache on the 24K it works as well. 
> Without cache it's unbearably slow of course. This is the same exact 
> build of the kernel and root file system for all boards.

The memcpy prefetch bug is still there for malta, so I had to build 
another kernel. This is with a CVS sync from this morning.

The first strace ls works now, but the second time I do it it hangs. 
Kill -9 frees it up and the board isn't hanging.

Greg Weeks

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From: Ralf Baechle <[email-masked]>
Date: Wed, 10 Aug 2005 20:14:55 +0100

> it in my .cvsrc which is what I just did.

Well, cvs's defaults seem to have been choosen following the principle
of maximum surprise and you're by far not the first to get traped by
that ...

  Ralf

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From: Greg Weeks <[email-masked]>
Date: Wed, 24 Aug 2005 08:25:34 -0400

>I cannot reproduce this problem on 24KEc Malta, sorry.
What patch are you using to get current CVS to boot on a malta? I've 
been disabling prefetch in memcpy, but if you're doing something else I 
want to try that. About 1 out of 3 "strace ls" either hangs or seg 
faults on me still.

Greg Weeks

---

From: Ralf Baechle <[email-masked]>
Date: Wed, 24 Aug 2005 14:35:24 +0100

> want to try that. About 1 out of 3 "strace ls" either hangs or seg 

I've disabled prefetching entirely in arch/mips/Kconfig and I'm using a
24Kc, not a 24KEc, stock gcc 3.4 & binutils 2.16 and it's running quite
nicely for me.

  Ralf