ksymoops and 64 bit mips

ksymoops and 64 bit mips

[Gilad Benjamini]

I tried using ksymoops to analyze an oops on my 64 bit SMP mips kernel.
I am running ksymoops on x86 platform.

Initially I got a lot of garbage.
Upgrdaing to ksymoops 2.4.5 , and using the --truncate=1 and 
-t elf32-little reduced 
the amount of garbage, but still all the output shown
was "No symbol available".

Any additional things I should do ?

TIA

Re: ksymoops and 64 bit mips

[Ralf Baechle]

On Wed, Jan 08, 2003 at 10:15:19PM +0200, Gilad Benjamini wrote:

> Initially I got a lot of garbage.
> Upgrdaing to ksymoops 2.4.5 , and using the --truncate=1 and 
> -t elf32-little reduced 
> the amount of garbage, but still all the output shown
> was "No symbol available".
> 
> Any additional things I should do ?

Possibly your ksymoops is get confused by the System.map file.  The vmlinux
file is a 32-bit ELF file but the System.map file contains the addresses
sign-extended to 64-bit.  As a bandaid you can just chop off the high
32-bits of all addresses in System.map.

  Ralf

RE: ksymoops and 64 bit mips

[Gilad Benjamini]

Au contraire.
System.map has 32 bit addresses, which I tried to sign extended 
with "ffffffff" (the wonders of sed), but that didn't help.

> -----Original Message-----
> From: Ralf Baechle [mailto:ralf@linux-mips.org]
> Sent: Thursday, January 09, 2003 3:38 PM
> To: Gilad Benjamini
> Cc: linux-mips@linux-mips.org
> Subject: Re: ksymoops and 64 bit mips
> 
> 
> On Wed, Jan 08, 2003 at 10:15:19PM +0200, Gilad Benjamini wrote:
> 
> > Initially I got a lot of garbage.
> > Upgrdaing to ksymoops 2.4.5 , and using the --truncate=1 and 
> > -t elf32-little reduced 
> > the amount of garbage, but still all the output shown
> > was "No symbol available".
> > 
> > Any additional things I should do ?
> 
> Possibly your ksymoops is get confused by the System.map 
> file.  The vmlinux
> file is a 32-bit ELF file but the System.map file contains 
> the addresses
> sign-extended to 64-bit.  As a bandaid you can just chop off the high
> 32-bits of all addresses in System.map.
> 
>   Ralf
> 

RE: ksymoops and 64 bit mips

[Gilad Benjamini]

Au contraire.
System.map has 32 bit addresses, which I tried to sign extended 
with "ffffffff" (the wonders of sed), but that didn't help.

> -----Original Message-----
> From: Ralf Baechle [mailto:ralf@linux-mips.org]
> Sent: Thursday, January 09, 2003 3:38 PM
> To: Gilad Benjamini
> Cc: linux-mips@linux-mips.org
> Subject: Re: ksymoops and 64 bit mips
> 
> 
> On Wed, Jan 08, 2003 at 10:15:19PM +0200, Gilad Benjamini wrote:
> 
> > Initially I got a lot of garbage.
> > Upgrdaing to ksymoops 2.4.5 , and using the --truncate=1 and 
> > -t elf32-little reduced 
> > the amount of garbage, but still all the output shown
> > was "No symbol available".
> > 
> > Any additional things I should do ?
> 
> Possibly your ksymoops is get confused by the System.map 
> file.  The vmlinux
> file is a 32-bit ELF file but the System.map file contains 
> the addresses
> sign-extended to 64-bit.  As a bandaid you can just chop off the high
> 32-bits of all addresses in System.map.
> 
>   Ralf
> 

Re: ksymoops and 64 bit mips

[Maciej W. Rozycki]

On Thu, 9 Jan 2003, Ralf Baechle wrote:

> > Initially I got a lot of garbage.
> > Upgrdaing to ksymoops 2.4.5 , and using the --truncate=1 and 
> > -t elf32-little reduced 
> > the amount of garbage, but still all the output shown
> > was "No symbol available".
> > 
> > Any additional things I should do ?
> 
> Possibly your ksymoops is get confused by the System.map file.  The vmlinux
> file is a 32-bit ELF file but the System.map file contains the addresses
> sign-extended to 64-bit.  As a bandaid you can just chop off the high
> 32-bits of all addresses in System.map.

 Recent versions of ksymoops contain code to handle 64-bit MIPS flexibly
and are expected to take care of address aliases.  They don't works very
well, though, and I've done a few fixes.  They are available in a ksymoops
2.4.8 package at my site and hopefully will be applied in a future
release.

 Anyway the cross-ksymoops case referred by Gilad is tricky -- you need to
build ksymoops linking against an appropriate BFD library, i.e. one that
supports a MIPS64 target.  Additionally MIPS64-specific nm and objdump
programs have to be available to that ksymoops binary (cf. KSYMOOPS_NM and
KSYMOOPS_OBJDUMP environment variables). 

 For detailed information on using a cross-setup see the ksymoops
documentation.

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +