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Message-ID: <4C1A92D4.504@caviumnetworks.com>
Date:   Thu, 17 Jun 2010 14:25:40 -0700
From:   David Daney <ddaney@caviumnetworks.com>
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To:     Jan Rovins <janr@adax.com>
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Subject: Re: Help with decoding a NMI Watchdog interrupt on an Octeon
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On 06/17/2010 02:03 PM, Jan Rovins wrote:
> Hi, I need some tips on how to go about deciphering the following NMI dump.
>
> This is from a 2.6.21.7 kernel that came with the Cavium Networks 1.8.1
> toolchain.
> Is there any way to get some kind of back trace from this, or just find
> out which function it was in?
>
> I have been playing around with objdump -x vmlinux but I cant zero in on
> anything this way.
>
> Thanks in advance,
>
> Jan
> *** NMI Watchdog interrupt on Core 0x6 ***
> $0 0x0000000000000000 at 0x000000001010cce0
> v0 0x000000000000003d v1 0x000000000000024a
> a0 0xffffffff807d7b70 a1 0x0000000000000000
> a2 0x000000000000024a a3 0x0000000000000000
> a4 0xffffffff807d7b60 a5 0x0000000000000080
> a6 0x0000000000000001 a7 0xa800000411c62578
> t0 0x0000000000000001 t1 0xa80000048ef3e880
> t2 0xffffffff82d40000 t3 0xa80000041f48c000
> s0 0xc0000000000d9640 s1 0xc000000000088028
> s2 0x0000000000000000 s3 0x0000000000000180
> s4 0x0000000000000000 s5 0x0000000000000000
> s6 0xb7a89c196f513832 s7 0x0000000000000000
> t8 0xffffffff807d0000 t9 0xffffffff807d0000
> k0 0x0000000000000000 k1 0x00000000104dbcbf
> gp 0xa80000041f48c000 sp 0xa80000041f48fcf0
> s8 0x0000000000000000 ra 0xc0000000023c5004
> epc 0xffffffff802b10b8

You may want to verify that epc value is being loaded from C0_ErrorEPC 
rather than C0_EPC.  SDK-1.8.1 gets this wrong.

Look in watchgog.c:octeon_watchdog_nmi_stage3.

Once you have it printing the ErrorEPC value, the trace actually tells 
you what was happening when the NMI fired.

objdump -d vmlinux will give you a disassembly of the kernel, and away 
you go.

David Daney

> status 0x000000001058cce4 cause 0x0000000040008c08
> sum0 0x0000002100000000 en0 0x0000009300008000
> Code around epc
> 0xffffffff802b10a8 000000002406ffff
> 0xffffffff802b10ac 0000000064a5ffff
> 0xffffffff802b10b0 0000000010a60005
> 0xffffffff802b10b4 0000000000000000
> 0xffffffff802b10b8 0000000080620000
> 0xffffffff802b10bc 000000001440fffb
> 0xffffffff802b10c0 0000000064630001
> 0xffffffff802b10c4 000000006463ffff
> 0xffffffff802b10c8 0000000003e00008
>
>
>