Re: [PATCH v8 4/5] powerpc/pseries: Dump the SLB contents on SLB MCE errors.

[Nicholas Piggin <npiggin@gmail.com>]

On Sun, 19 Aug 2018 22:38:32 +0530
Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com> wrote:

> From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
> 
> If we get a machine check exceptions due to SLB errors then dump the
> current SLB contents which will be very much helpful in debugging the
> root cause of SLB errors. Introduce an exclusive buffer per cpu to hold
> faulty SLB entries. In real mode mce handler saves the old SLB contents
> into this buffer accessible through paca and print it out later in virtual
> mode.
> 
> With this patch the console will log SLB contents like below on SLB MCE
> errors:
> 
> [  507.297236] SLB contents of cpu 0x1
> [  507.297237] Last SLB entry inserted at slot 16
> [  507.297238] 00 c000000008000000 400ea1b217000500
> [  507.297239]   1T  ESID=   c00000  VSID=      ea1b217 LLP:100
> [  507.297240] 01 d000000008000000 400d43642f000510
> [  507.297242]   1T  ESID=   d00000  VSID=      d43642f LLP:110
> [  507.297243] 11 f000000008000000 400a86c85f000500
> [  507.297244]   1T  ESID=   f00000  VSID=      a86c85f LLP:100
> [  507.297245] 12 00007f0008000000 4008119624000d90
> [  507.297246]   1T  ESID=       7f  VSID=      8119624 LLP:110
> [  507.297247] 13 0000000018000000 00092885f5150d90
> [  507.297247]  256M ESID=        1  VSID=   92885f5150 LLP:110
> [  507.297248] 14 0000010008000000 4009e7cb50000d90
> [  507.297249]   1T  ESID=        1  VSID=      9e7cb50 LLP:110
> [  507.297250] 15 d000000008000000 400d43642f000510
> [  507.297251]   1T  ESID=   d00000  VSID=      d43642f LLP:110
> [  507.297252] 16 d000000008000000 400d43642f000510
> [  507.297253]   1T  ESID=   d00000  VSID=      d43642f LLP:110
> [  507.297253] ----------------------------------
> [  507.297254] SLB cache ptr value = 3
> [  507.297254] Valid SLB cache entries:
> [  507.297255] 00 EA[0-35]=    7f000
> [  507.297256] 01 EA[0-35]=        1
> [  507.297257] 02 EA[0-35]=     1000
> [  507.297257] Rest of SLB cache entries:
> [  507.297258] 03 EA[0-35]=    7f000
> [  507.297258] 04 EA[0-35]=        1
> [  507.297259] 05 EA[0-35]=     1000
> [  507.297260] 06 EA[0-35]=       12
> [  507.297260] 07 EA[0-35]=    7f000
> 
> Suggested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
> ---
> 
> Changes in V8:
> - Limit the slb saving to single level of mce recursion.

Thanks, that looks good now.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>