Machine check exceptions

If linux encounters machine check exception it logs it to a syslog/debug log.

mcelog utility can be used to debug it:

git clone github.com/andikleen/mcelog.git

make

It can either load it from logs or parse it from stdin like so (CPU is 0x6e8) model fam is specified:

./mcelog --intel-cpu 6,14 --ascii
mcelog: Cannot open /dev/mem for DMI decoding: Permission denied
Jan 11 14:29:53 yonah kernel: [    0.161089] mce: [Hardware Error]:
CPU 0: Machine Check: 0 Bank 0: f200084000000800Jan 11 14:29:53 yonah kernel: [    0.161089] mce: [Hardware Error]:

Hardware event. This is not a software error.
CPU 0 BANK 0
MCG status:
MCi status:
Error overflow
Uncorrected error
Error enabled
Processor context corrupt
MCA: BUS error: -1 0 Level-0 Local-CPU-originated-request Generic Memory-access Request-did-not-timeout
BQ_DCU_READ_TYPE BQ_ERR_HARD_TYPE BQ_ERR_HARD_TYPE
timeout BINIT (ROB timeout). No micro-instruction retired for some time
failure that caused IERR
STATUS f200084000000800 MCGSTATUS 0

OR:

./mcelog --intel-cpu 6,14 --ascii
mcelog: Cannot open /dev/mem for DMI decoding: Permission denied

CPU 0: Machine Check: 0 Bank 4: b200000000040151

Hardware event. This is not a software error.
CPU 0 BANK 4
MCG status:
MCi status:
Uncorrected error
Error enabled
Processor context corrupt
MCA: Instruction CACHE Level-2 Instruction-Fetch Error
STATUS b200000000040151 MCGSTATUS 0


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