linux/Documentation/ABI/testing/pstore
Tony Luck ca01d6dd2d pstore: new filesystem interface to platform persistent storage
Some platforms have a small amount of non-volatile storage that
can be used to store information useful to diagnose the cause of
a system crash.  This is the generic part of a file system interface
that presents information from the crash as a series of files in
/dev/pstore.  Once the information has been seen, the underlying
storage is freed by deleting the files.

Signed-off-by: Tony Luck <tony.luck@intel.com>
2010-12-28 14:25:21 -08:00

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Where: /dev/pstore/...
Date: January 2011
Kernel Version: 2.6.38
Contact: tony.luck@intel.com
Description: Generic interface to platform dependent persistent storage.
Platforms that provide a mechanism to preserve some data
across system reboots can register with this driver to
provide a generic interface to show records captured in
the dying moments. In the case of a panic the last part
of the console log is captured, but other interesting
data can also be saved.
# mount -t pstore - /dev/pstore
$ ls -l /dev/pstore
total 0
-r--r--r-- 1 root root 7896 Nov 30 15:38 dmesg-erst-1
Different users of this interface will result in different
filename prefixes. Currently two are defined:
"dmesg" - saved console log
"mce" - architecture dependent data from fatal h/w error
Once the information in a file has been read, removing
the file will signal to the underlying persistent storage
device that it can reclaim the space for later re-use.
$ rm /dev/pstore/dmesg-erst-1
The expectation is that all files in /dev/pstore
will be saved elsewhere and erased from persistent store
soon after boot to free up space ready for the next
catastrophe.