xref: /linux/Documentation/ABI/testing/pstore (revision ca01d6dd2d7a2652000307520777538740efc286)
1*ca01d6ddSTony LuckWhere:		/dev/pstore/...
2*ca01d6ddSTony LuckDate:		January 2011
3*ca01d6ddSTony LuckKernel Version: 2.6.38
4*ca01d6ddSTony LuckContact:	tony.luck@intel.com
5*ca01d6ddSTony LuckDescription:	Generic interface to platform dependent persistent storage.
6*ca01d6ddSTony Luck
7*ca01d6ddSTony Luck		Platforms that provide a mechanism to preserve some data
8*ca01d6ddSTony Luck		across system reboots can register with this driver to
9*ca01d6ddSTony Luck		provide a generic interface to show records captured in
10*ca01d6ddSTony Luck		the dying moments.  In the case of a panic the last part
11*ca01d6ddSTony Luck		of the console log is captured, but other interesting
12*ca01d6ddSTony Luck		data can also be saved.
13*ca01d6ddSTony Luck
14*ca01d6ddSTony Luck		# mount -t pstore - /dev/pstore
15*ca01d6ddSTony Luck
16*ca01d6ddSTony Luck		$ ls -l /dev/pstore
17*ca01d6ddSTony Luck		total 0
18*ca01d6ddSTony Luck		-r--r--r-- 1 root root 7896 Nov 30 15:38 dmesg-erst-1
19*ca01d6ddSTony Luck
20*ca01d6ddSTony Luck		Different users of this interface will result in different
21*ca01d6ddSTony Luck		filename prefixes.  Currently two are defined:
22*ca01d6ddSTony Luck
23*ca01d6ddSTony Luck		"dmesg"	- saved console log
24*ca01d6ddSTony Luck		"mce"	- architecture dependent data from fatal h/w error
25*ca01d6ddSTony Luck
26*ca01d6ddSTony Luck		Once the information in a file has been read, removing
27*ca01d6ddSTony Luck		the file will signal to the underlying persistent storage
28*ca01d6ddSTony Luck		device that it can reclaim the space for later re-use.
29*ca01d6ddSTony Luck
30*ca01d6ddSTony Luck		$ rm /dev/pstore/dmesg-erst-1
31*ca01d6ddSTony Luck
32*ca01d6ddSTony Luck		The expectation is that all files in /dev/pstore
33*ca01d6ddSTony Luck		will be saved elsewhere and erased from persistent store
34*ca01d6ddSTony Luck		soon after boot to free up space ready for the next
35*ca01d6ddSTony Luck		catastrophe.
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