Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) What:		/sys/fs/pstore/... (or /dev/pstore/...)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) Date:		March 2011
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) KernelVersion: 2.6.39
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) Contact:	tony.luck@intel.com
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) Description:	Generic interface to platform dependent persistent storage.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) 		Platforms that provide a mechanism to preserve some data
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) 		across system reboots can register with this driver to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) 		provide a generic interface to show records captured in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) 		the dying moments.  In the case of a panic the last part
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) 		of the console log is captured, but other interesting
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) 		data can also be saved::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 		    # mount -t pstore -o kmsg_bytes=8000 - /sys/fs/pstore
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) 		    $ ls -l /sys/fs/pstore/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 		    total 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 		    -r--r--r-- 1 root root 7896 Nov 30 15:38 dmesg-erst-1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 		Different users of this interface will result in different
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 		filename prefixes.  Currently two are defined:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 		- "dmesg" - saved console log
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 		- "mce"   - architecture dependent data from fatal h/w error
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 		Once the information in a file has been read, removing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 		the file will signal to the underlying persistent storage
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 		device that it can reclaim the space for later re-use::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 		    $ rm /sys/fs/pstore/dmesg-erst-1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 		The expectation is that all files in /sys/fs/pstore/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 		will be saved elsewhere and erased from persistent store
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 		soon after boot to free up space ready for the next
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 		catastrophe.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 		The 'kmsg_bytes' mount option changes the target amount of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 		data saved on each oops/panic. Pstore saves (possibly
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 		multiple) files based on the record size of the underlying
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 		persistent storage until at least this amount is reached.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 		Default is 10 Kbytes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 		Pstore only supports one backend at a time. If multiple
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 		backends are available, the preferred backend may be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 		set by passing the pstore.backend= argument to the kernel at
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 		boot time.