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>

2 files changed, 42 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/pstore b/Documentation/ABI/testing/pstore
new file mode 100644
index 000000000000..f1fb2a004264
--- /dev/null
+++ b/Documentation/ABI/testing/pstore
@@ -0,0 +1,35 @@
+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.
diff --git a/Documentation/ABI/testing/sysfs-fs-pstore b/Documentation/ABI/testing/sysfs-fs-pstore
new file mode 100644
index 000000000000..8e659d854805
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-fs-pstore
@@ -0,0 +1,7 @@
+What:           /sys/fs/pstore/kmsg_bytes
+Date:           January 2011
+Kernel Version: 2.6.38
+Contact:        "Tony Luck" <tony.luck@intel.com>
+Description:
+                Controls amount of console log that will be saved
+                to persistent store on oops/panic.