kdump: add /sys/kernel/vmcoreinfo ABI documentation

/sys/kernel/vmcoreinfo was introduced long back but there is no ABI
documentation.  This patch adds the documentation.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
Cc: Dan Aloni <da-x@monatomic.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/ABI/testing/sysfs-kernel-vmcoreinfo b/Documentation/ABI/testing/sysfs-kernel-vmcoreinfo
new file mode 100644 (file)
index 0000000..7bd8116
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-vmcoreinfo
@@ -0,0 +1,14 @@
+What:          /sys/kernel/vmcoreinfo
+Date:          October 2007
+KernelVersion: 2.6.24
+Contact:       Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
+               Kexec Mailing List <kexec@lists.infradead.org>
+               Vivek Goyal <vgoyal@redhat.com>
+Description
+               Shows physical address and size of vmcoreinfo ELF note.
+               First value contains physical address of note in hex and
+               second value contains the size of note in hex. This ELF
+               note info is parsed by second kernel and exported to user
+               space as part of ELF note in /proc/vmcore file. This note
+               contains various information like struct size, symbol
+               values, page size etc.