--- zzzz-none-000/linux-3.10.107/tools/perf/Documentation/perf-buildid-cache.txt	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/tools/perf/Documentation/perf-buildid-cache.txt	2021-02-04 17:41:59.000000000 +0000
@@ -12,25 +12,48 @@
 
 DESCRIPTION
 -----------
-This command manages the build-id cache. It can add and remove files to/from
-the cache. In the future it should as well purge older entries, set upper
-limits for the space used by the cache, etc.
+This command manages the build-id cache. It can add, remove, update and purge
+files to/from the cache. In the future it should as well set upper limits for
+the space used by the cache, etc.
 
 OPTIONS
 -------
 -a::
 --add=::
         Add specified file to the cache.
+-k::
+--kcore::
+        Add specified kcore file to the cache. For the current host that is
+        /proc/kcore which requires root permissions to read. Be aware that
+        running 'perf buildid-cache' as root may update root's build-id cache
+        not the user's. Use the -v option to see where the file is created.
+        Note that the copied file contains only code sections not the whole core
+        image. Note also that files "kallsyms" and "modules" must also be in the
+        same directory and are also copied.  All 3 files are created with read
+        permissions for root only. kcore will not be added if there is already a
+        kcore in the cache (with the same build-id) that has the same modules at
+        the same addresses. Use the -v option to see if a copy of kcore is
+        actually made.
 -r::
 --remove=::
-        Remove specified file from the cache.
+        Remove a cached binary which has same build-id of specified file
+        from the cache.
+-p::
+--purge=::
+        Purge all cached binaries including older caches which have specified
+	path from the cache.
 -M::
---missing=:: 
+--missing=::
 	List missing build ids in the cache for the specified file.
 -u::
---update::
-	Update specified file of the cache. It can be used to update kallsyms
-	kernel dso to vmlinux in order to support annotation.
+--update=::
+	Update specified file of the cache. Note that this doesn't remove
+	older entires since those may be still needed for annotating old
+	(or remote) perf.data. Only if there is already a cache which has
+	exactly same build-id, that is replaced by new one. It can be used
+	to update kallsyms and kernel dso to vmlinux in order to support
+	annotation.
+
 -v::
 --verbose::
 	Be more verbose.