device coredump: add new device coredump class
Many devices run firmware and/or complex hardware, and most of that
can have bugs. When it misbehaves, however, it is often much harder
to debug than software running on the host.
Introduce a "device coredump" mechanism to allow dumping internal
device/firmware state through a generalized mechanism. As devices
are different and information needed can vary accordingly, this
doesn't prescribe a file format - it just provides mechanism to
get data to be able to capture it in a generalized way (e.g. in
distributions.)
The dumped data will be readable in sysfs in the virtual device's
data file under /sys/class/devcoredump/devcd*/. Writing to it will
free the data and remove the device, as does a 5-minute timeout.
Note that generalized capturing of such data may result in privacy
issues, so users generally need to be involved. In order to allow
certain users/system integrators/... to disable the feature at all,
introduce a Kconfig option to override the drivers that would like
to have the feature.
For now, this provides two ways of dumping data:
1) with a vmalloc'ed area, that is then given to the subsystem
and freed after retrieval or timeout
2) with a generalized reader/free function method
We could/should add more options, e.g. a list of pages, since the
vmalloc area is very limited on some architectures.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 809ecd6..d810a6f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2859,6 +2859,13 @@
S: Maintained
F: drivers/usb/dwc3/
+DEVICE COREDUMP (DEV_COREDUMP)
+M: Johannes Berg <johannes@sipsolutions.net>
+L: linux-kernel@vger.kernel.org
+S: Maintained
+F: drivers/base/devcoredump.c
+F: include/linux/devcoredump.h
+
DEVICE FREQUENCY (DEVFREQ)
M: MyungJoo Ham <myungjoo.ham@samsung.com>
M: Kyungmin Park <kyungmin.park@samsung.com>