linux_dsm_epyc7002/Documentation/gpu/msm-crash-dump.rst
Jordan Crouse 50f8d21863 drm/msm/adreno: Add a5xx specific registers for the GPU state
HLSQ, SP and TP registers are only accessible from a special
aperture and to make matters worse the aperture is blocked from
the CPU on targets that can support secure rendering. Luckily the
GPU hardware has its own purpose built register dumper that can
access the registers from the aperture. Add a5xx specific code
to program the crashdumper and retrieve the wayward registers
and dump them for the crash state.

Also, remove a block of registers the regular CPU accessible
list that aren't useful for debug which helps reduce the size
of the crash state file by a goodly amount.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
2018-07-30 08:50:06 -04:00

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=====================
MSM Crash Dump Format
=====================
Following a GPU hang the MSM driver outputs debugging information via
/sys/kernel/dri/X/show or via devcoredump (/sys/class/devcoredump/dcdX/data).
This document describes how the output is formatted.
Each entry is in the form key: value. Sections headers will not have a value
and all the contents of a section will be indented two spaces from the header.
Each section might have multiple array entries the start of which is designated
by a (-).
Mappings
--------
kernel
The kernel version that generated the dump (UTS_RELEASE).
module
The module that generated the crashdump.
time
The kernel time at crash formated as seconds.microseconds.
comm
Comm string for the binary that generated the fault.
cmdline
Command line for the binary that generated the fault.
revision
ID of the GPU that generated the crash formatted as
core.major.minor.patchlevel separated by dots.
rbbm-status
The current value of RBBM_STATUS which shows what top level GPU
components are in use at the time of crash.
ringbuffer
Section containing the contents of each ringbuffer. Each ringbuffer is
identified with an id number.
id
Ringbuffer ID (0 based index). Each ringbuffer in the section
will have its own unique id.
iova
GPU address of the ringbuffer.
last-fence
The last fence that was issued on the ringbuffer
retired-fence
The last fence retired on the ringbuffer.
rptr
The current read pointer (rptr) for the ringbuffer.
wptr
The current write pointer (wptr) for the ringbuffer.
size
Maximum size of the ringbuffer programmed in the hardware.
data
The contents of the ring encoded as ascii85. Only the used
portions of the ring will be printed.
registers
Set of registers values. Each entry is on its own line enclosed
by brackets { }.
offset
Byte offset of the register from the start of the
GPU memory region.
value
Hexadecimal value of the register.
registers-hlsq
(5xx only) Register values from the HLSQ aperture.
Same format as the register section.