Engine was inappropriately used to refer to execution queues and it
also created some confusion with hardware engines. Where it applies
the exec_queue variable name is changed to q and comments are also
updated.

Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/162
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

This is a preparation commit for a larger renaming of engine to exec queue.

Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Let's continue to add our existent simple logs to devcoredump one
by one. Any format change should come on follow-up work.

v2: remove unnecessary, and now duplicated, dma_fence annotation. (Matthew)
v3: avoid for_each with faulty_engine since that can be already freed at
    the time of the read/free. Instead, iterate in the full array of
    hw_engines. (Kasan)

Cc: Francois Dugast <francois.dugast@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Francois Dugast <francois.dugast@intel.com>

Let's start to move our existent logs to devcoredump one by
one. Any format change should come on follow-up work.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>

Let's start to move our existent logs to devcoredump one by
one. Any format change should come on follow-up work.

v2: Rebase and add the dma_fence locking annotation here.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>

Unfortunately devcoredump infrastructure does not provide and
interface for us to force the device removal upon the pci_remove
time of our device.

The devcoredump is linked at the device level, so when in use
it will prevent the module removal, but it doesn't prevent the
call of the pci_remove callback. This callback cannot fail
anyway and we end up clearing and freeing the entire pci device.

Hence, after we removed the pci device, we shouldn't allow any
read or free operations to avoid segmentation fault.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>

The goal is to use devcoredump infrastructure to report error states
captured at the crash time.

The error state will contain useful information for GPU hang debug, such
as INSTDONE registers and the current buffers getting executed, as well
as any other information that helps user space and allow later replays of
the error.

The proposal here is to avoid a Xe only error_state like i915 and use
a standard dev_coredump infrastructure to expose the error state.

For our own case, the data is only useful if it is a snapshot of the
time when the GPU crash has happened, since we reset the GPU immediately
after and the registers might have changed. So the proposal here is to
have an internal snapshot to be printed out later.

Also, usually a subsequent GPU hang can be only a cause of the initial
one. So we only save the 'first' hang. The dev_coredump has a delayed
work queue where it remove the coredump and free all the data within a
few moments of the error. When that happens we also reset our capture
state and allow further snapshots.

Right now this infra only print out the time of the hang. More information
will be migrated here on subsequent work. Also, in order to organize the
dump better, the goal is to propose dev_coredump changes itself to allow
multiple files and different controls. But for now we start Xe usage of
it without any dependency on dev_coredump core changes.

v2: Add dma_fence annotation for capture that might happen during long
    running. (Thomas and Matt)
    Use xe->drm.primary->index on drm_info msg. (Jani)
v3: checkpatch fixes
v4: Fix building and locking issues found by Francois.
    Actually let's kill all of the locking in here. gt_reset serialization
    already guarantee that there will be only one capture at the same time.
    Also, the devcoredump has its own locking to protect the free and reads
    and drivers don't need to duplicate it.
    Besides this, the dma_fence locking was pushed to a following patch
    since it is not needed in this one.
    Fix a use after free identified by KASAN: Do not stash the faulty_engine
    since that will be freed somewhere else.
v5: Fix Uptime - ktime_get_boottime actually returns the Uptime. (Francois)

Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>