To determine whether an engine has 'stuck', we simply check whether or
not is still on the same seqno for several seconds. To keep this simple
mechanism intact over the loss of a global seqno, we can simply add a
new global heartbeat seqno instead. As we cannot know the sequence in
which requests will then be completed, we use a primitive random number
generator instead (with a cycle long enough to not matter over an
interval of a few thousand requests between hangcheck samples).

The alternative to using a dedicated seqno on every request is to issue
a heartbeat request and query its progress through the system. Sadly
this requires us to reduce struct_mutex so that we can issue requests
without requiring that bkl.

v2: And without the extra CS_STALL for the hangcheck seqno -- we don't
need strict serialisation with what comes later, we just need to be sure
we don't write the hangcheck seqno before our batch is flushed.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190226094922.31617-1-chris@chris-wilson.co.uk

At a few points in our uABI, we check to see if the driver is wedged and
report -EIO back to the user in that case. However, as we perform the
check and reset asynchronously (where once before they were both
serialised by the struct_mutex), we may instead see the temporary wedging
used to cancel inflight rendering to avoid a deadlock during reset
(caused by either us timing out in our reset handler,
i915_wedge_on_timeout or with malice aforethought in intel_reset_prepare
for a stuck modeset). If we suspect this is the case, that is we see a
wedged driver *and* reset in progress, then wait until the reset is
resolved before reporting upon the wedged status.

v2: might_sleep() (Mika)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109580Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190220145637.23503-1-chris@chris-wilson.co.uk

While this is mainly only useful for ELSP[0], it is definitely useful to
know the current timeline seqno wrt to the queued set of requests for
that port, as this carries additional information above and beyond the
near-defunct global_seqno and global HWSP.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190211131004.11634-1-chris@chris-wilson.co.uk

Looking forward, we need to break the struct_mutex dependency on
i915_gem_active. In the meantime, external use of i915_gem_active is
quite beguiling, little do new users suspect that it implies a barrier
as each request it tracks must be ordered wrt the previous one. As one
of many, it can be used to track activity across multiple timelines, a
shared fence, which fits our unordered request submission much better. We
need to steer external users away from the singular, exclusive fence
imposed by i915_gem_active to i915_active instead. As part of that
process, we move i915_gem_active out of i915_request.c into
i915_active.c to start separating the two concepts, and rename it to
i915_active_request (both to tie it to the concept of tracking just one
request, and to give it a longer, less appealing name).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190205130005.2807-5-chris@chris-wilson.co.uk

A few years ago, see commit 688e6c72 ("drm/i915: Slaughter the
thundering i915_wait_request herd"), the issue of handling multiple
clients waiting in parallel was brought to our attention. The
requirement was that every client should be woken immediately upon its
request being signaled, without incurring any cpu overhead.

To handle certain fragility of our hw meant that we could not do a
simple check inside the irq handler (some generations required almost
unbounded delays before we could be sure of seqno coherency) and so
request completion checking required delegation.

Before commit 688e6c72, the solution was simple. Every client
waiting on a request would be woken on every interrupt and each would do
a heavyweight check to see if their request was complete. Commit
688e6c72 introduced an rbtree so that only the earliest waiter on
the global timeline would woken, and would wake the next and so on.
(Along with various complications to handle requests being reordered
along the global timeline, and also a requirement for kthread to provide
a delegate for fence signaling that had no process context.)

The global rbtree depends on knowing the execution timeline (and global
seqno). Without knowing that order, we must instead check all contexts
queued to the HW to see which may have advanced. We trim that list by
only checking queued contexts that are being waited on, but still we
keep a list of all active contexts and their active signalers that we
inspect from inside the irq handler. By moving the waiters onto the fence
signal list, we can combine the client wakeup with the dma_fence
signaling (a dramatic reduction in complexity, but does require the HW
being coherent, the seqno must be visible from the cpu before the
interrupt is raised - we keep a timer backup just in case).

Having previously fixed all the issues with irq-seqno serialisation (by
inserting delays onto the GPU after each request instead of random delays
on the CPU after each interrupt), we can rely on the seqno state to
perfom direct wakeups from the interrupt handler. This allows us to
preserve our single context switch behaviour of the current routine,
with the only downside that we lose the RT priority sorting of wakeups.
In general, direct wakeup latency of multiple clients is about the same
(about 10% better in most cases) with a reduction in total CPU time spent
in the waiter (about 20-50% depending on gen). Average herd behaviour is
improved, but at the cost of not delegating wakeups on task_prio.

v2: Capture fence signaling state for error state and add comments to
warm even the most cold of hearts.
v3: Check if the request is still active before busywaiting
v4: Reduce the amount of pointer misdirection with list_for_each_safe
and using a local i915_request variable inside the loops
v5: Add a missing pluralisation to a purely informative selftest message.

References: 688e6c72 ("drm/i915: Slaughter the thundering i915_wait_request herd")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190129205230.19056-2-chris@chris-wilson.co.uk

After noticing that we trigger preemption events for currently executing
requests, as well as requests that complete before the preemption and
attempting to suppress those preemption events, it is wise to not
consider the queue_priority to be authoritative. As we only track the
maximum priority seen between dequeue passes, if the maximum priority
request is no longer available for dequeuing (it completed or is even
executing on another engine), we have no knowledge of the previous
queue_priority as it would require us to keep a full history of enqueued
requests -- but we already have that history in the priolists!

Rename the queue_priority to queue_priority_hint so that we do not
confuse it as being exactly the maximum priority in the queue, but merely
an indication that we have seen a new maximum priority value and as such
we should check whether it should preempt the currently running request.

v2: s/preempt_priority_hint/queue_priority_hint/ as preempt implies it
being only used for the singular task of preemption and not the wider
question of waking up due to a change in the queue.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190129185452.20989-3-chris@chris-wilson.co.uk

To allow requests to forgo a common execution timeline, one question we
need to be able to answer is "is this request running?". To track
whether a request has started on HW, we can emit a breadcrumb at the
beginning of the request and check its timeline's HWSP to see if the
breadcrumb has advanced past the start of this request. (This is in
contrast to the global timeline where we need only ask if we are on the
global timeline and if the timeline has advanced past the end of the
previous request.)

There is still confusion from a preempted request, which has already
started but relinquished the HW to a high priority request. For the
common case, this discrepancy should be negligible. However, for
identification of hung requests, knowing which one was running at the
time of the hang will be much more important.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190129185452.20989-2-chris@chris-wilson.co.uk

Now that we have allocated ourselves a cacheline to store a breadcrumb,
we can emit a write from the GPU into the timeline's HWSP of the
per-context seqno as we complete each request. This drops the mirroring
of the per-engine HWSP and allows each context to operate independently.
We do not need to unwind the per-context timeline, and so requests are
always consistent with the timeline breadcrumb, greatly simplifying the
completion checks as we no longer need to be concerned about the
global_seqno changing mid check.

One complication though is that we have to be wary that the request may
outlive the HWSP and so avoid touching the potentially danging pointer
after we have retired the fence. We also have to guard our access of the
HWSP with RCU, the release of the obj->mm.pages should already be RCU-safe.

At this point, we are emitting both per-context and global seqno and
still using the single per-engine execution timeline for resolving
interrupts.

v2: s/fake_complete/mark_complete/
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190128181812.22804-5-chris@chris-wilson.co.uk

Allocate a page for use as a status page by a group of timelines, as we
only need a dword of storage for each (rounded up to the cacheline for
safety) we can pack multiple timelines into the same page. Each timeline
will then be able to track its own HW seqno.

v2: Reuse the common per-engine HWSP for the solitary ringbuffer
timeline, so that we do not have to emit (using per-gen specialised
vfuncs) the breadcrumb into the distinct timeline HWSP and instead can
keep on using the common MI_STORE_DWORD_INDEX. However, to maintain the
sleight-of-hand for the global/per-context seqno switchover, we will
store both temporarily (and so use a custom offset for the shared timeline
HWSP until the switch over).

v3: Keep things simple and allocate a page for each timeline, page
sharing comes next.

v4: I was caught repeating the same MI_STORE_DWORD_IMM over and over
again in selftests.

v5: And caught red handed copying create timeline + check.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190128181812.22804-3-chris@chris-wilson.co.uk

Currently we only allocate an object and vma if we are using a GGTT
virtual HWSP, and a plain struct page for a physical HWSP. For
convenience later on with global timelines, it will be useful to always
have the status page being tracked by a struct i915_vma. Make it so.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190128102356.15037-4-chris@chris-wilson.co.uk

Now that the submission backends are controlled via their own spinlocks,
with a wave of a magic wand we can lift the struct_mutex requirement
around GPU reset. That is we allow the submission frontend (userspace)
to keep on submitting while we process the GPU reset as we can suspend
the backend independently.

The major change is around the backoff/handoff strategy for performing
the reset. With no mutex deadlock, we no longer have to coordinate with
any waiter, and just perform the reset immediately.

Testcase: igt/gem_mmap_gtt/hang # regresses
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190125132230.22221-3-chris@chris-wilson.co.uk

Now that we know we measure the size of the engine->emit_breadcrumb()
correctly, we can remove the previous manual counting.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190125120005.25191-1-chris@chris-wilson.co.uk

Instead of tediously and fragilely counting up the number of dwords
required to emit the breadcrumb to seal a request, fake a request and
measure it automatically once during engine setup.

The downside is that this requires a fair amount of mocking to create a
proper breadcrumb. Still, should be less error prone in future as the
breadcrumb size fluctuates!
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190125100520.20163-1-chris@chris-wilson.co.uk

Since commit  d4ccceb0 ("drm/i915/icl: Ringbuffer interrupt handling")
we have required a mechanism to avoid touching the interrupt hardware
for breadcrumbs, superseding our mock interface for selftests.

The residual problem (ideas welcome) is in probing the mock ring
registers for ring_is_idle. Hmm, maybe we should just install
mock handlers for i915->uncore.mmio__write and friends? Only problem
being is that we would to truly mock some expected reads. :(

References: d4ccceb0 ("drm/i915/icl: Ringbuffer interrupt handling")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190118112225.13780-1-chris@chris-wilson.co.uk

Mixed C99 and kernel types use is getting ugly. Prefer kernel types.

sed -i 's/\buint\(8\|16\|32\|64\)_t\b/u\1/g'

Minor checkpatch fixes sprinkled on top of the changed lines.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/14ed72e7f04c9340a057855c5950b54811f8a477.1547629303.git.jani.nikula@intel.com

Currently the code to reset the GPU and our state is spread widely
across a few files. Pull the logic together into a common file.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190116153304.787-1-chris@chris-wilson.co.uk

Move the debug pretty printer into a standalone routine prior to
extending it in upcoming feature work.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190115212948.10423-1-chris@chris-wilson.co.uk

Keep track of the temporary rpm wakerefs used for user access to the
device, so that we can cancel them upon release and clearly identify any
leaks.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190114142129.24398-10-chris@chris-wilson.co.uk

The majority of runtime-pm operations are bounded and scoped within a
function; these are easy to verify that the wakeref are handled
correctly. We can employ the compiler to help us, and reduce the number
of wakerefs tracked when debugging, by passing around cookies provided
by the various rpm_get functions to their rpm_put counterpart. This
makes the pairing explicit, and given the required wakeref cookie the
compiler can verify that we pass an initialised value to the rpm_put
(quite handy for double checking error paths).

For regular builds, the compiler should be able to eliminate the unused
local variables and the program growth should be minimal. Fwiw, it came
out as a net improvement as gcc was able to refactor rpm_get and
rpm_get_if_in_use together,

v2: Just s/rpm_put/rpm_put_unchecked/ everywhere, leaving the manual
mark up for smaller more targeted patches.
v3: Mention the cookie in Returns
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190114142129.24398-2-chris@chris-wilson.co.uk

When we first introduced the reset to sanitize the GPU on taking over
from the BIOS and before returning control to third parties (the BIOS!),
we restricted it to only systems utilizing HW contexts as we were
uncertain of how stable our reset mechanism truly was. We now have
reasonable coverage across all machines that expose a GPU reset method,
and so we should be safe to sanitize the GPU state everywhere.

v2: We _have_ to skip the reset if it would clobber the display.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190103112104.19561-1-chris@chris-wilson.co.uk

First move the low hanging fruit, the fields that are only initialized
runtime. Use RUNTIME_INFO() exclusively to access the fields.

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c24fe7a4b0492a888690c46814c0ff21ce2f12b1.1546267488.git.jani.nikula@intel.com

Now that we have eliminated the CPU-side irq_seqno_barrier by moving the
delays on the GPU before emitting the MI_USER_INTERRUPT, we can remove
the engine->irq_seqno_barrier infrastructure. Though intentionally
slowing down the GPU is nasty, so is the code we can now remove!
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181228171641.16531-6-chris@chris-wilson.co.uk

The writing is on the wall for the existence of a single execution queue
along each engine, and as a consequence we will not be able to track
dependencies along the HW queue itself, i.e. we will not be able to use
HW semaphores on gen7 as they use a global set of registers (and unlike
gen8+ we can not effectively target memory to keep per-context seqno and
dependencies).

On the positive side, when we implement request reordering for gen7 we
also can not presume a simple execution queue and would also require
removing the current semaphore generation code. So this bring us another
step closer to request reordering for ringbuffer submission!

The negative side is that using interrupts to drive inter-engine
synchronisation is much slower (4us -> 15us to do a nop on each of the 3
engines on ivb). This is much better than it was at the time of introducing
the HW semaphores and equally important userspace weaned itself off
intermixing dependent BLT/RENDER operations (the prime culprit was glyph
rendering in UXA). So while we regress the microbenchmarks, it should not
impact the user.

References: https://bugs.freedesktop.org/show_bug.cgi?id=108888Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181228140736.32606-2-chris@chris-wilson.co.uk

Having completed a test run of gem_eio across all machines in CI we also
observe the phenomenon (of lost interrupts after resetting the GPU) on
gen3 machines as well as the previously sighted gen6/gen7. Let's apply
the same HWSTAM workaround that was effective for gen6+ for all, as
although we haven't seen the same failure on gen4/5 it seems prudent to
keep the code the same.

As a consequence we can remove the extra setting of HWSTAM and apply the
register from a single site.

v2: Delazy and move the HWSTAM into its own function
v3: Mask off all HWSP writes on driver unload and engine cleanup.
v4: And what about the physical hwsp?
v5: No, engine->init_hw() is not called from driver_init_hw(), don't be
daft. Really scrub HWSTAM as early as we can in driver_init_mmio()
v6: Rename set_hwsp as it was setting the mask not the hwsp register.
v7: Ville pointed out that although vcs(bsd) was introduced for g4x/ilk,
per-engine HWSTAM was not introduced until gen6!

References: https://bugs.freedesktop.org/show_bug.cgi?id=108735Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181218102712.11058-1-chris@chris-wilson.co.uk

Instead of using IS_GEN() for consecutive gen checks, let's pass the
range to IS_GEN_RANGE(). By code inspection these were the ranges deemed
necessary for spatch:

@@
expression e;
@@
(
- IS_GEN(e, 3) || IS_GEN(e, 2)
+ IS_GEN_RANGE(e, 2, 3)
|
- IS_GEN(e, 3) || IS_GEN(e, 4)
+ IS_GEN_RANGE(e, 3, 4)
|
- IS_GEN(e, 5) || IS_GEN(e, 6)
+ IS_GEN_RANGE(e, 5, 6)
|
- IS_GEN(e, 6) || IS_GEN(e, 7)
+ IS_GEN_RANGE(e, 6, 7)
|
- IS_GEN(e, 7) || IS_GEN(e, 8)
+ IS_GEN_RANGE(e, 7, 8)
|
- IS_GEN(e, 8) || IS_GEN(e, 9)
+ IS_GEN_RANGE(e, 8, 9)
|
- IS_GEN(e, 10) || IS_GEN(e, 9)
+ IS_GEN_RANGE(e, 9, 10)
|
- IS_GEN(e, 9) || IS_GEN(e, 10)
+ IS_GEN_RANGE(e, 9, 10)
)

After conversion, checking we don't have any missing IS_GEN_RANGE() ||
IS_GEN() was also done.
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181212181044.15886-3-lucas.demarchi@intel.com

Define IS_GEN() similarly to our IS_GEN_RANGE(). but use gen instead of
gen_mask to do the comparison. Now callers can pass then gen as a parameter,
so we don't require one macro for each gen.

The following spatch was used to convert the users of these macros:

@@
expression e;
@@
(
- IS_GEN2(e)
+ IS_GEN(e, 2)
|
- IS_GEN3(e)
+ IS_GEN(e, 3)
|
- IS_GEN4(e)
+ IS_GEN(e, 4)
|
- IS_GEN5(e)
+ IS_GEN(e, 5)
|
- IS_GEN6(e)
+ IS_GEN(e, 6)
|
- IS_GEN7(e)
+ IS_GEN(e, 7)
|
- IS_GEN8(e)
+ IS_GEN(e, 8)
|
- IS_GEN9(e)
+ IS_GEN(e, 9)
|
- IS_GEN10(e)
+ IS_GEN(e, 10)
|
- IS_GEN11(e)
+ IS_GEN(e, 11)
)

v2: use IS_GEN rather than GT_GEN and compare to info.gen rather than
    using the bitmask
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181212181044.15886-2-lucas.demarchi@intel.com

RANGE makes it longer, but clearer. We are also going to add a macro to
check an individual gen, so add the _RANGE prefix here.

Diff generated with:

sed 's/IS_GEN(/IS_GEN_RANGE(/g' drivers/gpu/drm/i915/{*/,}*.{c,h} -i

v2: use IS_GEN rather than GT_GEN
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181212181044.15886-1-lucas.demarchi@intel.com

Currently we allocate a scratch page for each engine, but since we only
ever write into it for post-sync operations, it is not exposed to
userspace nor do we care for coherency. As we then do not care about its
contents, we can use one page for all, reducing our allocations and
avoid complications by not assuming per-engine isolation.

For later use, it simplifies engine initialisation (by removing the
allocation that required struct_mutex!) and means that we can always rely
on there being a scratch page.

v2: Check that we allocated a large enough scratch for I830 w/a

Fixes: 06e562e7f515 ("drm/i915/ringbuffer: Delay after EMIT_INVALIDATE for gen4/gen5") # v4.18.20
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108850Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181204141522.13640-1-chris@chris-wilson.co.uk
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.18.20+
(cherry picked from commit 51797499)
[Joonas: Use new function in gen9_init_indirectctx_bb too]
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

For a lot of use cases we need 64bit sequence numbers. Currently drivers
overload the dma_fence structure to store the additional bits.

Stop doing that and make the sequence number in the dma_fence always
64bit.

For compatibility with hardware which can do only 32bit sequences the
comparisons in __dma_fence_is_later only takes the lower 32bits as significant
when the upper 32bits are all zero.

v2: change the logic in __dma_fence_is_later
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NChunming Zhou <david1.zhou@amd.com>
Link: https://patchwork.freedesktop.org/patch/266927/

We stopped re-applying the GT workarounds after engine reset since commit
59b449d5 ("drm/i915: Split out functions for different kinds of
workarounds").

Issue with this is that some of the GT workarounds live in the MMIO space
which gets lost during engine resets. So far the registers in 0x2xxx and
0xbxxx address range have been identified to be affected.

This losing of applied workarounds has obvious negative effects and can
even lead to hard system hangs (see the linked Bugzilla).

Rather than just restoring this re-application, because we have also
observed that it is not safe to just re-write all GT workarounds after
engine resets (GPU might be live and weird hardware states can happen),
we introduce a new class of per-engine workarounds and move only the
affected GT workarounds over.

Using the framework introduced in the previous patch, we therefore after
engine reset, re-apply only the workarounds living in the affected MMIO
address ranges.

v2:
 * Move Wa_1406609255:icl to engine workarounds as well.
 * Rename API. (Chris Wilson)
 * Drop redundant IS_KABYLAKE. (Chris Wilson)
 * Re-order engine wa/ init so latest platforms are first. (Rodrigo Vivi)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Bugzilla: https://bugzilla.freedesktop.org/show_bug.cgi?id=107945
Fixes: 59b449d5 ("drm/i915: Split out functions for different kinds of workarounds")
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Acked-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20181203133341.10258-1-tvrtko.ursulin@linux.intel.com
(cherry picked from commit 4a15c75c)
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Currently we allocate a scratch page for each engine, but since we only
ever write into it for post-sync operations, it is not exposed to
userspace nor do we care for coherency. As we then do not care about its
contents, we can use one page for all, reducing our allocations and
avoid complications by not assuming per-engine isolation.

For later use, it simplifies engine initialisation (by removing the
allocation that required struct_mutex!) and means that we can always rely
on there being a scratch page.

v2: Check that we allocated a large enough scratch for I830 w/a

Fixes: 06e562e7f515 ("drm/i915/ringbuffer: Delay after EMIT_INVALIDATE for gen4/gen5") # v4.18.20
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108850Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181204141522.13640-1-chris@chris-wilson.co.uk
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.18.20+

Convert the per context workaround handling code to run against the newly
introduced common workaround framework and fuse the two to use the
existing smarter list add helper, the one which does the sorted insert and
merges registers where possible.

This completes migration of all four classes of workarounds onto the
common framework.

Existing macros are kept untouched for smaller code churn.

v2:
 * Rename to list name ctx_wa_list and move from dev_priv to engine.

v3:
 * API rename and parameters tweaking. (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20181203133357.10341-1-tvrtko.ursulin@linux.intel.com

Instead of having a separate list of white-listed registers we can
trivially move this to the common workarounds framework.

This brings us one step closer to the goal of driving all workaround
classes using the same code.

v2:
 * Use GEM_DEBUG_WARN_ON for the sanity check. (Chris Wilson)

v3:
 * API rename. (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20181203125014.3219-6-tvrtko.ursulin@linux.intel.com

We stopped re-applying the GT workarounds after engine reset since commit
59b449d5 ("drm/i915: Split out functions for different kinds of
workarounds").

Issue with this is that some of the GT workarounds live in the MMIO space
which gets lost during engine resets. So far the registers in 0x2xxx and
0xbxxx address range have been identified to be affected.

This losing of applied workarounds has obvious negative effects and can
even lead to hard system hangs (see the linked Bugzilla).

Rather than just restoring this re-application, because we have also
observed that it is not safe to just re-write all GT workarounds after
engine resets (GPU might be live and weird hardware states can happen),
we introduce a new class of per-engine workarounds and move only the
affected GT workarounds over.

Using the framework introduced in the previous patch, we therefore after
engine reset, re-apply only the workarounds living in the affected MMIO
address ranges.

v2:
 * Move Wa_1406609255:icl to engine workarounds as well.
 * Rename API. (Chris Wilson)
 * Drop redundant IS_KABYLAKE. (Chris Wilson)
 * Re-order engine wa/ init so latest platforms are first. (Rodrigo Vivi)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Bugzilla: https://bugzilla.freedesktop.org/show_bug.cgi?id=107945
Fixes: 59b449d5 ("drm/i915: Split out functions for different kinds of workarounds")
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Acked-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20181203133341.10258-1-tvrtko.ursulin@linux.intel.com

When showing the list of waiters, include the task's status so that we
can tell if they have been woken up and are waiting for the CPU, or if
they are still waiting to be woken.

v2: task_state_to_char()
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181121151653.24595-1-chris@chris-wilson.co.uk

lockdep insists that if we give a lock a subclass, it must be used.
Failure to do so triggers a self-consistency check when reading
lockdep_stats:

[   49.902002] DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused)
[   49.902009] WARNING: CPU: 3 PID: 383 at kernel/locking/lockdep_proc.c:249 lockdep_stats_show+0x984/0xa10
[   49.902026] Modules linked in: nls_ascii nls_cp437 vfat fat crct10dif_pclmul crc32_pclmul crc32c_intel aesni_intel aes_x86_64 crypto_simd cryptd glue_helper intel_cstate intel_uncore intel_rapl_perf intel_gtt efivars prime_numbers ahci libahci i2c_i801 video button efivarfs [last unloaded: drm_kms_helper]
[   49.902059] CPU: 3 PID: 383 Comm: cat Tainted: G     U            4.20.0-rc2+ #304
[   49.902068] Hardware name: Intel Corporation NUC7i5BNK/NUC7i5BNB, BIOS BNKBL357.86A.0052.2017.0918.1346 09/18/2017
[   49.902079] RIP: 0010:lockdep_stats_show+0x984/0xa10
[   49.902086] Code: 00 85 c0 0f 84 aa f8 ff ff 8b 05 77 37 e2 00 85 c0 0f 85 9c f8 ff ff 48 c7 c6 e0 57 bc 81 48 c7 c7 28 30 bb 81 e8 6b 77 fa ff <0f> 0b e9 82 f8 ff ff 48 c7 44 24 50 00 00 00 00 45 31 e4 31 db 31
[   49.902103] RSP: 0018:ffffc90000247d58 EFLAGS: 00010292
[   49.902110] RAX: 0000000000000044 RBX: 00000000000002f0 RCX: 0000000000000000
[   49.902118] RDX: 0000000000000002 RSI: 0000000000000001 RDI: ffffffff810b3464
[   49.902126] RBP: 0000000000000039 R08: 0000000000000002 R09: 0000000000000000
[   49.902133] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000007ead
[   49.902141] R13: 0000000000000001 R14: ffff88884c021000 R15: 0000000000000097
[   49.902150] FS:  00007fb347e66540(0000) GS:ffff88885e600000(0000) knlGS:0000000000000000
[   49.902159] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   49.902165] CR2: 00007fb347aeb000 CR3: 00000008544bd005 CR4: 00000000001606e0
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181115203851.25739-1-chris@chris-wilson.co.uk

Whenever possible we should stick with IS_GEN<n> checks.

Bitmaks has been introduced on commit ae7617f0 ("drm/i915:
Allow optimized platform checks") for efficiency.

Let's stick with it whenever possible.

This patch was generated with coccinelle:

spatch -sp_file is_gen.cocci *{c,h} --in-place

is_gen.cocci:
@gen2@ expression e; @@
-INTEL_GEN(e) == 2
+IS_GEN2(e)
@gen3@ expression e; @@
-INTEL_GEN(e) == 3
+IS_GEN3(e)
@gen4@ expression e; @@
-INTEL_GEN(e) == 4
+IS_GEN4(e)
@gen5@ expression e; @@
-INTEL_GEN(e) == 5
+IS_GEN5(e)
@gen6@ expression e; @@
-INTEL_GEN(e) == 6
+IS_GEN6(e)
@gen7@ expression e; @@
-INTEL_GEN(e) == 7
+IS_GEN7(e)
@gen8@ expression e; @@
-INTEL_GEN(e) == 8
+IS_GEN8(e)
@gen9@ expression e; @@
-INTEL_GEN(e) == 9
+IS_GEN9(e)
@gen10@ expression e; @@
-INTEL_GEN(e) == 10
+IS_GEN10(e)
@gen11@ expression e; @@
-INTEL_GEN(e) == 11
+IS_GEN11(e)

Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181026195143.20353-1-rodrigo.vivi@intel.com

GEM_WARN_ON currently has dangerous semantics where it is completely
compiled out on !GEM_DEBUG builds. This can leave users who expect it to
be more like a WARN_ON, just without a warning in non-debug builds, in
complete ignorance.

Another gotcha with it is that it cannot be used as a statement. Which is
again different from a standard kernel WARN_ON.

This patch fixes both problems by making it behave as one would expect.

It can now be used both as an expression and as statement, and also the
condition evaluates properly in all builds - code under the conditional
will therefore not unexpectedly disappear.

To satisfy call sites which really want the code under the conditional to
completely disappear, we add GEM_DEBUG_WARN_ON and convert some of the
callers to it. This one can also be used as both expression and statement.

>From the above it follows GEM_DEBUG_WARN_ON should be used in situations
where we are certain the condition will be hit during development, but at
a place in code where error can be handled to the benefit of not crashing
the machine.

GEM_WARN_ON on the other hand should be used where condition may happen in
production and we just want to distinguish the level of debugging output
emitted between the production and debug build.

v2:
 * Dropped BUG_ON hunk.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Tomasz Lis <tomasz.lis@intel.com>
Reviewed-by: NTomasz Lis <tomasz.lis@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181012063142.16080-1-tvrtko.ursulin@linux.intel.com

Clang build with UBSAN enabled leads to the following build error:

drivers/gpu/drm/i915/intel_engine_cs.o: In function `intel_engine_init_execlist':
drivers/gpu/drm/i915/intel_engine_cs.c:411: undefined reference to `__compiletime_assert_411'

Again, for this to work the code would first need to be inlined and then
constant folded, which doesn't work for Clang because semantic analysis
happens before optimization/inlining.

Use GEM_BUG_ON() instead of BUILD_BUG_ON().

v2: Use is_power_of_2() from log2.h (Chris)

References: http://mid.mail-archive.com/20181015203410.155997-1-swboyd@chromium.orgReported-by: NStephen Boyd <swboyd@chromium.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: NNathan Chancellor <natechancellor@gmail.com>
Tested-by: NStephen Boyd <swboyd@chromium.org>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181016122938.18757-2-jani.nikula@intel.com

We need extra load failure point to better test error path in
i915_driver_init_mmio.
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMichal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20181011130008.24640-2-michal.wajdeczko@intel.com