Having provided for_each_engine_id() for cases where the third (id)
argument is useful, we can now replace all the remaining instances with
a simpler version that takes only two parameters. In many cases, this
also allows the elimination of the local variable used in the iterator
(usually 'i').

v2:
    s/dev_priv/(dev_priv__)/ in body of for_each_engine_masked() [Chris Wilson]
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1458757194-17783-2-git-send-email-david.s.gordon@intel.com

Refer to Global GTT consistently as GGTT, thus rename dev_priv->gtt
to dev_priv->ggtt and struct i915_gtt to struct i915_ggtt.

Fix a couple of whitespace problems while at it.

v2:
- Fix a typo in commit message.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Where we have a request we can use req->i915 directly instead
of going through the engine and device. Coccinelle script:

@@
function f;
identifier r;
@@
f(..., struct drm_i915_gem_request *r, ...)
{
...
- engine->dev->dev_private
+ r->i915
...
}
@@
struct drm_i915_gem_request *req;
@@
(
  req->
- engine->dev->dev_private
+ i915
)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1458219850-21007-1-git-send-email-tvrtko.ursulin@linux.intel.com

Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

The only steps requiring device access is the fence and swizzling
initialization, so split these out keeping them in their current place
and move the rest of init steps earlier.

v2-v3:
- unchanged
v4:
- move call to i915_gem_detect_bit_6_swizzle() to
  i915_gem_load_init_fences() and preserve the original order of
  the detection of HW fence capailities wrt. swizzling (Chris)

CC: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1458132843-21860-1-git-send-email-imre.deak@intel.com

In full gpu reset we prime all engines and reset domains corresponding to
each engine. Per engine reset is just a special case of this process
wherein only a single engine is reset. This change is aimed to modify
relevant functions to achieve this. There are some other steps we carry out
in case of engine reset which are addressed in later patches.

Reset func now accepts a mask of all engines that need to be reset. Where
per engine resets are supported, error handler populates the mask
accordingly otherwise all engines are specified.

v2: ALL_ENGINES mask fixup, better for_each_ring_masked (Chris)
v3: Whitespace fixes (Chris)
v4: Rebase due to s/ring/engine

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1458143640-20563-1-git-send-email-mika.kuoppala@intel.com

This time using only sed and a few by hand.

v2: Rename also intel_ring_id and intel_ring_initialized.
v3: Fixed typo in intel_ring_initialized.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1458126040-33105-1-git-send-email-tvrtko.ursulin@linux.intel.com

Some trivial ones, first pass done with Coccinelle:

@@
@@
(
- I915_NUM_RINGS
+ I915_NUM_ENGINES
|
- intel_ring_flag
+ intel_engine_flag
|
- for_each_ring
+ for_each_engine
|
- i915_gem_request_get_ring
+ i915_gem_request_get_engine
|
- intel_ring_idle
+ intel_engine_idle
|
- i915_gem_reset_ring_status
+ i915_gem_reset_engine_status
|
- i915_gem_reset_ring_cleanup
+ i915_gem_reset_engine_cleanup
|
- init_ring_lists
+ init_engine_lists
)

But that didn't fully work so I cleaned it up with:

for f in *.[hc]; do sed -i -e s/I915_NUM_RINGS/I915_NUM_ENGINES/ $f; done
for f in *.[hc]; do sed -i -e s/i915_gem_request_get_ring/i915_gem_request_get_engine/ $f; done
for f in *.[hc]; do sed -i -e s/intel_ring_flag/intel_engine_flag/ $f; done
for f in *.[hc]; do sed -i -e s/intel_ring_idle/intel_engine_idle/ $f; done
for f in *.[hc]; do sed -i -e s/init_ring_lists/init_engine_lists/ $f; done
for f in *.[hc]; do sed -i -e s/i915_gem_reset_ring_cleanup/i915_gem_reset_engine_cleanup/ $f; done
for f in *.[hc]; do sed -i -e s/i915_gem_reset_ring_status/i915_gem_reset_engine_status/ $f; done

v2: Rebase.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

below and a couple manual fixups.

@@
identifier I, J;
@@
struct I {
...
- struct intel_engine_cs *J;
+ struct intel_engine_cs *engine;
...
}
@@
identifier I, J;
@@
struct I {
...
- struct intel_engine_cs J;
+ struct intel_engine_cs engine;
...
}
@@
struct drm_i915_private *d;
@@
(
- d->ring
+ d->engine
)
@@
struct i915_execbuffer_params *p;
@@
(
- p->ring
+ p->engine
)
@@
struct intel_ringbuffer *r;
@@
(
- r->ring
+ r->engine
)
@@
struct drm_i915_gem_request *req;
@@
(
- req->ring
+ req->engine
)

v2: Script missed the tracepoint code - fixed up by hand.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

@@
identifier func;
@@
func(..., struct intel_engine_cs *
- ring
+ engine
, ...)
{
<...
- ring
+ engine
...>
}
@@
identifier func;
type T;
@@
T func(..., struct intel_engine_cs *
- ring
+ engine
, ...);
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Done by the Coccinelle script below plus a manual
intervention to GEN8_RING_SEMAPHORE_INIT.

@@
expression E;
@@
- struct intel_engine_cs *ring = E;
+ struct intel_engine_cs *engine = E;
<+...
- ring
+ engine
...+>
@@
@@
- struct intel_engine_cs *ring;
+ struct intel_engine_cs *engine;
<+...
- ring
+ engine
...+>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

   commit e5756c10
   Author: Imre Deak <imre.deak@intel.com>
   Date:   Fri Aug 14 18:43:30 2015 +0300

       drm/i915/bxt: don't allow cached GEM mappings on A stepping

Added an exception of disallowing snooping for Broxton A
stepping hardware but userptr was still enabling it regardless.

Move the check to HAS_SNOOP now that it is used from multiple
call sites and use it.

v2: Userptr cannot be supported when it cannot be coherent and
    generalize the code better. (Chris Wilson)

v3: Make has_snoop true only when !has_llc. (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1456920631-34302-1-git-send-email-tvrtko.ursulin@linux.intel.com

The multiple levels of indirect do nothing but hinder the compiler and
the pointer chasing turns to be quite painful but painless to fix.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDave Gordon <david.s.gordon@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1456484600-11477-1-git-send-email-tvrtko.ursulin@linux.intel.com

Elsewhere we have adopted the convention of using '_link' to denote
elements in the list (and '_list' for the actual list_head itself), and
that the name should indicate which list the link belongs to (and
preferrably not just where the link is being stored).

s/vma_link/obj_link/ (we iterate over obj->vma_list)
s/mm_list/vm_link/ (we iterate over vm->[in]active_list)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

This behavior of checking for a shmem backed GEM object was introduced here:
commit 4c914c0c
Author: Brad Volkin <bradley.d.volkin@intel.com>
Date:   Tue Feb 18 10:15:45 2014 -0800

    drm/i915: Refactor shmem pread setup

It is possible for an object to not be a shmem backed GEM object (for example
userptr objects). An example of how we hit this failure can be found through
copy_batch() in the command parser because we allocate a userptr object for the
batch which contains privileged instructions. Userptr calls
drm_gem_private_object_init() which explicitly sets the filp to none.

NOTE: I manually retyped this from a test machine. So I haven't even compiled
this exact patch.

v2: Use same logic as from a2a4f916c2f (Kristian, Dave Gordon)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Kristian Høgsberg <krh@bitplanet.net>
Cc: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: NBen Widawsky <benjamin.widawsky@intel.com>
Tested-by: Jordan Justen <jordan.l.justen@intel.com> (v1)
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com> (v1)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1455047053-2644-1-git-send-email-benjamin.widawsky@intel.com

We know this never runs from interrupt context so
don't need to use the flags variant.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This reverts commit 1b39a917.

Chris retracted his reviewed-by (which I failed to notice) and somehow
it blows up (I did it again!) as reported by Mika with the below
backtrace on module reload:

[   58.170374] IP: [<ffffffffa00e04d3>]
intel_logical_ring_cleanup+0x83/0x100 [i915]
...
[   58.170469] Call Trace:
[   58.170479]  [<ffffffffa00d0ed4>] i915_gem_cleanup_engines+0x34/0x60
[i915]
[   58.170493]  [<ffffffffa0154520>] i915_driver_unload+0x140/0x220
[i915]
[   58.170497]  [<ffffffff8154a4f4>] drm_dev_unregister+0x24/0xa0
[   58.170501]  [<ffffffff8154aace>] drm_put_dev+0x1e/0x60
[   58.170506]  [<ffffffffa00912a0>] i915_pci_remove+0x10/0x20 [i915]
[   58.170510]  [<ffffffff814766e4>] pci_device_remove+0x34/0xb0
[   58.170514]  [<ffffffff8156e7d5>] __device_release_driver+0x95/0x140
[   58.170518]  [<ffffffff8156e97c>] driver_detach+0xbc/0xc0
[   58.170521]  [<ffffffff8156d883>] bus_remove_driver+0x53/0xd0
[   58.170525]  [<ffffffff8156f3a7>] driver_unregister+0x27/0x50
[   58.170528]  [<ffffffff81475725>] pci_unregister_driver+0x25/0x70
[   58.170531]  [<ffffffff8154c274>] drm_pci_exit+0x74/0x90
[   58.170543]  [<ffffffffa0154cb0>] i915_exit+0x20/0x1aa [i915]
[   58.170548]  [<ffffffff8111846f>] SyS_delete_module+0x18f/0x1f0

Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Cc: Nick Hoath <nicholas.hoath@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Swap the order of context & engine cleanup, so that contexts are cleaned
up first, and *then* engines. This is a more sensible order anyway, but
in particular has become necessary since the 'intel_ring_initialized()
must be simple and inline' patch, which now uses ring->dev as an
'initialised' flag, so it can now be NULL after engine teardown. This
in turn can cause a problem in the context code, which (used to) check
the ring->dev->struct_mutex -- causing a fault if ring->dev was NULL.

Also rename the cleanup function to reflect what it actually does
(cleanup engines, not a ringbuffer), and fix an annoying whitespace issue.

v2: Also make the fix in i915_load_modeset_init, not just in
    i915_driver_unload (Chris Wilson)
v3: Had extra stuff in it.
v4: Reverted extra stuff (so we're back to v2).
    Rebased and updated commentary above (Dave Gordon).
Signed-off-by: NNick Hoath <nicholas.hoath@intel.com>
Signed-off-by: NDavid Gordon <david.s.gordon@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1453504211-7982-2-git-send-email-david.s.gordon@intel.com

commit 033908ae
Author: Dave Gordon <david.s.gordon@intel.com>
Date:   Thu Dec 10 18:51:23 2015 +0000

    drm/i915: mark GEM object pages dirty when mapped & written by the CPU

introduced a check into i915_gem_object_get_dirty_pages() that returned
a NULL pointer when called with a bad object, one that was not backed by
shmemfs. This WARN was too strict as we can work on all struct page
backed objects, and resulted in a WARN + GPF for existing userspace. In
order to differentiate the various types of objects, add a new flags field
to the i915_gem_object_ops struct to describe their capabilities, with
the first flag being whether the object has struct pages.

v2: Drop silly const before an integer in the structure declaration.

Testcase: igt/gem_userptr_blits/relocations
Reported-and-tested-by: NKristian Høgsberg Kristensen <krh@bitplanet.net>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Cc: Kristian Høgsberg Kristensen <krh@bitplanet.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NKristian Høgsberg Kristensen <krh@bitplanet.net>
Tested-by: NMichal Winiarski <michal.winiarski@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Fixes: 033908ae ("drm/i915: mark GEM object pages dirty when mapped & written by the CPU")
Link: http://patchwork.freedesktop.org/patch/msgid/1453487551-16799-1-git-send-email-chris@chris-wilson.co.uk
(cherry picked from commit de472664)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

commit 033908ae
Author: Dave Gordon <david.s.gordon@intel.com>
Date:   Thu Dec 10 18:51:23 2015 +0000

    drm/i915: mark GEM object pages dirty when mapped & written by the CPU

introduced a check into i915_gem_object_get_dirty_pages() that returned
a NULL pointer when called with a bad object, one that was not backed by
shmemfs. This WARN was too strict as we can work on all struct page
backed objects, and resulted in a WARN + GPF for existing userspace. In
order to differentiate the various types of objects, add a new flags field
to the i915_gem_object_ops struct to describe their capabilities, with
the first flag being whether the object has struct pages.

v2: Drop silly const before an integer in the structure declaration.

Testcase: igt/gem_userptr_blits/relocations
Reported-and-tested-by: NKristian Høgsberg Kristensen <krh@bitplanet.net>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Cc: Kristian Høgsberg Kristensen <krh@bitplanet.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NKristian Høgsberg Kristensen <krh@bitplanet.net>
Tested-by: NMichal Winiarski <michal.winiarski@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453487551-16799-1-git-send-email-chris@chris-wilson.co.uk

Previously intel_lr_context_(un)pin were operating on requests
which is in conflict with their names.

If we make them take a context and an engine, it makes the names
make more sense and it also makes future fixes possible.

v2: Rebase for default_context/kernel_context change.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Nick Hoath <nicholas.hoath@intel.com>

Factor out common clean-up code for the GEM load time init function.
Also rename i915_gem_load() to i915_gem_load_init() to have a better
match with its new clean-up function.

No functional change.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NDavid Weinehall <david.weinehall@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453209992-25995-5-git-send-email-imre.deak@intel.com

Factor out the common GEM shrinker clean-up code and call the shrinker
init function from the same function from where the corresponding
shrinker clean-up function is called. Also add sanity checking to the
shrinker and OOM registration calls.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NDavid Weinehall <david.weinehall@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453209992-25995-4-git-send-email-imre.deak@intel.com

This reverts commit 1803c035.

It seems to blow up on module unload due to a use-after free hitting a
BUG_ON with CONFIG_DEBUG_SG. Quoting from Tvrtko's mail:

"I've decoded the instructions and it pointed to SG_MAGIC checking:

488b8098010000  mov 0x198(%rax),%rax
ba21436587      mov $0x87654321,%edx
488b00          mov (%rax),%rax       *** CRASH

"Grep showed 0x87654321 is SG_MAGIC, so likely candidate for this code
pattern is:

static inline struct page *sg_page(struct scatterlist *sg)
{
    BUG_ON(sg->sg_magic != SG_MAGIC);
    BUG_ON(sg_is_chain(sg));
    return (struct page *)((sg)->page_link & ~0x3);
}

"Which would mean the offender is in intel_logical_ring_cleanup is most
likely:

...
    if (ring->status_page.obj) {
        kunmap(sg_page(ring->status_page.obj->pages->sgl));
        ring->status_page.obj = NULL;
    }
...

"I think that the i915_gem_context_fini will do a final unref on
dev_priv->kernel_context and then the ring buff has a copy which is
left dangling because:

    lrc_setup_hardware_status_page(ring,
        dev_priv->kernel_context->engine[ring->id].state);

and:

ring->status_page.obj = default_ctx_obj;

"Where default_ctx_obj == dev_priv->kernel_context->engine[ring->id].state
So indeed looks like the unload ordering is the trigger.  In fact it
is almost the same fragility wrt/ kernel_context hidden dependency I
expressed my worry about in an e-mail yesterday or so. It only shows
if CONFIG_DEBUG_SG is set, otherwise it accesses freed memory and
probably just survives."

This causes serious trouble in our CI system since it took out all
gen8+ machines. Not yet clear why this wasn't caught in pre-merge
testing.

Backtrace from CI, for posterity:

[  163.737836] general protection fault: 0000 [#1] PREEMPT SMP
[  163.737849] Modules linked in: ax88179_178a usbnet mii snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic i915(-) x86_pkg_temp_thermal intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec snd_hwdep snd_hda_core snd_pcm mei_me mei i2c_hid e1000e ptp pps_core [last unloaded: snd_hda_intel]
[  163.737902] CPU: 0 PID: 5812 Comm: rmmod Tainted: G     U  W       4.5.0-rc1-gfxbench+ #1
[  163.737911] Hardware name: System manufacturer System Product Name/Z170M-PLUS, BIOS 0505 11/16/2015
[  163.737920] task: ffff8800bb99cf80 ti: ffff88022ff2c000 task.ti: ffff88022ff2c000
[  163.737928] RIP: 0010:[<ffffffffa018f723>]  [<ffffffffa018f723>] intel_logical_ring_cleanup+0x83/0x100 [i915]
[  163.737969] RSP: 0018:ffff88022ff2fd30  EFLAGS: 00010282
[  163.737975] RAX: 6b6b6b6b6b6b6b6b RBX: ffff8800bb2f31b8 RCX: 0000000000000002
[  163.737982] RDX: 0000000087654321 RSI: 000000000000000d RDI: ffff8800bb2f31f0
[  163.737989] RBP: ffff88022ff2fd40 R08: 0000000000000000 R09: 0000000000000001
[  163.737996] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800bb2f0000
[  163.738003] R13: ffff8800bb2f8fc8 R14: ffff8800bb285668 R15: 000055af1ae55210
[  163.738010] FS:  00007f187014b700(0000) GS:ffff88023bc00000(0000) knlGS:0000000000000000
[  163.738021] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  163.738030] CR2: 0000558f84e4cbc8 CR3: 000000022cd55000 CR4: 00000000003406f0
[  163.738039] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  163.738048] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  163.738057] Stack:
[  163.738062]  ffff8800bb2f31b8 ffff8800bb2f0000 ffff88022ff2fd70 ffffffffa0180414
[  163.738079]  ffff8800bb2f0000 ffff8800bb285668 ffff8800bb2856c8 ffffffffa0242460
[  163.738094]  ffff88022ff2fd98 ffffffffa0202d30 ffff8800bb285668 ffff8800bb285668
[  163.738109] Call Trace:
[  163.738140]  [<ffffffffa0180414>] i915_gem_cleanup_engines+0x34/0x60 [i915]
[  163.738185]  [<ffffffffa0202d30>] i915_driver_unload+0x150/0x270 [i915]
[  163.738198]  [<ffffffff815100f4>] drm_dev_unregister+0x24/0xa0
[  163.738208]  [<ffffffff815106ce>] drm_put_dev+0x1e/0x60
[  163.738225]  [<ffffffffa01412a0>] i915_pci_remove+0x10/0x20 [i915]
[  163.738237]  [<ffffffff8143d9b4>] pci_device_remove+0x34/0xb0
[  163.738249]  [<ffffffff81533d15>] __device_release_driver+0x95/0x140
[  163.738259]  [<ffffffff81533eb6>] driver_detach+0xb6/0xc0
[  163.738268]  [<ffffffff81532de3>] bus_remove_driver+0x53/0xd0
[  163.738278]  [<ffffffff815348d7>] driver_unregister+0x27/0x50
[  163.738289]  [<ffffffff8143ca15>] pci_unregister_driver+0x25/0x70
[  163.738299]  [<ffffffff81511de4>] drm_pci_exit+0x74/0x90
[  163.738337]  [<ffffffffa02034a9>] i915_exit+0x20/0x1a5 [i915]
[  163.738349]  [<ffffffff8110400f>] SyS_delete_module+0x18f/0x1f0
[  163.738361]  [<ffffffff817b8a9b>] entry_SYSCALL_64_fastpath+0x16/0x73
[  163.738370] Code: ff d0 48 89 df e8 de a1 fd ff 48 8d 7b 38 e8 25 ab fd ff 48 8b 83 90 00 00 00 48 85 c0 74 25 48 8b 80 98 01 00 00 ba 21 43 65 87 <48> 8b 00 48 39 10 75 3c f6 40 08 01 75 38 48 c7 83 90 00 00 00
[  163.738459] RIP  [<ffffffffa018f723>] intel_logical_ring_cleanup+0x83/0x100 [i915]
[  163.738498]  RSP <ffff88022ff2fd30>
[  163.738507] ---[ end trace 68f69ce4740fa44f ]---

Cc: Nick Hoath <nicholas.hoath@intel.com>
Cc: Dave Gordon <david.s.gordon@intel.com>
Cc: Chris 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>
Tested-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Swap the order of context & engine cleanup, so that contexts are cleaned
up first, and *then* engines. This is a more sensible order anyway, but
in particular has become necessary since the 'intel_ring_initialized()
must be simple and inline' patch, which now uses ring->dev as an
'initialised' flag, so it can now be NULL after engine teardown. This
in turn can cause a problem in the context code, which (used to) check
the ring->dev->struct_mutex -- causing a fault if ring->dev was NULL.

Also rename the cleanup function to reflect what it actually does
(cleanup engines, not a ringbuffer), and fix an annoying whitespace issue.

v2: Also make the fix in i915_load_modeset_init, not just in
    i915_driver_unload (Chris Wilson)
v3: Had extra stuff in it.
v4: Reverted extra stuff (so we're back to v2).
    Rebased and updated commentary above (Dave Gordon).
Signed-off-by: NNick Hoath <nicholas.hoath@intel.com>
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v2)
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1453405067-32890-3-git-send-email-david.s.gordon@intel.comSigned-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Tvrtko was looking through the execbuffer-ioctl and noticed that the
uABI was tightly coupled to our internal engine identifiers. Close
inspection also revealed that we leak those internal engine identifiers
through the busy-ioctl, and those internal identifiers already do not
match the user identifiers. Fortuitiously, there is only one user of the
set of busy rings from the busy-ioctl, and they only wish to choose
between the RENDER and the BLT engines.

Let's fix the userspace ABI while we still can.

v2: Update the uAPI documentation to explain the identifiers.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Testcase: igt/gem_busy
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1452876706-21620-1-git-send-email-chris@chris-wilson.co.uk

At the moment execbuf ring selection is fully coupled to
internal ring ids which is not a good thing on its own.

This dependency is also spread between two source files and
not spelled out at either side which makes it hidden and
fragile.

This patch decouples this dependency by introducing an explicit
translation table of execbuf uAPI to ring id close to the only
call site (i915_gem_do_execbuffer).

This way we are free to change driver internal implementation
details without breaking userspace. All state relating to the
uAPI is now contained in, or next to, i915_gem_do_execbuffer.

As a side benefit, this patch decreases the compiled size
of i915_gem_do_execbuffer.

v2: Extract ring selection into eb_select_ring. (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1452870770-13981-1-git-send-email-tvrtko.ursulin@linux.intel.com

There are a few bits of code which the transformations implemented by
the previous patch reveal to be suboptimal, once the notion of a per-
ring default context has gone away. So this tidies up the leftovers.

It could have been squashed into the previous patch, but that would have
made that patch less clearly a simple transformation. In particular, any
change which alters the code block structure or indentation has been
deferred into this separate patch, because such things tend to make
diffs more difficult to read.

v4:	Rebased
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NNick Hoath <nicholas.hoath@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453230175-19330-4-git-send-email-david.s.gordon@intel.comSigned-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that we've eliminated a lot of uses of ring->default_context,
we can eliminate the pointer itself.

All the engines share the same default intel_context, so we can just
keep a single reference to it in the dev_priv structure rather than one
in each of the engine[] elements. This make refcounting more sensible
too, as we now have a refcount of one for the one pointer, rather than
a refcount of one but multiple pointers.

From an idea by Chris Wilson.

v2:	transform an extra instance of ring->default_context introduced by
    42f1cae8 drm/i915: Restore inhibiting the load of the default context
    That patch's commentary includes:
	v2: Mark the global default context as uninitialized on GPU reset so
	    that the context-local workarounds are reloaded upon re-enabling
    The code implementing that now also benefits from the replacement of
    the multiple (per-ring) pointers to the default context with a single
    pointer to the unique kernel context.

v4:	Rebased, remove underused local (Nick Hoath)
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NNick Hoath <nicholas.hoath@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1453230175-19330-3-git-send-email-david.s.gordon@intel.comSigned-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

There are a number of places where the driver needs a request, but isn't
working on behalf of any specific user or in a specific context. At
present, we associate them with the per-engine default context. A future
patch will abolish those per-engine context pointers; but we can already
eliminate a lot of the references to them, just by making the allocator
allow NULL as a shorthand for "an appropriate context for this ring",
which will mean that the callers don't need to know anything about how
the "appropriate context" is found (e.g. per-ring vs per-device, etc).

So this patch renames the existing i915_gem_request_alloc(), and makes
it local (static inline), and replaces it with a wrapper that provides
a default if the context is NULL, and also has a nicer calling
convention (doesn't require a pointer to an output parameter). Then we
change all callers to use the new convention:
OLD:
	err = i915_gem_request_alloc(ring, user_ctx, &req);
	if (err) ...
NEW:
	req = i915_gem_request_alloc(ring, user_ctx);
	if (IS_ERR(req)) ...
OLD:
	err = i915_gem_request_alloc(ring, ring->default_context, &req);
	if (err) ...
NEW:
	req = i915_gem_request_alloc(ring, NULL);
	if (IS_ERR(req)) ...

v4:	Rebased
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NNick Hoath <nicholas.hoath@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453230175-19330-2-git-send-email-david.s.gordon@intel.comSigned-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

No need to call ktime_get_raw_ns twice per unlimited wait and can
also elimate a local variable.

v2: Added comment about silencing the compiler warning. (Daniel Vetter)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDave Gordon <david.s.gordon@intel.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1452870672-13901-1-git-send-email-tvrtko.ursulin@linux.intel.com

Kernel and userspace are able to handle 4GB (1<<32) address space range,
but "A32 Stateless Model" is not. According to documentation, A32 accesses
are based on General State Base Address and bound checking is in place.
Because size field (instruction State Base Address) limitation, it is not
possible to address full 4GB memory region.

A32 Stateless Model is used by some libraries and without this patch, the
last page of 4GB address space is not accessible in 32bit processes.
Reported-by: NArtur Harasimiuk <artur.harasimiuk@intel.com>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452512367-23614-1-git-send-email-michel.thierry@intel.com
Cc: drm-intel-fixes@lists.freedesktop.org
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 1892faa9)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Kernel and userspace are able to handle 4GB (1<<32) address space range,
but "A32 Stateless Model" is not. According to documentation, A32 accesses
are based on General State Base Address and bound checking is in place.
Because size field (instruction State Base Address) limitation, it is not
possible to address full 4GB memory region.

A32 Stateless Model is used by some libraries and without this patch, the
last page of 4GB address space is not accessible in 32bit processes.
Reported-by: NArtur Harasimiuk <artur.harasimiuk@intel.com>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452512367-23614-1-git-send-email-michel.thierry@intel.com
Cc: drm-intel-fixes@lists.freedesktop.org
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Limit busywaiting only to the request currently being processed by the
GPU. If the request is not currently being processed by the GPU, there
is a very low likelihood of it being completed within the 2 microsecond
spin timeout and so we will just be wasting CPU cycles.

v2: Check for logical inversion when rebasing - we were incorrectly
checking for this request being active, and instead busywaiting for
when the GPU was not yet processing the request of interest.

v3: Try another colour for the seqno names.
v4: Another colour for the function names.

v5: Remove the forced coherency when checking for the active request. On
reflection and plenty of recent experimentation, the issue is not a
cache coherency problem - but an irq/seqno ordering problem (timing issue).
Here, we do not need the w/a to force ordering of the read with an
interrupt.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
Cc: "Rantala, Valtteri" <valtteri.rantala@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449833608-22125-4-git-send-email-chris@chris-wilson.co.uk
(cherry picked from commit 821485dc)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

When waiting for high frequency requests, the finite amount of time
required to set up the irq and wait upon it limits the response rate. By
busywaiting on the request completion for a short while we can service
the high frequency waits as quick as possible. However, if it is a slow
request, we want to sleep as quickly as possible. The tradeoff between
waiting and sleeping is roughly the time it takes to sleep on a request,
on the order of a microsecond. Based on measurements of synchronous
workloads from across big core and little atom, I have set the limit for
busywaiting as 10 microseconds. In most of the synchronous cases, we can
reduce the limit down to as little as 2 miscroseconds, but that leaves
quite a few test cases regressing by factors of 3 and more.

The code currently uses the jiffie clock, but that is far too coarse (on
the order of 10 milliseconds) and results in poor interactivity as the
CPU ends up being hogged by slow requests. To get microsecond resolution
we need to use a high resolution timer. The cheapest of which is polling
local_clock(), but that is only valid on the same CPU. If we switch CPUs
because the task was preempted, we can also use that as an indicator that
 the system is too busy to waste cycles on spinning and we should sleep
instead.

__i915_spin_request was introduced in
commit 2def4ad9 [v4.2]
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Apr 7 16:20:41 2015 +0100

     drm/i915: Optimistically spin for the request completion

v2: Drop full u64 for unsigned long - the timer is 32bit wraparound safe,
so we can use native register sizes on smaller architectures. Mention
the approximate microseconds units for elapsed time and add some extra
comments describing the reason for busywaiting.

v3: Raise the limit to 10us
v4: Now 5us.
Reported-by: NJens Axboe <axboe@kernel.dk>
Link: https://lkml.org/lkml/2015/11/12/621Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
Cc: "Rantala, Valtteri" <valtteri.rantala@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449833608-22125-3-git-send-email-chris@chris-wilson.co.uk
(cherry picked from commit ca5b721e)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The busywait in __i915_spin_request() does not respect pending signals
and so may consume the entire timeslice for the task instead of
returning to userspace to handle the signal.

In the worst case this could cause a delay in signal processing of 20ms,
which would be a noticeable jitter in cursor tracking. If a higher
resolution signal was being used, for example to provide fairness of a
server timeslices between clients, we could expect to detect some
unfairness between clients (i.e. some windows not updating as fast as
others). This issue was noticed when inspecting a report of poor
interactivity resulting from excessively high __i915_spin_request usage.

Fixes regression from
commit 2def4ad9 [v4.2]
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Apr 7 16:20:41 2015 +0100

     drm/i915: Optimistically spin for the request completion

v2: Try to assess the impact of the bug
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc; "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
Cc: "Rantala, Valtteri" <valtteri.rantala@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449833608-22125-2-git-send-email-chris@chris-wilson.co.uk
(cherry picked from commit 91b0c352)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

As we mark the preallocated objects as bound, we should also flag them
correctly as being map-and-fenceable (if appropriate!) so that later
users do not get confused and try and rebind the pinned vma in order to
get a map-and-fenceable binding.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: "Goel, Akash" <akash.goel@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: drm-intel-fixes@lists.freedesktop.org
Link: http://patchwork.freedesktop.org/patch/msgid/1448029000-10616-1-git-send-email-chris@chris-wilson.co.ukReviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit d0710abb)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Limit busywaiting only to the request currently being processed by the
GPU. If the request is not currently being processed by the GPU, there
is a very low likelihood of it being completed within the 2 microsecond
spin timeout and so we will just be wasting CPU cycles.

v2: Check for logical inversion when rebasing - we were incorrectly
checking for this request being active, and instead busywaiting for
when the GPU was not yet processing the request of interest.

v3: Try another colour for the seqno names.
v4: Another colour for the function names.

v5: Remove the forced coherency when checking for the active request. On
reflection and plenty of recent experimentation, the issue is not a
cache coherency problem - but an irq/seqno ordering problem (timing issue).
Here, we do not need the w/a to force ordering of the read with an
interrupt.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
Cc: "Rantala, Valtteri" <valtteri.rantala@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449833608-22125-4-git-send-email-chris@chris-wilson.co.uk

When waiting for high frequency requests, the finite amount of time
required to set up the irq and wait upon it limits the response rate. By
busywaiting on the request completion for a short while we can service
the high frequency waits as quick as possible. However, if it is a slow
request, we want to sleep as quickly as possible. The tradeoff between
waiting and sleeping is roughly the time it takes to sleep on a request,
on the order of a microsecond. Based on measurements of synchronous
workloads from across big core and little atom, I have set the limit for
busywaiting as 10 microseconds. In most of the synchronous cases, we can
reduce the limit down to as little as 2 miscroseconds, but that leaves
quite a few test cases regressing by factors of 3 and more.

The code currently uses the jiffie clock, but that is far too coarse (on
the order of 10 milliseconds) and results in poor interactivity as the
CPU ends up being hogged by slow requests. To get microsecond resolution
we need to use a high resolution timer. The cheapest of which is polling
local_clock(), but that is only valid on the same CPU. If we switch CPUs
because the task was preempted, we can also use that as an indicator that
 the system is too busy to waste cycles on spinning and we should sleep
instead.

__i915_spin_request was introduced in
commit 2def4ad9 [v4.2]
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Apr 7 16:20:41 2015 +0100

     drm/i915: Optimistically spin for the request completion

v2: Drop full u64 for unsigned long - the timer is 32bit wraparound safe,
so we can use native register sizes on smaller architectures. Mention
the approximate microseconds units for elapsed time and add some extra
comments describing the reason for busywaiting.

v3: Raise the limit to 10us
v4: Now 5us.
Reported-by: NJens Axboe <axboe@kernel.dk>
Link: https://lkml.org/lkml/2015/11/12/621Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
Cc: "Rantala, Valtteri" <valtteri.rantala@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449833608-22125-3-git-send-email-chris@chris-wilson.co.uk

The busywait in __i915_spin_request() does not respect pending signals
and so may consume the entire timeslice for the task instead of
returning to userspace to handle the signal.

In the worst case this could cause a delay in signal processing of 20ms,
which would be a noticeable jitter in cursor tracking. If a higher
resolution signal was being used, for example to provide fairness of a
server timeslices between clients, we could expect to detect some
unfairness between clients (i.e. some windows not updating as fast as
others). This issue was noticed when inspecting a report of poor
interactivity resulting from excessively high __i915_spin_request usage.

Fixes regression from
commit 2def4ad9 [v4.2]
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Apr 7 16:20:41 2015 +0100

     drm/i915: Optimistically spin for the request completion

v2: Try to assess the impact of the bug
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc; "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
Cc: "Rantala, Valtteri" <valtteri.rantala@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449833608-22125-2-git-send-email-chris@chris-wilson.co.uk