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Commit Graph

98 Commits

Author SHA1 Message Date
Daniel Vetter
8d77a9404e drm/gem: Be more friendly with locking checks
BUG_ON kills the driver, WARN_ON is much friendlier. And usually nothing
bad happens when the locking is slightly busted.

v2: Fix typos in commit message Thierry spotted.

Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-08-10 13:35:49 +02:00
Daniel Vetter
131e663bd6 drm/gem: rip out drm vma accounting for gem mmaps
Doesn't really add anything which can't be figured out through
proc files. And more clearly separates the new gem mmap handling
code from the old drm maps mmap handling code, which is surely a
good thing.

Cc:  Martin Peres <martin.peres@free.fr>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-07-14 12:18:45 +02:00
Dave Airlie
ca5a71de48 drm: Sanitize DRM_IOCTL_MODE_CREATE_DUMB input
Some drivers erroneously treat the .pitch and .size fields of struct
 drm_mode_create_dumb as inputs. While the include/uapi/drm/drm_mode.h
 header has a comment denoting them as outputs, that seemingly wasn't
 enough to make drivers use them properly.
 
 The result is that some userspace doesn't explicitly zero out those
 fields, assuming that the kernel won't use them. That causes problems
 since the data within the structure might be uninitialized, so bogus
 data may end up confusing drivers (ridiculously large values for the
 pitch, ...).
 
 This series attempts to improve the situation by fixing all drivers to
 not use the output fields. Furthermore to spare new drivers this bad
 surprise, the DRM core now zeros out these fields prior to handing the
 data structure to the driver.
 
 Lessons learned from this are that future IOCTLs should be properly
 documented (in the DRM DocBook for example) and should be rigorously
 defined. To prevent misuse like this, userspace should be required to
 zero out all output fields. The kernel should check for this and fail
 if that's not the case.
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Merge tag 'drm/gem-cma/for-3.19-rc1' of git://people.freedesktop.org/~tagr/linux into drm-next

drm: Sanitize DRM_IOCTL_MODE_CREATE_DUMB input

Some drivers erroneously treat the .pitch and .size fields of struct
drm_mode_create_dumb as inputs. While the include/uapi/drm/drm_mode.h
header has a comment denoting them as outputs, that seemingly wasn't
enough to make drivers use them properly.

The result is that some userspace doesn't explicitly zero out those
fields, assuming that the kernel won't use them. That causes problems
since the data within the structure might be uninitialized, so bogus
data may end up confusing drivers (ridiculously large values for the
pitch, ...).

This series attempts to improve the situation by fixing all drivers to
not use the output fields. Furthermore to spare new drivers this bad
surprise, the DRM core now zeros out these fields prior to handing the
data structure to the driver.

Lessons learned from this are that future IOCTLs should be properly
documented (in the DRM DocBook for example) and should be rigorously
defined. To prevent misuse like this, userspace should be required to
zero out all output fields. The kernel should check for this and fail
if that's not the case.

* tag 'drm/gem-cma/for-3.19-rc1' of git://people.freedesktop.org/~tagr/linux:
  drm/cma: Remove call to drm_gem_free_mmap_offset()
  drm: Sanitize DRM_IOCTL_MODE_CREATE_DUMB input
  drm/rcar: gem: dumb: pitch is an output
  drm/omap: gem: dumb: pitch is an output
  drm/cma: Introduce drm_gem_cma_dumb_create_internal()
  drm/doc: Add GEM/CMA helpers to kerneldoc
  drm/doc: mm: Fix indentation
  drm/gem: Fix a few kerneldoc typos
2014-11-15 09:50:21 +10:00
Thierry Reding
8bf8180feb drm/gem: Fix a few kerneldoc typos
While at it, adjust the drm_gem_handle_create() function declaration to
be more consistent with other functions in the file.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>
2014-11-13 13:27:08 +01:00
Thierry Reding
c6a843256a drm/gem: Fix typo in kerneldoc
The function being documented is drm_gem_object_handle_free(), not
drm_gem_object_free().

Signed-off-by: Thierry Reding <treding@nvidia.com>
2014-11-13 10:43:49 +01:00
Andrzej Hajda
1bcecfacde drm/core: use helper to check driver features
The patch replaces direct access to driver_features field
by calls to helper function.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-10-03 10:38:56 +02:00
Daniel Vetter
d9fc9413f9 drm: Extract <drm/drm_gem.h>
v2: Don't forget git add, noticed by David.

Cc: David Herrmann <dh.herrmann@gmail.com>

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-09-24 11:43:41 +10:00
Daniel Vetter
197633b924 drm/gem: Don't call drm_mmap from drm_gem_mmap
The only user I could dig out was i915 back when ums+gem was still a
thing. But we've just very much killed that, and even when someone
screams about that we should resurrect that with a special hack
(wrapping drm_gem_mmap) in i915, not in the core code.

So good riddance to another entry point of the legacy buffer mapping
code.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-09-24 11:42:58 +10:00
Dave Airlie
19524f7c59 Merge tag 'topic/core-stuff-2014-09-15' of git://anongit.freedesktop.org/drm-intel into drm-next
Here's the updated topic/core-stuff pull request with the two patches
already merged into drm-fixes dropped.

* tag 'topic/core-stuff-2014-09-15' of git://anongit.freedesktop.org/drm-intel:
  drm: Drop modeset locking from crtc init function
  drm/i915/hdmi: Enable pipe pixel replication for SD interlaced modes
  drm/edid: Reduce horizontal timings for pixel replicated modes
  drm: Include task->name and master status in debugfs clients info
  drm/gem: Fix kerneldoc typo
  drm: use c99 initializers in structures
  drm: fix drm_modeset_lock.h kernel-doc notation
2014-09-15 19:55:55 +10:00
Laurent Pinchart
2a5706a36d drm/gem: Fix kerneldoc typo
The drm_gem_private_object_init function is called drm_gem_object_init
in its kerneldoc. Fix it.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-09-15 08:56:28 +02:00
Daniel Vetter
67d0ec4e88 drm: Move piles of functions from drmP.h to drm_internal.h
This way drivers can't grow crazy ideas any more, and it also
helps a bit in reviewing EXPORT_SYMBOLS.

v2: Even more stuff. Unfortunately we can't move drm_vm_open_locked
because exynos does some horrible stuff with it.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-09-12 11:16:29 +02:00
David Herrmann
0cdbe8ac69 drm/gem: remove misleading gfp parameter to get_pages()
drm_gem_get_pages() currently allows passing a 'gfp' parameter that is
passed to shmem combined with mapping_gfp_mask(). Given that the default
mapping_gfp_mask() is GFP_HIGHUSER, it is _very_ unlikely that anyone will
ever make use of that parameter. In fact, all drivers currently pass
redundant flags or 0.

This patch removes the 'gfp' parameter. The only reason to keep it is to
remove flags like __GFP_WAIT. But in its current form, it can only be used
to add flags. So to remove __GFP_WAIT, you'd have to drop it from the
mapping_gfp_mask, which again is stupid as this mask is used by shmem-core
for other allocations, too.

If any driver ever requires that parameter, we can introduce a new helper
that takes the raw 'gfp' parameter. The caller'd be responsible to combine
it with mapping_gfp_mask() in a suitable way. The current
drm_gem_get_pages() helper would then simply use mapping_gfp_mask() and
call the new helper. This is what shmem_read_mapping_pages{_gfp,} does
right now.

Moreover, the gfp-zone flag-usage is not obvious: If you pass a modified
zone, shmem core will WARN() or even BUG(). In other words, the following
must be true for 'gfp' passed to shmem_read_mapping_pages_gfp():
    gfp_zone(mapping_gfp_mask(mapping)) == gfp_zone(gfp)
Add a comment to drm_gem_read_pages() explaining that constraint.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
2014-07-08 00:29:53 +02:00
David Herrmann
2123000b01 drm/gem: replace misleading comment
shmem supports page-relocations during swapin since quite some time. It
was implemented in:

    commit bde05d1ccd
    Author: Hugh Dickins <hughd@google.com>
    Date:   Tue May 29 15:06:38 2012 -0700

        shmem: replace page if mapping excludes its zone

The gem-comment about wrongly placed DMA32 pages is no longer valid.
Replace it with a proper comment but keep the BUG_ON() to verify correct
shmem behavior.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-05-27 15:50:57 +10:00
Dave Airlie
978c605016 Merge branch 'drm-docs' of ssh://people.freedesktop.org/~danvet/drm into drm-next
Here's my drm documentation update and driver api polish pull request.
Alex reviewed the entire pile, I've applied a little bit of spelling
polish in a few places since then and otherwise the Usual Suspects (David,
Rob, ...) don't seem up to have another look at it (I've poked them on
irc). So I think it's as good as it gets ;-)

Note that I've dropped the final imx breaker patch since that's blocked on
imx getting sane. Once that's landed I'll ping you to pick up that
straggler.

* 'drm-docs' of ssh://people.freedesktop.org/~danvet/drm: (34 commits)
  drm/imx: remove drm_mode_connector_detach_encoder harder
  drm: kerneldoc polish for drm_crtc.c
  drm: kerneldoc polish for drm_crtc_helper.c
  drm: drop error code for drm_helper_resume_force_mode
  drm/crtc-helper: remove LOCKING from kerneldoc
  drm: remove return value from drm_helper_mode_fill_fb_struct
  drm/doc: Fix misplaced </para>
  drm: remove drm_display_mode->private_size
  drm: polish function kerneldoc for drm_modes.[hc]
  drm/modes: drop maxPitch from drm_mode_validate_size
  drm/modes: drop return value from drm_display_mode_from_videomode
  drm/modes: remove drm_mode_height/width
  drm: extract drm_modes.h for drm_crtc.h functions
  drm: move drm_mode related functions into drm_modes.c
  drm/doc: Repleace LOCKING kerneldoc sections in drm_modes.c
  drm/doc: Integrate drm_modes.c kerneldoc
  drm/kms: rip out drm_mode_connector_detach_encoder
  drm/doc: Add function reference documentation for drm_mm.c
  drm/doc: Overview documentation for drm_mm.c
  drm/mm: Remove MM_UNUSED_TARGET
  ...
2014-03-18 19:09:10 +10:00
David Herrmann
a8469aa81d drm/gem: dont init "ret" in drm_gem_mmap()
There is no need to initialize this variable, so drop it. Otherwise, the
compiler won't warn if we use it unintialized.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
2014-03-16 12:11:01 +01:00
David Herrmann
7747234797 drm/gem: free vma-node during object-cleanup
All drivers currently need to clean up the vma-node manually. There is no
fancy logic involved so lets just clean it up unconditionally. The
vma-manager correctly catches multiple calls so we are fine.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
2014-03-16 12:11:01 +01:00
David Herrmann
16d2831d6f drm/gem: fix indentation
Remove double-whitespace and wrong indentation.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
2014-03-16 12:11:01 +01:00
Daniel Vetter
89d61fc0f5 drm/doc: Clean up and integrate kerneldoc for drm_gem.c
Fairly incomplete, but at least a start.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-03-13 12:48:27 +01:00
Daniel Vetter
6ab11a2635 drm/gem: Always initialize the gem object in object_init
At least drm/i915 expects that the obj->dev pointer is set even in
failure paths. Specifically when the shmem initialization fails we
call i915_gem_object_free which needs to deref obj->base.dev to get at
the slab pointer in the device private structure. And the shmem
allocation can easily fail when userspace is hitting open file limits.

Doing the structure init even when the shmem file allocation fails
prevents this Oops.

This is a regression from

commit 89c8233f82
Author: David Herrmann <dh.herrmann@gmail.com>
Date:   Thu Jul 11 11:56:32 2013 +0200

    drm/gem: simplify object initialization

v2: Add regression note which Chris supplied.

Testcase: igt/gem_fd_exhaustion
Reported-and-Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
References: http://lists.freedesktop.org/archives/intel-gfx/2014-January/038433.html
Cc: stable@vger.kernel.org
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-01-21 10:19:58 +01:00
Daniel Vetter
b04a590623 drm: store the gem vma offset manager in a typed pointer
This was hidden in a generic void * dev->mm_private. But only ever
used for gem. But thanks to this fake generic pretension no one
noticed that Rob's drm drivers are now all broken.

So just give the offset manager a type pointer and fix up msm, omapdrm
and tilcdc.

v2: Fixup compile fail.

v3: Fixup rebase fail that David spotted.

Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-01-14 12:38:32 +10:00
Kristian Hogsberg
ee61c7303f drm: Don't reference objects in the flink name idr
There's no reason to keep a reference to objects in the name idr.  Each
handle to an object has a reference to the object and just before we
destroy the last handle we take the object out of the name idr.  Thus,
if an object is in the name idr, there's at least one reference to the
object.

Or to put it another way, the name idr reference will never keep the
object alive.  It just looks like it, which is confusing.

Signed-off-by: Kristian Høgsberg <krh@bitplanet.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-12-18 10:48:17 +10:00
David Herrmann
16eb5f4379 drm: kill ->gem_init_object() and friends
All drivers embed gem-objects into their own buffer objects. There is no
reason to keep drm_gem_object_alloc(), gem->driver_private and
->gem_init_object() anymore.

New drivers are highly encouraged to do the same. There is no benefit in
allocating gem-objects separately.

Cc: Dave Airlie <airlied@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Ben Skeggs <skeggsb@gmail.com>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-10-09 14:38:02 +10:00
Thierry Reding
9c78485506 drm/prime: Remove PRIME handles only if supported
Drivers that don't support PRIME will not have initialized the PRIME
specific private component of struct drm_file. If called for such
drivers, the drm_gem_remove_prime_handles() function will crash. Fix
it by checking for PRIME support prior to removing the PRIME handles.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>
2013-08-30 09:11:59 +10:00
David Herrmann
ca481c9b2a drm/gem: implement vma access management
We implement automatic vma mmap() access management for all drivers using
gem_mmap. We use the vma manager to add each open-file that creates a
gem-handle to the vma-node of the underlying gem object. Once the handle
is destroyed, we drop the open-file again.

This allows us to use drm_vma_node_is_allowed() on _any_ gem object to see
whether an open-file is granted access. In drm_gem_mmap() we use this to
verify that unprivileged users cannot guess gem offsets and map arbitrary
buffers.

Note that this manages access for _all_ gem users (also TTM+GEM), but the
actual access checks are only done for drm_gem_mmap(). TTM drivers use the
TTM mmap helpers, which need to do that separately.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-27 11:54:56 +10:00
David Herrmann
88d7ebe593 drm/vma: add access management helpers
The VMA offset manager uses a device-global address-space. Hence, any
user can currently map any offset-node they want. They only need to guess
the right offset. If we wanted per open-file offset spaces, we'd either
need VM_NONLINEAR mappings or multiple "struct address_space" trees. As
both doesn't really scale, we implement access management in the VMA
manager itself.

We use an rb-tree to store open-files for each VMA node. On each mmap
call, GEM, TTM or the drivers must check whether the current user is
allowed to map this file.

We add a separate lock for each node as there is no generic lock available
for the caller to protect the node easily.

As we currently don't know whether an object may be used for mmap(), we
have to do access management for all objects. If it turns out to slow down
handle creation/deletion significantly, we can optimize it in several
ways:
 - Most times only a single filp is added per bo so we could use a static
   "struct file *main_filp" which is checked/added/removed first before we
   fall back to the rbtree+drm_vma_offset_file.
   This could be even done lockless with rcu.
 - Let user-space pass a hint whether mmap() should be supported on the
   bo and avoid access-management if not.
 - .. there are probably more ideas once we have benchmarks ..

v2: add drm_vma_node_verify_access() helper

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-27 11:54:54 +10:00
Daniel Vetter
d0b2c5334f drm/prime: Always add exported buffers to the handle cache
... not only when the dma-buf is freshly created. In contrived
examples someone else could have exported/imported the dma-buf already
and handed us the gem object with a flink name. If such on object gets
reexported as a dma_buf we won't have it in the handle cache already,
which breaks the guarantee that for dma-buf imports we always hand
back an existing handle if there is one.

This is exercised by igt/prime_self_import/with_one_bo_two_files

Now if we extend the locked sections just a notch more we can also
plug th racy buf/handle cache setup in handle_to_fd:

If evil userspace races a concurrent gem close against a prime export
operation we can end up tearing down the gem handle before the dma buf
handle cache is set up. When handle_to_fd gets around to adding the
handle to the cache there will be no one left to clean it up,
effectily leaking the bo (and the dma-buf, since the handle cache
holds a ref on the dma-buf):

Thread A			Thread B

handle_to_fd:

lookup gem object from handle
creates new dma_buf

				gem_close on the same handle
				obj->dma_buf is set, but file priv buf
				handle cache has no entry

				obj->handle_count drops to 0

drm_prime_add_buf_handle sets up the handle cache

-> We have a dma-buf reference in the handle cache, but since the
handle_count of the gem object already dropped to 0 no on will clean
it up. When closing the drm device fd we'll hit the WARN_ON in
drm_prime_destroy_file_private.

The important change is to extend the critical section of the
filp->prime.lock to cover the gem handle lookup. This serializes with
a concurrent gem handle close.

This leak is exercised by igt/prime_self_import/export-vs-gem_close-race

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-21 13:05:03 +10:00
Daniel Vetter
838cd4455e drm/prime: Simplify drm_gem_remove_prime_handles
with the reworking semantics and locking of the obj->dma_buf pointer
this pointer is always set as long as there's still a gem handle
around and a dma_buf associated with this gem object.

Also, the per file-priv lookup-cache for dma-buf importing is also
unified between foreign and native objects.

Hence we don't need to special case the clean any more and can simply
drop the clause which only runs for foreing objects, i.e. with
obj->import_attach set.

Note that with this change (actually with the previous one to always
set up obj->dma_buf even for foreign objects) it is no longer required
to set obj->import_attach when importing a foreing object. So update
comments accordingly, too.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-21 12:58:18 +10:00
Daniel Vetter
319c933c71 drm/prime: proper locking+refcounting for obj->dma_buf link
The export dma-buf cache is semantically similar to an flink name. So
semantically it makes sense to treat it the same and remove the name
(i.e. the dma_buf pointer) and its references when the last gem handle
disappears.

Again we need to be careful, but double so: Not just could someone
race and export with a gem close ioctl (so we need to recheck
obj->handle_count again when assigning the new name), but multiple
exports can also race against each another. This is prevented by
holding the dev->object_name_lock across the entire section which
touches obj->dma_buf.

With the new scheme we also need to reinstate the obj->dma_buf link at
import time (in case the only reference userspace has held in-between
was through the dma-buf fd and not through any native gem handle). For
simplicity we don't check whether it's a native object but
unconditionally set up that link - with the new scheme of removing the
obj->dma_buf reference when the last handle disappears we can do that.

To make it clear that this is not just for exported buffers anymore
als rename it from export_dma_buf to dma_buf.

To make sure that now one can race a fd_to_handle or handle_to_fd with
gem_close we use the same tricks as in flink of extending the
dev->object_name_locking critical section. With this change we finally
have a guaranteed 1:1 relationship (at least for native objects)
between gem objects and dma-bufs, even accounting for races (which can
happen since the dma-buf itself holds a reference while in-flight).

This prevent igt/prime_self_import/export-vs-gem_close-race from
Oopsing the kernel. There is still a leak though since the per-file
priv dma-buf/handle cache handling is racy. That will be fixed in a
later patch.

v2: Remove the bogus dma_buf_put from the export_and_register_object
failure path if we've raced with the handle count dropping to 0.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-21 12:58:17 +10:00
Daniel Vetter
20228c4478 drm/gem: completely close gem_open vs. gem_close races
The gem flink name holds a reference onto the object itself, and this
self-reference would prevent an flink'ed object from every being
freed. To break that loop we remove the flink name when the last
userspace handle disappears, i.e. when obj->handle_count reaches 0.

Now in gem_open we drop the dev->object_name_lock between the flink
name lookup and actually adding the handle. This means a concurrent
gem_close of the last handle could result in the flink name getting
reaped right inbetween, i.e.

Thread 1		Thread 2
gem_open		gem_close

flink -> obj lookup
			handle_count drops to 0
			remove flink name
create_handle
handle_count++

If someone now flinks this object again, we'll get a new flink name.

We can close this race by removing the lock dropping and making the
entire lookup+handle_create sequence atomic. Unfortunately to still be
able to share the handle_create logic this requires a
handle_create_tail function which drops the lock - we can't hold the
object_name_lock while calling into a driver's ->gem_open callback.

Note that for flink fixing this race isn't really important, since
racing gem_open against gem_close is clearly a userspace bug. And no
matter how the race ends, we won't leak any references.

But with dma-buf where the userspace dma-buf fd itself is refcounted
this is a valid sequence and hence we should fix it. Therefore this
patch here is just a warm-up exercise (and for consistency between
flink buffer sharing and dma-buf buffer sharing with self-imports).

Also note that this extension of the critical section in gem_open
protected by dev->object_name_lock only works because it's now a
mutex: A spinlock would conflict with the potential memory allocation
in idr_preload().

This is exercises by igt/gem_flink_race/flink_name.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-21 12:58:17 +10:00
Daniel Vetter
cd4f013f3a drm/gem: switch dev->object_name_lock to a mutex
I want to wrap the creation of a dma-buf from a gem object in it,
so that the obj->export_dma_buf cache can be atomically filled in.

Instead of creating a new mutex just for that variable I've figured
I can reuse the existing dev->object_name_lock, especially since
the new semantics will exactly mirror the flink obj->name already
protected by that lock.

v2: idr_preload/idr_preload_end is now an atomic section, so need to
move the mutex locking outside.

[airlied: fix up conflict with patch to make debugfs use lock]

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-21 12:58:01 +10:00
Daniel Vetter
becee2a57f drm/gem: make drm_gem_object_handle_unreference_unlocked static
No one outside of drm should use this, the official interfaces are
drm_gem_handle_create and drm_gem_handle_delete. The handle refcounting
is purely an implementation detail of gem.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-21 12:53:46 +10:00
Daniel Vetter
a8e11d1c43 drm/gem: fix up flink name create race
This is the 2nd attempt, I've always been a bit dissatisified with the
tricky nature of the first one:

http://lists.freedesktop.org/archives/dri-devel/2012-July/025451.html

The issue is that the flink ioctl can race with calling gem_close on
the last gem handle. In that case we'll end up with a zero handle
count, but an flink name (and it's corresponding reference). Which
results in a neat space leak.

In my first attempt I've solved this by rechecking the handle count.
But fundamentally the issue is that ->handle_count isn't your usual
refcount - it can be resurrected from 0 among other things.

For those special beasts atomic_t often suggest way more ordering that
it actually guarantees. To prevent being tricked by those hairy
semantics take the easy way out and simply protect the handle with the
existing dev->object_name_lock.

With that change implemented it's dead easy to fix the flink vs. gem
close reace: When we try to create the name we simply have to check
whether there's still officially a gem handle around and if not refuse
to create the flink name. Since the handle count decrement and flink
name destruction is now also protected by that lock the reace is gone
and we can't ever leak the flink reference again.

Outside of the drm core only the exynos driver looks at the handle
count, and tbh I have no idea why (it's just for debug dmesg output
luckily).

I've considered inlining the drm_gem_object_handle_free, but I plan to
add more name-like things (like the exported dma_buf) to this scheme,
so it's clearer to leave the handle freeing in its own function.

This is exercised by the new gem_flink_race i-g-t testcase, which on
my snb leaks gem objects at a rate of roughly 1k objects/s.

v2: Fix up the error path handling in handle_create and make it more
robust by simply calling object_handle_unreference.

v3: Fix up the handle_unreference logic bug - atomic_dec_and_test
retursn 1 for 0. Oops.

v4: Squash in inlining of drm_gem_object_handle_reference as suggested
by Dave Airlie and add a note that we now have a testcase.

Cc: Dave Airlie <airlied@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-21 12:53:45 +10:00
Daniel Vetter
1216f73237 drm/gem: WARN about unbalanced handle refcounts
Trying to drop a reference we don't have is a pretty serious bug.
Trying to paper over it is an even worse offense.

So scream into dmesg with a big WARN in case that ever happens.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-19 10:47:37 +10:00
Daniel Vetter
6bc505b86a drm/gem: remove bogus NULL check from drm_gem_object_handle_unreference_unlocked
Calling this function with a NULL object is simply a bug, so papering
over a NULL object not a good idea.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-19 10:47:13 +10:00
Daniel Vetter
36da5908a2 drm/gem: move drm_gem_object_handle_unreference_unlocked into drm_gem.c
We have three callers of this function now and it's neither
performance critical nor really small. So an inline function feels
like overkill and unecessarily separates the different parts of the
code.

Since all callers of drm_gem_object_handle_free are now in drm_gem.c
we can make that static (and remove the unused EXPORT_SYMBOL). To
avoid a forward declaration move it (and drm_gem_object_free_bug) up a
bit.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-19 10:46:56 +10:00
Rob Clark
bcc5c9d50e drm/gem: add shmem get/put page helpers
Basically just extracting some code duplicated in gma500, omapdrm, udl,
and upcoming msm driver.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-19 10:36:04 +10:00
Rob Clark
367bbd4920 drm/gem: add drm_gem_create_mmap_offset_size()
Variant of drm_gem_create_mmap_offset() which doesn't make the
assumption that virtual size and physical size (obj->size) are the same.
This is needed in omapdrm to deal with tiled buffers.  And lets us get
rid of a duplicated and slightly modified version of
drm_gem_create_mmap_offset() in omapdrm.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-19 10:34:43 +10:00
Daniel Vetter
43387b37fa drm/gem: create drm_gem_dumb_destroy
All the gem based kms drivers really want the same function to
destroy a dumb framebuffer backing storage object.

So give it to them and roll it out in all drivers.

This still leaves the option open for kms drivers which don't use GEM
for backing storage, but it does decently simplify matters for gem
drivers.

Acked-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Ben Skeggs <skeggsb@gmail.com>
Reviwed-by: Rob Clark <robdclark@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-08-07 09:59:24 +10:00
David Herrmann
aed2c03c8d drm/gem: fix mmap vma size calculations
The VMA manager is page-size based so drm_vma_node_size() returns the size
in pages. However, drm_gem_mmap_obj() requires the size in bytes. Apply
PAGE_SHIFT so we no longer get EINVAL during mmaps due to too small
buffers.

This bug was introduced in commit:
  0de23977cf
  "drm/gem: convert to new unified vma manager"

Fixes i915 gtt mmap failure reported by Sedat Dilek in:
  Re: linux-next: Tree for Jul 25 [ call-trace: drm | drm-intel related? ]

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>
2013-07-26 20:28:02 +10:00
David Herrmann
0de23977cf drm/gem: convert to new unified vma manager
Use the new vma manager instead of the old hashtable. Also convert all
drivers to use the new convenience helpers. This drops all the
(map_list.hash.key << PAGE_SHIFT) non-sense.

Locking and access-management is exactly the same as before with an
additional lock inside of the vma-manager, which strictly wouldn't be
needed for gem.

v2:
 - rebase on drm-next
 - init nodes via drm_vma_node_reset() in drm_gem.c
v3:
 - fix tegra
v4:
 - remove duplicate if (drm_vma_node_has_offset()) checks
 - inline now trivial drm_vma_node_offset_addr() calls
v5:
 - skip node-reset on gem-init due to kzalloc()
 - do not allow mapping gem-objects with offsets (backwards compat)
 - remove unneccessary casts

Cc: Inki Dae <inki.dae@samsung.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@gmail.com>
2013-07-25 20:47:06 +10:00
David Herrmann
89c8233f82 drm/gem: simplify object initialization
drm_gem_object_init() and drm_gem_private_object_init() do exactly the
same (except for shmem alloc) so make the first use the latter to reduce
code duplication.

Also drop the return code from drm_gem_private_object_init(). It seems
unlikely that we will extend it any time soon so no reason to keep it
around. This simplifies code paths in drivers, too.

Last but not least, fix gma500 to call drm_gem_object_release() before
freeing objects that were allocated via drm_gem_private_object_init().
That isn't actually necessary for now, but might be in the future.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Acked-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>
2013-07-23 19:37:53 +10:00
David Herrmann
77ef8bbc87 drm: make drm_mm_init() return void
There is no reason to return "int" as this function never fails.
Furthermore, several drivers (ast, sis) already depend on this.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-07-02 13:34:41 +10:00
YoungJun Cho
2e07fb2293 drm/gem: fix not to assign error value to gem name
If idr_alloc() is failed, obj->name can be error value. Also
it cleans up duplicated flink processing code.

This regression has been introduced in

commit 2e928815c1
Author: Tejun Heo <tj@kernel.org>
Date:   Wed Feb 27 17:04:08 2013 -0800

    drm: convert to idr_alloc()

Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: stable@vger.kernel.org
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-06-28 12:31:23 +10:00
YoungJun Cho
4368dd846d drm/gem: add mutex lock when using drm_gem_mmap_obj
The drm_gem_mmap_obj() has to be protected with dev->struct_mutex,
but some caller functions do not. So it adds mutex lock to missing
callers and adds assertion to check whether drm_gem_mmap_obj() is
called with mutex lock or not.

Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-06-28 12:30:15 +10:00
Laurent Pinchart
1c5aafa6ee drm/gem: Split drm_gem_mmap() into object search and object mapping
The drm_gem_mmap() function first finds the GEM object to be mapped
based on the fake mmap offset and then maps the object. Split the object
mapping code into a standalone drm_gem_mmap_obj() function that can be
used to implement dma-buf mmap() operations.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
2013-06-08 09:14:03 +02:00
Dave Airlie
219b47339c drm/prime: keep a reference from the handle to exported dma-buf (v6)
Currently we have a problem with this:
1. i915: create gem object
2. i915: export gem object to prime
3. radeon: import gem object
4. close prime fd
5. radeon: unref object
6. i915: unref object

i915 has an imported object reference in its file priv, that isn't
cleaned up properly until fd close. The reference gets added at step 2,
but at step 6 we don't have enough info to clean it up.

The solution is to take a reference on the dma-buf when we export it,
and drop the reference when the gem handle goes away.

So when we export a dma_buf from a gem object, we keep track of it
with the handle, we take a reference to the dma_buf. When we close
the handle (i.e. userspace is finished with the buffer), we drop
the reference to the dma_buf, and it gets collected.

This patch isn't meant to fix any other problem or bikesheds, and it doesn't
fix any races with other scenarios.

v1.1: move export symbol line back up.

v2: okay I had to do a bit more, as the first patch showed a leak
on one of my tests, that I found using the dma-buf debugfs support,
the problem case is exporting a buffer twice with the same handle,
we'd add another export handle for it unnecessarily, however
we now fail if we try to export the same object with a different gem handle,
however I'm not sure if that is a case I want to support, and I've
gotten the code to WARN_ON if we hit something like that.

v2.1: rebase this patch, write better commit msg.
v3: cleanup error handling, track import vs export in linked list,
these two patches were separate previously, but seem to work better
like this.
v4: danvet is correct, this code is no longer useful, since the buffer
better exist, so remove it.
v5: always take a reference to the dma buf object, import or export.
(Imre Deak contributed this originally)
v6: square the circle, remove import vs export tracking now
that there is no difference

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-05-01 09:30:15 +10:00
Tejun Heo
2e928815c1 drm: convert to idr_alloc()
Convert to the much saner new idr interface.

* drm_ctxbitmap_next() error handling in drm_addctx() seems broken.
  drm_ctxbitmap_next() return -errno on failure not -1.

[artem.savkov@gmail.com: missing idr_preload_end in drm_gem_flink_ioctl]
[jslaby@suse.cz: fix drm_gem_flink_ioctl() return value]
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David Airlie <airlied@linux.ie>
Signed-off-by: Artem Savkov <artem.savkov@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:15 -08:00
Tejun Heo
4d53233a36 drm: don't use idr_remove_all()
idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.

* drm_ctxbitmap_cleanup() was calling idr_remove_all() but forgetting
  idr_destroy() thus leaking all buffered free idr_layers.  Replace it
  with idr_destroy().

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David Airlie <airlied@linux.ie>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:13 -08:00
Konstantin Khlebnikov
314e51b985 mm: kill vma flag VM_RESERVED and mm->reserved_vm counter
A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:

 | effect                 | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump      | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock           | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP

This patch removes reserved_vm counter from mm_struct.  Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.

Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.

remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.

[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:19 +09:00
David Howells
760285e7e7 UAPI: (Scripted) Convert #include "..." to #include <path/...> in drivers/gpu/
Convert #include "..." to #include <path/...> in drivers/gpu/.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
2012-10-02 18:01:07 +01:00