Commit Graph

14 Commits

Author SHA1 Message Date
Jani Nikula a10f361d17 Revert "drm/i915: Expand subslice mask"
This reverts commit 1ac159e23c ("drm/i915: Expand subslice mask"),
which kills ICL due to GEM_BUG_ON() sanity checks before CI even gets a
chance to do anything.

The commit exposes an issue in commit 1e40d4aea5 ("drm/i915/cnl:
Implement WaProgramMgsrForCorrectSliceSpecificMmioReads"), which will
also need to be addressed.

There's a proposed fix [1], but considering the seeming uncertainty with
the fix as well as the size of the regressing commit (in this context,
the one that actually brings down ICL), this warrants a revert to get
ICL working, and gives us time to get all of this right without
rushing. Even if this means shooting the messenger.

<3>[    9.426327] intel_sseu_get_subslices:46 GEM_BUG_ON(slice >= sseu->max_slices)
<4>[    9.426355] ------------[ cut here ]------------
<2>[    9.426357] kernel BUG at drivers/gpu/drm/i915/gt/intel_sseu.c:46!
<4>[    9.426371] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
<4>[    9.426377] CPU: 1 PID: 364 Comm: systemd-udevd Not tainted 5.2.0-rc2-CI-CI_DRM_6159+ #1
<4>[    9.426385] Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3183.A00.1905020411 05/02/2019
<4>[    9.426444] RIP: 0010:intel_sseu_get_subslices+0x8a/0xe0 [i915]
<4>[    9.426452] Code: d5 76 b7 e0 48 8b 35 9d 24 21 00 49 c7 c0 07 f0 72 a0 b9 2e 00 00 00 48 c7 c2 00 8e 6d a0 48 c7 c7 a5 14 5b a0 e8 36 3c be e0 <0f> 0b 48 c7 c1 80 d5 6f a0 ba 30 00 00 00 48 c7 c6 00 8e 6d a0 48
<4>[    9.426468] RSP: 0018:ffffc9000037b9c8 EFLAGS: 00010282
<4>[    9.426475] RAX: 000000000000000f RBX: 0000000000000000 RCX: 0000000000000000
<4>[    9.426482] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88849e346f98
<4>[    9.426490] RBP: ffff88848a200000 R08: 0000000000000004 R09: ffff88849d50b000
<4>[    9.426497] R10: 0000000000000000 R11: ffff88849e346f98 R12: ffff88848a209e78
<4>[    9.426505] R13: 0000000003000000 R14: ffff88848a20b1a8 R15: 0000000000000000
<4>[    9.426513] FS:  00007f73d5ae8680(0000) GS:ffff88849fc80000(0000) knlGS:0000000000000000
<4>[    9.426521] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[    9.426527] CR2: 0000561417b01260 CR3: 0000000494764003 CR4: 0000000000760ee0
<4>[    9.426535] PKRU: 55555554
<4>[    9.426538] Call Trace:
<4>[    9.426585]  wa_init_mcr+0xd5/0x110 [i915]
<4>[    9.426597]  ? lock_acquire+0xa6/0x1c0
<4>[    9.426645]  icl_gt_workarounds_init+0x21/0x1a0 [i915]
<4>[    9.426694]  ? i915_driver_load+0xfcf/0x18a0 [i915]
<4>[    9.426739]  gt_init_workarounds+0x14c/0x230 [i915]
<4>[    9.426748]  ? _raw_spin_unlock_irq+0x24/0x50
<4>[    9.426789]  intel_gt_init_workarounds+0x1b/0x30 [i915]
<4>[    9.426835]  i915_driver_load+0xfd7/0x18a0 [i915]
<4>[    9.426843]  ? lock_acquire+0xa6/0x1c0
<4>[    9.426850]  ? __pm_runtime_resume+0x4f/0x80
<4>[    9.426857]  ? _raw_spin_unlock_irqrestore+0x4c/0x60
<4>[    9.426863]  ? _raw_spin_unlock_irqrestore+0x4c/0x60
<4>[    9.426870]  ? lockdep_hardirqs_on+0xe3/0x1b0
<4>[    9.426915]  i915_pci_probe+0x29/0xa0 [i915]
<4>[    9.426923]  pci_device_probe+0x9e/0x120
<4>[    9.426930]  really_probe+0xea/0x3c0
<4>[    9.426936]  driver_probe_device+0x10b/0x120
<4>[    9.426942]  device_driver_attach+0x4a/0x50
<4>[    9.426948]  __driver_attach+0x97/0x130
<4>[    9.426954]  ? device_driver_attach+0x50/0x50
<4>[    9.426960]  bus_for_each_dev+0x74/0xc0
<4>[    9.426966]  bus_add_driver+0x13f/0x210
<4>[    9.426971]  ? 0xffffffffa083b000
<4>[    9.426976]  driver_register+0x56/0xe0
<4>[    9.426982]  ? 0xffffffffa083b000
<4>[    9.426987]  do_one_initcall+0x58/0x300
<4>[    9.426994]  ? do_init_module+0x1d/0x1f6
<4>[    9.427001]  ? rcu_read_lock_sched_held+0x6f/0x80
<4>[    9.427007]  ? kmem_cache_alloc_trace+0x261/0x290
<4>[    9.427014]  do_init_module+0x56/0x1f6
<4>[    9.427020]  load_module+0x24d1/0x2990
<4>[    9.427032]  ? __se_sys_finit_module+0xd3/0xf0
<4>[    9.427037]  __se_sys_finit_module+0xd3/0xf0
<4>[    9.427047]  do_syscall_64+0x55/0x1c0
<4>[    9.427053]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4>[    9.427059] RIP: 0033:0x7f73d5609839
<4>[    9.427064] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48
<4>[    9.427082] RSP: 002b:00007ffdf34477b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
<4>[    9.427091] RAX: ffffffffffffffda RBX: 00005559fd5d7b40 RCX: 00007f73d5609839
<4>[    9.427099] RDX: 0000000000000000 RSI: 00007f73d52e8145 RDI: 000000000000000f
<4>[    9.427106] RBP: 00007f73d52e8145 R08: 0000000000000000 R09: 00007ffdf34478d0
<4>[    9.427114] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000000
<4>[    9.427121] R13: 00005559fd5c90f0 R14: 0000000000020000 R15: 00005559fd5d7b40
<4>[    9.427131] Modules linked in: i915(+) mei_hdcp x86_pkg_temp_thermal coretemp snd_hda_intel crct10dif_pclmul crc32_pclmul snd_hda_codec snd_hwdep e1000e snd_hda_core ghash_clmulni_intel ptp snd_pcm cdc_ether usbnet mii pps_core mei_me mei prime_numbers btusb btrtl btbcm btintel bluetooth ecdh_generic ecc
<4>[    9.427254] ---[ end trace af3eeb543bd66e66 ]---

[1] http://patchwork.freedesktop.org/patch/msgid/20190528200655.11605-1-chris@chris-wilson.co.uk

References: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_6159/fi-icl-u2/pstore0-1517155098_Oops_1.log
References: 1e40d4aea5 ("drm/i915/cnl: Implement WaProgramMgsrForCorrectSliceSpecificMmioReads")
Fixes: 1ac159e23c ("drm/i915: Expand subslice mask")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Yunwei Zhang <yunwei.zhang@intel.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190529082150.31526-1-jani.nikula@intel.com
2019-05-29 17:18:18 +03:00
Stuart Summers 1ac159e23c drm/i915: Expand subslice mask
Currently, the subslice_mask runtime parameter is stored as an
array of subslices per slice. Expand the subslice mask array to
better match what is presented to userspace through the
I915_QUERY_TOPOLOGY_INFO ioctl. The index into this array is
then calculated:
  slice * subslice stride + subslice index / 8

v2: fix spacing in set_sseu_info args
    use set_sseu_info to initialize sseu data when building
    device status in debugfs
    rename variables in intel_engine_types.h to avoid checkpatch
    warnings
v3: update headers in intel_sseu.h
v4: add const to some sseu_dev_info variables
    use sseu->eu_stride for EU stride calculations
v5: address review comments from Tvrtko and Daniele
v6: remove extra space in intel_sseu_get_subslices
    return the correct subslice enable in for_each_instdone
    add GEM_BUG_ON to ensure user doesn't pass invalid ss_mask size
    use printk formatted string for subslice mask
v7: remove string.h header and rebase

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190524154022.13575-6-stuart.summers@intel.com
2019-05-28 11:20:32 -07:00
Stuart Summers 135a63b682 drm/i915: Add macro for SSEU stride calculation
Subslice stride and EU stride are calculated multiple times in
i915_query. Move this calculation to a macro to reduce code duplication.

v2: update headers in intel_sseu.h
v3: use GEN_SSEU_STRIDE for stride calculations in intel_sseu.h
    apply s/bits/max_entries/ to GEN_SSEU_STRIDE parameter

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190524154022.13575-3-stuart.summers@intel.com
2019-05-28 11:18:17 -07:00
Tvrtko Ursulin c5d3e39caa drm/i915: Engine discovery query
Engine discovery query allows userspace to enumerate engines, probe their
configuration features, all without needing to maintain the internal PCI
ID based database.

A new query for the generic i915 query ioctl is added named
DRM_I915_QUERY_ENGINE_INFO, together with accompanying structure
drm_i915_query_engine_info. The address of latter should be passed to the
kernel in the query.data_ptr field, and should be large enough for the
kernel to fill out all known engines as struct drm_i915_engine_info
elements trailing the query.

As with other queries, setting the item query length to zero allows
userspace to query minimum required buffer size.

Enumerated engines have common type mask which can be used to query all
hardware engines, versus engines userspace can submit to using the execbuf
uAPI.

Engines also have capabilities which are per engine class namespace of
bits describing features not present on all engine instances.

v2:
 * Fixed HEVC assignment.
 * Reorder some fields, rename type to flags, increase width. (Lionel)
 * No need to allocate temporary storage if we do it engine by engine.
   (Lionel)

v3:
 * Describe engine flags and mark mbz fields. (Lionel)
 * HEVC only applies to VCS.

v4:
 * Squash SFC flag into main patch.
 * Tidy some comments.

v5:
 * Add uabi_ prefix to engine capabilities. (Chris Wilson)
 * Report exact size of engine info array. (Chris Wilson)
 * Drop the engine flags. (Joonas Lahtinen)
 * Added some more reserved fields.
 * Move flags after class/instance.

v6:
 * Do not check engine info array was zeroed by userspace but zero the
   unused fields for them instead.

v7:
 * Simplify length calculation loop. (Lionel Landwerlin)

v8:
 * Remove MBZ comments where not applicable.
 * Rename ABI flags to match engine class define naming.
 * Rename SFC ABI flag to reflect it applies to VCS and VECS.
 * SFC is wired to even _logical_ engine instances.
 * SFC applies to VCS and VECS.
 * HEVC is present on all instances on Gen11. (Tony)
 * Simplify length calculation even more. (Chris Wilson)
 * Move info_ptr assigment closer to loop for clarity. (Chris Wilson)
 * Use vdbox_sfc_access from runtime info.
 * Rebase for RUNTIME_INFO.
 * Refactor for lower indentation.
 * Rename uAPI class/instance to engine_class/instance to avoid C++
   keyword.

v9:
 * Rebase for s/num_rings/num_engines/ in RUNTIME_INFO.

v10:
 * Use new copy_query_item.

v11:
 * Consolidate with struct i915_engine_class_instnace.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tony Ye <tony.ye@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> # v7
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190522090054.6007-1-tvrtko.ursulin@linux.intel.com
2019-05-22 14:17:55 +01:00
Abdiel Janulgue 5a80e4a2cd drm/i915/query: Split out query item checks
This simplifies adding new query item objects.

v2: Use query_hdr (Tvrtko, Chris).
    int instead of u32 in return (Tvrtko)
v3: More naming fixes (Tvrtko)

Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190211173251.7131-1-abdiel.janulgue@linux.intel.com
2019-02-26 10:32:57 +00:00
Jani Nikula 3eb0930a42 Merge drm/drm-next into drm-intel-next-queued
Generally catch up with 5.0-rc1, and specifically get the changes:

96d4f267e4 ("Remove 'type' argument from access_ok() function")
0b2c8f8b6b ("i915: fix missing user_access_end() in page fault exception case")
594cc251fd ("make 'user_access_begin()' do 'access_ok()'")

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2019-01-08 10:50:22 +02:00
Linus Torvalds 96d4f267e4 Remove 'type' argument from access_ok() function
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-03 18:57:57 -08:00
Jani Nikula 0258404f9d drm/i915: start moving runtime device info to a separate struct
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: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c24fe7a4b0492a888690c46814c0ff21ce2f12b1.1546267488.git.jani.nikula@intel.com
2019-01-02 12:46:29 +02:00
Daniele Ceraolo Spurio eef4670ead drm/i915/query: fix subslice length
We dump the info as an array of u8, so we want to know the length
in number of bytes. Current code is still safe because the
variable we use BITS_PER_TYPE on is a u8.

Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181109004013.34394-1-daniele.ceraolospurio@intel.com
2018-11-09 11:42:00 -08:00
Chris Wilson 74f6e18391 drm/i915: Convert to BITS_PER_TYPE
In commit 9144d75e22 ("include/linux/bitops.h: introduce BITS_PER_TYPE"),
we made BITS_PER_TYPE available to all and now we can use the macro to
replace some open-coded computation of sizeof(T) * BITS_PER_BYTE.

Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180926104707.17410-1-chris@chris-wilson.co.uk
2018-09-26 13:32:03 +01:00
Chris Wilson a33b1dc8a7 drm/i915/query: nospec expects no more than an unsigned long
nospec quite reasonably asserts that it will never be used with an index
larger than unsigned long (that being the largest possibly index into an
C array). However, our ubi uses the convention of u64 for any large
integer, running afoul of the assertion on 32b. Reduce our index to an
unsigned long, checking for type overflow first.

  drivers/gpu/drm/i915/i915_query.c: In function 'i915_query_ioctl':
  include/linux/compiler.h:339:38: error: call to '__compiletime_assert_119' declared with attribute error: BUILD_BUG_ON failed: sizeof(_s) > sizeof(long)

Reported-by: kbuild-all@01.org
Fixes: 84b510e22d ("drm/i915/query: Protect tainted function pointer lookup")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180522121018.15199-1-chris@chris-wilson.co.uk
2018-05-22 16:55:57 +01:00
Chris Wilson 84b510e22d drm/i915/query: Protect tainted function pointer lookup
Smatch identifies i915_query_ioctl() as being a potential victim of
Spectre due to its use of a tainted user index into a function pointer
array. Use array_index_nospec() to defang the user index before using it
to lookup the function pointer.

Fixes: a446ae2c6e ("drm/i915: add query uAPI")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180521210530.26008-1-chris@chris-wilson.co.uk
2018-05-22 10:47:07 +01:00
Lionel Landwerlin c822e05918 drm/i915: expose rcs topology through query uAPI
With the introduction of asymmetric slices in CNL, we cannot rely on
the previous SUBSLICE_MASK getparam to tell userspace what subslices
are available. Here we introduce a more detailed way of querying the
Gen's GPU topology that doesn't aggregate numbers.

This is essential for monitoring parts of the GPU with the OA unit,
because counters need to be normalized to the number of
EUs/subslices/slices. The current aggregated numbers like EU_TOTAL do
not gives us sufficient information.

The Mesa series making use of this API is :

    https://patchwork.freedesktop.org/series/38795/

As a bonus we can draw representations of the GPU :

    https://imgur.com/a/vuqpa

v2: Rename uapi struct s/_mask/_info/ (Tvrtko)
    Report max_slice/subslice/eus_per_subslice rather than strides (Tvrtko)
    Add uapi macros to read data from *_info structs (Tvrtko)

v3: Use !!(v & DRM_I915_BIT()) for uapi macros instead of custom shifts (Tvrtko)

v4: factorize query item writting (Tvrtko)
    tweak uapi struct/define names (Tvrtko)

v5: Replace ALIGN() macro (Chris)

v6: Updated uapi comments (Tvrtko)
    Moved flags != 0 checks into vfuncs (Tvrtko)

v7: Use access_ok() before copying anything, to avoid overflows (Chris)
    Switch BUG_ON() to GEM_WARN_ON() (Tvrtko)

v8: Tweak uapi comments style to match the coding style (Lionel)

v9: Fix error in comment about computation of enabled subslice (Tvrtko)

v10: Fix/update comments in uAPI (Sagar)

v11: Drop drm_i915_query_(slice|subslice|eu)_info in favor of a single
     drm_i915_query_topology_info (Joonas)

v12: Add subslice_stride/eu_stride in drm_i915_query_topology_info (Joonas)

v13: Fix comment in uAPI (Joonas)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180306122857.27317-7-lionel.g.landwerlin@intel.com
2018-03-08 10:07:24 +00:00
Lionel Landwerlin a446ae2c6e drm/i915: add query uAPI
There are a number of information that are readable from hardware
registers and that we would like to make accessible to userspace. One
particular example is the topology of the execution units (how are
execution units grouped in subslices and slices and also which ones
have been fused off for die recovery).

At the moment the GET_PARAM ioctl covers some basic needs, but
generally is only able to return a single value for each defined
parameter. This is a bit problematic with topology descriptions which
are array/maps of available units.

This change introduces a new ioctl that can deal with requests to fill
structures of potentially variable lengths. The user is expected fill
a query with length fields set at 0 on the first call, the kernel then
sets the length fields to the their expected values. A second call to
the kernel with length fields at their expected values will trigger a
copy of the data to the pointed memory locations.

The scope of this uAPI is only to provide information to userspace,
not to allow configuration of the device.

v2: Simplify dispatcher code iteration (Tvrtko)
    Tweak uapi drm_i915_query_item structure (Tvrtko)

v3: Rename pad fields into flags (Chris)
    Return error on flags field != 0 (Chris)
    Only copy length back to userspace in drm_i915_query_item (Chris)

v4: Use array of functions instead of switch (Chris)

v5: More comments in uapi (Tvrtko)
    Return query item errors in length field (All)

v6: Tweak uapi comments style to match the coding style (Lionel)

v7: Add i915_query.h (Joonas)

v8: (Lionel) Change the behavior of the item iterator to report
    invalid queries into the query item rather than stopping the
    iteration. This enables userspace applications to query newer
    items on older kernels and only have failure on the items that are
    not supported.

v9: Edit copyright headers (Joonas)

v10: Typos & comments in uapi (Joonas)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180306122857.27317-6-lionel.g.landwerlin@intel.com
2018-03-08 10:07:18 +00:00