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linux/include/drm
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Linus Torvalds 710051ebb7 drm: fix EDID struct for old ARM OABI format 
[ Upstream commit 47f15561b6 ]

When building the kernel for arm with the "-mabi=apcs-gnu" option, gcc
will force alignment of all structures and unions to a word boundary
(see also STRUCTURE_SIZE_BOUNDARY and the "-mstructure-size-boundary=XX"
option if you're a gcc person), even when the members of said structures
do not want or need said alignment.

This completely messes up the structure alignment of 'struct edid' on
those targets, because even though all the embedded structures are
marked with "__attribute__((packed))", the unions that contain them are
not.

This was exposed by commit f1e4c916f9 ("drm/edid: add EDID block count
and size helpers"), but the bug is pre-existing.  That commit just made
the structure layout problem cause a build failure due to the addition
of the

        BUILD_BUG_ON(sizeof(*edid) != EDID_LENGTH);

sanity check in drivers/gpu/drm/drm_edid.c:edid_block_data().

This legacy union alignment should probably not be used in the first
place, but we can fix the layout by adding the packed attribute to the
union entries even when each member is already packed and it shouldn't
matter in a sane build environment.

You can see this issue with a trivial test program:

  union {
	struct {
		char c[5];
	};
	struct {
		char d;
		unsigned e;
	} __attribute__((packed));
  } a = { "1234" };

where building this with a normal "gcc -S" will result in the expected
5-byte size of said union:

	.type	a, @object
	.size	a, 5

but with an ARM compiler and the old ABI:

    arm-linux-gnu-gcc -mabi=apcs-gnu -mfloat-abi=soft -S t.c

you get

	.type	a, %object
	.size	a, 8

instead, because even though each member of the union is packed, the
union itself still gets aligned.

This was reported by Sudip for the spear3xx_defconfig target.

Link: https://lore.kernel.org/lkml/YpCUzStDnSgQLNFN@debian/
Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2022-06-09 10:22:44 +02:00
..
bridge drm: bridge: dw-hdmi: Attach to next bridge if available 2021-07-28 16:33:13 +03:00
i2c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ttm drm/ttm: remove ttm_bo_vm_insert_huge() 2021-11-18 19:17:08 +01:00
amd_asic_type.h drm/amdgpu: add cyan_skillfish asic type 2021-07-23 10:08:00 -04:00
drm_aperture.h drm/aperture: Pass DRM driver structure instead of driver name 2021-07-01 11:11:55 +02:00
drm_atomic.h drm: fix doc warnings in drm_atomic.h 2021-06-04 12:40:01 -04:00
drm_atomic_helper.h drm: automatic legacy gamma support 2020-12-15 15:46:03 +02:00
drm_atomic_state_helper.h drm/bridge: Add a drm_bridge_state object 2020-01-31 16:00:21 +01:00
drm_atomic_uapi.h drm: extract drm_atomic_uapi.c 2018-09-09 14:19:18 +02:00
drm_audio_component.h ALSA: hda/i915 - fix list corruption with concurrent probes 2020-10-09 16:46:04 +02:00
drm_auth.h drm: clarify usage of drm leases 2021-07-29 09:12:01 +02:00
drm_blend.h drm: Add per-plane pixel blend mode property 2018-08-24 17:31:37 +01:00
drm_bridge.h drm: bridge: Mark deprecated operations in drm_bridge_funcs 2021-07-12 21:44:19 +02:00
drm_bridge_connector.h drm: Add helper to create a connector for a chain of bridges 2020-02-26 13:31:41 +02:00
drm_cache.h drm: Add a prefetching memcpy_from_wc 2021-06-07 16:07:08 +02:00
drm_client.h drm/gem: Store client buffer mappings as struct dma_buf_map 2020-11-09 09:19:45 +01:00
drm_color_mgmt.h drm: Inline drm_color_lut_extract() 2019-11-29 21:29:17 +02:00
drm_connector.h drm/connector: Fix typo in documentation 2022-04-08 14:24:12 +02:00
drm_crtc.h drm: drm_crc: fix a kernel-doc markup 2021-01-14 15:11:46 +01:00
drm_crtc_helper.h drm: Split out drm_probe_helper.h 2019-01-24 13:20:42 +01:00
drm_damage_helper.h drm/plane: Move drm_plane_enable_fb_damage_clips into core 2021-07-27 12:21:22 +02:00
drm_debugfs.h drm/debugfs: remove checks for return value of drm_debugfs functions. 2020-03-18 17:32:20 +01:00
drm_debugfs_crc.h drm/crc: Only report a single overflow when a CRC fd is opened 2018-07-06 14:57:03 +02:00
drm_device.h drm: IRQ midlayer is now legacy 2021-08-10 20:14:01 +02:00
drm_displayid.h drm/displayid: rename displayid_hdr to displayid_header 2021-03-31 15:42:39 +03:00
drm_dp_aux_bus.h drm: Introduce the DP AUX bus 2021-06-11 12:30:39 -07:00
drm_dp_dual_mode_helper.h drm/dp_dual_mode: Pass drm_device to drm_lspcon_(get|set)_mode() 2021-04-27 18:43:44 -04:00
drm_dp_helper.h drm/dp: Fix off-by-one in register cache size 2022-04-08 14:24:04 +02:00
drm_dp_mst_helper.h drm/dp_mst: Use kHz as link rate units when settig source max link caps at init 2021-05-27 15:30:59 -04:00
drm_drv.h drm: IRQ midlayer is now legacy 2021-08-10 20:14:01 +02:00
drm_dsc.h - Display hotplug fix for gen2/gen3 (Chris) 2021-01-07 12:20:29 +01:00
drm_edid.h drm: fix EDID struct for old ARM OABI format 2022-06-09 10:22:44 +02:00
drm_encoder.h drm/encoder: Add macro drmm_plain_encoder_alloc() 2021-03-29 16:46:43 +01:00
drm_encoder_slave.h drm: remove include of drmP.h from drm_encoder_slave.h 2019-01-09 22:35:35 +01:00
drm_fb_cma_helper.h drm: Add and export function drm_fb_cma_sync_non_coherent 2021-05-25 11:42:09 +01:00
drm_fb_helper.h drm/aperture: Inline fbdev conflict helpers into aperture helpers 2021-04-14 09:00:04 +02:00
drm_file.h drm: add lockdep assert to drm_is_current_master_locked 2021-08-05 12:08:15 +02:00
drm_fixed.h drm: Add drm_fixp_from_fraction and drm_fixp2int_ceil 2016-02-05 15:23:48 +10:00
drm_flip_work.h drm/kms-helpers: Use recommened kerneldoc for struct member refs 2017-01-25 16:18:57 +01:00
drm_format_helper.h drm/format-helper: Add blitter functions 2021-05-01 12:45:03 +02:00
drm_fourcc.h drm: Define DRM_FORMAT_MAX_PLANES 2021-08-02 16:41:20 +02:00
drm_framebuffer.h drm: Define DRM_FORMAT_MAX_PLANES 2021-08-02 16:41:20 +02:00
drm_gem.h drm: Drop drm_gem_object_put_locked() 2021-07-27 18:09:18 -07:00
drm_gem_atomic_helper.h drm/gem: Provide offset-adjusted framebuffer BO mappings 2021-08-08 20:26:16 +02:00
drm_gem_cma_helper.h drm: Add support for GEM buffers backed by non-coherent memory 2021-05-25 11:41:07 +01:00
drm_gem_framebuffer_helper.h drm/gem: Provide offset-adjusted framebuffer BO mappings 2021-08-08 20:26:16 +02:00
drm_gem_shmem_helper.h drm/shmem-helper: Removed drm_gem_shmem_create_object_cached() 2020-11-24 09:10:33 +01:00
drm_gem_ttm_helper.h drm/gem-ttm-helper: Provide helper for struct drm_driver.dumb_map_offset 2021-04-11 20:14:45 +02:00
drm_gem_vram_helper.h drm/vram-helper: Unexport drm_vram_helper_{alloc,release}_mm() 2021-07-05 08:55:11 +02:00
drm_hashtab.h drm: drop extern from function decls 2017-03-24 09:36:06 +01:00
drm_hdcp.h drm/hdcp: DP HDCP2.2 errata LC_Send_L_Prime=16 2021-03-31 14:27:43 +03:00
drm_ioctl.h drm: Return -ENOTTY for non-drm ioctls 2021-07-20 15:57:43 +02:00
drm_lease.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
drm_legacy.h drm: IRQ midlayer is now legacy 2021-08-10 20:14:01 +02:00
drm_managed.h drm: Remove drmm_add_final_kfree() declaration from public headers 2020-12-05 20:01:12 +01:00
drm_mipi_dbi.h drm/dbi: Print errors for mipi_dbi_command() 2021-07-05 00:22:51 +02:00
drm_mipi_dsi.h drm/dsi: Add _NO_ to MIPI_DSI_* flags disabling features 2021-07-27 09:48:24 +02:00
drm_mm.h drm: fix spelling error in comments 2020-09-17 13:39:44 +02:00
drm_mode_config.h drm/modifiers: Enforce consistency between the cap an IN_FORMATS 2021-05-12 11:31:29 +02:00
drm_mode_object.h drm: remove drm_mode_object_{un/reference} aliases 2018-03-19 09:09:46 -04:00
drm_modes.h drm/modes: add non-OF stub for of_get_drm_display_mode 2021-01-08 19:42:14 +01:00
drm_modeset_helper.h drm: remove drmP.h from drm_modeset_helper.h 2019-02-07 21:48:34 +01:00
drm_modeset_helper_vtables.h drm/atomic-helper: make drm_gem_plane_helper_prepare_fb the default 2021-06-24 15:35:13 +02:00
drm_modeset_lock.h drm/modeset-lock: Take the modeset BKL for legacy drivers 2020-08-17 13:41:50 -04:00
drm_of.h drm: of: Fix linking when CONFIG_OF is not set 2020-01-09 10:40:58 +10:00
drm_panel.h drm/dp: Move panel DP AUX backlight support to drm_dp_helper 2021-07-13 06:38:37 -07:00
drm_pciids.h drm/radeon: change SPDX identifier to MIT 2018-10-15 16:16:12 -05:00
drm_plane.h drm/plane: Move drm_plane_enable_fb_damage_clips into core 2021-07-27 12:21:22 +02:00
drm_plane_helper.h drm: Unexport drm_plane_helper_check_update 2018-10-05 22:45:19 +02:00
drm_prime.h drm/prime: split array import functions v4 2020-11-30 15:00:45 +01:00
drm_print.h drm/print: fixup spelling in a comment 2021-07-20 15:08:18 +02:00
drm_probe_helper.h drm: Split out drm_probe_helper.h 2019-01-24 13:20:42 +01:00
drm_property.h drm: document drm_property_enum.value for bitfields 2021-07-26 10:08:22 +02:00
drm_rect.h drm/plane: remove drm_helper_get_plane_damage_clips 2021-07-27 12:21:22 +02:00
drm_scdc_helper.h drm/scdc: Fix typo in bit definition of SCDC_STATUS_FLAGS 2019-11-04 17:58:46 +01:00
drm_self_refresh_helper.h drm/atomic: fix self-refresh helpers crtc state dereference 2019-11-06 13:00:21 -05:00
drm_simple_kms_helper.h drm/simple-kms: Support custom CRTC state 2021-08-08 20:14:08 +02:00
drm_syncobj.h drm/syncobj: add new drm_syncobj_add_point interface v4 2019-04-01 12:05:53 +02:00
drm_sysfs.h drm: uevent for connector status change 2019-08-06 13:16:54 +05:30
drm_util.h drm: Move EXPORT_SYMBOL_FOR_TESTS_ONLY under a separate Kconfig 2019-11-07 21:22:15 +00:00
drm_utils.h drm: export drm_timeout_abs_to_jiffies 2019-03-07 12:00:30 -06:00
drm_vblank.h drm/vblank: Document drm_crtc_vblank_restore constraints 2021-02-10 12:38:55 +01:00
drm_vblank_work.h drm/vblank: Add vblank works 2020-07-16 18:16:31 -04:00
drm_vma_manager.h drm/vma: Add a driver_private member to vma_node. 2021-06-11 10:53:18 +02:00
drm_writeback.h drm/writeback: wire drm_writeback.h to kernel-doc 2020-04-07 17:39:46 +02:00
gma_drm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335 2019-06-05 17:37:06 +02:00
gpu_scheduler.h drm/sched: Allow using a dedicated workqueue for the timeout/fault tdr 2021-07-01 08:53:25 +02:00
gud.h drm: Add GUD USB Display driver 2021-03-16 13:12:46 +01:00
i915_component.h drm/i915/tgl: Add additional ports for Tiger Lake 2019-07-11 16:31:14 -07:00
i915_drm.h drm: Move port definition back to i915 header 2019-08-30 14:08:26 +05:30
i915_mei_hdcp_interface.h drm/i915: significantly reduce the use of <drm/i915_drm.h> 2020-02-27 08:35:09 +02:00
i915_pciids.h drm/i915/adl_p: Add PCI Devices IDs 2021-05-07 10:51:38 +03:00
intel-gtt.h iommu/vt-d: Move intel_iommu_gfx_mapped to Intel IOMMU header 2020-09-04 12:12:45 +02:00
intel_lpe_audio.h ALSA: x86: Register multiple PCM devices for the LPE audio card 2017-05-03 16:24:00 +03:00
spsc_queue.h drm: move amd_gpu_scheduler into common location 2017-12-07 11:51:56 -05:00
task_barrier.h drm: Add Reusable task barrier. 2019-12-18 16:09:12 -05:00