6.15-stable review patch. If anyone has any objections, please let me know.
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From: Boris Brezillon boris.brezillon@collabora.com
[ Upstream commit 95cbab48782bf62e4093837dc15ac6133902c12f ]
drm_panthor_gpu_info::shader_present is currently automatically offset by 4 byte to meet Arm's 32-bit/64-bit field alignment rules, but those constraints don't stand on 32-bit x86 and cause a mismatch when running an x86 binary in a user emulated environment like FEX. It's also generally agreed that uAPIs should explicitly pad their struct fields, which we originally intended to do, but a mistake slipped through during the submission process, leading drm_panthor_gpu_info::shader_present to be misaligned.
This uAPI change doesn't break any of the existing users of panthor which are either arm32 or arm64 where the 64-bit alignment of u64 fields is already enforced a the compiler level.
Changes in v2: - Rename the garbage field into pad0 and adjust the comment accordingly - Add Liviu's A-b
Changes in v3: - Add R-bs
Fixes: 0f25e493a246 ("drm/panthor: Add uAPI") Acked-by: Liviu Dudau liviu.dudau@arm.com Reviewed-by: Adrián Larumbe adrian.larumbe@collabora.com Reviewed-by: Steven Price steven.price@arm.com Link: https://lore.kernel.org/r/20250606080932.4140010-2-boris.brezillon@collabora... Signed-off-by: Boris Brezillon boris.brezillon@collabora.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/uapi/drm/panthor_drm.h | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h index 97e2c4510e69..dbb907eae443 100644 --- a/include/uapi/drm/panthor_drm.h +++ b/include/uapi/drm/panthor_drm.h @@ -293,6 +293,9 @@ struct drm_panthor_gpu_info { /** @as_present: Bitmask encoding the number of address-space exposed by the MMU. */ __u32 as_present;
+ /** @pad0: MBZ. */ + __u32 pad0; + /** @shader_present: Bitmask encoding the shader cores exposed by the GPU. */ __u64 shader_present;