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
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| @@ -296,6 +296,9 @@ struct drm_panthor_gpu_info { · 295 unmodified lines | ||
| 296 | 296 | /** @as_present: Bitmask encoding the number of address-space exposed by the MMU. */ |
| 297 | 297 | __u32 as_present; |
| 298 | 298 | |
| 299 | + /** @pad0: MBZ. */ | |
| 300 | + __u32 pad0; | |
| 301 | + | |
| 299 | 302 | /** @shader_present: Bitmask encoding the shader cores exposed by the GPU. */ |
| 300 | 303 | __u64 shader_present; |
| 301 | 304 | |