On 2025-10-09 12:19, Christian König wrote:
> On 09.10.25 17:06, Ard Biesheuvel wrote:
>> From: Ard Biesheuvel <[email protected]>
>>
>> Test the existing CPP macro _LINUX_FPU_COMPILATION_UNIT, which is set
>> when building source files that are permitted to use floating point,
>> in the implementation of DC_FP_START/END so that those are only usable
>> in non-FP code. This is a requirement of the generic kernel mode FPU
>> API, as some architectures (i.e., arm64) cannot safely enable FP codegen
>> in arbitrary code.
>
> If I'm not completely mistaken that is actually an issue on basically all
> architectures, at least x86 is affected as well if I'm not completely
> mistaken.
>
>> Cc: Austin Zheng <[email protected]>
>> Cc: Jun Lei <[email protected]>
>> Cc: Harry Wentland <[email protected]>
>> Cc: Leo Li <[email protected]>
>> Cc: Rodrigo Siqueira <[email protected]>
>> Cc: Alex Deucher <[email protected]>
>> Cc: "Christian König" <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>> Signed-off-by: Ard Biesheuvel <[email protected]>
>
> Anyway, patch looks sane to me but I'm not so deep in the DC code to fully
> judge.
>
> Fell free to add Acked-by: Christian König <[email protected]>, but
> Harry and Leo need to take a look.
>
Thanks. Good safe-guard. Flags a bunch of issues in the
current code. Let me fix them before merging it.
Reviewed-by: Harry Wentland <[email protected]>
Harry
> Thanks,
> Christian.
>
>> ---
>> drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.h | 8 ++++++++
>> drivers/gpu/drm/amd/display/dc/os_types.h | 2 --
>> 2 files changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.h
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.h
>> index b8275b397920..4e921632bc4e 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.h
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.h
>> @@ -31,4 +31,12 @@ void dc_assert_fp_enabled(void);
>> void dc_fpu_begin(const char *function_name, const int line);
>> void dc_fpu_end(const char *function_name, const int line);
>>
>> +#ifndef _LINUX_FPU_COMPILATION_UNIT
>> +#define DC_FP_START() dc_fpu_begin(__func__, __LINE__)
>> +#define DC_FP_END() dc_fpu_end(__func__, __LINE__)
>> +#else
>> +#define DC_FP_START() BUILD_BUG()
>> +#define DC_FP_END() BUILD_BUG()
>> +#endif
>> +
>> #endif /* __DC_FPU_H__ */
>> diff --git a/drivers/gpu/drm/amd/display/dc/os_types.h
>> b/drivers/gpu/drm/amd/display/dc/os_types.h
>> index 782316348941..6af831710489 100644
>> --- a/drivers/gpu/drm/amd/display/dc/os_types.h
>> +++ b/drivers/gpu/drm/amd/display/dc/os_types.h
>> @@ -55,8 +55,6 @@
>>
>> #if defined(CONFIG_DRM_AMD_DC_FP)
>> #include "amdgpu_dm/dc_fpu.h"
>> -#define DC_FP_START() dc_fpu_begin(__func__, __LINE__)
>> -#define DC_FP_END() dc_fpu_end(__func__, __LINE__)
>> #endif /* CONFIG_DRM_AMD_DC_FP */
>>
>> /*
>
