drm/amd/display: Add DC_FP helper to check FPU state

To fully isolate FPU operations in a single place, we must avoid
situations where compilers spill FP values to registers due to FP enable
in a specific C file. Note that even if we isolate all FPU functions in
a single file and call its interface from other files, the compiler
might enable the use of FPU before we call DC_FP_START. Nevertheless, it
is the programmer's responsibility to invoke DC_FP_START/END in the
correct place. To highlight situations where developers forgot to use
the FP protection before calling the DC FPU interface functions, we
introduce a helper that checks if the function is invoked under FP
protection. If not, it will trigger a kernel warning.

Changes cince V3:
- Rebase

Changes cince V2 (Christian):
- Do not use this_cpu_* between get/put_cpu_ptr().
- In the kernel documentation, better describe restrictions.
- Make dc_assert_fp_enabled trigger the ASSERT message.

Changes since V1:
- Remove fp_enable variables
- Rename dc_is_fp_enabled to dc_assert_fp_enabled
- Replace wrong variable type

Cc: Harry Wentland <[email protected]>
Cc: Anson Jacob <[email protected]>
Cc: Christian König <[email protected]>
Cc: Hersen Wu <[email protected]>
Cc: Aric Cyr <[email protected]>
Cc: Jun Lei <[email protected]>
Cc: Dmytro Laktyushkin <[email protected]>
Cc: Qingqing Zhuo <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Rodrigo Siqueira <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

0 files changed, 0 insertions, 0 deletions