Re: [RFC PATCH 09/12] riscv: Add support for kernel-mode FPU

[Samuel Holland]

On 2023-12-11 10:11 AM, Christoph Hellwig wrote:
>> +#ifdef __riscv_f
>> +
>> +#define kernel_fpu_begin() \
>> +	static_assert(false, "floating-point code must use a separate translation unit")
>> +#define kernel_fpu_end() kernel_fpu_begin()
>> +
>> +#else
>> +
>> +void kernel_fpu_begin(void);
>> +void kernel_fpu_end(void);
>> +
>> +#endif
> 
> I'll assume this is related to trick that places code in a separate
> translation unit, but I fail to understand it.  Can you add a comment
> explaining it?

Yes, I can add a comment. Here, __riscv_f refers to RISC-V's F extension for
single-precision floating point, which is enabled by CC_FLAGS_FPU.