Re: [RFC v2] linux-user/riscv: Add syscall riscv_hwprobe

[Richard Henderson <richard.henderson@linaro.org>]

On 6/3/23 08:50, Andrew Jones wrote:
> On Fri, Jun 02, 2023 at 07:58:30PM -0700, Richard Henderson wrote:
>> On 6/2/23 07:02, Andrew Jones wrote:
>>>> +struct riscv_hwprobe {
>>>> +    int64_t  key;
>>>> +    uint64_t value;
>>>> +};
>>>
>>> The above is all uapi so Linux's arch/riscv/include/uapi/asm/hwprobe.h
>>> should be picked up on Linux header update. You'll need to modify the
>>> script, scripts/update-linux-headers.sh, to do that by adding a new
>>> riscv-specific block. Hacking this by importing the header file manually
>>> is fine for an RFC, but that should be a separate patch or part of the
>>> syscall define hack patch. And hack patches should be clearly tagged as
>>> "NOT FOR MERGE".
>>
>>
>> Not true.  linux-user/ never looks at linux-headers/.
> 
> Ah, thanks. I should have known better than to try and review a linux-user
> patch, since I know almost nothing about it! Is uapi like this usually
> duplicated, as was done in this patch?

Yes, because linux-headers is only for the "native" compiler, whereas linux-user requires 
the ABI of the guest.

If we were doing this all from scratch, we would mechanically parse and rewrite linux-headers.


r~