Re: [Qemu-devel] [PULL v3 47/55] linux headers: update against Linux 5.2-rc1

[Laurent Vivier <laurent@vivier.eu>]

On 23/05/2019 21:16, Alex Bennée wrote:
> 
> Laurent Vivier <laurent@vivier.eu> writes:
> 
>> On 23/05/2019 13:56, Cornelia Huck wrote:
>>> On Wed, 22 May 2019 15:22:23 +0200
>>> Aleksandar Markovic <aleksandar.m.mail@gmail.com> wrote:
>>>
>>>> The alternative way of invoking via IPCV6 (else part of “ifdef
>>>> __NR_MSGSND”) should work for MIPS in the present stage of headers and
>>>> kernel.
>>>
>>> I tried to do that so that we have at least a workaround for now; but
>>> this fails building on my x86 laptop (the safe_syscall6 for ipc
>>> complains about missing __NR_ipc). Maybe I'm holding it wrong (should
>>> that be conditional on the host?), but I think that really needs to be
>>> done by the mips maintainers...
>>>
>>
>> Perhaps a simple workaround could be:
>>
>> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
>> index e311fcda0517..5b431736032c 100644
>> --- a/linux-user/syscall.c
>> +++ b/linux-user/syscall.c
>> @@ -761,14 +761,8 @@ safe_syscall2(int, nanosleep, const struct timespec *, req,
>>   safe_syscall4(int, clock_nanosleep, const clockid_t, clock, int, flags,
>>                 const struct timespec *, req, struct timespec *, rem)
>>   #endif
>> -#ifdef __NR_msgsnd
>> -safe_syscall4(int, msgsnd, int, msgid, const void *, msgp, size_t, sz,
>> -              int, flags)
>> -safe_syscall5(int, msgrcv, int, msgid, void *, msgp, size_t, sz,
>> -              long, msgtype, int, flags)
>> -safe_syscall4(int, semtimedop, int, semid, struct sembuf *, tsops,
>> -              unsigned, nsops, const struct timespec *, timeout)
>> -#else
>> +
>> +#ifdef __NR_ipc
>>   /* This host kernel architecture uses a single ipc syscall; fake up
>>    * wrappers for the sub-operations to hide this implementation detail.
>>    * Annoyingly we can't include linux/ipc.h to get the constant definitions
>> @@ -783,14 +777,30 @@ safe_syscall4(int, semtimedop, int, semid, struct sembuf *, tsops,
>>
>>   safe_syscall6(int, ipc, int, call, long, first, long, second, long, third,
>>                 void *, ptr, long, fifth)
>> +#endif
> 
> *sigh* almost but for arches we get complaints when the ipc syscall is
>   defined but not used....
> 
>    https://app.shippable.com/github/stsquad/qemu/runs/835/summary/console

Yes, I've know.

I have sent a patch with an updated #if:

  #if !defined(__NR_msgsnd) || !defined(__NR_msgrcv) || !defined(__NR_semtimedop)

And it should work on any arch.

Thanks,
Laurent