Re: [RFC PATCH v4 27/29] Hexagon (linux-user/hexagon) Linux user emulation

[Laurent Vivier <laurent@vivier.eu>]

Le 30/09/2020 à 22:47, Taylor Simpson a écrit :
> 
> 
>> -----Original Message-----
>> From: Laurent Vivier <laurent@vivier.eu>
>> Sent: Monday, September 28, 2020 3:03 PM
>> To: Taylor Simpson <tsimpson@quicinc.com>; qemu-devel@nongnu.org
>> Cc: richard.henderson@linaro.org; philmd@redhat.com; riku.voipio@iki.fi;
>> aleksandar.m.mail@gmail.com; ale@rev.ng
>> Subject: Re: [RFC PATCH v4 27/29] Hexagon (linux-user/hexagon) Linux user
>> emulation
>>
>>> +
>>> +syscall_nr_generators += {
>>> +  'hexagon': generator(sh,
>>> +                       arguments: [ 'cat', 'syscall_nr.h', '>', '@OUTPUT@' ],
>>> +                     output: '@BASENAME@_nr.h')
>>
>> Why do we need that?
>> The syscall_nr_generators is used to generate syscall_nr.h from syscall.tbl
> 
> The other linux-user targets have this in their meson.build files.  I'll remove if it's not needed.

Not all the targets (only the ones with syscall.tbl) and they call
syscallhdr.sh and not cat. So you can remove it.

>>
>>> +}
>>> diff --git a/linux-user/meson.build b/linux-user/meson.build
>>> index 2b94e4b..8b1dfc8 100644
>>> --- a/linux-user/meson.build
>>> +++ b/linux-user/meson.build
>>> @@ -22,6 +22,7 @@ syscall_nr_generators = {}
>>>
>>>  subdir('alpha')
>>>  subdir('arm')
>>> +subdir('hexagon')
>>
>> so you don't need that either
> 
> OK
> 
>>> -    grep -e "#define __NR_" -e "#define __NR3264"
>>> +    grep -e "#define __NR_" -e "#define __NR3264" | grep -v
>> __NR_syscalls
>>
>> Why do you remove __NR_syscalls?
> 
> Older kernels have a bunch of
> #undef __NR_syscalls
> #define __NR_syscalls  X
> 
> The script removes all #undef's but leaves the #define's, so we get compile errors.  That symbol isn't used by qemu so it's safe to remove.
> 

As the syscall_nr.h generated from syscall.tbl don't have this symbol, I
think we can remove it. But I'm very surprised it doesn't work with it
for you.

Could you put this one-line change in a separate patch?

The best would be to re-run it once the change is made to update all the
generated syscall_nr.h without the __NR_syscalls line.

Moreover the syscall_nr.h I generate from linux-5.9 for hexagon is
different from the one you put in this series (the 1024 -> 1079 part is
missing).

Thanks,
Laurent