glibc for 32-bit kernel without __ARCH_WANT_TIME32_SYSCALLS

[Palmer Dabbelt]

On Fri, 21 Jun 2019 02:34:18 PDT (-0700), fweimer@redhat.com wrote:
> * Alistair Francis:
>
>> Linux 5.1 has removed the __ARCH_WANT_TIME32_SYSCALLS define for the
>> RISC-V 32-bit port. This means that glibc (with the latest 32-bit
>> RISC-V port submission) fails to build as there are a lot of missing
>> syscalls, __NR_futex is the first one I see.
>>
>> I looked at adjusting the syscalls to use the new 64-bit versions
>> (such as __NR_futex64) but this seems to be a large job with a lot of
>> manual changes. Is there a better way that I should be doing this?
>> Have any other 32-bit architectures removed
>> __ARCH_WANT_TIME32_SYSCALLS or are in the process of removing
>> __ARCH_WANT_TIME32_SYSCALLS?
>
> Maybe look at the x86-64 x32 port?  It may make sense to align with that
> and pretend that the time-related system calls are always 64-bit on the
> 32-bit RISC-V port.

The plan is to just actually always have 64-bit kernel time calls on 32-bit
RISC-V, which is what has been blocking the port.  I was under the impression
it was possible to do this with a very new kernel, but I haven't had time to
actively look in to it so I might be wrong.

I'm adding Arnd, who was doing the work on the kernel side.

Arnd: I'm not sure if you read libc-alpha.  Can we pull the tirgger in a
64-bit-only time_t rv32i glibc port?