Re: [PATCH 7/8] csky: Use latest system call ABI

[Arnd Bergmann]

On Mon, Feb 18, 2019 at 11:40 PM Joseph Myers <joseph@xxxxxxxxxxxxxxxx> wrote:
>
> On Mon, 18 Feb 2019, Arnd Bergmann wrote:
>
> > We don't yet have an upstream glibc port for csky, so there is no user
>
> We do.  It's in 2.29.
...
On Tue, Feb 19, 2019 at 3:18 AM Guo Ren <guoren@xxxxxxxxxx> wrote:
>
> Mao Han has merged csky port into glibc 2.29, so we should keep the
> __ARCH_WANT_TIME32_SYSCALLS.

My mistake. I've dropped patch 7/8 from this series now.

> > diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
> > index 6959e0b1e956..398113c845f5 100644
> > --- a/arch/csky/Kconfig
> > +++ b/arch/csky/Kconfig
> > @@ -1,6 +1,5 @@
> >  config CSKY
> >       def_bool y
> > -     select ARCH_32BIT_OFF_T
> >       select ARCH_HAS_SYNC_DMA_FOR_CPU
> >       select ARCH_HAS_SYNC_DMA_FOR_DEVICE
> >       select ARCH_USE_BUILTIN_BSWAP
> > diff --git a/arch/csky/include/uapi/asm/unistd.h b/arch/csky/include/uapi/asm/unistd.h
> > index ec60e49cea66..224c9a9ab45b 100644
> > --- a/arch/csky/include/uapi/asm/unistd.h
> > +++ b/arch/csky/include/uapi/asm/unistd.h
> > @@ -2,8 +2,6 @@
> >  // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
> >
> >  #define __ARCH_WANT_SYS_CLONE
> > -#define __ARCH_WANT_SET_GET_RLIMIT
> Seems it's not related to y2038 issue. Is __ARCH_WANT_SET_GET_RLIMIT no
> use ?

In new architectures, we do not need to set CONFIG_ARCH_32BIT_OFF_T
or __ARCH_WANT_SET_GET_RLIMIT, since we can assume that user
space always uses a 64-bit off_t and a 'struct rlimit' matching the
kernel's rlimit64, with the prlimit64() system call replacing both getrlimit
and setrlimit on the kernel/user ABI side.

I don't know if glibc still uses the 32-bit off_t behavior or the old
getrlimit/setrlimit, but if we're not also changing the time32 interfaces,
the safest option seems to be to leave all three in place.

     Arnd