Re: [PATCH v2 1/6] sysv/linux: Rename alpha functions to be alpha specific

[Stepan Golosunov <stepan at golosunov dot pp dot ru>]

11.02.2020 в 09:56:59 -0800 Alistair Francis написал(а):
> On Tue, Feb 11, 2020 at 8:23 AM Zack Weinberg <zackw@panix.com> wrote:
> >
> > On Tue, Feb 11, 2020 at 11:06 AM Alistair Francis <alistair23@gmail.com> wrote:
> > >
> > > On Tue, Feb 11, 2020 at 6:39 AM Zack Weinberg <zackw@panix.com> wrote:
> > > >
> > > > On Tue, Feb 11, 2020 at 8:25 AM Adhemerval Zanella
> > > > <adhemerval.zanella@linaro.org> wrote:
> > > > > On 10/02/2020 22:10, Zack Weinberg wrote:
> > > > > >
> > > > > > This doesn't address any of my concerns.  It should not be necessary
> > > > > > to duplicate an *internal header* full of functions whose operation
> > > > > > is, or ought to be, completely generic, just because the exposed API
> > > > > > is different on Alpha.
> > > > >
> > > > > The 32-bit timeval struct are alpha specific in a sense that no other
> > > > > 64-bit architectures have 32 time_t.
> > > > >
> > > > > We could certainly make it generic and add even more internally
> > > > > pre-processor magic to fit alpha code in generic definitions, but I
> > > > > think it is really a worthless complication.  It is a legacy API,
> > > > > and it is highly unlikely that any other port will use such code.
> > > >
> > > > I think we're talking past each other.  This patch is about
> > > > tv32-compat.h.  tv32-compat.h contains conversion functions between
> > > > e.g. struct timeval with 32-bit time_t and struct timeval with 64-bit
> > > > time_t.  I still don't see any reason why these conversion functions
> > >
> > > The generic patches added by this series convert between a 64-bit
> > > time_t and a wordsize time_t. Alpha is different in that it converts
> > > between a 64-bit time_t and a 32-bit time_t on a 64-bit arch.
> >
> > Yes, I understand that, but the definition of the 32-bit-time_t struct
> > timeval is
> >
> >   struct __timeval32 {
> >      __time32_t tv_sec;
> >      __suseconds_t tv_usec;
> >   };
> 
> This is what the Alpha specific calls use.
> 
> The generic one uses (the name is confusing, I thought I had changed it)
> 
> struct __timeval32
> {
>   long tv_sec;         /* Seconds.  */
>   long tv_usec;        /* Microseconds.  */
> };

This probably won't work for x32 and sparc64.

I suspect that it will be much simpler to have __timeval32 with 32-bit
fields and then do something like this:

int
__getitimer64 (__itimer_which_t which, struct __itimerval64 *curr_value)
{
#if KERNEL_OLD_TIMEVAL_IS_TIMEVAL64
  return INLINE_SYSCALL_CALL (getitimer, which, &curr_value);
#else
  struct __itimerval32 curr_value_32;
  if (INLINE_SYSCALL_CALL (getitimer, which, &curr_value_32) == -1)
    return -1;

  /* Write all fields of 'curr_value' regardless of overflow.  */
  curr_value->it_interval
    = valid_timeval32_to_timeval64 (curr_value_32.it_interval);
  curr_value->it_value
    = valid_timeval32_to_timeval64 (curr_value_32.it_value);
  return 0;
#endif
}

where KERNEL_OLD_TIMEVAL_IS_TIMEVAL64 needs to be true on 64-bit
architectures and x32.