Re: [PATCH 3/4] Consolidate pread/pread64 implementations

[Mike Frysinger <vapier at gentoo dot org>]

On 05 Jan 2016 10:49, Adhemerval Zanella wrote:
> On 04-01-2016 22:53, Mike Frysinger wrote:
> > On 04 Jan 2016 10:42, Adhemerval Zanella wrote:
> >> On 29-12-2015 15:28, Mike Frysinger wrote:
> >>> On 18 Nov 2015 12:02, Adhemerval Zanella wrote:
> >>>> This patch consolidates all the pread/pread64 implementation for Linux
> >>>> in only one (sysdeps/unix/sysv/linux/pread.c).  It also removes the
> >>>> syscall from the auto-generation using assembly macros.
> >>>>
> >>>> For pread{64} offset argument placement the new SYSCALL_LL{64} macro
> >>>> is used.  For pread ports that do not define __NR_pread will use
> >>>> __NR_pread64 and for pread64 ports that dot define __NR_pread64 will
> >>>> use __NR_pread for the syscall.
> >>>
> >>> pretty sure you just broke sh here.  while it doesn't have the 64-bit
> >>> arg alignment issue, it has a wart where it copied the kernel interface
> >>> of one.  you can see it in the files you deleted:
> >>
> >> Indeed, my understanding is SH also requires __ASSUME_ALIGNED_REGISTER_PAIRS.
> >> I will change it for the 1/4 patch part.
> > 
> > just to be clear, SuperH (the ABI) does not have these 64-bit register
> > pair requirements like ARM/EABI.  its syscall ABI for pread64/pwrite64
> > has legacy cruft where there's a dummy reg before the 64-bit value.  so
> > you can (and want) to use the same logic just for these two syscalls as
> > the result happens to look the same.
> 
> Right, so for SuperH kernel interface the 64-bit pair cruft is only for
> pread64/pwrite64 or is it for all 64-bits arguments?

just pread64/pwrite64:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/sh/kernel/sys_sh32.c?h=v4.3
-mike

Attachment: signature.asc
Description: Digital signature