Linux powerpc new system call instruction and ABI
Joakim.Tjernlund at infinera.com
Wed May 19 18:08:03 AEST 2021
On Wed, 2021-05-19 at 17:55 +1000, Nicholas Piggin wrote:
> Excerpts from Joakim Tjernlund's message of May 19, 2021 5:33 pm:
> > On Wed, 2021-05-19 at 02:13 +0300, Dmitry V. Levin wrote:
> > > Hi,
> > >
> > > On Thu, Jun 11, 2020 at 06:12:01PM +1000, Nicholas Piggin wrote:
> > > [...]
> > > > - Error handling: The consensus among kernel, glibc, and musl is to move to
> > > > using negative return values in r3 rather than CR0[SO]=1 to indicate error,
> > > > which matches most other architectures, and is closer to a function call.
> > What about syscalls like times(2) which can return -1 without it being an error?
> They do become errors / indistinguishable and have to be dealt with by
> libc or userspace. Which does follow what most architectures do (all
> except ia64, mips, sparc, and powerpc actually).
> Interesting question though, it should have been noted.
I always figured the ppc way was superior. It begs the question if not the other archs should
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