On Wed, 2021-05-19 at 10:22 -0500, Segher Boessenkool wrote: > On Wed, May 19, 2021 at 03:06:49PM +0000, Joakim Tjernlund wrote: > > On Wed, 2021-05-19 at 09:38 -0500, Segher Boessenkool wrote: > > > On Wed, May 19, 2021 at 06:42:40PM +1000, Nicholas Piggin wrote: > > > > Excerpts from Joakim Tjernlund's message of May 19, 2021 6:08 pm: > > > > > I always figured the ppc way was superior. It begs the question if not the other archs should > > > > > change instead? > > > > > > > > It is superior in some ways, not enough to be worth being different. > > > > > > The PowerPC syscall ABI *requires* using cr0.3 for indicating errors, > > > you will have to do that whether you conflate the concepts of return > > > code and error indicator or not! > > > > > > > Other archs are unlikely to change because it would be painful for > > > > not much benefit. > > > > > > Other archs cannot easily change for much the same reason :-) > > > > Really? I figured you could just add extra error indication in kernel syscall I/F. > > Eventually user space could migrate to the new indication. > > You seem to assume all user space uses glibc, or *any* libc even? This > is false. Some programs do system calls directly. Do not break the > kernel ABI :-) Adding an extra indicator does not break ABI, does it ? W.r.t breaking ABI, isn't that what PowerPC is trying to do with the new syscall I/F? Jocke
