On Tue, May 15, 2018 at 09:22:23AM +0100, Mark Rutland wrote: > On Mon, May 14, 2018 at 10:24:45PM +0200, Dominik Brodowski wrote: > > On Mon, May 14, 2018 at 12:41:10PM +0100, Mark Rutland wrote: > > > I agree it would be nicer if it had a wrapper that took a pt_regs, even > > > if it does nothing with it. > > > > > > We can't use SYSCALL_DEFINE0() due to the fault injection muck, we'd > > > need a ksys_ni_syscall() for our traps.c logic, and adding this > > > uniformly would involve some arch-specific rework for x86, too, so I > > > decided it was not worth the effort. > > > > Couldn't you just open-code the "return -ENOSYS;" in traps.c? > > I guess so. I was just worried that debug logic might be added to the generic > ni_syscall() in future, and wanted to avoid potential divergence. > > > Error injection has no reasonable stable ABI/API expectations, so that's not > > a show-stopper either. > > If people are happy with using SYSCALL_DEFINE0() for ni_syscall, I'm happy to > do that -- it's just that we'll need a fixup for x86 as that will change the > symbol name. For me, it's less about using SYSCALL_DEFINE0() for ni_syscall, but more about keeping the syscall invokation easy. Therefore, we do pass a pointer struct pt_regs to sys_ni_syscall() on x86, even though it does not expect it. /* this is a lie, but it does not hurt as sys_ni_syscall just returns -EINVAL */ extern asmlinkage long sys_ni_syscall(const struct pt_regs *); Thanks, Dominik
