Hi Arnd, On Mon, Nov 28, 2022 at 02:54:39PM +0100, Arnd Bergmann wrote: > On Sun, Nov 27, 2022, at 21:18, Jason A. Donenfeld wrote: > >> > >> config GENERIC_VDSO_RANDOM_WHATEVER > >> bool > >> select VGETRANDOM_ALLOC > >> > >> This gives a clear Kconfig dependency instead of the random > >> ADVISE_SYSCALLS select. > > > > That's much better indeed. I was trying to straddle the two conventions > > of `#define __ARCH_...` for syscalls and a Kconfig for vDSO functions, > > but doing it all together as you've suggested is nicer. > > > > I'll try to figure this out, though so far futzing around suggests there > > might have to be both, because of unistd.h being a userspace header. > > That is, include/uapi/asm-generic/unistd.h typically needs a `#if > > __ARCH_WANT..., #define ...` in it. I'll give it a spin and you'll see > > for v8. At the very least it should get rid of the more awkward > > `select ADVISE_SYSCALLS if X86_64` part, and will better separate the > > arch code from non-arch code. > > I think you should not need an __ARCH_WANT_SYS_* symbol for this, > the only place we actually need them for is the asm-generic/unistd.h > header which is still used on a couple of architectures (I have > an experimental series for replacing it with a generic syscall.tbl > file, but it's not ready for 6.2). In most cases, the __ARCH_WANT_SYS_* > symbols are only used for syscalls that are part of the table for > old architectures but get skipped on newer targets that always had > a replacement syscalls (e.g. getrlimit getting replaced by prlimit64) > > I think we should just reserve the syscall number for all architectures > right away and #define the __NR_* macro. libc will generally need > a runtime check anyway, and defining it now avoids the problem of > the tables getting out of sync. > > The Kconfig symbol is fine in this case. Oh, great, okay. I'll get rid of the __ARCH stuff entirely then. I jumped the gun and posted v8 earlier today, but I'll include this in a v9, whenever it makes sense to send that. So when reading v8, just assume all he __ARCH_WANT_SYS_* business has been removed. Jason
