* Jason A. Donenfeld: > Hi Florian, > > On Thu, Nov 24, 2022 at 06:25:39AM +0100, Florian Weimer wrote: >> * Jason A. Donenfeld: >> >> > Hi Florian, >> > >> > On Wed, Nov 23, 2022 at 11:46:58AM +0100, Florian Weimer wrote: >> >> * Jason A. Donenfeld: >> >> >> >> > + * The vgetrandom() function in userspace requires an opaque state, which this >> >> > + * function provides to userspace, by mapping a certain number of special pages >> >> > + * into the calling process. It takes a hint as to the number of opaque states >> >> > + * desired, and returns the number of opaque states actually allocated, the >> >> > + * size of each one in bytes, and the address of the first state. >> >> > + */ >> >> > +SYSCALL_DEFINE3(vgetrandom_alloc, unsigned long __user *, num, >> >> > + unsigned long __user *, size_per_each, unsigned int, flags) >> >> >> >> I think you should make this __u64, so that you get a consistent >> >> userspace interface on all architectures, without the need for compat >> >> system calls. >> > >> > That would be quite unconventional. Most syscalls that take lengths do >> > so with the native register size (`unsigned long`, `size_t`), rather >> > than u64. If you can point to a recent trend away from this by >> > indicating some commits that added new syscalls with u64, I'd be happy >> > to be shown otherwise. But AFAIK, that's not the way it's done. >> >> See clone3 and struct clone_args. > > The struct is one thing. But actually, clone3 takes a `size_t`: > > SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size) > > I take from this that I too should use `size_t` rather than `unsigned > long.` And it doesn't seem like there's any compat clone3. But vgetrandom_alloc does not use unsigned long, but unsigned long *. You need to look at the contents for struct clone_args for comparison. Thanks, Florian
