Re: [PATCH for 4.18 2/6] rseq: use get_user/put_user rather than __get_user/__put_user

[Linus Torvalds]

On Mon, Jul 9, 2018 at 10:28 AM Mathieu Desnoyers
<mathieu.desnoyers@xxxxxxxxxxxx> wrote:
>
> So, another twist to this story: ppc32 does not implement u64 get_user().

I was going to say that "that's not possible", since we actually have
64-bit arguments at least in the form of "loff_t __user *".

But when I started looking, it turns out that yeah, we do
"copy_from_user()" on them, and instead made the x86 copy_from_user()
have special cases for constant sizes.

So a 8-byte copy_from_user() is fine. It ends up being a "get_user()"
on x86 anyway.

                Linus