[PATCH] powerpc/32: Avoid miscompilation w/GCC 4.6.3 - don't inline copy_to/from_user()

[David Laight]

From: Michael Ellerman
> Sent: 26 June 2017 14:34
..
> Al also pointed out that inlining copy_to/from_user() is probably of little or
> no benefit, which is correct
...

I was a bit horrified at the x86-64 versions of copy_to/from_user() as well.
With code that (tries to) error kernel pointers that cross stack frame
boundaries I'm fairly sure they expand to a lot of code.

I also suspect the cost of that kernel address check is not insignificant
especially if it has to walk down several stack frames.
(Never mind what happens to code compiled without stack frames.)

	David