powerpc: add machine check safe copy_to_user

	select ARCH_HAS_STRICT_KERNEL_RWX	if ((PPC_BOOK3S_64 || PPC32) && !RELOCATABLE && !HIBERNATION)

	select ARCH_HAS_TICK_BROADCAST		if GENERIC_CLOCKEVENTS_BROADCAST

	select ARCH_HAS_UACCESS_FLUSHCACHE

	select ARCH_HAS_UACCESS_MCSAFE		if PPC64

	select ARCH_HAS_UBSAN_SANITIZE_ALL

	select ARCH_HAVE_NMI_SAFE_CMPXCHG

	select ARCH_KEEP_MEMBLOCK

	return ret;

}

static __always_inline unsigned long __must_check

copy_to_user_mcsafe(void __user *to, const void *from, unsigned long n)

{

	if (likely(check_copy_size(from, n, true))) {

		if (access_ok(to, n)) {

			allow_write_to_user(to, n);

			n = memcpy_mcsafe((void *)to, from, n);

			prevent_write_to_user(to, n);

		}

	}

	return n;

}

extern unsigned long __clear_user(void __user *addr, unsigned long size);

static inline unsigned long clear_user(void __user *addr, unsigned long size)