[RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap()

[Peter Zijlstra]

On Wed, Mar 29, 2017 at 11:15:56AM -0700, Kees Cook wrote:
> +static __always_inline unsigned long __arch_rare_write_end(void)
> +{
> +	unsigned long cr0;
> +
> +	barrier();
> +	cr0 = read_cr0() ^ X86_CR0_WP;
> +	BUG_ON(!(cr0 & X86_CR0_WP));
> +	write_cr0(cr0);
> +	barrier();
> +	preempt_enable_no_resched();

NAK

> +	return cr0 ^ X86_CR0_WP;
> +}