Re: [Xen-devel] [PATCH v5 1/2] xen: add xen_is_preemptible_hypercall()

[David Vrabel]

On 27/01/15 01:51, Luis R. Rodriguez wrote:
> 
> +#ifndef CONFIG_PREEMPT
> +extern struct { char _entry[32]; } preemptible_hypercall_page[];
> +
> +static inline bool xen_is_preemptible_hypercall(struct pt_regs *regs)
> +{
> +	return !user_mode_vm(regs) &&
> +		regs->ip >= (unsigned long)preemptible_hypercall_page &&
> +		regs->ip < (unsigned long)preemptible_hypercall_page + PAGE_SIZE;

I asked for this test to be optimized.

	return (regs->ip >> PAGE_SHIFT)
            == ((unsigned long)preemptible_hypercall_page >> PAGE_SHIFT)
	    && !user_mode_vm(regs);

David
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