52 строки
1.4 KiB
C
52 строки
1.4 KiB
C
/*
|
|
* Copyright (C) 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 as published
|
|
* by the Free Software Foundation.
|
|
*/
|
|
|
|
#ifndef __ASM_SIMD_H
|
|
#define __ASM_SIMD_H
|
|
|
|
#include <linux/compiler.h>
|
|
#include <linux/irqflags.h>
|
|
#include <linux/percpu.h>
|
|
#include <linux/preempt.h>
|
|
#include <linux/types.h>
|
|
|
|
#ifdef CONFIG_KERNEL_MODE_NEON
|
|
|
|
DECLARE_PER_CPU(bool, kernel_neon_busy);
|
|
|
|
/*
|
|
* may_use_simd - whether it is allowable at this time to issue SIMD
|
|
* instructions or access the SIMD register file
|
|
*
|
|
* Callers must not assume that the result remains true beyond the next
|
|
* preempt_enable() or return from softirq context.
|
|
*/
|
|
static __must_check inline bool may_use_simd(void)
|
|
{
|
|
/*
|
|
* kernel_neon_busy is only set while preemption is disabled,
|
|
* and is clear whenever preemption is enabled. Since
|
|
* this_cpu_read() is atomic w.r.t. preemption, kernel_neon_busy
|
|
* cannot change under our feet -- if it's set we cannot be
|
|
* migrated, and if it's clear we cannot be migrated to a CPU
|
|
* where it is set.
|
|
*/
|
|
return !in_irq() && !irqs_disabled() && !in_nmi() &&
|
|
!this_cpu_read(kernel_neon_busy);
|
|
}
|
|
|
|
#else /* ! CONFIG_KERNEL_MODE_NEON */
|
|
|
|
static __must_check inline bool may_use_simd(void) {
|
|
return false;
|
|
}
|
|
|
|
#endif /* ! CONFIG_KERNEL_MODE_NEON */
|
|
|
|
#endif
|