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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
* Copyright (C) 2023 SiFive
*/
#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>
#include <linux/thread_info.h>
#include <asm/vector.h>
#ifdef CONFIG_RISCV_ISA_V
/*
* may_use_simd - whether it is allowable at this time to issue vector
* instructions or access the vector 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)
{
/*
* RISCV_KERNEL_MODE_V is only set while preemption is disabled,
* and is clear whenever preemption is enabled.
*/
if (in_hardirq() || in_nmi())
return false;
/*
* Nesting is achieved in preempt_v by spreading the control for
* preemptible and non-preemptible kernel-mode Vector into two fields.
* Only non-preempt_v can nest on top of preempt_v, if non-preempt_v is
* unavailable, then preempt_v is not allowed.
*/
return !(riscv_v_flags() & RISCV_KERNEL_MODE_V);
}
#else /* ! CONFIG_RISCV_ISA_V */
static __must_check inline bool may_use_simd(void)
{
return false;
}
#endif /* ! CONFIG_RISCV_ISA_V */
#endif
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