arch/arm64/include/asm/simd.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
   4  */
   5
   6 #ifndef __ASM_SIMD_H
   7 #define __ASM_SIMD_H
   8
   9 #include <linux/compiler.h>
  10 #include <linux/irqflags.h>
  11 #include <linux/percpu.h>
  12 #include <linux/preempt.h>
  13 #include <linux/types.h>
  14
  15 #ifdef CONFIG_KERNEL_MODE_NEON
  16
  17 /*
  18  * may_use_simd - whether it is allowable at this time to issue SIMD
  19  *                instructions or access the SIMD register file
  20  *
  21  * Callers must not assume that the result remains true beyond the next
  22  * preempt_enable() or return from softirq context.
  23  */
  24 static __must_check inline bool may_use_simd(void)
  25 {
  26         /*
  27          * We must make sure that the SVE has been initialized properly
  28          * before using the SIMD in kernel.
  29          */
  30         return !WARN_ON(!system_capabilities_finalized()) &&
  31                system_supports_fpsimd() &&
  32                !in_hardirq() && !irqs_disabled() && !in_nmi();
  33 }
  34
  35 #else /* ! CONFIG_KERNEL_MODE_NEON */
  36
  37 static __must_check inline bool may_use_simd(void) {
  38         return false;
  39 }
  40
  41 #endif /* ! CONFIG_KERNEL_MODE_NEON */
  42
  43 #endif