arch/loongarch/kernel/kfpu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2023 Loongson Technology Corporation Limited
   4  */
   5
   6 #include <linux/cpu.h>
   7 #include <linux/init.h>
   8 #include <asm/fpu.h>
   9 #include <asm/smp.h>
  10
  11 static DEFINE_PER_CPU(bool, in_kernel_fpu);
  12
  13 void kernel_fpu_begin(void)
  14 {
  15         preempt_disable();
  16
  17         WARN_ON(this_cpu_read(in_kernel_fpu));
  18
  19         this_cpu_write(in_kernel_fpu, true);
  20
  21         if (!is_fpu_owner())
  22                 enable_fpu();
  23         else
  24                 _save_fp(&current->thread.fpu);
  25
  26         write_fcsr(LOONGARCH_FCSR0, 0);
  27 }
  28 EXPORT_SYMBOL_GPL(kernel_fpu_begin);
  29
  30 void kernel_fpu_end(void)
  31 {
  32         WARN_ON(!this_cpu_read(in_kernel_fpu));
  33
  34         if (!is_fpu_owner())
  35                 disable_fpu();
  36         else
  37                 _restore_fp(&current->thread.fpu);
  38
  39         this_cpu_write(in_kernel_fpu, false);
  40
  41         preempt_enable();
  42 }
  43 EXPORT_SYMBOL_GPL(kernel_fpu_end);