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kernel/linux-rt-4.4.41/arch/mips/loongson64/loongson-3/cop2-ex.c 1.56 KB
5113f6f70   김현기   kernel add
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  /*
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Copyright (C) 2014 Lemote Corporation.
   *   written by Huacai Chen <chenhc@lemote.com>
   *
   * based on arch/mips/cavium-octeon/cpu.c
   * Copyright (C) 2009 Wind River Systems,
   *   written by Ralf Baechle <ralf@linux-mips.org>
   */
  #include <linux/init.h>
  #include <linux/sched.h>
  #include <linux/notifier.h>
  
  #include <asm/fpu.h>
  #include <asm/cop2.h>
  #include <asm/current.h>
  #include <asm/mipsregs.h>
  
  static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,
  	void *data)
  {
  	int fpu_owned;
  	int fr = !test_thread_flag(TIF_32BIT_FPREGS);
  
  	switch (action) {
  	case CU2_EXCEPTION:
  		preempt_disable();
  		fpu_owned = __is_fpu_owner();
  		if (!fr)
  			set_c0_status(ST0_CU1 | ST0_CU2);
  		else
  			set_c0_status(ST0_CU1 | ST0_CU2 | ST0_FR);
  		enable_fpu_hazard();
  		KSTK_STATUS(current) |= (ST0_CU1 | ST0_CU2);
  		if (fr)
  			KSTK_STATUS(current) |= ST0_FR;
  		else
  			KSTK_STATUS(current) &= ~ST0_FR;
  		/* If FPU is owned, we needn't init or restore fp */
  		if (!fpu_owned) {
  			set_thread_flag(TIF_USEDFPU);
  			if (!used_math()) {
  				_init_fpu(current->thread.fpu.fcr31);
  				set_used_math();
  			} else
  				_restore_fp(current);
  		}
  		preempt_enable();
  
  		return NOTIFY_STOP;	/* Don't call default notifier */
  	}
  
  	return NOTIFY_OK;		/* Let default notifier send signals */
  }
  
  static int __init loongson_cu2_setup(void)
  {
  	return cu2_notifier(loongson_cu2_call, 0);
  }
  early_initcall(loongson_cu2_setup);