arch/mips/loongson64/loongson-3/cop2-ex.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2014 Lemote Corporation.
   7  *   written by Huacai Chen <chenhc@lemote.com>
   8  *
   9  * based on arch/mips/cavium-octeon/cpu.c
  10  * Copyright (C) 2009 Wind River Systems,
  11  *   written by Ralf Baechle <ralf@linux-mips.org>
  12  */
  13 #include <linux/init.h>
  14 #include <linux/sched.h>
  15 #include <linux/notifier.h>
  16
  17 #include <asm/fpu.h>
  18 #include <asm/cop2.h>
  19 #include <asm/current.h>
  20 #include <asm/mipsregs.h>
  21
  22 static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,
  23         void *data)
  24 {
  25         int fpu_owned;
  26         int fr = !test_thread_flag(TIF_32BIT_FPREGS);
  27
  28         switch (action) {
  29         case CU2_EXCEPTION:
  30                 preempt_disable();
  31                 fpu_owned = __is_fpu_owner();
  32                 if (!fr)
  33                         set_c0_status(ST0_CU1 | ST0_CU2);
  34                 else
  35                         set_c0_status(ST0_CU1 | ST0_CU2 | ST0_FR);
  36                 enable_fpu_hazard();
  37                 KSTK_STATUS(current) |= (ST0_CU1 | ST0_CU2);
  38                 if (fr)
  39                         KSTK_STATUS(current) |= ST0_FR;
  40                 else
  41                         KSTK_STATUS(current) &= ~ST0_FR;
  42                 /* If FPU is owned, we needn't init or restore fp */
  43                 if (!fpu_owned) {
  44                         set_thread_flag(TIF_USEDFPU);
  45                         if (!used_math()) {
  46                                 _init_fpu(current->thread.fpu.fcr31);
  47                                 set_used_math();
  48                         } else
  49                                 _restore_fp(current);
  50                 }
  51                 preempt_enable();
  52
  53                 return NOTIFY_STOP;     /* Don't call default notifier */
  54         }
  55
  56         return NOTIFY_OK;               /* Let default notifier send signals */
  57 }
  58
  59 static int __init loongson_cu2_setup(void)
  60 {
  61         return cu2_notifier(loongson_cu2_call, 0);
  62 }
  63 early_initcall(loongson_cu2_setup);