arch/mips/loongson64/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 #include <linux/ptrace.h>
  17
  18 #include <asm/fpu.h>
  19 #include <asm/cop2.h>
  20 #include <asm/current.h>
  21 #include <asm/mipsregs.h>
  22
  23 static int loongson_cu2_call(struct notifier_block *nfb, unsigned long action,
  24         void *data)
  25 {
  26         int fpu_owned;
  27         int fr = !test_thread_flag(TIF_32BIT_FPREGS);
  28
  29         switch (action) {
  30         case CU2_EXCEPTION:
  31                 preempt_disable();
  32                 fpu_owned = __is_fpu_owner();
  33                 if (!fr)
  34                         set_c0_status(ST0_CU1 | ST0_CU2);
  35                 else
  36                         set_c0_status(ST0_CU1 | ST0_CU2 | ST0_FR);
  37                 enable_fpu_hazard();
  38                 KSTK_STATUS(current) |= (ST0_CU1 | ST0_CU2);
  39                 if (fr)
  40                         KSTK_STATUS(current) |= ST0_FR;
  41                 else
  42                         KSTK_STATUS(current) &= ~ST0_FR;
  43                 /* If FPU is owned, we needn't init or restore fp */
  44                 if (!fpu_owned) {
  45                         set_thread_flag(TIF_USEDFPU);
  46                         init_fp_ctx(current);
  47                         _restore_fp(current);
  48                 }
  49                 preempt_enable();
  50
  51                 return NOTIFY_STOP;     /* Don't call default notifier */
  52         }
  53
  54         return NOTIFY_OK;               /* Let default notifier send signals */
  55 }
  56
  57 static int __init loongson_cu2_setup(void)
  58 {
  59         return cu2_notifier(loongson_cu2_call, 0);
  60 }
  61 early_initcall(loongson_cu2_setup);