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 loongson_cu2_call(struct notifier_block * nfb,unsigned long action,void * data)22static 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 loongson_cu2_setup(void)59static int __init loongson_cu2_setup(void) 60 { 61 return cu2_notifier(loongson_cu2_call, 0); 62 } 63 early_initcall(loongson_cu2_setup); 64