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); 62