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
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
59static int __init loongson_cu2_setup(void)
60{
61	return cu2_notifier(loongson_cu2_call, 0);
62}
63early_initcall(loongson_cu2_setup);
64