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) 2013 Broadcom Corporation.
7 *
8 * based on arch/mips/cavium-octeon/cpu.c
9 * Copyright (C) 2009 Wind River Systems,
10 *   written by Ralf Baechle <ralf@linux-mips.org>
11 */
12#include <linux/init.h>
13#include <linux/irqflags.h>
14#include <linux/notifier.h>
15#include <linux/prefetch.h>
16#include <linux/sched.h>
17
18#include <asm/cop2.h>
19#include <asm/current.h>
20#include <asm/mipsregs.h>
21#include <asm/page.h>
22
23#include <asm/netlogic/mips-extns.h>
24
25/*
26 * 64 bit ops are done in inline assembly to support 32 bit
27 * compilation
28 */
29void nlm_cop2_save(struct nlm_cop2_state *r)
30{
31	asm volatile(
32		".set	push\n"
33		".set	noat\n"
34		"dmfc2	$1, $0, 0\n"
35		"sd	$1, 0(%1)\n"
36		"dmfc2	$1, $0, 1\n"
37		"sd	$1, 8(%1)\n"
38		"dmfc2	$1, $0, 2\n"
39		"sd	$1, 16(%1)\n"
40		"dmfc2	$1, $0, 3\n"
41		"sd	$1, 24(%1)\n"
42		"dmfc2	$1, $1, 0\n"
43		"sd	$1, 0(%2)\n"
44		"dmfc2	$1, $1, 1\n"
45		"sd	$1, 8(%2)\n"
46		"dmfc2	$1, $1, 2\n"
47		"sd	$1, 16(%2)\n"
48		"dmfc2	$1, $1, 3\n"
49		"sd	$1, 24(%2)\n"
50		".set	pop\n"
51		: "=m"(*r)
52		: "r"(r->tx), "r"(r->rx));
53
54	r->tx_msg_status = __read_32bit_c2_register($2, 0);
55	r->rx_msg_status = __read_32bit_c2_register($3, 0) & 0x0fffffff;
56}
57
58void nlm_cop2_restore(struct nlm_cop2_state *r)
59{
60	u32 rstat;
61
62	asm volatile(
63		".set	push\n"
64		".set	noat\n"
65		"ld	$1, 0(%1)\n"
66		"dmtc2	$1, $0, 0\n"
67		"ld	$1, 8(%1)\n"
68		"dmtc2	$1, $0, 1\n"
69		"ld	$1, 16(%1)\n"
70		"dmtc2	$1, $0, 2\n"
71		"ld	$1, 24(%1)\n"
72		"dmtc2	$1, $0, 3\n"
73		"ld	$1, 0(%2)\n"
74		"dmtc2	$1, $1, 0\n"
75		"ld	$1, 8(%2)\n"
76		"dmtc2	$1, $1, 1\n"
77		"ld	$1, 16(%2)\n"
78		"dmtc2	$1, $1, 2\n"
79		"ld	$1, 24(%2)\n"
80		"dmtc2	$1, $1, 3\n"
81		".set	pop\n"
82		: : "m"(*r), "r"(r->tx), "r"(r->rx));
83
84	__write_32bit_c2_register($2, 0, r->tx_msg_status);
85	rstat = __read_32bit_c2_register($3, 0) & 0xf0000000u;
86	__write_32bit_c2_register($3, 0, r->rx_msg_status | rstat);
87}
88
89static int nlm_cu2_call(struct notifier_block *nfb, unsigned long action,
90	void *data)
91{
92	unsigned long flags;
93	unsigned int status;
94
95	switch (action) {
96	case CU2_EXCEPTION:
97		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
98			break;
99		local_irq_save(flags);
100		KSTK_STATUS(current) |= ST0_CU2;
101		status = read_c0_status();
102		write_c0_status(status | ST0_CU2);
103		nlm_cop2_restore(&(current->thread.cp2));
104		write_c0_status(status & ~ST0_CU2);
105		local_irq_restore(flags);
106		pr_info("COP2 access enabled for pid %d (%s)\n",
107					current->pid, current->comm);
108		return NOTIFY_BAD;	/* Don't call default notifier */
109	}
110
111	return NOTIFY_OK;		/* Let default notifier send signals */
112}
113
114static int __init nlm_cu2_setup(void)
115{
116	return cu2_notifier(nlm_cu2_call, 0);
117}
118early_initcall(nlm_cu2_setup);
119