1/*
2 * HW exception handling
3 *
4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
5 * Copyright (C) 2008 PetaLogix
6 *
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License.  See the file COPYING in the main directory of this
9 * archive for more details.
10 */
11
12/*
13 * This file handles the architecture-dependent parts of hardware exceptions
14 */
15
16#include <linux/export.h>
17#include <linux/kernel.h>
18#include <linux/signal.h>
19#include <linux/sched.h>
20#include <linux/kallsyms.h>
21
22#include <asm/exceptions.h>
23#include <asm/entry.h>		/* For KM CPU var */
24#include <linux/uaccess.h>
25#include <linux/errno.h>
26#include <linux/ptrace.h>
27#include <asm/current.h>
28#include <asm/cacheflush.h>
29
30#define MICROBLAZE_ILL_OPCODE_EXCEPTION	0x02
31#define MICROBLAZE_IBUS_EXCEPTION	0x03
32#define MICROBLAZE_DBUS_EXCEPTION	0x04
33#define MICROBLAZE_DIV_ZERO_EXCEPTION	0x05
34#define MICROBLAZE_FPU_EXCEPTION	0x06
35#define MICROBLAZE_PRIVILEGED_EXCEPTION	0x07
36
37static DEFINE_SPINLOCK(die_lock);
38
39void die(const char *str, struct pt_regs *fp, long err)
40{
41	console_verbose();
42	spin_lock_irq(&die_lock);
43	pr_warn("Oops: %s, sig: %ld\n", str, err);
44	show_regs(fp);
45	spin_unlock_irq(&die_lock);
46	/* do_exit() should take care of panic'ing from an interrupt
47	 * context so we don't handle it here
48	 */
49	do_exit(err);
50}
51
52/* for user application debugging */
53asmlinkage void sw_exception(struct pt_regs *regs)
54{
55	_exception(SIGTRAP, regs, TRAP_BRKPT, regs->r16);
56	flush_dcache_range(regs->r16, regs->r16 + 0x4);
57	flush_icache_range(regs->r16, regs->r16 + 0x4);
58}
59
60void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
61{
62	siginfo_t info;
63
64	if (kernel_mode(regs))
65		die("Exception in kernel mode", regs, signr);
66
67	info.si_signo = signr;
68	info.si_errno = 0;
69	info.si_code = code;
70	info.si_addr = (void __user *) addr;
71	force_sig_info(signr, &info, current);
72}
73
74asmlinkage void full_exception(struct pt_regs *regs, unsigned int type,
75							int fsr, int addr)
76{
77#ifdef CONFIG_MMU
78	addr = regs->pc;
79#endif
80
81#if 0
82	pr_warn("Exception %02x in %s mode, FSR=%08x PC=%08x ESR=%08x\n",
83			type, user_mode(regs) ? "user" : "kernel", fsr,
84			(unsigned int) regs->pc, (unsigned int) regs->esr);
85#endif
86
87	switch (type & 0x1F) {
88	case MICROBLAZE_ILL_OPCODE_EXCEPTION:
89		if (user_mode(regs)) {
90			pr_debug("Illegal opcode exception in user mode\n");
91			_exception(SIGILL, regs, ILL_ILLOPC, addr);
92			return;
93		}
94		pr_warn("Illegal opcode exception in kernel mode.\n");
95		die("opcode exception", regs, SIGBUS);
96		break;
97	case MICROBLAZE_IBUS_EXCEPTION:
98		if (user_mode(regs)) {
99			pr_debug("Instruction bus error exception in user mode\n");
100			_exception(SIGBUS, regs, BUS_ADRERR, addr);
101			return;
102		}
103		pr_warn("Instruction bus error exception in kernel mode.\n");
104		die("bus exception", regs, SIGBUS);
105		break;
106	case MICROBLAZE_DBUS_EXCEPTION:
107		if (user_mode(regs)) {
108			pr_debug("Data bus error exception in user mode\n");
109			_exception(SIGBUS, regs, BUS_ADRERR, addr);
110			return;
111		}
112		pr_warn("Data bus error exception in kernel mode.\n");
113		die("bus exception", regs, SIGBUS);
114		break;
115	case MICROBLAZE_DIV_ZERO_EXCEPTION:
116		if (user_mode(regs)) {
117			pr_debug("Divide by zero exception in user mode\n");
118			_exception(SIGFPE, regs, FPE_INTDIV, addr);
119			return;
120		}
121		pr_warn("Divide by zero exception in kernel mode.\n");
122		die("Divide by zero exception", regs, SIGBUS);
123		break;
124	case MICROBLAZE_FPU_EXCEPTION:
125		pr_debug("FPU exception\n");
126		/* IEEE FP exception */
127		/* I removed fsr variable and use code var for storing fsr */
128		if (fsr & FSR_IO)
129			fsr = FPE_FLTINV;
130		else if (fsr & FSR_OF)
131			fsr = FPE_FLTOVF;
132		else if (fsr & FSR_UF)
133			fsr = FPE_FLTUND;
134		else if (fsr & FSR_DZ)
135			fsr = FPE_FLTDIV;
136		else if (fsr & FSR_DO)
137			fsr = FPE_FLTRES;
138		_exception(SIGFPE, regs, fsr, addr);
139		break;
140
141#ifdef CONFIG_MMU
142	case MICROBLAZE_PRIVILEGED_EXCEPTION:
143		pr_debug("Privileged exception\n");
144		_exception(SIGILL, regs, ILL_PRVOPC, addr);
145		break;
146#endif
147	default:
148	/* FIXME what to do in unexpected exception */
149		pr_warn("Unexpected exception %02x PC=%08x in %s mode\n",
150			type, (unsigned int) addr,
151			kernel_mode(regs) ? "kernel" : "user");
152	}
153	return;
154}
155