1/*
2 * Hardware exception handling
3 *
4 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
5 * Copyright (C) 2004 Microtronix Datacom Ltd.
6 * Copyright (C) 2001 Vic Phillips
7 *
8 * This file is subject to the terms and conditions of the GNU General
9 * Public License.  See the file COPYING in the main directory of this
10 * archive for more details.
11 */
12
13#include <linux/sched.h>
14#include <linux/kernel.h>
15#include <linux/signal.h>
16#include <linux/export.h>
17#include <linux/mm.h>
18#include <linux/ptrace.h>
19
20#include <asm/traps.h>
21#include <asm/sections.h>
22#include <asm/uaccess.h>
23
24static DEFINE_SPINLOCK(die_lock);
25
26static void _send_sig(int signo, int code, unsigned long addr)
27{
28	siginfo_t info;
29
30	info.si_signo = signo;
31	info.si_errno = 0;
32	info.si_code = code;
33	info.si_addr = (void __user *) addr;
34	force_sig_info(signo, &info, current);
35}
36
37void die(const char *str, struct pt_regs *regs, long err)
38{
39	console_verbose();
40	spin_lock_irq(&die_lock);
41	pr_warn("Oops: %s, sig: %ld\n", str, err);
42	show_regs(regs);
43	spin_unlock_irq(&die_lock);
44	/*
45	 * do_exit() should take care of panic'ing from an interrupt
46	 * context so we don't handle it here
47	 */
48	do_exit(err);
49}
50
51void _exception(int signo, struct pt_regs *regs, int code, unsigned long addr)
52{
53	if (!user_mode(regs))
54		die("Exception in kernel mode", regs, signo);
55
56	_send_sig(signo, code, addr);
57}
58
59/*
60 * The show_stack is an external API which we do not use ourselves.
61 */
62
63int kstack_depth_to_print = 48;
64
65void show_stack(struct task_struct *task, unsigned long *stack)
66{
67	unsigned long *endstack, addr;
68	int i;
69
70	if (!stack) {
71		if (task)
72			stack = (unsigned long *)task->thread.ksp;
73		else
74			stack = (unsigned long *)&stack;
75	}
76
77	addr = (unsigned long) stack;
78	endstack = (unsigned long *) PAGE_ALIGN(addr);
79
80	pr_emerg("Stack from %08lx:", (unsigned long)stack);
81	for (i = 0; i < kstack_depth_to_print; i++) {
82		if (stack + 1 > endstack)
83			break;
84		if (i % 8 == 0)
85			pr_emerg("\n       ");
86		pr_emerg(" %08lx", *stack++);
87	}
88
89	pr_emerg("\nCall Trace:");
90	i = 0;
91	while (stack + 1 <= endstack) {
92		addr = *stack++;
93		/*
94		 * If the address is either in the text segment of the
95		 * kernel, or in the region which contains vmalloc'ed
96		 * memory, it *may* be the address of a calling
97		 * routine; if so, print it so that someone tracing
98		 * down the cause of the crash will be able to figure
99		 * out the call path that was taken.
100		 */
101		if (((addr >= (unsigned long) _stext) &&
102		     (addr <= (unsigned long) _etext))) {
103			if (i % 4 == 0)
104				pr_emerg("\n       ");
105			pr_emerg(" [<%08lx>]", addr);
106			i++;
107		}
108	}
109	pr_emerg("\n");
110}
111
112void __init trap_init(void)
113{
114	/* Nothing to do here */
115}
116
117/* Breakpoint handler */
118asmlinkage void breakpoint_c(struct pt_regs *fp)
119{
120	/*
121	 * The breakpoint entry code has moved the PC on by 4 bytes, so we must
122	 * move it back. This could be done on the host but we do it here
123	 * because monitor.S of JTAG gdbserver does it too.
124	 */
125	fp->ea -= 4;
126	_exception(SIGTRAP, fp, TRAP_BRKPT, fp->ea);
127}
128
129#ifndef CONFIG_NIOS2_ALIGNMENT_TRAP
130/* Alignment exception handler */
131asmlinkage void handle_unaligned_c(struct pt_regs *fp, int cause)
132{
133	unsigned long addr = RDCTL(CTL_BADADDR);
134
135	cause >>= 2;
136	fp->ea -= 4;
137
138	if (fixup_exception(fp))
139		return;
140
141	if (!user_mode(fp)) {
142		pr_alert("Unaligned access from kernel mode, this might be a hardware\n");
143		pr_alert("problem, dump registers and restart the instruction\n");
144		pr_alert("  BADADDR 0x%08lx\n", addr);
145		pr_alert("  cause   %d\n", cause);
146		pr_alert("  op-code 0x%08lx\n", *(unsigned long *)(fp->ea));
147		show_regs(fp);
148		return;
149	}
150
151	_exception(SIGBUS, fp, BUS_ADRALN, addr);
152}
153#endif /* CONFIG_NIOS2_ALIGNMENT_TRAP */
154
155/* Illegal instruction handler */
156asmlinkage void handle_illegal_c(struct pt_regs *fp)
157{
158	fp->ea -= 4;
159	_exception(SIGILL, fp, ILL_ILLOPC, fp->ea);
160}
161
162/* Supervisor instruction handler */
163asmlinkage void handle_supervisor_instr(struct pt_regs *fp)
164{
165	fp->ea -= 4;
166	_exception(SIGILL, fp, ILL_PRVOPC, fp->ea);
167}
168
169/* Division error handler */
170asmlinkage void handle_diverror_c(struct pt_regs *fp)
171{
172	fp->ea -= 4;
173	_exception(SIGFPE, fp, FPE_INTDIV, fp->ea);
174}
175
176/* Unhandled exception handler */
177asmlinkage void unhandled_exception(struct pt_regs *regs, int cause)
178{
179	unsigned long addr = RDCTL(CTL_BADADDR);
180
181	cause /= 4;
182
183	pr_emerg("Unhandled exception #%d in %s mode (badaddr=0x%08lx)\n",
184			cause, user_mode(regs) ? "user" : "kernel", addr);
185
186	regs->ea -= 4;
187	show_regs(regs);
188
189	pr_emerg("opcode: 0x%08lx\n", *(unsigned long *)(regs->ea));
190}
191
192asmlinkage void handle_trap_1_c(struct pt_regs *fp)
193{
194	_send_sig(SIGUSR1, 0, fp->ea);
195}
196
197asmlinkage void handle_trap_2_c(struct pt_regs *fp)
198{
199	_send_sig(SIGUSR2, 0, fp->ea);
200}
201
202asmlinkage void handle_trap_3_c(struct pt_regs *fp)
203{
204	_send_sig(SIGILL, ILL_ILLTRP, fp->ea);
205}
206