1 #include <linux/bug.h>
2 #include <linux/io.h>
3 #include <linux/types.h>
4 #include <linux/kdebug.h>
5 #include <linux/signal.h>
6 #include <linux/sched.h>
7 #include <linux/uaccess.h>
8 #include <linux/hardirq.h>
9 #include <linux/kernel.h>
10 #include <linux/kexec.h>
11 #include <linux/module.h>
12 #include <asm/unwinder.h>
13 #include <asm/traps.h>
14
15 static DEFINE_SPINLOCK(die_lock);
16
17 void die(const char *str, struct pt_regs *regs, long err)
18 {
19 static int die_counter;
20
21 oops_enter();
22
23 spin_lock_irq(&die_lock);
24 console_verbose();
25 bust_spinlocks(1);
26
27 printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
28 print_modules();
29 show_regs(regs);
30
31 printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
32 task_pid_nr(current), task_stack_page(current) + 1);
33
34 if (!user_mode(regs) || in_interrupt())
35 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
36 (unsigned long)task_stack_page(current));
37
38 notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
39
40 bust_spinlocks(0);
41 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
42 spin_unlock_irq(&die_lock);
43 oops_exit();
44
45 if (kexec_should_crash(current))
46 crash_kexec(regs);
47
48 if (in_interrupt())
49 panic("Fatal exception in interrupt");
50
51 if (panic_on_oops)
52 panic("Fatal exception");
53
54 do_exit(SIGSEGV);
55 }
56
57 void die_if_kernel(const char *str, struct pt_regs *regs, long err)
58 {
59 if (!user_mode(regs))
60 die(str, regs, err);
61 }
62
63 /*
64 * try and fix up kernelspace address errors
65 * - userspace errors just cause EFAULT to be returned, resulting in SEGV
66 * - kernel/userspace interfaces cause a jump to an appropriate handler
67 * - other kernel errors are bad
68 */
69 void die_if_no_fixup(const char *str, struct pt_regs *regs, long err)
70 {
71 if (!user_mode(regs)) {
72 const struct exception_table_entry *fixup;
73 fixup = search_exception_tables(regs->pc);
74 if (fixup) {
75 regs->pc = fixup->fixup;
76 return;
77 }
78
79 die(str, regs, err);
80 }
81 }
82
83 #ifdef CONFIG_GENERIC_BUG
84 static void handle_BUG(struct pt_regs *regs)
85 {
86 const struct bug_entry *bug;
87 unsigned long bugaddr = regs->pc;
88 enum bug_trap_type tt;
89
90 if (!is_valid_bugaddr(bugaddr))
91 goto invalid;
92
93 bug = find_bug(bugaddr);
94
95 /* Switch unwinders when unwind_stack() is called */
96 if (bug->flags & BUGFLAG_UNWINDER)
97 unwinder_faulted = 1;
98
99 tt = report_bug(bugaddr, regs);
100 if (tt == BUG_TRAP_TYPE_WARN) {
101 regs->pc += instruction_size(bugaddr);
102 return;
103 }
104
105 invalid:
106 die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
107 }
108
109 int is_valid_bugaddr(unsigned long addr)
110 {
111 insn_size_t opcode;
112
113 if (addr < PAGE_OFFSET)
114 return 0;
115 if (probe_kernel_address((insn_size_t *)addr, opcode))
116 return 0;
117 if (opcode == TRAPA_BUG_OPCODE)
118 return 1;
119
120 return 0;
121 }
122 #endif
123
124 /*
125 * Generic trap handler.
126 */
127 BUILD_TRAP_HANDLER(debug)
128 {
129 TRAP_HANDLER_DECL;
130
131 /* Rewind */
132 regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
133
134 if (notify_die(DIE_TRAP, "debug trap", regs, 0, vec & 0xff,
135 SIGTRAP) == NOTIFY_STOP)
136 return;
137
138 force_sig(SIGTRAP, current);
139 }
140
141 /*
142 * Special handler for BUG() traps.
143 */
144 BUILD_TRAP_HANDLER(bug)
145 {
146 TRAP_HANDLER_DECL;
147
148 /* Rewind */
149 regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
150
151 if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
152 SIGTRAP) == NOTIFY_STOP)
153 return;
154
155 #ifdef CONFIG_GENERIC_BUG
156 if (__kernel_text_address(instruction_pointer(regs))) {
157 insn_size_t insn = *(insn_size_t *)instruction_pointer(regs);
158 if (insn == TRAPA_BUG_OPCODE)
159 handle_BUG(regs);
160 return;
161 }
162 #endif
163
164 force_sig(SIGTRAP, current);
165 }
166
167 BUILD_TRAP_HANDLER(nmi)
168 {
169 unsigned int cpu = smp_processor_id();
170 TRAP_HANDLER_DECL;
171
172 nmi_enter();
173 nmi_count(cpu)++;
174
175 switch (notify_die(DIE_NMI, "NMI", regs, 0, vec & 0xff, SIGINT)) {
176 case NOTIFY_OK:
177 case NOTIFY_STOP:
178 break;
179 case NOTIFY_BAD:
180 die("Fatal Non-Maskable Interrupt", regs, SIGINT);
181 default:
182 printk(KERN_ALERT "Got NMI, but nobody cared. Ignoring...\n");
183 break;
184 }
185
186 nmi_exit();
187 }
188
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.