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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
15static DEFINE_SPINLOCK(die_lock);
16
17void 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
57void 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 */
69void 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
84static 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
105invalid:
106 die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
107}
108
109int 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 */
127BUILD_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 */
144BUILD_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
167BUILD_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}
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/bug.h>
3#include <linux/io.h>
4#include <linux/types.h>
5#include <linux/kdebug.h>
6#include <linux/signal.h>
7#include <linux/sched.h>
8#include <linux/sched/debug.h>
9#include <linux/sched/task_stack.h>
10#include <linux/uaccess.h>
11#include <linux/hardirq.h>
12#include <linux/kernel.h>
13#include <linux/kexec.h>
14#include <linux/sched/signal.h>
15
16#include <linux/extable.h>
17#include <linux/module.h> /* print_modules */
18#include <asm/unwinder.h>
19#include <asm/traps.h>
20
21static DEFINE_SPINLOCK(die_lock);
22
23void die(const char *str, struct pt_regs *regs, long err)
24{
25 static int die_counter;
26
27 oops_enter();
28
29 spin_lock_irq(&die_lock);
30 console_verbose();
31 bust_spinlocks(1);
32
33 printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
34 print_modules();
35 show_regs(regs);
36
37 printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
38 task_pid_nr(current), task_stack_page(current) + 1);
39
40 if (!user_mode(regs) || in_interrupt())
41 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
42 (unsigned long)task_stack_page(current));
43
44 notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
45
46 bust_spinlocks(0);
47 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
48 spin_unlock_irq(&die_lock);
49 oops_exit();
50
51 if (kexec_should_crash(current))
52 crash_kexec(regs);
53
54 if (in_interrupt())
55 panic("Fatal exception in interrupt");
56
57 if (panic_on_oops)
58 panic("Fatal exception");
59
60 do_exit(SIGSEGV);
61}
62
63void die_if_kernel(const char *str, struct pt_regs *regs, long err)
64{
65 if (!user_mode(regs))
66 die(str, regs, err);
67}
68
69/*
70 * try and fix up kernelspace address errors
71 * - userspace errors just cause EFAULT to be returned, resulting in SEGV
72 * - kernel/userspace interfaces cause a jump to an appropriate handler
73 * - other kernel errors are bad
74 */
75void die_if_no_fixup(const char *str, struct pt_regs *regs, long err)
76{
77 if (!user_mode(regs)) {
78 const struct exception_table_entry *fixup;
79 fixup = search_exception_tables(regs->pc);
80 if (fixup) {
81 regs->pc = fixup->fixup;
82 return;
83 }
84
85 die(str, regs, err);
86 }
87}
88
89#ifdef CONFIG_GENERIC_BUG
90static void handle_BUG(struct pt_regs *regs)
91{
92 const struct bug_entry *bug;
93 unsigned long bugaddr = regs->pc;
94 enum bug_trap_type tt;
95
96 if (!is_valid_bugaddr(bugaddr))
97 goto invalid;
98
99 bug = find_bug(bugaddr);
100
101 /* Switch unwinders when unwind_stack() is called */
102 if (bug->flags & BUGFLAG_UNWINDER)
103 unwinder_faulted = 1;
104
105 tt = report_bug(bugaddr, regs);
106 if (tt == BUG_TRAP_TYPE_WARN) {
107 regs->pc += instruction_size(bugaddr);
108 return;
109 }
110
111invalid:
112 die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
113}
114
115int is_valid_bugaddr(unsigned long addr)
116{
117 insn_size_t opcode;
118
119 if (addr < PAGE_OFFSET)
120 return 0;
121 if (probe_kernel_address((insn_size_t *)addr, opcode))
122 return 0;
123 if (opcode == TRAPA_BUG_OPCODE)
124 return 1;
125
126 return 0;
127}
128#endif
129
130/*
131 * Generic trap handler.
132 */
133BUILD_TRAP_HANDLER(debug)
134{
135 TRAP_HANDLER_DECL;
136
137 /* Rewind */
138 regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
139
140 if (notify_die(DIE_TRAP, "debug trap", regs, 0, vec & 0xff,
141 SIGTRAP) == NOTIFY_STOP)
142 return;
143
144 force_sig(SIGTRAP);
145}
146
147/*
148 * Special handler for BUG() traps.
149 */
150BUILD_TRAP_HANDLER(bug)
151{
152 TRAP_HANDLER_DECL;
153
154 /* Rewind */
155 regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
156
157 if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
158 SIGTRAP) == NOTIFY_STOP)
159 return;
160
161#ifdef CONFIG_GENERIC_BUG
162 if (__kernel_text_address(instruction_pointer(regs))) {
163 insn_size_t insn = *(insn_size_t *)instruction_pointer(regs);
164 if (insn == TRAPA_BUG_OPCODE)
165 handle_BUG(regs);
166 return;
167 }
168#endif
169
170 force_sig(SIGTRAP);
171}
172
173BUILD_TRAP_HANDLER(nmi)
174{
175 unsigned int cpu = smp_processor_id();
176 TRAP_HANDLER_DECL;
177
178 nmi_enter();
179 nmi_count(cpu)++;
180
181 switch (notify_die(DIE_NMI, "NMI", regs, 0, vec & 0xff, SIGINT)) {
182 case NOTIFY_OK:
183 case NOTIFY_STOP:
184 break;
185 case NOTIFY_BAD:
186 die("Fatal Non-Maskable Interrupt", regs, SIGINT);
187 default:
188 printk(KERN_ALERT "Got NMI, but nobody cared. Ignoring...\n");
189 break;
190 }
191
192 nmi_exit();
193}