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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 <asm/unwinder.h>
10#include <asm/traps.h>
11
12#ifdef CONFIG_GENERIC_BUG
13static void handle_BUG(struct pt_regs *regs)
14{
15 const struct bug_entry *bug;
16 unsigned long bugaddr = regs->pc;
17 enum bug_trap_type tt;
18
19 if (!is_valid_bugaddr(bugaddr))
20 goto invalid;
21
22 bug = find_bug(bugaddr);
23
24 /* Switch unwinders when unwind_stack() is called */
25 if (bug->flags & BUGFLAG_UNWINDER)
26 unwinder_faulted = 1;
27
28 tt = report_bug(bugaddr, regs);
29 if (tt == BUG_TRAP_TYPE_WARN) {
30 regs->pc += instruction_size(bugaddr);
31 return;
32 }
33
34invalid:
35 die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
36}
37
38int is_valid_bugaddr(unsigned long addr)
39{
40 insn_size_t opcode;
41
42 if (addr < PAGE_OFFSET)
43 return 0;
44 if (probe_kernel_address((insn_size_t *)addr, opcode))
45 return 0;
46 if (opcode == TRAPA_BUG_OPCODE)
47 return 1;
48
49 return 0;
50}
51#endif
52
53/*
54 * Generic trap handler.
55 */
56BUILD_TRAP_HANDLER(debug)
57{
58 TRAP_HANDLER_DECL;
59
60 /* Rewind */
61 regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
62
63 if (notify_die(DIE_TRAP, "debug trap", regs, 0, vec & 0xff,
64 SIGTRAP) == NOTIFY_STOP)
65 return;
66
67 force_sig(SIGTRAP, current);
68}
69
70/*
71 * Special handler for BUG() traps.
72 */
73BUILD_TRAP_HANDLER(bug)
74{
75 TRAP_HANDLER_DECL;
76
77 /* Rewind */
78 regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
79
80 if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
81 SIGTRAP) == NOTIFY_STOP)
82 return;
83
84#ifdef CONFIG_GENERIC_BUG
85 if (__kernel_text_address(instruction_pointer(regs))) {
86 insn_size_t insn = *(insn_size_t *)instruction_pointer(regs);
87 if (insn == TRAPA_BUG_OPCODE)
88 handle_BUG(regs);
89 return;
90 }
91#endif
92
93 force_sig(SIGTRAP, current);
94}
95
96BUILD_TRAP_HANDLER(nmi)
97{
98 unsigned int cpu = smp_processor_id();
99 TRAP_HANDLER_DECL;
100
101 nmi_enter();
102 nmi_count(cpu)++;
103
104 switch (notify_die(DIE_NMI, "NMI", regs, 0, vec & 0xff, SIGINT)) {
105 case NOTIFY_OK:
106 case NOTIFY_STOP:
107 break;
108 case NOTIFY_BAD:
109 die("Fatal Non-Maskable Interrupt", regs, SIGINT);
110 default:
111 printk(KERN_ALERT "Got NMI, but nobody cared. Ignoring...\n");
112 break;
113 }
114
115 nmi_exit();
116}
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, current);
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, current);
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}