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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
5a4f7c66 PM |
2 | #include <linux/bug.h> |
3 | #include <linux/io.h> | |
4 | #include <linux/types.h> | |
5 | #include <linux/kdebug.h> | |
47a3eb95 PM |
6 | #include <linux/signal.h> |
7 | #include <linux/sched.h> | |
b17b0153 | 8 | #include <linux/sched/debug.h> |
68db0cf1 | 9 | #include <linux/sched/task_stack.h> |
9a33fc21 | 10 | #include <linux/uaccess.h> |
1e1030dc | 11 | #include <linux/hardirq.h> |
5f857bce PM |
12 | #include <linux/kernel.h> |
13 | #include <linux/kexec.h> | |
3f07c014 IM |
14 | #include <linux/sched/signal.h> |
15 | ||
d92280d1 PG |
16 | #include <linux/extable.h> |
17 | #include <linux/module.h> /* print_modules */ | |
e115f2c1 | 18 | #include <asm/unwinder.h> |
e839ca52 | 19 | #include <asm/traps.h> |
5a4f7c66 | 20 | |
5f857bce PM |
21 | static DEFINE_SPINLOCK(die_lock); |
22 | ||
9fd5a04d | 23 | void __noreturn die(const char *str, struct pt_regs *regs, long err) |
5f857bce PM |
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()) | |
ebf0a36a DS |
41 | dump_mem("Stack: ", KERN_DEFAULT, regs->regs[15], |
42 | THREAD_SIZE + (unsigned long)task_stack_page(current)); | |
5f857bce PM |
43 | |
44 | notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV); | |
45 | ||
46 | bust_spinlocks(0); | |
373d4d09 | 47 | add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); |
5f857bce PM |
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 | ||
63 | void 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 | */ | |
75 | void 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 | ||
626ac8e1 PM |
89 | #ifdef CONFIG_GENERIC_BUG |
90 | static void handle_BUG(struct pt_regs *regs) | |
5a4f7c66 | 91 | { |
e115f2c1 PM |
92 | const struct bug_entry *bug; |
93 | unsigned long bugaddr = regs->pc; | |
5a4f7c66 | 94 | enum bug_trap_type tt; |
e115f2c1 PM |
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); | |
5a4f7c66 | 106 | if (tt == BUG_TRAP_TYPE_WARN) { |
e115f2c1 | 107 | regs->pc += instruction_size(bugaddr); |
5a4f7c66 PM |
108 | return; |
109 | } | |
110 | ||
e115f2c1 | 111 | invalid: |
5a4f7c66 PM |
112 | die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff); |
113 | } | |
114 | ||
115 | int is_valid_bugaddr(unsigned long addr) | |
116 | { | |
2bcfffa4 | 117 | insn_size_t opcode; |
9a33fc21 PM |
118 | |
119 | if (addr < PAGE_OFFSET) | |
120 | return 0; | |
25f12ae4 | 121 | if (get_kernel_nofault(opcode, (insn_size_t *)addr)) |
9a33fc21 | 122 | return 0; |
e115f2c1 | 123 | if (opcode == TRAPA_BUG_OPCODE) |
b344e24a MF |
124 | return 1; |
125 | ||
126 | return 0; | |
5a4f7c66 PM |
127 | } |
128 | #endif | |
129 | ||
130 | /* | |
131 | * Generic trap handler. | |
132 | */ | |
133 | BUILD_TRAP_HANDLER(debug) | |
134 | { | |
135 | TRAP_HANDLER_DECL; | |
136 | ||
137 | /* Rewind */ | |
9d56dd3b | 138 | regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); |
5a4f7c66 PM |
139 | |
140 | if (notify_die(DIE_TRAP, "debug trap", regs, 0, vec & 0xff, | |
141 | SIGTRAP) == NOTIFY_STOP) | |
142 | return; | |
143 | ||
3cf5d076 | 144 | force_sig(SIGTRAP); |
5a4f7c66 PM |
145 | } |
146 | ||
147 | /* | |
148 | * Special handler for BUG() traps. | |
149 | */ | |
150 | BUILD_TRAP_HANDLER(bug) | |
151 | { | |
152 | TRAP_HANDLER_DECL; | |
153 | ||
154 | /* Rewind */ | |
9d56dd3b | 155 | regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); |
5a4f7c66 PM |
156 | |
157 | if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff, | |
158 | SIGTRAP) == NOTIFY_STOP) | |
159 | return; | |
160 | ||
626ac8e1 | 161 | #ifdef CONFIG_GENERIC_BUG |
5a4f7c66 | 162 | if (__kernel_text_address(instruction_pointer(regs))) { |
2bcfffa4 | 163 | insn_size_t insn = *(insn_size_t *)instruction_pointer(regs); |
5a4f7c66 PM |
164 | if (insn == TRAPA_BUG_OPCODE) |
165 | handle_BUG(regs); | |
0ec39885 | 166 | return; |
5a4f7c66 PM |
167 | } |
168 | #endif | |
169 | ||
3cf5d076 | 170 | force_sig(SIGTRAP); |
5a4f7c66 | 171 | } |
1e1030dc | 172 | |
178ba00c PZ |
173 | #ifdef CONFIG_DYNAMIC_FTRACE |
174 | extern void arch_ftrace_nmi_enter(void); | |
175 | extern void arch_ftrace_nmi_exit(void); | |
176 | #else | |
177 | static inline void arch_ftrace_nmi_enter(void) { } | |
178 | static inline void arch_ftrace_nmi_exit(void) { } | |
179 | #endif | |
180 | ||
1e1030dc PM |
181 | BUILD_TRAP_HANDLER(nmi) |
182 | { | |
183 | TRAP_HANDLER_DECL; | |
184 | ||
178ba00c PZ |
185 | arch_ftrace_nmi_enter(); |
186 | ||
1e1030dc | 187 | nmi_enter(); |
fe3f1d5d | 188 | this_cpu_inc(irq_stat.__nmi_count); |
1e1030dc PM |
189 | |
190 | switch (notify_die(DIE_NMI, "NMI", regs, 0, vec & 0xff, SIGINT)) { | |
191 | case NOTIFY_OK: | |
192 | case NOTIFY_STOP: | |
193 | break; | |
194 | case NOTIFY_BAD: | |
195 | die("Fatal Non-Maskable Interrupt", regs, SIGINT); | |
196 | default: | |
197 | printk(KERN_ALERT "Got NMI, but nobody cared. Ignoring...\n"); | |
198 | break; | |
199 | } | |
200 | ||
201 | nmi_exit(); | |
178ba00c PZ |
202 | |
203 | arch_ftrace_nmi_exit(); | |
1e1030dc | 204 | } |