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