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