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 15 static DEFINE_SPINLOCK(die_lock); 16 17 void 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 57 void 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 */ 69 void 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 84 static 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 } 104 105 invalid: 106 die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff); 107 } 108 109 int 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 */ 127 BUILD_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 */ 144 BUILD_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 } 166 167 BUILD_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 } 188