text: /*
   *  Copyright (C) 1991, 1992  Linus Torvalds
   *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
   */
  #include <linux/kallsyms.h>
  #include <linux/kprobes.h>
  #include <linux/uaccess.h>
  #include <linux/utsname.h>
  #include <linux/hardirq.h>
  #include <linux/kdebug.h>
  #include <linux/module.h>
  #include <linux/ptrace.h>
  #include <linux/ftrace.h>
  #include <linux/kexec.h>
  #include <linux/bug.h>
  #include <linux/nmi.h>
  #include <linux/sysfs.h>
  
  #include <asm/stacktrace.h>
  
  
  int panic_on_unrecovered_nmi;
  int panic_on_io_nmi;
  unsigned int code_bytes = 64;
  int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
  static int die_counter;
  
  static void printk_stack_address(unsigned long address, int reliable)
  {
  	pr_cont(" [<%p>] %s%pB\n",
  		(void *)address, reliable ? "" : "? ", (void *)address);
  }
  
  void printk_address(unsigned long address)
  {
  	pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address);
  }
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  static void
  print_ftrace_graph_addr(unsigned long addr, void *data,
  			const struct stacktrace_ops *ops,
  			struct thread_info *tinfo, int *graph)
  {
  	struct task_struct *task;
  	unsigned long ret_addr;
  	int index;
  
  	if (addr != (unsigned long)return_to_handler)
  		return;
  
  	task = tinfo->task;
  	index = task->curr_ret_stack;
  
  	if (!task->ret_stack || index < *graph)
  		return;
  
  	index -= *graph;
  	ret_addr = task->ret_stack[index].ret;
  
  	ops->address(data, ret_addr, 1);
  
  	(*graph)++;
  }
  #else
  static inline void
  print_ftrace_graph_addr(unsigned long addr, void *data,
  			const struct stacktrace_ops *ops,
  			struct thread_info *tinfo, int *graph)
  { }
  #endif
  
  /*
   * x86-64 can have up to three kernel stacks:
   * process stack
   * interrupt stack
   * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
   */
  
  static inline int valid_stack_ptr(struct thread_info *tinfo,
  			void *p, unsigned int size, void *end)
  {
  	void *t = tinfo;
  	if (end) {
  		if (p < end && p >= (end-THREAD_SIZE))
  			return 1;
  		else
  			return 0;
  	}
  	return p > t && p < t + THREAD_SIZE - size;
  }
  
  unsigned long
  print_context_stack(struct thread_info *tinfo,
  		unsigned long *stack, unsigned long bp,
  		const struct stacktrace_ops *ops, void *data,
  		unsigned long *end, int *graph)
  {
  	struct stack_frame *frame = (struct stack_frame *)bp;
  
  	while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
  		unsigned long addr;
  
  		addr = *stack;
  		if (__kernel_text_address(addr)) {
  			if ((unsigned long) stack == bp + sizeof(long)) {
  				ops->address(data, addr, 1);
  				frame = frame->next_frame;
  				bp = (unsigned long) frame;
  			} else {
  				ops->address(data, addr, 0);
  			}
  			print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
  		}
  		stack++;
  	}
  	return bp;
  }
  EXPORT_SYMBOL_GPL(print_context_stack);
  
  unsigned long
  print_context_stack_bp(struct thread_info *tinfo,
  		       unsigned long *stack, unsigned long bp,
  		       const struct stacktrace_ops *ops, void *data,
  		       unsigned long *end, int *graph)
  {
  	struct stack_frame *frame = (struct stack_frame *)bp;
  	unsigned long *ret_addr = &frame->return_address;
  
  	while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
  		unsigned long addr = *ret_addr;
  
  		if (!__kernel_text_address(addr))
  			break;
  
  		ops->address(data, addr, 1);
  		frame = frame->next_frame;
  		ret_addr = &frame->return_address;
  		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
  	}
  
  	return (unsigned long)frame;
  }
  EXPORT_SYMBOL_GPL(print_context_stack_bp);
  
  static int print_trace_stack(void *data, char *name)
  {
  	printk("%s <%s> ", (char *)data, name);
  	return 0;
  }
  
  /*
   * Print one address/symbol entries per line.
   */
  static void print_trace_address(void *data, unsigned long addr, int reliable)
  {
  	touch_nmi_watchdog();
  	printk(data);
  	printk_stack_address(addr, reliable);
  }
  
  static const struct stacktrace_ops print_trace_ops = {
  	.stack			= print_trace_stack,
  	.address		= print_trace_address,
  	.walk_stack		= print_context_stack,
  };
  
  void
  show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
  		unsigned long *stack, unsigned long bp, char *log_lvl)
  {
  	printk("%sCall Trace:\n", log_lvl);
  	dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
  }
  
  void show_trace(struct task_struct *task, struct pt_regs *regs,
  		unsigned long *stack, unsigned long bp)
  {
  	show_trace_log_lvl(task, regs, stack, bp, "");
  }
  
  void show_stack(struct task_struct *task, unsigned long *sp)
  {
  	unsigned long bp = 0;
  	unsigned long stack;
  
  	/*
  	 * Stack frames below this one aren't interesting.  Don't show them
  	 * if we're printing for %current.
  	 */
  	if (!sp && (!task || task == current)) {
  		sp = &stack;
  		bp = stack_frame(current, NULL);
  	}
  
  	show_stack_log_lvl(task, NULL, sp, bp, "");
  }
  
  static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
  static int die_owner = -1;
  static unsigned int die_nest_count;
  
  unsigned long oops_begin(void)
  {
  	int cpu;
  	unsigned long flags;
  
  	oops_enter();
  
  	/* racy, but better than risking deadlock. */
  	raw_local_irq_save(flags);
  	cpu = smp_processor_id();
  	if (!arch_spin_trylock(&die_lock)) {
  		if (cpu == die_owner)
  			/* nested oops. should stop eventually */;
  		else
  			arch_spin_lock(&die_lock);
  	}
  	die_nest_count++;
  	die_owner = cpu;
  	console_verbose();
  	bust_spinlocks(1);
  	return flags;
  }
  EXPORT_SYMBOL_GPL(oops_begin);
  NOKPROBE_SYMBOL(oops_begin);
  
  void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
  {
  	if (regs && kexec_should_crash(current))
  		crash_kexec(regs);
  
  	bust_spinlocks(0);
  	die_owner = -1;
  	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
  	die_nest_count--;
  	if (!die_nest_count)
  		/* Nest count reaches zero, release the lock. */
  		arch_spin_unlock(&die_lock);
  	raw_local_irq_restore(flags);
  	oops_exit();
  
  	if (!signr)
  		return;
  	if (in_interrupt())
  		panic("Fatal exception in interrupt");
  	if (panic_on_oops)
  		panic("Fatal exception");
  	do_exit(signr);
  }
  NOKPROBE_SYMBOL(oops_end);
  
  int __die(const char *str, struct pt_regs *regs, long err)
  {
  #ifdef CONFIG_X86_32
  	unsigned short ss;
  	unsigned long sp;
  #endif
  	printk(KERN_DEFAULT
  	       "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
  #ifdef CONFIG_PREEMPT
  	printk("PREEMPT ");
  #endif
  #ifdef CONFIG_SMP
  	printk("SMP ");
  #endif
  #ifdef CONFIG_DEBUG_PAGEALLOC
  	printk("DEBUG_PAGEALLOC");
  #endif
  	printk("\n");
  	if (notify_die(DIE_OOPS, str, regs, err,
  			current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
  		return 1;
  
  	print_modules();
  	show_regs(regs);
  #ifdef CONFIG_X86_32
  	if (user_mode_vm(regs)) {
  		sp = regs->sp;
  		ss = regs->ss & 0xffff;
  	} else {
  		sp = kernel_stack_pointer(regs);
  		savesegment(ss, ss);
  	}
  	printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
  	print_symbol("%s", regs->ip);
  	printk(" SS:ESP %04x:%08lx\n", ss, sp);
  #else
  	/* Executive summary in case the oops scrolled away */
  	printk(KERN_ALERT "RIP ");
  	printk_address(regs->ip);
  	printk(" RSP <%016lx>\n", regs->sp);
  #endif
  	return 0;
  }
  NOKPROBE_SYMBOL(__die);
  
  /*
   * This is gone through when something in the kernel has done something bad
   * and is about to be terminated:
   */
  void die(const char *str, struct pt_regs *regs, long err)
  {
  	unsigned long flags = oops_begin();
  	int sig = SIGSEGV;
  
  	if (!user_mode_vm(regs))
  		report_bug(regs->ip, regs);
  
  	if (__die(str, regs, err))
  		sig = 0;
  	oops_end(flags, regs, sig);
  }
  
  static int __init kstack_setup(char *s)
  {
  	ssize_t ret;
  	unsigned long val;
  
  	if (!s)
  		return -EINVAL;
  
  	ret = kstrtoul(s, 0, &val);
  	if (ret)
  		return ret;
  	kstack_depth_to_print = val;
  	return 0;
  }
  early_param("kstack", kstack_setup);
  
  static int __init code_bytes_setup(char *s)
  {
  	ssize_t ret;
  	unsigned long val;
  
  	if (!s)
  		return -EINVAL;
  
  	ret = kstrtoul(s, 0, &val);
  	if (ret)
  		return ret;
  
  	code_bytes = val;
  	if (code_bytes > 8192)
  		code_bytes = 8192;
  
  	return 1;
  }
  __setup("code_bytes=", code_bytes_setup);
  