text: /* SPDX-License-Identifier: GPL-2.0 */
  #ifndef __LINUX_STACKTRACE_H
  #define __LINUX_STACKTRACE_H
  
  #include <linux/types.h>
  #include <asm/errno.h>
  
  struct task_struct;
  struct pt_regs;
  
  #ifdef CONFIG_STACKTRACE
  void stack_trace_print(const unsigned long *trace, unsigned int nr_entries,
  		       int spaces);
  int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,
  			unsigned int nr_entries, int spaces);
  unsigned int stack_trace_save(unsigned long *store, unsigned int size,
  			      unsigned int skipnr);
  unsigned int stack_trace_save_tsk(struct task_struct *task,
  				  unsigned long *store, unsigned int size,
  				  unsigned int skipnr);
  unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
  				   unsigned int size, unsigned int skipnr);
  unsigned int stack_trace_save_user(unsigned long *store, unsigned int size);
  
  /* Internal interfaces. Do not use in generic code */
  #ifdef CONFIG_ARCH_STACKWALK
  
  /**
   * stack_trace_consume_fn - Callback for arch_stack_walk()
   * @cookie:	Caller supplied pointer handed back by arch_stack_walk()
   * @addr:	The stack entry address to consume
   * @reliable:	True when the stack entry is reliable. Required by
   *		some printk based consumers.
   *
   * Return:	True, if the entry was consumed or skipped
   *		False, if there is no space left to store
   */
  typedef bool (*stack_trace_consume_fn)(void *cookie, unsigned long addr,
  				       bool reliable);
  /**
   * arch_stack_walk - Architecture specific function to walk the stack
   * @consume_entry:	Callback which is invoked by the architecture code for
   *			each entry.
   * @cookie:		Caller supplied pointer which is handed back to
   *			@consume_entry
   * @task:		Pointer to a task struct, can be NULL
   * @regs:		Pointer to registers, can be NULL
   *
   * ============ ======= ============================================
   * task	        regs
   * ============ ======= ============================================
   * task		NULL	Stack trace from task (can be current)
   * current	regs	Stack trace starting on regs->stackpointer
   * ============ ======= ============================================
   */
  void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
  		     struct task_struct *task, struct pt_regs *regs);
  int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, void *cookie,
  			     struct task_struct *task);
  void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
  			  const struct pt_regs *regs);
  
  #else /* CONFIG_ARCH_STACKWALK */
  struct stack_trace {
  	unsigned int nr_entries, max_entries;
  	unsigned long *entries;
  	unsigned int skip;	/* input argument: How many entries to skip */
  };
  
  extern void save_stack_trace(struct stack_trace *trace);
  extern void save_stack_trace_regs(struct pt_regs *regs,
  				  struct stack_trace *trace);
  extern void save_stack_trace_tsk(struct task_struct *tsk,
  				struct stack_trace *trace);
  extern int save_stack_trace_tsk_reliable(struct task_struct *tsk,
  					 struct stack_trace *trace);
  extern void save_stack_trace_user(struct stack_trace *trace);
  #endif /* !CONFIG_ARCH_STACKWALK */
  #endif /* CONFIG_STACKTRACE */
  
  #if defined(CONFIG_STACKTRACE) && defined(CONFIG_HAVE_RELIABLE_STACKTRACE)
  int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
  				  unsigned int size);
  #else
  static inline int stack_trace_save_tsk_reliable(struct task_struct *tsk,
  						unsigned long *store,
  						unsigned int size)
  {
  	return -ENOSYS;
  }
  #endif
  
  #endif /* __LINUX_STACKTRACE_H */
  