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kernel/linux-imx6_3.14.28/arch/mips/kernel/stacktrace.c 2.03 KB
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  /*
   * Stack trace management functions
   *
   *  Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   */
  #include <linux/sched.h>
  #include <linux/stacktrace.h>
  #include <linux/export.h>
  #include <asm/stacktrace.h>
  
  /*
   * Save stack-backtrace addresses into a stack_trace buffer:
   */
  static void save_raw_context_stack(struct stack_trace *trace,
  	unsigned long reg29)
  {
  	unsigned long *sp = (unsigned long *)reg29;
  	unsigned long addr;
  
  	while (!kstack_end(sp)) {
  		addr = *sp++;
  		if (__kernel_text_address(addr)) {
  			if (trace->skip > 0)
  				trace->skip--;
  			else
  				trace->entries[trace->nr_entries++] = addr;
  			if (trace->nr_entries >= trace->max_entries)
  				break;
  		}
  	}
  }
  
  static void save_context_stack(struct stack_trace *trace,
  	struct task_struct *tsk, struct pt_regs *regs)
  {
  	unsigned long sp = regs->regs[29];
  #ifdef CONFIG_KALLSYMS
  	unsigned long ra = regs->regs[31];
  	unsigned long pc = regs->cp0_epc;
  
  	if (raw_show_trace || !__kernel_text_address(pc)) {
  		unsigned long stack_page =
  			(unsigned long)task_stack_page(tsk);
  		if (stack_page && sp >= stack_page &&
  		    sp <= stack_page + THREAD_SIZE - 32)
  			save_raw_context_stack(trace, sp);
  		return;
  	}
  	do {
  		if (trace->skip > 0)
  			trace->skip--;
  		else
  			trace->entries[trace->nr_entries++] = pc;
  		if (trace->nr_entries >= trace->max_entries)
  			break;
  		pc = unwind_stack(tsk, &sp, pc, &ra);
  	} while (pc);
  #else
  	save_raw_context_stack(trace, sp);
  #endif
  }
  
  /*
   * Save stack-backtrace addresses into a stack_trace buffer.
   */
  void save_stack_trace(struct stack_trace *trace)
  {
  	save_stack_trace_tsk(current, trace);
  }
  EXPORT_SYMBOL_GPL(save_stack_trace);
  
  void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  {
  	struct pt_regs dummyregs;
  	struct pt_regs *regs = &dummyregs;
  
  	WARN_ON(trace->nr_entries || !trace->max_entries);
  
  	if (tsk != current) {
  		regs->regs[29] = tsk->thread.reg29;
  		regs->regs[31] = 0;
  		regs->cp0_epc = tsk->thread.reg31;
  	} else
  		prepare_frametrace(regs);
  	save_context_stack(trace, tsk, regs);
  }
  EXPORT_SYMBOL_GPL(save_stack_trace_tsk);