/* * 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);