/* * Stack trace management functions * *  Copyright (C) 2009 Helge Deller <deller@gmx.de> *  based on arch/x86/kernel/stacktrace.c by Ingo Molnar <mingo@redhat.com> *  and parisc unwind functions by Randolph Chung <tausq@debian.org> * *  TODO: Userspace stacktrace (CONFIG_USER_STACKTRACE_SUPPORT) */#include <linux/module.h>#include <linux/stacktrace.h> #include <asm/unwind.h> static void dump_trace(struct task_struct *task, struct stack_trace *trace){	struct unwind_frame_info info; 	/* initialize unwind info */	if (task == current) {		unsigned long sp;		struct pt_regs r;HERE:		asm volatile ("copy %%r30, %0" : "=r"(sp));		memset(&r, 0, sizeof(struct pt_regs));		r.iaoq[0] = (unsigned long)&&HERE;		r.gr[2] = (unsigned long)__builtin_return_address(0);		r.gr[30] = sp;		unwind_frame_init(&info, task, &r);	} else {		unwind_frame_init_from_blocked_task(&info, task);	} 	/* unwind stack and save entries in stack_trace struct */	trace->nr_entries = 0;	while (trace->nr_entries < trace->max_entries) {		if (unwind_once(&info) < 0 || info.ip == 0)			break; 		if (__kernel_text_address(info.ip))			trace->entries[trace->nr_entries++] = info.ip;	}}  /* * Save stack-backtrace addresses into a stack_trace buffer. */void save_stack_trace(struct stack_trace *trace){	dump_trace(current, trace);	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = ULONG_MAX;}EXPORT_SYMBOL_GPL(save_stack_trace); void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace){	dump_trace(tsk, trace);	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = ULONG_MAX;}EXPORT_SYMBOL_GPL(save_stack_trace_tsk);