/* * Stack trace management functions * *  Copyright IBM Corp. 2006 *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com> */ #include <linux/sched.h>#include <linux/stacktrace.h>#include <linux/kallsyms.h>#include <linux/module.h> static unsigned long save_context_stack(struct stack_trace *trace,					unsigned long sp,					unsigned long low,					unsigned long high,					int savesched){	struct stack_frame *sf;	struct pt_regs *regs;	unsigned long addr; 	while(1) {		sp &= PSW_ADDR_INSN;		if (sp < low || sp > high)			return sp;		sf = (struct stack_frame *)sp;		while(1) {			addr = sf->gprs[8] & PSW_ADDR_INSN;			if (!trace->skip)				trace->entries[trace->nr_entries++] = addr;			else				trace->skip--;			if (trace->nr_entries >= trace->max_entries)				return sp;			low = sp;			sp = sf->back_chain & PSW_ADDR_INSN;			if (!sp)				break;			if (sp <= low || sp > high - sizeof(*sf))				return sp;			sf = (struct stack_frame *)sp;		}		/* Zero backchain detected, check for interrupt frame. */		sp = (unsigned long)(sf + 1);		if (sp <= low || sp > high - sizeof(*regs))			return sp;		regs = (struct pt_regs *)sp;		addr = regs->psw.addr & PSW_ADDR_INSN;		if (savesched || !in_sched_functions(addr)) {			if (!trace->skip)				trace->entries[trace->nr_entries++] = addr;			else				trace->skip--;		}		if (trace->nr_entries >= trace->max_entries)			return sp;		low = sp;		sp = regs->gprs[15];	}} void save_stack_trace(struct stack_trace *trace){	register unsigned long sp asm ("15");	unsigned long orig_sp, new_sp; 	orig_sp = sp & PSW_ADDR_INSN;	new_sp = save_context_stack(trace, orig_sp,				    S390_lowcore.panic_stack - PAGE_SIZE,				    S390_lowcore.panic_stack, 1);	if (new_sp != orig_sp)		return;	new_sp = save_context_stack(trace, new_sp,				    S390_lowcore.async_stack - ASYNC_SIZE,				    S390_lowcore.async_stack, 1);	if (new_sp != orig_sp)		return;	save_context_stack(trace, new_sp,			   S390_lowcore.thread_info,			   S390_lowcore.thread_info + THREAD_SIZE, 1);}EXPORT_SYMBOL_GPL(save_stack_trace); void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace){	unsigned long sp, low, high; 	sp = tsk->thread.ksp & PSW_ADDR_INSN;	low = (unsigned long) task_stack_page(tsk);	high = (unsigned long) task_pt_regs(tsk);	save_context_stack(trace, sp, low, high, 0);	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = ULONG_MAX;}EXPORT_SYMBOL_GPL(save_stack_trace_tsk);