#include <linux/export.h>#include <linux/sched.h>#include <linux/stacktrace.h> #include <asm/stacktrace.h> #if defined(CONFIG_FRAME_POINTER) #ifdef CONFIG_KALLSYMS#include <linux/kallsyms.h>#include <linux/module.h> static unsigned long tbi_boing_addr;static unsigned long tbi_boing_size; static void tbi_boing_init(void){	/* We need to know where TBIBoingVec is and it's size */	unsigned long size;	unsigned long offset;	char modname[MODULE_NAME_LEN];	char name[KSYM_NAME_LEN];	tbi_boing_addr = kallsyms_lookup_name("___TBIBoingVec");	if (!tbi_boing_addr)		tbi_boing_addr = 1;	else if (!lookup_symbol_attrs(tbi_boing_addr, &size,				      &offset, modname, name))		tbi_boing_size = size;}#endif #define ALIGN_DOWN(addr, size)  ((addr)&(~((size)-1))) /* * Unwind the current stack frame and store the new register values in the * structure passed as argument. Unwinding is equivalent to a function return, * hence the new PC value rather than LR should be used for backtrace. */int notrace unwind_frame(struct stackframe *frame){	struct metag_frame *fp = (struct metag_frame *)frame->fp;	unsigned long lr;	unsigned long fpnew; 	if (frame->fp & 0x7)		return -EINVAL; 	fpnew = fp->fp;	lr = fp->lr - 4; #ifdef CONFIG_KALLSYMS	/* If we've reached TBIBoingVec then we're at an interrupt	 * entry point or a syscall entry point. The frame pointer	 * points to a pt_regs which can be used to continue tracing on	 * the other side of the boing.	 */	if (!tbi_boing_addr)		tbi_boing_init();	if (tbi_boing_size && lr >= tbi_boing_addr &&	    lr < tbi_boing_addr + tbi_boing_size) {		struct pt_regs *regs = (struct pt_regs *)fpnew;		if (user_mode(regs))			return -EINVAL;		fpnew = regs->ctx.AX[1].U0;		lr = regs->ctx.DX[4].U1;	}#endif 	/* stack grows up, so frame pointers must decrease */	if (fpnew < (ALIGN_DOWN((unsigned long)fp, THREAD_SIZE) +		     sizeof(struct thread_info)) || fpnew >= (unsigned long)fp)		return -EINVAL; 	/* restore the registers from the stack frame */	frame->fp = fpnew;	frame->pc = lr; 	return 0;}#elseint notrace unwind_frame(struct stackframe *frame){	struct metag_frame *sp = (struct metag_frame *)frame->sp; 	if (frame->sp & 0x7)		return -EINVAL; 	while (!kstack_end(sp)) {		unsigned long addr = sp->lr - 4;		sp--; 		if (__kernel_text_address(addr)) {			frame->sp = (unsigned long)sp;			frame->pc = addr;			return 0;		}	}	return -EINVAL;}#endif void notrace walk_stackframe(struct stackframe *frame,		     int (*fn)(struct stackframe *, void *), void *data){	while (1) {		int ret; 		if (fn(frame, data))			break;		ret = unwind_frame(frame);		if (ret < 0)			break;	}}EXPORT_SYMBOL(walk_stackframe); #ifdef CONFIG_STACKTRACEstruct stack_trace_data {	struct stack_trace *trace;	unsigned int no_sched_functions;	unsigned int skip;}; static int save_trace(struct stackframe *frame, void *d){	struct stack_trace_data *data = d;	struct stack_trace *trace = data->trace;	unsigned long addr = frame->pc; 	if (data->no_sched_functions && in_sched_functions(addr))		return 0;	if (data->skip) {		data->skip--;		return 0;	} 	trace->entries[trace->nr_entries++] = addr; 	return trace->nr_entries >= trace->max_entries;} void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace){	struct stack_trace_data data;	struct stackframe frame; 	data.trace = trace;	data.skip = trace->skip; 	if (tsk != current) {#ifdef CONFIG_SMP		/*		 * What guarantees do we have here that 'tsk' is not		 * running on another CPU?  For now, ignore it as we		 * can't guarantee we won't explode.		 */		if (trace->nr_entries < trace->max_entries)			trace->entries[trace->nr_entries++] = ULONG_MAX;		return;#else		data.no_sched_functions = 1;		frame.fp = thread_saved_fp(tsk);		frame.sp = thread_saved_sp(tsk);		frame.lr = 0;		/* recovered from the stack */		frame.pc = thread_saved_pc(tsk);#endif	} else {		register unsigned long current_sp asm ("A0StP"); 		data.no_sched_functions = 0;		frame.fp = (unsigned long)__builtin_frame_address(0);		frame.sp = current_sp;		frame.lr = (unsigned long)__builtin_return_address(0);		frame.pc = (unsigned long)save_stack_trace_tsk;	} 	walk_stackframe(&frame, save_trace, &data);	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = ULONG_MAX;} void save_stack_trace(struct stack_trace *trace){	save_stack_trace_tsk(current, trace);}EXPORT_SYMBOL_GPL(save_stack_trace);#endif