/* * kdb helper for dumping the ftrace buffer * * Copyright (C) 2010 Jason Wessel <jason.wessel@windriver.com> * * ftrace_dump_buf based on ftrace_dump: * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com> * */#include <linux/init.h>#include <linux/kgdb.h>#include <linux/kdb.h>#include <linux/ftrace.h> #include "trace.h"#include "trace_output.h" static void ftrace_dump_buf(int skip_lines, long cpu_file){	/* use static because iter can be a bit big for the stack */	static struct trace_iterator iter;	static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];	struct trace_array *tr;	unsigned int old_userobj;	int cnt = 0, cpu; 	trace_init_global_iter(&iter);	iter.buffer_iter = buffer_iter;	tr = iter.tr; 	for_each_tracing_cpu(cpu) {		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);	} 	old_userobj = tr->trace_flags; 	/* don't look at user memory in panic mode */	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ; 	kdb_printf("Dumping ftrace buffer:\n"); 	/* reset all but tr, trace, and overruns */	memset(&iter.seq, 0,		   sizeof(struct trace_iterator) -		   offsetof(struct trace_iterator, seq));	iter.iter_flags |= TRACE_FILE_LAT_FMT;	iter.pos = -1; 	if (cpu_file == RING_BUFFER_ALL_CPUS) {		for_each_tracing_cpu(cpu) {			iter.buffer_iter[cpu] =			ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu);			ring_buffer_read_start(iter.buffer_iter[cpu]);			tracing_iter_reset(&iter, cpu);		}	} else {		iter.cpu_file = cpu_file;		iter.buffer_iter[cpu_file] =			ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu_file);		ring_buffer_read_start(iter.buffer_iter[cpu_file]);		tracing_iter_reset(&iter, cpu_file);	} 	while (trace_find_next_entry_inc(&iter)) {		if (!cnt)			kdb_printf("---------------------------------\n");		cnt++; 		if (!skip_lines) {			print_trace_line(&iter);			trace_printk_seq(&iter.seq);		} else {			skip_lines--;		} 		if (KDB_FLAG(CMD_INTERRUPT))			goto out;	} 	if (!cnt)		kdb_printf("   (ftrace buffer empty)\n");	else		kdb_printf("---------------------------------\n"); out:	tr->trace_flags = old_userobj; 	for_each_tracing_cpu(cpu) {		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);	} 	for_each_tracing_cpu(cpu) {		if (iter.buffer_iter[cpu]) {			ring_buffer_read_finish(iter.buffer_iter[cpu]);			iter.buffer_iter[cpu] = NULL;		}	}} /* * kdb_ftdump - Dump the ftrace log buffer */static int kdb_ftdump(int argc, const char **argv){	int skip_lines = 0;	long cpu_file;	char *cp; 	if (argc > 2)		return KDB_ARGCOUNT; 	if (argc) {		skip_lines = simple_strtol(argv[1], &cp, 0);		if (*cp)			skip_lines = 0;	} 	if (argc == 2) {		cpu_file = simple_strtol(argv[2], &cp, 0);		if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||		    !cpu_online(cpu_file))			return KDB_BADINT;	} else {		cpu_file = RING_BUFFER_ALL_CPUS;	} 	kdb_trap_printk++;	ftrace_dump_buf(skip_lines, cpu_file);	kdb_trap_printk--; 	return 0;} static __init int kdb_ftrace_register(void){	kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",			    "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE);	return 0;} late_initcall(kdb_ftrace_register);