text: /*
   * Memory mapped I/O tracing
   *
   * Copyright (C) 2008 Pekka Paalanen <pq@iki.fi>
   */
  
  #define DEBUG 1
  
  #include <linux/kernel.h>
  #include <linux/mmiotrace.h>
  #include <linux/pci.h>
  #include <linux/slab.h>
  #include <linux/time.h>
  
  #include <linux/atomic.h>
  
  #include "trace.h"
  #include "trace_output.h"
  
  struct header_iter {
  	struct pci_dev *dev;
  };
  
  static struct trace_array *mmio_trace_array;
  static bool overrun_detected;
  static unsigned long prev_overruns;
  static atomic_t dropped_count;
  
  static void mmio_reset_data(struct trace_array *tr)
  {
  	overrun_detected = false;
  	prev_overruns = 0;
  
  	tracing_reset_online_cpus(&tr->trace_buffer);
  }
  
  static int mmio_trace_init(struct trace_array *tr)
  {
  	pr_debug("in %s\n", __func__);
  	mmio_trace_array = tr;
  
  	mmio_reset_data(tr);
  	enable_mmiotrace();
  	return 0;
  }
  
  static void mmio_trace_reset(struct trace_array *tr)
  {
  	pr_debug("in %s\n", __func__);
  
  	disable_mmiotrace();
  	mmio_reset_data(tr);
  	mmio_trace_array = NULL;
  }
  
  static void mmio_trace_start(struct trace_array *tr)
  {
  	pr_debug("in %s\n", __func__);
  	mmio_reset_data(tr);
  }
  
  static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  {
  	int i;
  	resource_size_t start, end;
  	const struct pci_driver *drv = pci_dev_driver(dev);
  
  	trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  			 dev->bus->number, dev->devfn,
  			 dev->vendor, dev->device, dev->irq);
  	for (i = 0; i < 7; i++) {
  		start = dev->resource[i].start;
  		trace_seq_printf(s, " %llx",
  			(unsigned long long)(start |
  			(dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  	}
  	for (i = 0; i < 7; i++) {
  		start = dev->resource[i].start;
  		end = dev->resource[i].end;
  		trace_seq_printf(s, " %llx",
  			dev->resource[i].start < dev->resource[i].end ?
  			(unsigned long long)(end - start) + 1 : 0);
  	}
  	if (drv)
  		trace_seq_printf(s, " %s\n", drv->name);
  	else
  		trace_seq_puts(s, " \n");
  }
  
  static void destroy_header_iter(struct header_iter *hiter)
  {
  	if (!hiter)
  		return;
  	pci_dev_put(hiter->dev);
  	kfree(hiter);
  }
  
  static void mmio_pipe_open(struct trace_iterator *iter)
  {
  	struct header_iter *hiter;
  	struct trace_seq *s = &iter->seq;
  
  	trace_seq_puts(s, "VERSION 20070824\n");
  
  	hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
  	if (!hiter)
  		return;
  
  	hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
  	iter->private = hiter;
  }
  
  /* XXX: This is not called when the pipe is closed! */
  static void mmio_close(struct trace_iterator *iter)
  {
  	struct header_iter *hiter = iter->private;
  	destroy_header_iter(hiter);
  	iter->private = NULL;
  }
  
  static unsigned long count_overruns(struct trace_iterator *iter)
  {
  	unsigned long cnt = atomic_xchg(&dropped_count, 0);
  	unsigned long over = ring_buffer_overruns(iter->trace_buffer->buffer);
  
  	if (over > prev_overruns)
  		cnt += over - prev_overruns;
  	prev_overruns = over;
  	return cnt;
  }
  
  static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
  				char __user *ubuf, size_t cnt, loff_t *ppos)
  {
  	ssize_t ret;
  	struct header_iter *hiter = iter->private;
  	struct trace_seq *s = &iter->seq;
  	unsigned long n;
  
  	n = count_overruns(iter);
  	if (n) {
  		/* XXX: This is later than where events were lost. */
  		trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
  		if (!overrun_detected)
  			pr_warn("mmiotrace has lost events\n");
  		overrun_detected = true;
  		goto print_out;
  	}
  
  	if (!hiter)
  		return 0;
  
  	mmio_print_pcidev(s, hiter->dev);
  	hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
  
  	if (!hiter->dev) {
  		destroy_header_iter(hiter);
  		iter->private = NULL;
  	}
  
  print_out:
  	ret = trace_seq_to_user(s, ubuf, cnt);
  	return (ret == -EBUSY) ? 0 : ret;
  }
  
  static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
  {
  	struct trace_entry *entry = iter->ent;
  	struct trace_mmiotrace_rw *field;
  	struct mmiotrace_rw *rw;
  	struct trace_seq *s	= &iter->seq;
  	unsigned long long t	= ns2usecs(iter->ts);
  	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
  	unsigned secs		= (unsigned long)t;
  
  	trace_assign_type(field, entry);
  	rw = &field->rw;
  
  	switch (rw->opcode) {
  	case MMIO_READ:
  		trace_seq_printf(s,
  			"R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
  			rw->width, secs, usec_rem, rw->map_id,
  			(unsigned long long)rw->phys,
  			rw->value, rw->pc, 0);
  		break;
  	case MMIO_WRITE:
  		trace_seq_printf(s,
  			"W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
  			rw->width, secs, usec_rem, rw->map_id,
  			(unsigned long long)rw->phys,
  			rw->value, rw->pc, 0);
  		break;
  	case MMIO_UNKNOWN_OP:
  		trace_seq_printf(s,
  			"UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
  			"%02lx 0x%lx %d\n",
  			secs, usec_rem, rw->map_id,
  			(unsigned long long)rw->phys,
  			(rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
  			(rw->value >> 0) & 0xff, rw->pc, 0);
  		break;
  	default:
  		trace_seq_puts(s, "rw what?\n");
  		break;
  	}
  
  	return trace_handle_return(s);
  }
  
  static enum print_line_t mmio_print_map(struct trace_iterator *iter)
  {
  	struct trace_entry *entry = iter->ent;
  	struct trace_mmiotrace_map *field;
  	struct mmiotrace_map *m;
  	struct trace_seq *s	= &iter->seq;
  	unsigned long long t	= ns2usecs(iter->ts);
  	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
  	unsigned secs		= (unsigned long)t;
  
  	trace_assign_type(field, entry);
  	m = &field->map;
  
  	switch (m->opcode) {
  	case MMIO_PROBE:
  		trace_seq_printf(s,
  			"MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
  			secs, usec_rem, m->map_id,
  			(unsigned long long)m->phys, m->virt, m->len,
  			0UL, 0);
  		break;
  	case MMIO_UNPROBE:
  		trace_seq_printf(s,
  			"UNMAP %u.%06lu %d 0x%lx %d\n",
  			secs, usec_rem, m->map_id, 0UL, 0);
  		break;
  	default:
  		trace_seq_puts(s, "map what?\n");
  		break;
  	}
  
  	return trace_handle_return(s);
  }
  
  static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
  {
  	struct trace_entry *entry = iter->ent;
  	struct print_entry *print = (struct print_entry *)entry;
  	const char *msg		= print->buf;
  	struct trace_seq *s	= &iter->seq;
  	unsigned long long t	= ns2usecs(iter->ts);
  	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
  	unsigned secs		= (unsigned long)t;
  
  	/* The trailing newline must be in the message. */
  	trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
  
  	return trace_handle_return(s);
  }
  
  static enum print_line_t mmio_print_line(struct trace_iterator *iter)
  {
  	switch (iter->ent->type) {
  	case TRACE_MMIO_RW:
  		return mmio_print_rw(iter);
  	case TRACE_MMIO_MAP:
  		return mmio_print_map(iter);
  	case TRACE_PRINT:
  		return mmio_print_mark(iter);
  	default:
  		return TRACE_TYPE_HANDLED; /* ignore unknown entries */
  	}
  }
  
  static struct tracer mmio_tracer __read_mostly =
  {
  	.name		= "mmiotrace",
  	.init		= mmio_trace_init,
  	.reset		= mmio_trace_reset,
  	.start		= mmio_trace_start,
  	.pipe_open	= mmio_pipe_open,
  	.close		= mmio_close,
  	.read		= mmio_read,
  	.print_line	= mmio_print_line,
  };
  
  __init static int init_mmio_trace(void)
  {
  	return register_tracer(&mmio_tracer);
  }
  device_initcall(init_mmio_trace);
  
  static void __trace_mmiotrace_rw(struct trace_array *tr,
  				struct trace_array_cpu *data,
  				struct mmiotrace_rw *rw)
  {
  	struct trace_event_call *call = &event_mmiotrace_rw;
  	struct ring_buffer *buffer = tr->trace_buffer.buffer;
  	struct ring_buffer_event *event;
  	struct trace_mmiotrace_rw *entry;
  	int pc = preempt_count();
  
  	event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
  					  sizeof(*entry), 0, pc);
  	if (!event) {
  		atomic_inc(&dropped_count);
  		return;
  	}
  	entry	= ring_buffer_event_data(event);
  	entry->rw			= *rw;
  
  	if (!call_filter_check_discard(call, entry, buffer, event))
  		trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
  }
  
  void mmio_trace_rw(struct mmiotrace_rw *rw)
  {
  	struct trace_array *tr = mmio_trace_array;
  	struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
  	__trace_mmiotrace_rw(tr, data, rw);
  }
  
  static void __trace_mmiotrace_map(struct trace_array *tr,
  				struct trace_array_cpu *data,
  				struct mmiotrace_map *map)
  {
  	struct trace_event_call *call = &event_mmiotrace_map;
  	struct ring_buffer *buffer = tr->trace_buffer.buffer;
  	struct ring_buffer_event *event;
  	struct trace_mmiotrace_map *entry;
  	int pc = preempt_count();
  
  	event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
  					  sizeof(*entry), 0, pc);
  	if (!event) {
  		atomic_inc(&dropped_count);
  		return;
  	}
  	entry	= ring_buffer_event_data(event);
  	entry->map			= *map;
  
  	if (!call_filter_check_discard(call, entry, buffer, event))
  		trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
  }
  
  void mmio_trace_mapping(struct mmiotrace_map *map)
  {
  	struct trace_array *tr = mmio_trace_array;
  	struct trace_array_cpu *data;
  
  	preempt_disable();
  	data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
  	__trace_mmiotrace_map(tr, data, map);
  	preempt_enable();
  }
  
  int mmio_trace_printk(const char *fmt, va_list args)
  {
  	return trace_vprintk(0, fmt, args);
  }
  