kernel/trace/trace_mmiotrace.c

   1 /*
   2  * Memory mapped I/O tracing
   3  *
   4  * Copyright (C) 2008 Pekka Paalanen <pq@iki.fi>
   5  */
   6
   7 #define DEBUG 1
   8
   9 #include <linux/kernel.h>
  10 #include <linux/mmiotrace.h>
  11 #include <linux/pci.h>
  12 #include <linux/slab.h>
  13 #include <linux/time.h>
  14
  15 #include <linux/atomic.h>
  16
  17 #include "trace.h"
  18 #include "trace_output.h"
  19
  20 struct header_iter {
  21         struct pci_dev *dev;
  22 };
  23
  24 static struct trace_array *mmio_trace_array;
  25 static bool overrun_detected;
  26 static unsigned long prev_overruns;
  27 static atomic_t dropped_count;
  28
  29 static void mmio_reset_data(struct trace_array *tr)
  30 {
  31         overrun_detected = false;
  32         prev_overruns = 0;
  33
  34         tracing_reset_online_cpus(&tr->trace_buffer);
  35 }
  36
  37 static int mmio_trace_init(struct trace_array *tr)
  38 {
  39         pr_debug("in %s\n", __func__);
  40         mmio_trace_array = tr;
  41
  42         mmio_reset_data(tr);
  43         enable_mmiotrace();
  44         return 0;
  45 }
  46
  47 static void mmio_trace_reset(struct trace_array *tr)
  48 {
  49         pr_debug("in %s\n", __func__);
  50
  51         disable_mmiotrace();
  52         mmio_reset_data(tr);
  53         mmio_trace_array = NULL;
  54 }
  55
  56 static void mmio_trace_start(struct trace_array *tr)
  57 {
  58         pr_debug("in %s\n", __func__);
  59         mmio_reset_data(tr);
  60 }
  61
  62 static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  63 {
  64         int i;
  65         resource_size_t start, end;
  66         const struct pci_driver *drv = pci_dev_driver(dev);
  67
  68         trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  69                          dev->bus->number, dev->devfn,
  70                          dev->vendor, dev->device, dev->irq);
  71         for (i = 0; i < 7; i++) {
  72                 start = dev->resource[i].start;
  73                 trace_seq_printf(s, " %llx",
  74                         (unsigned long long)(start |
  75                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  76         }
  77         for (i = 0; i < 7; i++) {
  78                 start = dev->resource[i].start;
  79                 end = dev->resource[i].end;
  80                 trace_seq_printf(s, " %llx",
  81                         dev->resource[i].start < dev->resource[i].end ?
  82                         (unsigned long long)(end - start) + 1 : 0);
  83         }
  84         if (drv)
  85                 trace_seq_printf(s, " %s\n", drv->name);
  86         else
  87                 trace_seq_puts(s, " \n");
  88 }
  89
  90 static void destroy_header_iter(struct header_iter *hiter)
  91 {
  92         if (!hiter)
  93                 return;
  94         pci_dev_put(hiter->dev);
  95         kfree(hiter);
  96 }
  97
  98 static void mmio_pipe_open(struct trace_iterator *iter)
  99 {
 100         struct header_iter *hiter;
 101         struct trace_seq *s = &iter->seq;
 102
 103         trace_seq_puts(s, "VERSION 20070824\n");
 104
 105         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 106         if (!hiter)
 107                 return;
 108
 109         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 110         iter->private = hiter;
 111 }
 112
 113 /* XXX: This is not called when the pipe is closed! */
 114 static void mmio_close(struct trace_iterator *iter)
 115 {
 116         struct header_iter *hiter = iter->private;
 117         destroy_header_iter(hiter);
 118         iter->private = NULL;
 119 }
 120
 121 static unsigned long count_overruns(struct trace_iterator *iter)
 122 {
 123         unsigned long cnt = atomic_xchg(&dropped_count, 0);
 124         unsigned long over = ring_buffer_overruns(iter->trace_buffer->buffer);
 125
 126         if (over > prev_overruns)
 127                 cnt += over - prev_overruns;
 128         prev_overruns = over;
 129         return cnt;
 130 }
 131
 132 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 133                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 134 {
 135         ssize_t ret;
 136         struct header_iter *hiter = iter->private;
 137         struct trace_seq *s = &iter->seq;
 138         unsigned long n;
 139
 140         n = count_overruns(iter);
 141         if (n) {
 142                 /* XXX: This is later than where events were lost. */
 143                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 144                 if (!overrun_detected)
 145                         pr_warn("mmiotrace has lost events\n");
 146                 overrun_detected = true;
 147                 goto print_out;
 148         }
 149
 150         if (!hiter)
 151                 return 0;
 152
 153         mmio_print_pcidev(s, hiter->dev);
 154         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 155
 156         if (!hiter->dev) {
 157                 destroy_header_iter(hiter);
 158                 iter->private = NULL;
 159         }
 160
 161 print_out:
 162         ret = trace_seq_to_user(s, ubuf, cnt);
 163         return (ret == -EBUSY) ? 0 : ret;
 164 }
 165
 166 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 167 {
 168         struct trace_entry *entry = iter->ent;
 169         struct trace_mmiotrace_rw *field;
 170         struct mmiotrace_rw *rw;
 171         struct trace_seq *s     = &iter->seq;
 172         unsigned long long t    = ns2usecs(iter->ts);
 173         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 174         unsigned secs           = (unsigned long)t;
 175
 176         trace_assign_type(field, entry);
 177         rw = &field->rw;
 178
 179         switch (rw->opcode) {
 180         case MMIO_READ:
 181                 trace_seq_printf(s,
 182                         "R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 183                         rw->width, secs, usec_rem, rw->map_id,
 184                         (unsigned long long)rw->phys,
 185                         rw->value, rw->pc, 0);
 186                 break;
 187         case MMIO_WRITE:
 188                 trace_seq_printf(s,
 189                         "W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 190                         rw->width, secs, usec_rem, rw->map_id,
 191                         (unsigned long long)rw->phys,
 192                         rw->value, rw->pc, 0);
 193                 break;
 194         case MMIO_UNKNOWN_OP:
 195                 trace_seq_printf(s,
 196                         "UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
 197                         "%02lx 0x%lx %d\n",
 198                         secs, usec_rem, rw->map_id,
 199                         (unsigned long long)rw->phys,
 200                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 201                         (rw->value >> 0) & 0xff, rw->pc, 0);
 202                 break;
 203         default:
 204                 trace_seq_puts(s, "rw what?\n");
 205                 break;
 206         }
 207
 208         return trace_handle_return(s);
 209 }
 210
 211 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 212 {
 213         struct trace_entry *entry = iter->ent;
 214         struct trace_mmiotrace_map *field;
 215         struct mmiotrace_map *m;
 216         struct trace_seq *s     = &iter->seq;
 217         unsigned long long t    = ns2usecs(iter->ts);
 218         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 219         unsigned secs           = (unsigned long)t;
 220
 221         trace_assign_type(field, entry);
 222         m = &field->map;
 223
 224         switch (m->opcode) {
 225         case MMIO_PROBE:
 226                 trace_seq_printf(s,
 227                         "MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 228                         secs, usec_rem, m->map_id,
 229                         (unsigned long long)m->phys, m->virt, m->len,
 230                         0UL, 0);
 231                 break;
 232         case MMIO_UNPROBE:
 233                 trace_seq_printf(s,
 234                         "UNMAP %u.%06lu %d 0x%lx %d\n",
 235                         secs, usec_rem, m->map_id, 0UL, 0);
 236                 break;
 237         default:
 238                 trace_seq_puts(s, "map what?\n");
 239                 break;
 240         }
 241
 242         return trace_handle_return(s);
 243 }
 244
 245 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 246 {
 247         struct trace_entry *entry = iter->ent;
 248         struct print_entry *print = (struct print_entry *)entry;
 249         const char *msg         = print->buf;
 250         struct trace_seq *s     = &iter->seq;
 251         unsigned long long t    = ns2usecs(iter->ts);
 252         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 253         unsigned secs           = (unsigned long)t;
 254
 255         /* The trailing newline must be in the message. */
 256         trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
 257
 258         return trace_handle_return(s);
 259 }
 260
 261 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 262 {
 263         switch (iter->ent->type) {
 264         case TRACE_MMIO_RW:
 265                 return mmio_print_rw(iter);
 266         case TRACE_MMIO_MAP:
 267                 return mmio_print_map(iter);
 268         case TRACE_PRINT:
 269                 return mmio_print_mark(iter);
 270         default:
 271                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 272         }
 273 }
 274
 275 static struct tracer mmio_tracer __read_mostly =
 276 {
 277         .name           = "mmiotrace",
 278         .init           = mmio_trace_init,
 279         .reset          = mmio_trace_reset,
 280         .start          = mmio_trace_start,
 281         .pipe_open      = mmio_pipe_open,
 282         .close          = mmio_close,
 283         .read           = mmio_read,
 284         .print_line     = mmio_print_line,
 285 };
 286
 287 __init static int init_mmio_trace(void)
 288 {
 289         return register_tracer(&mmio_tracer);
 290 }
 291 device_initcall(init_mmio_trace);
 292
 293 static void __trace_mmiotrace_rw(struct trace_array *tr,
 294                                 struct trace_array_cpu *data,
 295                                 struct mmiotrace_rw *rw)
 296 {
 297         struct trace_event_call *call = &event_mmiotrace_rw;
 298         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 299         struct ring_buffer_event *event;
 300         struct trace_mmiotrace_rw *entry;
 301         int pc = preempt_count();
 302
 303         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
 304                                           sizeof(*entry), 0, pc);
 305         if (!event) {
 306                 atomic_inc(&dropped_count);
 307                 return;
 308         }
 309         entry   = ring_buffer_event_data(event);
 310         entry->rw                       = *rw;
 311
 312         if (!call_filter_check_discard(call, entry, buffer, event))
 313                 trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
 314 }
 315
 316 void mmio_trace_rw(struct mmiotrace_rw *rw)
 317 {
 318         struct trace_array *tr = mmio_trace_array;
 319         struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
 320         __trace_mmiotrace_rw(tr, data, rw);
 321 }
 322
 323 static void __trace_mmiotrace_map(struct trace_array *tr,
 324                                 struct trace_array_cpu *data,
 325                                 struct mmiotrace_map *map)
 326 {
 327         struct trace_event_call *call = &event_mmiotrace_map;
 328         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 329         struct ring_buffer_event *event;
 330         struct trace_mmiotrace_map *entry;
 331         int pc = preempt_count();
 332
 333         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
 334                                           sizeof(*entry), 0, pc);
 335         if (!event) {
 336                 atomic_inc(&dropped_count);
 337                 return;
 338         }
 339         entry   = ring_buffer_event_data(event);
 340         entry->map                      = *map;
 341
 342         if (!call_filter_check_discard(call, entry, buffer, event))
 343                 trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
 344 }
 345
 346 void mmio_trace_mapping(struct mmiotrace_map *map)
 347 {
 348         struct trace_array *tr = mmio_trace_array;
 349         struct trace_array_cpu *data;
 350
 351         preempt_disable();
 352         data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
 353         __trace_mmiotrace_map(tr, data, map);
 354         preempt_enable();
 355 }
 356
 357 int mmio_trace_printk(const char *fmt, va_list args)
 358 {
 359         return trace_vprintk(0, fmt, args);
 360 }