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/time.h>
  13
  14 #include <asm/atomic.h>
  15
  16 #include "trace.h"
  17 #include "trace_output.h"
  18
  19 struct header_iter {
  20         struct pci_dev *dev;
  21 };
  22
  23 static struct trace_array *mmio_trace_array;
  24 static bool overrun_detected;
  25 static unsigned long prev_overruns;
  26 static atomic_t dropped_count;
  27
  28 static void mmio_reset_data(struct trace_array *tr)
  29 {
  30         overrun_detected = false;
  31         prev_overruns = 0;
  32
  33         tracing_reset_online_cpus(tr);
  34 }
  35
  36 static int mmio_trace_init(struct trace_array *tr)
  37 {
  38         pr_debug("in %s\n", __func__);
  39         mmio_trace_array = tr;
  40
  41         mmio_reset_data(tr);
  42         enable_mmiotrace();
  43         return 0;
  44 }
  45
  46 static void mmio_trace_reset(struct trace_array *tr)
  47 {
  48         pr_debug("in %s\n", __func__);
  49
  50         disable_mmiotrace();
  51         mmio_reset_data(tr);
  52         mmio_trace_array = NULL;
  53 }
  54
  55 static void mmio_trace_start(struct trace_array *tr)
  56 {
  57         pr_debug("in %s\n", __func__);
  58         mmio_reset_data(tr);
  59 }
  60
  61 static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  62 {
  63         int ret = 0;
  64         int i;
  65         resource_size_t start, end;
  66         const struct pci_driver *drv = pci_dev_driver(dev);
  67
  68         /* XXX: incomplete checks for trace_seq_printf() return value */
  69         ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  70                                 dev->bus->number, dev->devfn,
  71                                 dev->vendor, dev->device, dev->irq);
  72         /*
  73          * XXX: is pci_resource_to_user() appropriate, since we are
  74          * supposed to interpret the __ioremap() phys_addr argument based on
  75          * these printed values?
  76          */
  77         for (i = 0; i < 7; i++) {
  78                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  79                 ret += trace_seq_printf(s, " %llx",
  80                         (unsigned long long)(start |
  81                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  82         }
  83         for (i = 0; i < 7; i++) {
  84                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  85                 ret += trace_seq_printf(s, " %llx",
  86                         dev->resource[i].start < dev->resource[i].end ?
  87                         (unsigned long long)(end - start) + 1 : 0);
  88         }
  89         if (drv)
  90                 ret += trace_seq_printf(s, " %s\n", drv->name);
  91         else
  92                 ret += trace_seq_printf(s, " \n");
  93         return ret;
  94 }
  95
  96 static void destroy_header_iter(struct header_iter *hiter)
  97 {
  98         if (!hiter)
  99                 return;
 100         pci_dev_put(hiter->dev);
 101         kfree(hiter);
 102 }
 103
 104 static void mmio_pipe_open(struct trace_iterator *iter)
 105 {
 106         struct header_iter *hiter;
 107         struct trace_seq *s = &iter->seq;
 108
 109         trace_seq_printf(s, "VERSION 20070824\n");
 110
 111         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 112         if (!hiter)
 113                 return;
 114
 115         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 116         iter->private = hiter;
 117 }
 118
 119 /* XXX: This is not called when the pipe is closed! */
 120 static void mmio_close(struct trace_iterator *iter)
 121 {
 122         struct header_iter *hiter = iter->private;
 123         destroy_header_iter(hiter);
 124         iter->private = NULL;
 125 }
 126
 127 static unsigned long count_overruns(struct trace_iterator *iter)
 128 {
 129         unsigned long cnt = atomic_xchg(&dropped_count, 0);
 130         unsigned long over = ring_buffer_overruns(iter->tr->buffer);
 131
 132         if (over > prev_overruns)
 133                 cnt += over - prev_overruns;
 134         prev_overruns = over;
 135         return cnt;
 136 }
 137
 138 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 139                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 140 {
 141         ssize_t ret;
 142         struct header_iter *hiter = iter->private;
 143         struct trace_seq *s = &iter->seq;
 144         unsigned long n;
 145
 146         n = count_overruns(iter);
 147         if (n) {
 148                 /* XXX: This is later than where events were lost. */
 149                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 150                 if (!overrun_detected)
 151                         pr_warning("mmiotrace has lost events.\n");
 152                 overrun_detected = true;
 153                 goto print_out;
 154         }
 155
 156         if (!hiter)
 157                 return 0;
 158
 159         mmio_print_pcidev(s, hiter->dev);
 160         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 161
 162         if (!hiter->dev) {
 163                 destroy_header_iter(hiter);
 164                 iter->private = NULL;
 165         }
 166
 167 print_out:
 168         ret = trace_seq_to_user(s, ubuf, cnt);
 169         return (ret == -EBUSY) ? 0 : ret;
 170 }
 171
 172 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 173 {
 174         struct trace_entry *entry = iter->ent;
 175         struct trace_mmiotrace_rw *field;
 176         struct mmiotrace_rw *rw;
 177         struct trace_seq *s     = &iter->seq;
 178         unsigned long long t    = ns2usecs(iter->ts);
 179         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 180         unsigned secs           = (unsigned long)t;
 181         int ret = 1;
 182
 183         trace_assign_type(field, entry);
 184         rw = &field->rw;
 185
 186         switch (rw->opcode) {
 187         case MMIO_READ:
 188                 ret = trace_seq_printf(s,
 189                         "R %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_WRITE:
 195                 ret = trace_seq_printf(s,
 196                         "W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 197                         rw->width, secs, usec_rem, rw->map_id,
 198                         (unsigned long long)rw->phys,
 199                         rw->value, rw->pc, 0);
 200                 break;
 201         case MMIO_UNKNOWN_OP:
 202                 ret = trace_seq_printf(s,
 203                         "UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
 204                         "%02lx 0x%lx %d\n",
 205                         secs, usec_rem, rw->map_id,
 206                         (unsigned long long)rw->phys,
 207                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 208                         (rw->value >> 0) & 0xff, rw->pc, 0);
 209                 break;
 210         default:
 211                 ret = trace_seq_printf(s, "rw what?\n");
 212                 break;
 213         }
 214         if (ret)
 215                 return TRACE_TYPE_HANDLED;
 216         return TRACE_TYPE_PARTIAL_LINE;
 217 }
 218
 219 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 220 {
 221         struct trace_entry *entry = iter->ent;
 222         struct trace_mmiotrace_map *field;
 223         struct mmiotrace_map *m;
 224         struct trace_seq *s     = &iter->seq;
 225         unsigned long long t    = ns2usecs(iter->ts);
 226         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 227         unsigned secs           = (unsigned long)t;
 228         int ret;
 229
 230         trace_assign_type(field, entry);
 231         m = &field->map;
 232
 233         switch (m->opcode) {
 234         case MMIO_PROBE:
 235                 ret = trace_seq_printf(s,
 236                         "MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 237                         secs, usec_rem, m->map_id,
 238                         (unsigned long long)m->phys, m->virt, m->len,
 239                         0UL, 0);
 240                 break;
 241         case MMIO_UNPROBE:
 242                 ret = trace_seq_printf(s,
 243                         "UNMAP %u.%06lu %d 0x%lx %d\n",
 244                         secs, usec_rem, m->map_id, 0UL, 0);
 245                 break;
 246         default:
 247                 ret = trace_seq_printf(s, "map what?\n");
 248                 break;
 249         }
 250         if (ret)
 251                 return TRACE_TYPE_HANDLED;
 252         return TRACE_TYPE_PARTIAL_LINE;
 253 }
 254
 255 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 256 {
 257         struct trace_entry *entry = iter->ent;
 258         struct print_entry *print = (struct print_entry *)entry;
 259         const char *msg         = print->buf;
 260         struct trace_seq *s     = &iter->seq;
 261         unsigned long long t    = ns2usecs(iter->ts);
 262         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 263         unsigned secs           = (unsigned long)t;
 264         int ret;
 265
 266         /* The trailing newline must be in the message. */
 267         ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
 268         if (!ret)
 269                 return TRACE_TYPE_PARTIAL_LINE;
 270
 271         return TRACE_TYPE_HANDLED;
 272 }
 273
 274 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 275 {
 276         switch (iter->ent->type) {
 277         case TRACE_MMIO_RW:
 278                 return mmio_print_rw(iter);
 279         case TRACE_MMIO_MAP:
 280                 return mmio_print_map(iter);
 281         case TRACE_PRINT:
 282                 return mmio_print_mark(iter);
 283         default:
 284                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 285         }
 286 }
 287
 288 static struct tracer mmio_tracer __read_mostly =
 289 {
 290         .name           = "mmiotrace",
 291         .init           = mmio_trace_init,
 292         .reset          = mmio_trace_reset,
 293         .start          = mmio_trace_start,
 294         .pipe_open      = mmio_pipe_open,
 295         .close          = mmio_close,
 296         .read           = mmio_read,
 297         .print_line     = mmio_print_line,
 298 };
 299
 300 __init static int init_mmio_trace(void)
 301 {
 302         return register_tracer(&mmio_tracer);
 303 }
 304 device_initcall(init_mmio_trace);
 305
 306 static void __trace_mmiotrace_rw(struct trace_array *tr,
 307                                 struct trace_array_cpu *data,
 308                                 struct mmiotrace_rw *rw)
 309 {
 310         struct ring_buffer_event *event;
 311         struct trace_mmiotrace_rw *entry;
 312         int pc = preempt_count();
 313
 314         event = trace_buffer_lock_reserve(tr, TRACE_MMIO_RW,
 315                                           sizeof(*entry), 0, pc);
 316         if (!event) {
 317                 atomic_inc(&dropped_count);
 318                 return;
 319         }
 320         entry   = ring_buffer_event_data(event);
 321         entry->rw                       = *rw;
 322         trace_buffer_unlock_commit(tr, event, 0, pc);
 323 }
 324
 325 void mmio_trace_rw(struct mmiotrace_rw *rw)
 326 {
 327         struct trace_array *tr = mmio_trace_array;
 328         struct trace_array_cpu *data = tr->data[smp_processor_id()];
 329         __trace_mmiotrace_rw(tr, data, rw);
 330 }
 331
 332 static void __trace_mmiotrace_map(struct trace_array *tr,
 333                                 struct trace_array_cpu *data,
 334                                 struct mmiotrace_map *map)
 335 {
 336         struct ring_buffer_event *event;
 337         struct trace_mmiotrace_map *entry;
 338         int pc = preempt_count();
 339
 340         event = trace_buffer_lock_reserve(tr, TRACE_MMIO_MAP,
 341                                           sizeof(*entry), 0, pc);
 342         if (!event) {
 343                 atomic_inc(&dropped_count);
 344                 return;
 345         }
 346         entry   = ring_buffer_event_data(event);
 347         entry->map                      = *map;
 348         trace_buffer_unlock_commit(tr, event, 0, pc);
 349 }
 350
 351 void mmio_trace_mapping(struct mmiotrace_map *map)
 352 {
 353         struct trace_array *tr = mmio_trace_array;
 354         struct trace_array_cpu *data;
 355
 356         preempt_disable();
 357         data = tr->data[smp_processor_id()];
 358         __trace_mmiotrace_map(tr, data, map);
 359         preempt_enable();
 360 }
 361
 362 int mmio_trace_printk(const char *fmt, va_list args)
 363 {
 364         return trace_vprintk(0, fmt, args);
 365 }