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 <asm/atomic.h>
  13
  14 #include "trace.h"
  15
  16 struct header_iter {
  17         struct pci_dev *dev;
  18 };
  19
  20 static struct trace_array *mmio_trace_array;
  21 static bool overrun_detected;
  22 static unsigned long prev_overruns;
  23 static atomic_t dropped_count;
  24
  25 static void mmio_reset_data(struct trace_array *tr)
  26 {
  27         overrun_detected = false;
  28         prev_overruns = 0;
  29
  30         tracing_reset_online_cpus(tr);
  31 }
  32
  33 static int mmio_trace_init(struct trace_array *tr)
  34 {
  35         pr_debug("in %s\n", __func__);
  36         mmio_trace_array = tr;
  37
  38         mmio_reset_data(tr);
  39         enable_mmiotrace();
  40         return 0;
  41 }
  42
  43 static void mmio_trace_reset(struct trace_array *tr)
  44 {
  45         pr_debug("in %s\n", __func__);
  46
  47         disable_mmiotrace();
  48         mmio_reset_data(tr);
  49         mmio_trace_array = NULL;
  50 }
  51
  52 static void mmio_trace_start(struct trace_array *tr)
  53 {
  54         pr_debug("in %s\n", __func__);
  55         mmio_reset_data(tr);
  56 }
  57
  58 static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  59 {
  60         int ret = 0;
  61         int i;
  62         resource_size_t start, end;
  63         const struct pci_driver *drv = pci_dev_driver(dev);
  64
  65         /* XXX: incomplete checks for trace_seq_printf() return value */
  66         ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  67                                 dev->bus->number, dev->devfn,
  68                                 dev->vendor, dev->device, dev->irq);
  69         /*
  70          * XXX: is pci_resource_to_user() appropriate, since we are
  71          * supposed to interpret the __ioremap() phys_addr argument based on
  72          * these printed values?
  73          */
  74         for (i = 0; i < 7; i++) {
  75                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  76                 ret += trace_seq_printf(s, " %llx",
  77                         (unsigned long long)(start |
  78                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  79         }
  80         for (i = 0; i < 7; i++) {
  81                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  82                 ret += trace_seq_printf(s, " %llx",
  83                         dev->resource[i].start < dev->resource[i].end ?
  84                         (unsigned long long)(end - start) + 1 : 0);
  85         }
  86         if (drv)
  87                 ret += trace_seq_printf(s, " %s\n", drv->name);
  88         else
  89                 ret += trace_seq_printf(s, " \n");
  90         return ret;
  91 }
  92
  93 static void destroy_header_iter(struct header_iter *hiter)
  94 {
  95         if (!hiter)
  96                 return;
  97         pci_dev_put(hiter->dev);
  98         kfree(hiter);
  99 }
 100
 101 static void mmio_pipe_open(struct trace_iterator *iter)
 102 {
 103         struct header_iter *hiter;
 104         struct trace_seq *s = &iter->seq;
 105
 106         trace_seq_printf(s, "VERSION 20070824\n");
 107
 108         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 109         if (!hiter)
 110                 return;
 111
 112         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 113         iter->private = hiter;
 114 }
 115
 116 /* XXX: This is not called when the pipe is closed! */
 117 static void mmio_close(struct trace_iterator *iter)
 118 {
 119         struct header_iter *hiter = iter->private;
 120         destroy_header_iter(hiter);
 121         iter->private = NULL;
 122 }
 123
 124 static unsigned long count_overruns(struct trace_iterator *iter)
 125 {
 126         unsigned long cnt = atomic_xchg(&dropped_count, 0);
 127         unsigned long over = ring_buffer_overruns(iter->tr->buffer);
 128
 129         if (over > prev_overruns)
 130                 cnt += over - prev_overruns;
 131         prev_overruns = over;
 132         return cnt;
 133 }
 134
 135 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 136                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 137 {
 138         ssize_t ret;
 139         struct header_iter *hiter = iter->private;
 140         struct trace_seq *s = &iter->seq;
 141         unsigned long n;
 142
 143         n = count_overruns(iter);
 144         if (n) {
 145                 /* XXX: This is later than where events were lost. */
 146                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 147                 if (!overrun_detected)
 148                         pr_warning("mmiotrace has lost events.\n");
 149                 overrun_detected = true;
 150                 goto print_out;
 151         }
 152
 153         if (!hiter)
 154                 return 0;
 155
 156         mmio_print_pcidev(s, hiter->dev);
 157         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 158
 159         if (!hiter->dev) {
 160                 destroy_header_iter(hiter);
 161                 iter->private = NULL;
 162         }
 163
 164 print_out:
 165         ret = trace_seq_to_user(s, ubuf, cnt);
 166         return (ret == -EBUSY) ? 0 : ret;
 167 }
 168
 169 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 170 {
 171         struct trace_entry *entry = iter->ent;
 172         struct trace_mmiotrace_rw *field;
 173         struct mmiotrace_rw *rw;
 174         struct trace_seq *s     = &iter->seq;
 175         unsigned long long t    = ns2usecs(iter->ts);
 176         unsigned long usec_rem  = do_div(t, 1000000ULL);
 177         unsigned secs           = (unsigned long)t;
 178         int ret = 1;
 179
 180         trace_assign_type(field, entry);
 181         rw = &field->rw;
 182
 183         switch (rw->opcode) {
 184         case MMIO_READ:
 185                 ret = trace_seq_printf(s,
 186                         "R %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 187                         rw->width, secs, usec_rem, rw->map_id,
 188                         (unsigned long long)rw->phys,
 189                         rw->value, rw->pc, 0);
 190                 break;
 191         case MMIO_WRITE:
 192                 ret = trace_seq_printf(s,
 193                         "W %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 194                         rw->width, secs, usec_rem, rw->map_id,
 195                         (unsigned long long)rw->phys,
 196                         rw->value, rw->pc, 0);
 197                 break;
 198         case MMIO_UNKNOWN_OP:
 199                 ret = trace_seq_printf(s,
 200                         "UNKNOWN %lu.%06lu %d 0x%llx %02x,%02x,%02x 0x%lx %d\n",
 201                         secs, usec_rem, rw->map_id,
 202                         (unsigned long long)rw->phys,
 203                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 204                         (rw->value >> 0) & 0xff, rw->pc, 0);
 205                 break;
 206         default:
 207                 ret = trace_seq_printf(s, "rw what?\n");
 208                 break;
 209         }
 210         if (ret)
 211                 return TRACE_TYPE_HANDLED;
 212         return TRACE_TYPE_PARTIAL_LINE;
 213 }
 214
 215 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 216 {
 217         struct trace_entry *entry = iter->ent;
 218         struct trace_mmiotrace_map *field;
 219         struct mmiotrace_map *m;
 220         struct trace_seq *s     = &iter->seq;
 221         unsigned long long t    = ns2usecs(iter->ts);
 222         unsigned long usec_rem  = do_div(t, 1000000ULL);
 223         unsigned secs           = (unsigned long)t;
 224         int ret;
 225
 226         trace_assign_type(field, entry);
 227         m = &field->map;
 228
 229         switch (m->opcode) {
 230         case MMIO_PROBE:
 231                 ret = trace_seq_printf(s,
 232                         "MAP %lu.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 233                         secs, usec_rem, m->map_id,
 234                         (unsigned long long)m->phys, m->virt, m->len,
 235                         0UL, 0);
 236                 break;
 237         case MMIO_UNPROBE:
 238                 ret = trace_seq_printf(s,
 239                         "UNMAP %lu.%06lu %d 0x%lx %d\n",
 240                         secs, usec_rem, m->map_id, 0UL, 0);
 241                 break;
 242         default:
 243                 ret = trace_seq_printf(s, "map what?\n");
 244                 break;
 245         }
 246         if (ret)
 247                 return TRACE_TYPE_HANDLED;
 248         return TRACE_TYPE_PARTIAL_LINE;
 249 }
 250
 251 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 252 {
 253         struct trace_entry *entry = iter->ent;
 254         struct print_entry *print = (struct print_entry *)entry;
 255         const char *msg         = print->buf;
 256         struct trace_seq *s     = &iter->seq;
 257         unsigned long long t    = ns2usecs(iter->ts);
 258         unsigned long usec_rem  = do_div(t, 1000000ULL);
 259         unsigned secs           = (unsigned long)t;
 260         int ret;
 261
 262         /* The trailing newline must be in the message. */
 263         ret = trace_seq_printf(s, "MARK %lu.%06lu %s", secs, usec_rem, msg);
 264         if (!ret)
 265                 return TRACE_TYPE_PARTIAL_LINE;
 266
 267         if (entry->flags & TRACE_FLAG_CONT)
 268                 trace_seq_print_cont(s, iter);
 269
 270         return TRACE_TYPE_HANDLED;
 271 }
 272
 273 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 274 {
 275         switch (iter->ent->type) {
 276         case TRACE_MMIO_RW:
 277                 return mmio_print_rw(iter);
 278         case TRACE_MMIO_MAP:
 279                 return mmio_print_map(iter);
 280         case TRACE_PRINT:
 281                 return mmio_print_mark(iter);
 282         default:
 283                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 284         }
 285 }
 286
 287 static struct tracer mmio_tracer __read_mostly =
 288 {
 289         .name           = "mmiotrace",
 290         .init           = mmio_trace_init,
 291         .reset          = mmio_trace_reset,
 292         .start          = mmio_trace_start,
 293         .pipe_open      = mmio_pipe_open,
 294         .close          = mmio_close,
 295         .read           = mmio_read,
 296         .print_line     = mmio_print_line,
 297 };
 298
 299 __init static int init_mmio_trace(void)
 300 {
 301         return register_tracer(&mmio_tracer);
 302 }
 303 device_initcall(init_mmio_trace);
 304
 305 static void __trace_mmiotrace_rw(struct trace_array *tr,
 306                                 struct trace_array_cpu *data,
 307                                 struct mmiotrace_rw *rw)
 308 {
 309         struct ring_buffer_event *event;
 310         struct trace_mmiotrace_rw *entry;
 311         unsigned long irq_flags;
 312
 313         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 314                                            &irq_flags);
 315         if (!event) {
 316                 atomic_inc(&dropped_count);
 317                 return;
 318         }
 319         entry   = ring_buffer_event_data(event);
 320         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
 321         entry->ent.type                 = TRACE_MMIO_RW;
 322         entry->rw                       = *rw;
 323         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 324
 325         trace_wake_up();
 326 }
 327
 328 void mmio_trace_rw(struct mmiotrace_rw *rw)
 329 {
 330         struct trace_array *tr = mmio_trace_array;
 331         struct trace_array_cpu *data = tr->data[smp_processor_id()];
 332         __trace_mmiotrace_rw(tr, data, rw);
 333 }
 334
 335 static void __trace_mmiotrace_map(struct trace_array *tr,
 336                                 struct trace_array_cpu *data,
 337                                 struct mmiotrace_map *map)
 338 {
 339         struct ring_buffer_event *event;
 340         struct trace_mmiotrace_map *entry;
 341         unsigned long irq_flags;
 342
 343         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 344                                            &irq_flags);
 345         if (!event) {
 346                 atomic_inc(&dropped_count);
 347                 return;
 348         }
 349         entry   = ring_buffer_event_data(event);
 350         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
 351         entry->ent.type                 = TRACE_MMIO_MAP;
 352         entry->map                      = *map;
 353         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 354
 355         trace_wake_up();
 356 }
 357
 358 void mmio_trace_mapping(struct mmiotrace_map *map)
 359 {
 360         struct trace_array *tr = mmio_trace_array;
 361         struct trace_array_cpu *data;
 362
 363         preempt_disable();
 364         data = tr->data[smp_processor_id()];
 365         __trace_mmiotrace_map(tr, data, map);
 366         preempt_enable();
 367 }
 368
 369 int mmio_trace_printk(const char *fmt, va_list args)
 370 {
 371         return trace_vprintk(0, -1, fmt, args);
 372 }