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