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
  13 #include "trace.h"
  14
  15 struct header_iter {
  16         struct pci_dev *dev;
  17 };
  18
  19 static struct trace_array *mmio_trace_array;
  20 static bool overrun_detected;
  21 static unsigned long prev_overruns;
  22
  23 static void mmio_reset_data(struct trace_array *tr)
  24 {
  25         int cpu;
  26
  27         overrun_detected = false;
  28         prev_overruns = 0;
  29         tr->time_start = ftrace_now(tr->cpu);
  30
  31         for_each_online_cpu(cpu)
  32                 tracing_reset(tr, cpu);
  33 }
  34
  35 static void mmio_trace_init(struct trace_array *tr)
  36 {
  37         pr_debug("in %s\n", __func__);
  38         mmio_trace_array = tr;
  39         if (tr->ctrl) {
  40                 mmio_reset_data(tr);
  41                 enable_mmiotrace();
  42         }
  43 }
  44
  45 static void mmio_trace_reset(struct trace_array *tr)
  46 {
  47         pr_debug("in %s\n", __func__);
  48         if (tr->ctrl)
  49                 disable_mmiotrace();
  50         mmio_reset_data(tr);
  51         mmio_trace_array = NULL;
  52 }
  53
  54 static void mmio_trace_ctrl_update(struct trace_array *tr)
  55 {
  56         pr_debug("in %s\n", __func__);
  57         if (tr->ctrl) {
  58                 mmio_reset_data(tr);
  59                 enable_mmiotrace();
  60         } else {
  61                 disable_mmiotrace();
  62         }
  63 }
  64
  65 static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  66 {
  67         int ret = 0;
  68         int i;
  69         resource_size_t start, end;
  70         const struct pci_driver *drv = pci_dev_driver(dev);
  71
  72         /* XXX: incomplete checks for trace_seq_printf() return value */
  73         ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  74                                 dev->bus->number, dev->devfn,
  75                                 dev->vendor, dev->device, dev->irq);
  76         /*
  77          * XXX: is pci_resource_to_user() appropriate, since we are
  78          * supposed to interpret the __ioremap() phys_addr argument based on
  79          * these printed values?
  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                         (unsigned long long)(start |
  85                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  86         }
  87         for (i = 0; i < 7; i++) {
  88                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  89                 ret += trace_seq_printf(s, " %llx",
  90                         dev->resource[i].start < dev->resource[i].end ?
  91                         (unsigned long long)(end - start) + 1 : 0);
  92         }
  93         if (drv)
  94                 ret += trace_seq_printf(s, " %s\n", drv->name);
  95         else
  96                 ret += trace_seq_printf(s, " \n");
  97         return ret;
  98 }
  99
 100 static void destroy_header_iter(struct header_iter *hiter)
 101 {
 102         if (!hiter)
 103                 return;
 104         pci_dev_put(hiter->dev);
 105         kfree(hiter);
 106 }
 107
 108 static void mmio_pipe_open(struct trace_iterator *iter)
 109 {
 110         struct header_iter *hiter;
 111         struct trace_seq *s = &iter->seq;
 112
 113         trace_seq_printf(s, "VERSION 20070824\n");
 114
 115         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 116         if (!hiter)
 117                 return;
 118
 119         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 120         iter->private = hiter;
 121 }
 122
 123 /* XXX: This is not called when the pipe is closed! */
 124 static void mmio_close(struct trace_iterator *iter)
 125 {
 126         struct header_iter *hiter = iter->private;
 127         destroy_header_iter(hiter);
 128         iter->private = NULL;
 129 }
 130
 131 static unsigned long count_overruns(struct trace_iterator *iter)
 132 {
 133         unsigned long cnt = 0;
 134         unsigned long over = ring_buffer_overruns(iter->tr->buffer);
 135
 136         if (over > prev_overruns)
 137                 cnt = over - prev_overruns;
 138         prev_overruns = over;
 139         return cnt;
 140 }
 141
 142 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 143                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 144 {
 145         ssize_t ret;
 146         struct header_iter *hiter = iter->private;
 147         struct trace_seq *s = &iter->seq;
 148         unsigned long n;
 149
 150         n = count_overruns(iter);
 151         if (n) {
 152                 /* XXX: This is later than where events were lost. */
 153                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 154                 if (!overrun_detected)
 155                         pr_warning("mmiotrace has lost events.\n");
 156                 overrun_detected = true;
 157                 goto print_out;
 158         }
 159
 160         if (!hiter)
 161                 return 0;
 162
 163         mmio_print_pcidev(s, hiter->dev);
 164         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 165
 166         if (!hiter->dev) {
 167                 destroy_header_iter(hiter);
 168                 iter->private = NULL;
 169         }
 170
 171 print_out:
 172         ret = trace_seq_to_user(s, ubuf, cnt);
 173         return (ret == -EBUSY) ? 0 : ret;
 174 }
 175
 176 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 177 {
 178         struct trace_entry *entry = iter->ent;
 179         struct trace_mmiotrace_rw *field;
 180         struct mmiotrace_rw *rw;
 181         struct trace_seq *s     = &iter->seq;
 182         unsigned long long t    = ns2usecs(iter->ts);
 183         unsigned long usec_rem  = do_div(t, 1000000ULL);
 184         unsigned secs           = (unsigned long)t;
 185         int ret = 1;
 186
 187         trace_assign_type(field, entry);
 188         rw = &field->rw;
 189
 190         switch (rw->opcode) {
 191         case MMIO_READ:
 192                 ret = trace_seq_printf(s,
 193                         "R %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_WRITE:
 199                 ret = trace_seq_printf(s,
 200                         "W %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 201                         rw->width, secs, usec_rem, rw->map_id,
 202                         (unsigned long long)rw->phys,
 203                         rw->value, rw->pc, 0);
 204                 break;
 205         case MMIO_UNKNOWN_OP:
 206                 ret = trace_seq_printf(s,
 207                         "UNKNOWN %lu.%06lu %d 0x%llx %02x,%02x,%02x 0x%lx %d\n",
 208                         secs, usec_rem, rw->map_id,
 209                         (unsigned long long)rw->phys,
 210                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 211                         (rw->value >> 0) & 0xff, rw->pc, 0);
 212                 break;
 213         default:
 214                 ret = trace_seq_printf(s, "rw what?\n");
 215                 break;
 216         }
 217         if (ret)
 218                 return TRACE_TYPE_HANDLED;
 219         return TRACE_TYPE_PARTIAL_LINE;
 220 }
 221
 222 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 223 {
 224         struct trace_entry *entry = iter->ent;
 225         struct trace_mmiotrace_map *field;
 226         struct mmiotrace_map *m;
 227         struct trace_seq *s     = &iter->seq;
 228         unsigned long long t    = ns2usecs(iter->ts);
 229         unsigned long usec_rem  = do_div(t, 1000000ULL);
 230         unsigned secs           = (unsigned long)t;
 231         int ret;
 232
 233         trace_assign_type(field, entry);
 234         m = &field->map;
 235
 236         switch (m->opcode) {
 237         case MMIO_PROBE:
 238                 ret = trace_seq_printf(s,
 239                         "MAP %lu.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 240                         secs, usec_rem, m->map_id,
 241                         (unsigned long long)m->phys, m->virt, m->len,
 242                         0UL, 0);
 243                 break;
 244         case MMIO_UNPROBE:
 245                 ret = trace_seq_printf(s,
 246                         "UNMAP %lu.%06lu %d 0x%lx %d\n",
 247                         secs, usec_rem, m->map_id, 0UL, 0);
 248                 break;
 249         default:
 250                 ret = trace_seq_printf(s, "map what?\n");
 251                 break;
 252         }
 253         if (ret)
 254                 return TRACE_TYPE_HANDLED;
 255         return TRACE_TYPE_PARTIAL_LINE;
 256 }
 257
 258 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 259 {
 260         struct trace_entry *entry = iter->ent;
 261         struct print_entry *print = (struct print_entry *)entry;
 262         const char *msg         = print->buf;
 263         struct trace_seq *s     = &iter->seq;
 264         unsigned long long t    = ns2usecs(iter->ts);
 265         unsigned long usec_rem  = do_div(t, 1000000ULL);
 266         unsigned secs           = (unsigned long)t;
 267         int ret;
 268
 269         /* The trailing newline must be in the message. */
 270         ret = trace_seq_printf(s, "MARK %lu.%06lu %s", secs, usec_rem, msg);
 271         if (!ret)
 272                 return TRACE_TYPE_PARTIAL_LINE;
 273
 274         if (entry->flags & TRACE_FLAG_CONT)
 275                 trace_seq_print_cont(s, iter);
 276
 277         return TRACE_TYPE_HANDLED;
 278 }
 279
 280 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 281 {
 282         switch (iter->ent->type) {
 283         case TRACE_MMIO_RW:
 284                 return mmio_print_rw(iter);
 285         case TRACE_MMIO_MAP:
 286                 return mmio_print_map(iter);
 287         case TRACE_PRINT:
 288                 return mmio_print_mark(iter);
 289         default:
 290                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 291         }
 292 }
 293
 294 static struct tracer mmio_tracer __read_mostly =
 295 {
 296         .name           = "mmiotrace",
 297         .init           = mmio_trace_init,
 298         .reset          = mmio_trace_reset,
 299         .pipe_open      = mmio_pipe_open,
 300         .close          = mmio_close,
 301         .read           = mmio_read,
 302         .ctrl_update    = mmio_trace_ctrl_update,
 303         .print_line     = mmio_print_line,
 304 };
 305
 306 __init static int init_mmio_trace(void)
 307 {
 308         return register_tracer(&mmio_tracer);
 309 }
 310 device_initcall(init_mmio_trace);
 311
 312 static void __trace_mmiotrace_rw(struct trace_array *tr,
 313                                 struct trace_array_cpu *data,
 314                                 struct mmiotrace_rw *rw)
 315 {
 316         struct ring_buffer_event *event;
 317         struct trace_mmiotrace_rw *entry;
 318         unsigned long irq_flags;
 319
 320         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 321                                            &irq_flags);
 322         if (!event)
 323                 return;
 324         entry   = ring_buffer_event_data(event);
 325         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
 326         entry->ent.type                 = TRACE_MMIO_RW;
 327         entry->rw                       = *rw;
 328         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 329
 330         trace_wake_up();
 331 }
 332
 333 void mmio_trace_rw(struct mmiotrace_rw *rw)
 334 {
 335         struct trace_array *tr = mmio_trace_array;
 336         struct trace_array_cpu *data = tr->data[smp_processor_id()];
 337         __trace_mmiotrace_rw(tr, data, rw);
 338 }
 339
 340 static void __trace_mmiotrace_map(struct trace_array *tr,
 341                                 struct trace_array_cpu *data,
 342                                 struct mmiotrace_map *map)
 343 {
 344         struct ring_buffer_event *event;
 345         struct trace_mmiotrace_map *entry;
 346         unsigned long irq_flags;
 347
 348         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 349                                            &irq_flags);
 350         if (!event)
 351                 return;
 352         entry   = ring_buffer_event_data(event);
 353         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
 354         entry->ent.type                 = TRACE_MMIO_MAP;
 355         entry->map                      = *map;
 356         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 357
 358         trace_wake_up();
 359 }
 360
 361 void mmio_trace_mapping(struct mmiotrace_map *map)
 362 {
 363         struct trace_array *tr = mmio_trace_array;
 364         struct trace_array_cpu *data;
 365
 366         preempt_disable();
 367         data = tr->data[smp_processor_id()];
 368         __trace_mmiotrace_map(tr, data, map);
 369         preempt_enable();
 370 }
 371
 372 int mmio_trace_printk(const char *fmt, va_list args)
 373 {
 374         return trace_vprintk(0, fmt, args);
 375 }