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
  22 static void mmio_reset_data(struct trace_array *tr)
  23 {
  24         int cpu;
  25
  26         overrun_detected = false;
  27         tr->time_start = ftrace_now(tr->cpu);
  28
  29         for_each_online_cpu(cpu)
  30                 tracing_reset(tr, cpu);
  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         int cpu;
 127         unsigned long cnt = 0;
 128 /* FIXME: */
 129 #if 0
 130         for_each_online_cpu(cpu) {
 131                 cnt += iter->overrun[cpu];
 132                 iter->overrun[cpu] = 0;
 133         }
 134 #endif
 135         (void)cpu;
 136         return cnt;
 137 }
 138
 139 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 140                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 141 {
 142         ssize_t ret;
 143         struct header_iter *hiter = iter->private;
 144         struct trace_seq *s = &iter->seq;
 145         unsigned long n;
 146
 147         n = count_overruns(iter);
 148         if (n) {
 149                 /* XXX: This is later than where events were lost. */
 150                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 151                 if (!overrun_detected)
 152                         pr_warning("mmiotrace has lost events.\n");
 153                 overrun_detected = true;
 154                 goto print_out;
 155         }
 156
 157         if (!hiter)
 158                 return 0;
 159
 160         mmio_print_pcidev(s, hiter->dev);
 161         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 162
 163         if (!hiter->dev) {
 164                 destroy_header_iter(hiter);
 165                 iter->private = NULL;
 166         }
 167
 168 print_out:
 169         ret = trace_seq_to_user(s, ubuf, cnt);
 170         return (ret == -EBUSY) ? 0 : ret;
 171 }
 172
 173 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 174 {
 175         struct trace_entry *entry = iter->ent;
 176         struct trace_mmiotrace_rw *field;
 177         struct mmiotrace_rw *rw;
 178         struct trace_seq *s     = &iter->seq;
 179         unsigned long long t    = ns2usecs(iter->ts);
 180         unsigned long usec_rem  = do_div(t, 1000000ULL);
 181         unsigned secs           = (unsigned long)t;
 182         int ret = 1;
 183
 184         trace_assign_type(field, entry);
 185         rw = &field->rw;
 186
 187         switch (rw->opcode) {
 188         case MMIO_READ:
 189                 ret = trace_seq_printf(s,
 190                         "R %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 191                         rw->width, secs, usec_rem, rw->map_id,
 192                         (unsigned long long)rw->phys,
 193                         rw->value, rw->pc, 0);
 194                 break;
 195         case MMIO_WRITE:
 196                 ret = trace_seq_printf(s,
 197                         "W %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 198                         rw->width, secs, usec_rem, rw->map_id,
 199                         (unsigned long long)rw->phys,
 200                         rw->value, rw->pc, 0);
 201                 break;
 202         case MMIO_UNKNOWN_OP:
 203                 ret = trace_seq_printf(s,
 204                         "UNKNOWN %lu.%06lu %d 0x%llx %02x,%02x,%02x 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, 1000000ULL);
 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 %lu.%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 %lu.%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, 1000000ULL);
 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 %lu.%06lu %s", secs, usec_rem, msg);
 268         if (!ret)
 269                 return TRACE_TYPE_PARTIAL_LINE;
 270
 271         if (entry->flags & TRACE_FLAG_CONT)
 272                 trace_seq_print_cont(s, iter);
 273
 274         return TRACE_TYPE_HANDLED;
 275 }
 276
 277 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 278 {
 279         switch (iter->ent->type) {
 280         case TRACE_MMIO_RW:
 281                 return mmio_print_rw(iter);
 282         case TRACE_MMIO_MAP:
 283                 return mmio_print_map(iter);
 284         case TRACE_PRINT:
 285                 return mmio_print_mark(iter);
 286         default:
 287                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 288         }
 289 }
 290
 291 static struct tracer mmio_tracer __read_mostly =
 292 {
 293         .name           = "mmiotrace",
 294         .init           = mmio_trace_init,
 295         .reset          = mmio_trace_reset,
 296         .start          = mmio_trace_start,
 297         .pipe_open      = mmio_pipe_open,
 298         .close          = mmio_close,
 299         .read           = mmio_read,
 300         .print_line     = mmio_print_line,
 301 };
 302
 303 __init static int init_mmio_trace(void)
 304 {
 305         return register_tracer(&mmio_tracer);
 306 }
 307 device_initcall(init_mmio_trace);
 308
 309 static void __trace_mmiotrace_rw(struct trace_array *tr,
 310                                 struct trace_array_cpu *data,
 311                                 struct mmiotrace_rw *rw)
 312 {
 313         struct ring_buffer_event *event;
 314         struct trace_mmiotrace_rw *entry;
 315         unsigned long irq_flags;
 316
 317         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 318                                            &irq_flags);
 319         if (!event)
 320                 return;
 321         entry   = ring_buffer_event_data(event);
 322         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
 323         entry->ent.type                 = TRACE_MMIO_RW;
 324         entry->rw                       = *rw;
 325         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 326
 327         trace_wake_up();
 328 }
 329
 330 void mmio_trace_rw(struct mmiotrace_rw *rw)
 331 {
 332         struct trace_array *tr = mmio_trace_array;
 333         struct trace_array_cpu *data = tr->data[smp_processor_id()];
 334         __trace_mmiotrace_rw(tr, data, rw);
 335 }
 336
 337 static void __trace_mmiotrace_map(struct trace_array *tr,
 338                                 struct trace_array_cpu *data,
 339                                 struct mmiotrace_map *map)
 340 {
 341         struct ring_buffer_event *event;
 342         struct trace_mmiotrace_map *entry;
 343         unsigned long irq_flags;
 344
 345         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 346                                            &irq_flags);
 347         if (!event)
 348                 return;
 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, fmt, args);
 372 }