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