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 <linux/slab.h>
  13 #include <linux/time.h>
  14
  15 #include <linux/atomic.h>
  16
  17 #include "trace.h"
  18 #include "trace_output.h"
  19
  20 struct header_iter {
  21         struct pci_dev *dev;
  22 };
  23
  24 static struct trace_array *mmio_trace_array;
  25 static bool overrun_detected;
  26 static unsigned long prev_overruns;
  27 static atomic_t dropped_count;
  28
  29 static void mmio_reset_data(struct trace_array *tr)
  30 {
  31         overrun_detected = false;
  32         prev_overruns = 0;
  33
  34         tracing_reset_online_cpus(&tr->trace_buffer);
  35 }
  36
  37 static int mmio_trace_init(struct trace_array *tr)
  38 {
  39         pr_debug("in %s\n", __func__);
  40         mmio_trace_array = tr;
  41
  42         mmio_reset_data(tr);
  43         enable_mmiotrace();
  44         return 0;
  45 }
  46
  47 static void mmio_trace_reset(struct trace_array *tr)
  48 {
  49         pr_debug("in %s\n", __func__);
  50
  51         disable_mmiotrace();
  52         mmio_reset_data(tr);
  53         mmio_trace_array = NULL;
  54 }
  55
  56 static void mmio_trace_start(struct trace_array *tr)
  57 {
  58         pr_debug("in %s\n", __func__);
  59         mmio_reset_data(tr);
  60 }
  61
  62 static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  63 {
  64         int i;
  65         resource_size_t start, end;
  66         const struct pci_driver *drv = pci_dev_driver(dev);
  67
  68         trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  69                          dev->bus->number, dev->devfn,
  70                          dev->vendor, dev->device, dev->irq);
  71         /*
  72          * XXX: is pci_resource_to_user() appropriate, since we are
  73          * supposed to interpret the __ioremap() phys_addr argument based on
  74          * these printed values?
  75          */
  76         for (i = 0; i < 7; i++) {
  77                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  78                 trace_seq_printf(s, " %llx",
  79                         (unsigned long long)(start |
  80                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  81         }
  82         for (i = 0; i < 7; i++) {
  83                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  84                 trace_seq_printf(s, " %llx",
  85                         dev->resource[i].start < dev->resource[i].end ?
  86                         (unsigned long long)(end - start) + 1 : 0);
  87         }
  88         if (drv)
  89                 trace_seq_printf(s, " %s\n", drv->name);
  90         else
  91                 trace_seq_puts(s, " \n");
  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_puts(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->trace_buffer->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_warn("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, USEC_PER_SEC);
 178         unsigned secs           = (unsigned long)t;
 179
 180         trace_assign_type(field, entry);
 181         rw = &field->rw;
 182
 183         switch (rw->opcode) {
 184         case MMIO_READ:
 185                 trace_seq_printf(s,
 186                         "R %d %u.%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                 trace_seq_printf(s,
 193                         "W %d %u.%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                 trace_seq_printf(s,
 200                         "UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
 201                         "%02lx 0x%lx %d\n",
 202                         secs, usec_rem, rw->map_id,
 203                         (unsigned long long)rw->phys,
 204                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 205                         (rw->value >> 0) & 0xff, rw->pc, 0);
 206                 break;
 207         default:
 208                 trace_seq_puts(s, "rw what?\n");
 209                 break;
 210         }
 211
 212         return trace_handle_return(s);
 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, USEC_PER_SEC);
 223         unsigned secs           = (unsigned long)t;
 224
 225         trace_assign_type(field, entry);
 226         m = &field->map;
 227
 228         switch (m->opcode) {
 229         case MMIO_PROBE:
 230                 trace_seq_printf(s,
 231                         "MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 232                         secs, usec_rem, m->map_id,
 233                         (unsigned long long)m->phys, m->virt, m->len,
 234                         0UL, 0);
 235                 break;
 236         case MMIO_UNPROBE:
 237                 trace_seq_printf(s,
 238                         "UNMAP %u.%06lu %d 0x%lx %d\n",
 239                         secs, usec_rem, m->map_id, 0UL, 0);
 240                 break;
 241         default:
 242                 trace_seq_puts(s, "map what?\n");
 243                 break;
 244         }
 245
 246         return trace_handle_return(s);
 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, USEC_PER_SEC);
 257         unsigned secs           = (unsigned long)t;
 258
 259         /* The trailing newline must be in the message. */
 260         trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
 261
 262         return trace_handle_return(s);
 263 }
 264
 265 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 266 {
 267         switch (iter->ent->type) {
 268         case TRACE_MMIO_RW:
 269                 return mmio_print_rw(iter);
 270         case TRACE_MMIO_MAP:
 271                 return mmio_print_map(iter);
 272         case TRACE_PRINT:
 273                 return mmio_print_mark(iter);
 274         default:
 275                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 276         }
 277 }
 278
 279 static struct tracer mmio_tracer __read_mostly =
 280 {
 281         .name           = "mmiotrace",
 282         .init           = mmio_trace_init,
 283         .reset          = mmio_trace_reset,
 284         .start          = mmio_trace_start,
 285         .pipe_open      = mmio_pipe_open,
 286         .close          = mmio_close,
 287         .read           = mmio_read,
 288         .print_line     = mmio_print_line,
 289 };
 290
 291 __init static int init_mmio_trace(void)
 292 {
 293         return register_tracer(&mmio_tracer);
 294 }
 295 device_initcall(init_mmio_trace);
 296
 297 static void __trace_mmiotrace_rw(struct trace_array *tr,
 298                                 struct trace_array_cpu *data,
 299                                 struct mmiotrace_rw *rw)
 300 {
 301         struct trace_event_call *call = &event_mmiotrace_rw;
 302         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 303         struct ring_buffer_event *event;
 304         struct trace_mmiotrace_rw *entry;
 305         int pc = preempt_count();
 306
 307         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
 308                                           sizeof(*entry), 0, pc);
 309         if (!event) {
 310                 atomic_inc(&dropped_count);
 311                 return;
 312         }
 313         entry   = ring_buffer_event_data(event);
 314         entry->rw                       = *rw;
 315
 316         if (!call_filter_check_discard(call, entry, buffer, event))
 317                 trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
 318 }
 319
 320 void mmio_trace_rw(struct mmiotrace_rw *rw)
 321 {
 322         struct trace_array *tr = mmio_trace_array;
 323         struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
 324         __trace_mmiotrace_rw(tr, data, rw);
 325 }
 326
 327 static void __trace_mmiotrace_map(struct trace_array *tr,
 328                                 struct trace_array_cpu *data,
 329                                 struct mmiotrace_map *map)
 330 {
 331         struct trace_event_call *call = &event_mmiotrace_map;
 332         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 333         struct ring_buffer_event *event;
 334         struct trace_mmiotrace_map *entry;
 335         int pc = preempt_count();
 336
 337         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
 338                                           sizeof(*entry), 0, pc);
 339         if (!event) {
 340                 atomic_inc(&dropped_count);
 341                 return;
 342         }
 343         entry   = ring_buffer_event_data(event);
 344         entry->map                      = *map;
 345
 346         if (!call_filter_check_discard(call, entry, buffer, event))
 347                 trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
 348 }
 349
 350 void mmio_trace_mapping(struct mmiotrace_map *map)
 351 {
 352         struct trace_array *tr = mmio_trace_array;
 353         struct trace_array_cpu *data;
 354
 355         preempt_disable();
 356         data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
 357         __trace_mmiotrace_map(tr, data, map);
 358         preempt_enable();
 359 }
 360
 361 int mmio_trace_printk(const char *fmt, va_list args)
 362 {
 363         return trace_vprintk(0, fmt, args);
 364 }