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 int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  63 {
  64         int ret = 0;
  65         int i;
  66         resource_size_t start, end;
  67         const struct pci_driver *drv = pci_dev_driver(dev);
  68
  69         /* XXX: incomplete checks for trace_seq_printf() return value */
  70         ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  71                                 dev->bus->number, dev->devfn,
  72                                 dev->vendor, dev->device, dev->irq);
  73         /*
  74          * XXX: is pci_resource_to_user() appropriate, since we are
  75          * supposed to interpret the __ioremap() phys_addr argument based on
  76          * these printed values?
  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                         (unsigned long long)(start |
  82                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  83         }
  84         for (i = 0; i < 7; i++) {
  85                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  86                 ret += trace_seq_printf(s, " %llx",
  87                         dev->resource[i].start < dev->resource[i].end ?
  88                         (unsigned long long)(end - start) + 1 : 0);
  89         }
  90         if (drv)
  91                 ret += trace_seq_printf(s, " %s\n", drv->name);
  92         else
  93                 ret += trace_seq_puts(s, " \n");
  94         return ret;
  95 }
  96
  97 static void destroy_header_iter(struct header_iter *hiter)
  98 {
  99         if (!hiter)
 100                 return;
 101         pci_dev_put(hiter->dev);
 102         kfree(hiter);
 103 }
 104
 105 static void mmio_pipe_open(struct trace_iterator *iter)
 106 {
 107         struct header_iter *hiter;
 108         struct trace_seq *s = &iter->seq;
 109
 110         trace_seq_puts(s, "VERSION 20070824\n");
 111
 112         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 113         if (!hiter)
 114                 return;
 115
 116         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 117         iter->private = hiter;
 118 }
 119
 120 /* XXX: This is not called when the pipe is closed! */
 121 static void mmio_close(struct trace_iterator *iter)
 122 {
 123         struct header_iter *hiter = iter->private;
 124         destroy_header_iter(hiter);
 125         iter->private = NULL;
 126 }
 127
 128 static unsigned long count_overruns(struct trace_iterator *iter)
 129 {
 130         unsigned long cnt = atomic_xchg(&dropped_count, 0);
 131         unsigned long over = ring_buffer_overruns(iter->trace_buffer->buffer);
 132
 133         if (over > prev_overruns)
 134                 cnt += over - prev_overruns;
 135         prev_overruns = over;
 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, USEC_PER_SEC);
 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 %u.%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 %u.%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 %u.%06lu %d 0x%llx %02lx,%02lx,"
 205                         "%02lx 0x%lx %d\n",
 206                         secs, usec_rem, rw->map_id,
 207                         (unsigned long long)rw->phys,
 208                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 209                         (rw->value >> 0) & 0xff, rw->pc, 0);
 210                 break;
 211         default:
 212                 ret = trace_seq_puts(s, "rw what?\n");
 213                 break;
 214         }
 215         if (ret)
 216                 return TRACE_TYPE_HANDLED;
 217         return TRACE_TYPE_PARTIAL_LINE;
 218 }
 219
 220 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 221 {
 222         struct trace_entry *entry = iter->ent;
 223         struct trace_mmiotrace_map *field;
 224         struct mmiotrace_map *m;
 225         struct trace_seq *s     = &iter->seq;
 226         unsigned long long t    = ns2usecs(iter->ts);
 227         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 228         unsigned secs           = (unsigned long)t;
 229         int ret;
 230
 231         trace_assign_type(field, entry);
 232         m = &field->map;
 233
 234         switch (m->opcode) {
 235         case MMIO_PROBE:
 236                 ret = trace_seq_printf(s,
 237                         "MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 238                         secs, usec_rem, m->map_id,
 239                         (unsigned long long)m->phys, m->virt, m->len,
 240                         0UL, 0);
 241                 break;
 242         case MMIO_UNPROBE:
 243                 ret = trace_seq_printf(s,
 244                         "UNMAP %u.%06lu %d 0x%lx %d\n",
 245                         secs, usec_rem, m->map_id, 0UL, 0);
 246                 break;
 247         default:
 248                 ret = trace_seq_puts(s, "map what?\n");
 249                 break;
 250         }
 251         if (ret)
 252                 return TRACE_TYPE_HANDLED;
 253         return TRACE_TYPE_PARTIAL_LINE;
 254 }
 255
 256 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 257 {
 258         struct trace_entry *entry = iter->ent;
 259         struct print_entry *print = (struct print_entry *)entry;
 260         const char *msg         = print->buf;
 261         struct trace_seq *s     = &iter->seq;
 262         unsigned long long t    = ns2usecs(iter->ts);
 263         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 264         unsigned secs           = (unsigned long)t;
 265         int ret;
 266
 267         /* The trailing newline must be in the message. */
 268         ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
 269         if (!ret)
 270                 return TRACE_TYPE_PARTIAL_LINE;
 271
 272         return TRACE_TYPE_HANDLED;
 273 }
 274
 275 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 276 {
 277         switch (iter->ent->type) {
 278         case TRACE_MMIO_RW:
 279                 return mmio_print_rw(iter);
 280         case TRACE_MMIO_MAP:
 281                 return mmio_print_map(iter);
 282         case TRACE_PRINT:
 283                 return mmio_print_mark(iter);
 284         default:
 285                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 286         }
 287 }
 288
 289 static struct tracer mmio_tracer __read_mostly =
 290 {
 291         .name           = "mmiotrace",
 292         .init           = mmio_trace_init,
 293         .reset          = mmio_trace_reset,
 294         .start          = mmio_trace_start,
 295         .pipe_open      = mmio_pipe_open,
 296         .close          = mmio_close,
 297         .read           = mmio_read,
 298         .print_line     = mmio_print_line,
 299 };
 300
 301 __init static int init_mmio_trace(void)
 302 {
 303         return register_tracer(&mmio_tracer);
 304 }
 305 device_initcall(init_mmio_trace);
 306
 307 static void __trace_mmiotrace_rw(struct trace_array *tr,
 308                                 struct trace_array_cpu *data,
 309                                 struct mmiotrace_rw *rw)
 310 {
 311         struct ftrace_event_call *call = &event_mmiotrace_rw;
 312         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 313         struct ring_buffer_event *event;
 314         struct trace_mmiotrace_rw *entry;
 315         int pc = preempt_count();
 316
 317         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
 318                                           sizeof(*entry), 0, pc);
 319         if (!event) {
 320                 atomic_inc(&dropped_count);
 321                 return;
 322         }
 323         entry   = ring_buffer_event_data(event);
 324         entry->rw                       = *rw;
 325
 326         if (!filter_check_discard(call, entry, buffer, event))
 327                 trace_buffer_unlock_commit(buffer, event, 0, pc);
 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 = per_cpu_ptr(tr->trace_buffer.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 ftrace_event_call *call = &event_mmiotrace_map;
 342         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 343         struct ring_buffer_event *event;
 344         struct trace_mmiotrace_map *entry;
 345         int pc = preempt_count();
 346
 347         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
 348                                           sizeof(*entry), 0, pc);
 349         if (!event) {
 350                 atomic_inc(&dropped_count);
 351                 return;
 352         }
 353         entry   = ring_buffer_event_data(event);
 354         entry->map                      = *map;
 355
 356         if (!filter_check_discard(call, entry, buffer, event))
 357                 trace_buffer_unlock_commit(buffer, event, 0, pc);
 358 }
 359
 360 void mmio_trace_mapping(struct mmiotrace_map *map)
 361 {
 362         struct trace_array *tr = mmio_trace_array;
 363         struct trace_array_cpu *data;
 364
 365         preempt_disable();
 366         data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id());
 367         __trace_mmiotrace_map(tr, data, map);
 368         preempt_enable();
 369 }
 370
 371 int mmio_trace_printk(const char *fmt, va_list args)
 372 {
 373         return trace_vprintk(0, fmt, args);
 374 }