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 int mmio_trace_init(struct trace_array *tr)
  36 {
  37         pr_debug("in %s\n", __func__);
  38         mmio_trace_array = tr;
  39
  40         mmio_reset_data(tr);
  41         enable_mmiotrace();
  42         return 0;
  43 }
  44
  45 static void mmio_trace_reset(struct trace_array *tr)
  46 {
  47         pr_debug("in %s\n", __func__);
  48
  49         disable_mmiotrace();
  50         mmio_reset_data(tr);
  51         mmio_trace_array = NULL;
  52 }
  53
  54 static void mmio_trace_start(struct trace_array *tr)
  55 {
  56         pr_debug("in %s\n", __func__);
  57         mmio_reset_data(tr);
  58 }
  59
  60 static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  61 {
  62         int ret = 0;
  63         int i;
  64         resource_size_t start, end;
  65         const struct pci_driver *drv = pci_dev_driver(dev);
  66
  67         /* XXX: incomplete checks for trace_seq_printf() return value */
  68         ret += 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                 ret += 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                 ret += 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                 ret += trace_seq_printf(s, " %s\n", drv->name);
  90         else
  91                 ret += trace_seq_printf(s, " \n");
  92         return ret;
  93 }
  94
  95 static void destroy_header_iter(struct header_iter *hiter)
  96 {
  97         if (!hiter)
  98                 return;
  99         pci_dev_put(hiter->dev);
 100         kfree(hiter);
 101 }
 102
 103 static void mmio_pipe_open(struct trace_iterator *iter)
 104 {
 105         struct header_iter *hiter;
 106         struct trace_seq *s = &iter->seq;
 107
 108         trace_seq_printf(s, "VERSION 20070824\n");
 109
 110         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 111         if (!hiter)
 112                 return;
 113
 114         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 115         iter->private = hiter;
 116 }
 117
 118 /* XXX: This is not called when the pipe is closed! */
 119 static void mmio_close(struct trace_iterator *iter)
 120 {
 121         struct header_iter *hiter = iter->private;
 122         destroy_header_iter(hiter);
 123         iter->private = NULL;
 124 }
 125
 126 static unsigned long count_overruns(struct trace_iterator *iter)
 127 {
 128         unsigned long cnt = 0;
 129         unsigned long over = ring_buffer_overruns(iter->tr->buffer);
 130
 131         if (over > prev_overruns)
 132                 cnt = over - prev_overruns;
 133         prev_overruns = over;
 134         return cnt;
 135 }
 136
 137 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 138                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 139 {
 140         ssize_t ret;
 141         struct header_iter *hiter = iter->private;
 142         struct trace_seq *s = &iter->seq;
 143         unsigned long n;
 144
 145         n = count_overruns(iter);
 146         if (n) {
 147                 /* XXX: This is later than where events were lost. */
 148                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 149                 if (!overrun_detected)
 150                         pr_warning("mmiotrace has lost events.\n");
 151                 overrun_detected = true;
 152                 goto print_out;
 153         }
 154
 155         if (!hiter)
 156                 return 0;
 157
 158         mmio_print_pcidev(s, hiter->dev);
 159         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 160
 161         if (!hiter->dev) {
 162                 destroy_header_iter(hiter);
 163                 iter->private = NULL;
 164         }
 165
 166 print_out:
 167         ret = trace_seq_to_user(s, ubuf, cnt);
 168         return (ret == -EBUSY) ? 0 : ret;
 169 }
 170
 171 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 172 {
 173         struct trace_entry *entry = iter->ent;
 174         struct trace_mmiotrace_rw *field;
 175         struct mmiotrace_rw *rw;
 176         struct trace_seq *s     = &iter->seq;
 177         unsigned long long t    = ns2usecs(iter->ts);
 178         unsigned long usec_rem  = do_div(t, 1000000ULL);
 179         unsigned secs           = (unsigned long)t;
 180         int ret = 1;
 181
 182         trace_assign_type(field, entry);
 183         rw = &field->rw;
 184
 185         switch (rw->opcode) {
 186         case MMIO_READ:
 187                 ret = trace_seq_printf(s,
 188                         "R %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 189                         rw->width, secs, usec_rem, rw->map_id,
 190                         (unsigned long long)rw->phys,
 191                         rw->value, rw->pc, 0);
 192                 break;
 193         case MMIO_WRITE:
 194                 ret = trace_seq_printf(s,
 195                         "W %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 196                         rw->width, secs, usec_rem, rw->map_id,
 197                         (unsigned long long)rw->phys,
 198                         rw->value, rw->pc, 0);
 199                 break;
 200         case MMIO_UNKNOWN_OP:
 201                 ret = trace_seq_printf(s,
 202                         "UNKNOWN %lu.%06lu %d 0x%llx %02x,%02x,%02x 0x%lx %d\n",
 203                         secs, usec_rem, rw->map_id,
 204                         (unsigned long long)rw->phys,
 205                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 206                         (rw->value >> 0) & 0xff, rw->pc, 0);
 207                 break;
 208         default:
 209                 ret = trace_seq_printf(s, "rw what?\n");
 210                 break;
 211         }
 212         if (ret)
 213                 return TRACE_TYPE_HANDLED;
 214         return TRACE_TYPE_PARTIAL_LINE;
 215 }
 216
 217 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 218 {
 219         struct trace_entry *entry = iter->ent;
 220         struct trace_mmiotrace_map *field;
 221         struct mmiotrace_map *m;
 222         struct trace_seq *s     = &iter->seq;
 223         unsigned long long t    = ns2usecs(iter->ts);
 224         unsigned long usec_rem  = do_div(t, 1000000ULL);
 225         unsigned secs           = (unsigned long)t;
 226         int ret;
 227
 228         trace_assign_type(field, entry);
 229         m = &field->map;
 230
 231         switch (m->opcode) {
 232         case MMIO_PROBE:
 233                 ret = trace_seq_printf(s,
 234                         "MAP %lu.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 235                         secs, usec_rem, m->map_id,
 236                         (unsigned long long)m->phys, m->virt, m->len,
 237                         0UL, 0);
 238                 break;
 239         case MMIO_UNPROBE:
 240                 ret = trace_seq_printf(s,
 241                         "UNMAP %lu.%06lu %d 0x%lx %d\n",
 242                         secs, usec_rem, m->map_id, 0UL, 0);
 243                 break;
 244         default:
 245                 ret = trace_seq_printf(s, "map what?\n");
 246                 break;
 247         }
 248         if (ret)
 249                 return TRACE_TYPE_HANDLED;
 250         return TRACE_TYPE_PARTIAL_LINE;
 251 }
 252
 253 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 254 {
 255         struct trace_entry *entry = iter->ent;
 256         struct print_entry *print = (struct print_entry *)entry;
 257         const char *msg         = print->buf;
 258         struct trace_seq *s     = &iter->seq;
 259         unsigned long long t    = ns2usecs(iter->ts);
 260         unsigned long usec_rem  = do_div(t, 1000000ULL);
 261         unsigned secs           = (unsigned long)t;
 262         int ret;
 263
 264         /* The trailing newline must be in the message. */
 265         ret = trace_seq_printf(s, "MARK %lu.%06lu %s", secs, usec_rem, msg);
 266         if (!ret)
 267                 return TRACE_TYPE_PARTIAL_LINE;
 268
 269         if (entry->flags & TRACE_FLAG_CONT)
 270                 trace_seq_print_cont(s, iter);
 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 ring_buffer_event *event;
 312         struct trace_mmiotrace_rw *entry;
 313         unsigned long irq_flags;
 314
 315         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 316                                            &irq_flags);
 317         if (!event)
 318                 return;
 319         entry   = ring_buffer_event_data(event);
 320         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
 321         entry->ent.type                 = TRACE_MMIO_RW;
 322         entry->rw                       = *rw;
 323         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 324
 325         trace_wake_up();
 326 }
 327
 328 void mmio_trace_rw(struct mmiotrace_rw *rw)
 329 {
 330         struct trace_array *tr = mmio_trace_array;
 331         struct trace_array_cpu *data = tr->data[smp_processor_id()];
 332         __trace_mmiotrace_rw(tr, data, rw);
 333 }
 334
 335 static void __trace_mmiotrace_map(struct trace_array *tr,
 336                                 struct trace_array_cpu *data,
 337                                 struct mmiotrace_map *map)
 338 {
 339         struct ring_buffer_event *event;
 340         struct trace_mmiotrace_map *entry;
 341         unsigned long irq_flags;
 342
 343         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 344                                            &irq_flags);
 345         if (!event)
 346                 return;
 347         entry   = ring_buffer_event_data(event);
 348         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
 349         entry->ent.type                 = TRACE_MMIO_MAP;
 350         entry->map                      = *map;
 351         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 352
 353         trace_wake_up();
 354 }
 355
 356 void mmio_trace_mapping(struct mmiotrace_map *map)
 357 {
 358         struct trace_array *tr = mmio_trace_array;
 359         struct trace_array_cpu *data;
 360
 361         preempt_disable();
 362         data = tr->data[smp_processor_id()];
 363         __trace_mmiotrace_map(tr, data, map);
 364         preempt_enable();
 365 }
 366
 367 int mmio_trace_printk(const char *fmt, va_list args)
 368 {
 369         return trace_vprintk(0, fmt, args);
 370 }