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 void mmio_trace_init(struct trace_array *tr)
  34 {
  35         pr_debug("in %s\n", __func__);
  36         mmio_trace_array = tr;
  37         if (tr->ctrl) {
  38                 mmio_reset_data(tr);
  39                 enable_mmiotrace();
  40         }
  41 }
  42
  43 static void mmio_trace_reset(struct trace_array *tr)
  44 {
  45         pr_debug("in %s\n", __func__);
  46         if (tr->ctrl)
  47                 disable_mmiotrace();
  48         mmio_reset_data(tr);
  49         mmio_trace_array = NULL;
  50 }
  51
  52 static void mmio_trace_ctrl_update(struct trace_array *tr)
  53 {
  54         pr_debug("in %s\n", __func__);
  55         if (tr->ctrl) {
  56                 mmio_reset_data(tr);
  57                 enable_mmiotrace();
  58         } else {
  59                 disable_mmiotrace();
  60         }
  61 }
  62
  63 static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  64 {
  65         int ret = 0;
  66         int i;
  67         resource_size_t start, end;
  68         const struct pci_driver *drv = pci_dev_driver(dev);
  69
  70         /* XXX: incomplete checks for trace_seq_printf() return value */
  71         ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  72                                 dev->bus->number, dev->devfn,
  73                                 dev->vendor, dev->device, dev->irq);
  74         /*
  75          * XXX: is pci_resource_to_user() appropriate, since we are
  76          * supposed to interpret the __ioremap() phys_addr argument based on
  77          * these printed values?
  78          */
  79         for (i = 0; i < 7; i++) {
  80                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  81                 ret += trace_seq_printf(s, " %llx",
  82                         (unsigned long long)(start |
  83                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  84         }
  85         for (i = 0; i < 7; i++) {
  86                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  87                 ret += trace_seq_printf(s, " %llx",
  88                         dev->resource[i].start < dev->resource[i].end ?
  89                         (unsigned long long)(end - start) + 1 : 0);
  90         }
  91         if (drv)
  92                 ret += trace_seq_printf(s, " %s\n", drv->name);
  93         else
  94                 ret += trace_seq_printf(s, " \n");
  95         return ret;
  96 }
  97
  98 static void destroy_header_iter(struct header_iter *hiter)
  99 {
 100         if (!hiter)
 101                 return;
 102         pci_dev_put(hiter->dev);
 103         kfree(hiter);
 104 }
 105
 106 static void mmio_pipe_open(struct trace_iterator *iter)
 107 {
 108         struct header_iter *hiter;
 109         struct trace_seq *s = &iter->seq;
 110
 111         trace_seq_printf(s, "VERSION 20070824\n");
 112
 113         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 114         if (!hiter)
 115                 return;
 116
 117         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 118         iter->private = hiter;
 119 }
 120
 121 /* XXX: This is not called when the pipe is closed! */
 122 static void mmio_close(struct trace_iterator *iter)
 123 {
 124         struct header_iter *hiter = iter->private;
 125         destroy_header_iter(hiter);
 126         iter->private = NULL;
 127 }
 128
 129 static unsigned long count_overruns(struct trace_iterator *iter)
 130 {
 131         int cpu;
 132         unsigned long cnt = 0;
 133 /* FIXME: */
 134 #if 0
 135         for_each_online_cpu(cpu) {
 136                 cnt += iter->overrun[cpu];
 137                 iter->overrun[cpu] = 0;
 138         }
 139 #endif
 140         (void)cpu;
 141         return cnt;
 142 }
 143
 144 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 145                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 146 {
 147         ssize_t ret;
 148         struct header_iter *hiter = iter->private;
 149         struct trace_seq *s = &iter->seq;
 150         unsigned long n;
 151
 152         n = count_overruns(iter);
 153         if (n) {
 154                 /* XXX: This is later than where events were lost. */
 155                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 156                 if (!overrun_detected)
 157                         pr_warning("mmiotrace has lost events.\n");
 158                 overrun_detected = true;
 159                 goto print_out;
 160         }
 161
 162         if (!hiter)
 163                 return 0;
 164
 165         mmio_print_pcidev(s, hiter->dev);
 166         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 167
 168         if (!hiter->dev) {
 169                 destroy_header_iter(hiter);
 170                 iter->private = NULL;
 171         }
 172
 173 print_out:
 174         ret = trace_seq_to_user(s, ubuf, cnt);
 175         return (ret == -EBUSY) ? 0 : ret;
 176 }
 177
 178 static int mmio_print_rw(struct trace_iterator *iter)
 179 {
 180         struct trace_entry *entry = iter->ent;
 181         struct mmiotrace_rw *rw = &entry->field.mmiorw;
 182         struct trace_seq *s     = &iter->seq;
 183         unsigned long long t    = ns2usecs(iter->ts);
 184         unsigned long usec_rem  = do_div(t, 1000000ULL);
 185         unsigned secs           = (unsigned long)t;
 186         int ret = 1;
 187
 188         switch (entry->field.mmiorw.opcode) {
 189         case MMIO_READ:
 190                 ret = trace_seq_printf(s,
 191                         "R %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_WRITE:
 197                 ret = trace_seq_printf(s,
 198                         "W %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 199                         rw->width, secs, usec_rem, rw->map_id,
 200                         (unsigned long long)rw->phys,
 201                         rw->value, rw->pc, 0);
 202                 break;
 203         case MMIO_UNKNOWN_OP:
 204                 ret = trace_seq_printf(s,
 205                         "UNKNOWN %lu.%06lu %d 0x%llx %02x,%02x,%02x 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_printf(s, "rw what?\n");
 213                 break;
 214         }
 215         if (ret)
 216                 return 1;
 217         return 0;
 218 }
 219
 220 static int mmio_print_map(struct trace_iterator *iter)
 221 {
 222         struct trace_entry *entry = iter->ent;
 223         struct mmiotrace_map *m = &entry->field.mmiomap;
 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 = 1;
 229
 230         switch (entry->field.mmiorw.opcode) {
 231         case MMIO_PROBE:
 232                 ret = trace_seq_printf(s,
 233                         "MAP %lu.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 234                         secs, usec_rem, m->map_id,
 235                         (unsigned long long)m->phys, m->virt, m->len,
 236                         0UL, 0);
 237                 break;
 238         case MMIO_UNPROBE:
 239                 ret = trace_seq_printf(s,
 240                         "UNMAP %lu.%06lu %d 0x%lx %d\n",
 241                         secs, usec_rem, m->map_id, 0UL, 0);
 242                 break;
 243         default:
 244                 ret = trace_seq_printf(s, "map what?\n");
 245                 break;
 246         }
 247         if (ret)
 248                 return 1;
 249         return 0;
 250 }
 251
 252 static int mmio_print_mark(struct trace_iterator *iter)
 253 {
 254         struct trace_entry *entry = iter->ent;
 255         const char *msg         = entry->field.print.buf;
 256         struct trace_seq *s     = &iter->seq;
 257         unsigned long long t    = ns2usecs(iter->ts);
 258         unsigned long usec_rem  = do_div(t, 1000000ULL);
 259         unsigned secs           = (unsigned long)t;
 260         int ret;
 261
 262         /* The trailing newline must be in the message. */
 263         ret = trace_seq_printf(s, "MARK %lu.%06lu %s", secs, usec_rem, msg);
 264         if (!ret)
 265                 return 0;
 266
 267         if (entry->field.flags & TRACE_FLAG_CONT)
 268                 trace_seq_print_cont(s, iter);
 269
 270         return 1;
 271 }
 272
 273 /* return 0 to abort printing without consuming current entry in pipe mode */
 274 static int mmio_print_line(struct trace_iterator *iter)
 275 {
 276         switch (iter->ent->type) {
 277         case TRACE_MMIO_RW:
 278                 return mmio_print_rw(iter);
 279         case TRACE_MMIO_MAP:
 280                 return mmio_print_map(iter);
 281         case TRACE_PRINT:
 282                 return mmio_print_mark(iter);
 283         default:
 284                 return 1; /* ignore unknown entries */
 285         }
 286 }
 287
 288 static struct tracer mmio_tracer __read_mostly =
 289 {
 290         .name           = "mmiotrace",
 291         .init           = mmio_trace_init,
 292         .reset          = mmio_trace_reset,
 293         .pipe_open      = mmio_pipe_open,
 294         .close          = mmio_close,
 295         .read           = mmio_read,
 296         .ctrl_update    = mmio_trace_ctrl_update,
 297         .print_line     = mmio_print_line,
 298 };
 299
 300 __init static int init_mmio_trace(void)
 301 {
 302         return register_tracer(&mmio_tracer);
 303 }
 304 device_initcall(init_mmio_trace);
 305
 306 static void __trace_mmiotrace_rw(struct trace_array *tr,
 307                                 struct trace_array_cpu *data,
 308                                 struct mmiotrace_rw *rw)
 309 {
 310         struct ring_buffer_event *event;
 311         struct trace_entry *entry;
 312         unsigned long irq_flags;
 313
 314         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 315                                            &irq_flags);
 316         if (!event)
 317                 return;
 318         entry   = ring_buffer_event_data(event);
 319         tracing_generic_entry_update(entry, 0);
 320         entry->type                     = TRACE_MMIO_RW;
 321         entry->field.mmiorw             = *rw;
 322         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 323
 324         trace_wake_up();
 325 }
 326
 327 void mmio_trace_rw(struct mmiotrace_rw *rw)
 328 {
 329         struct trace_array *tr = mmio_trace_array;
 330         struct trace_array_cpu *data = tr->data[smp_processor_id()];
 331         __trace_mmiotrace_rw(tr, data, rw);
 332 }
 333
 334 static void __trace_mmiotrace_map(struct trace_array *tr,
 335                                 struct trace_array_cpu *data,
 336                                 struct mmiotrace_map *map)
 337 {
 338         struct ring_buffer_event *event;
 339         struct trace_entry *entry;
 340         unsigned long irq_flags;
 341
 342         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 343                                            &irq_flags);
 344         if (!event)
 345                 return;
 346         entry   = ring_buffer_event_data(event);
 347         tracing_generic_entry_update(entry, 0);
 348         entry->type                     = TRACE_MMIO_MAP;
 349         entry->field.mmiomap            = *map;
 350         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 351
 352         trace_wake_up();
 353 }
 354
 355 void mmio_trace_mapping(struct mmiotrace_map *map)
 356 {
 357         struct trace_array *tr = mmio_trace_array;
 358         struct trace_array_cpu *data;
 359
 360         preempt_disable();
 361         data = tr->data[smp_processor_id()];
 362         __trace_mmiotrace_map(tr, data, map);
 363         preempt_enable();
 364 }
 365
 366 int mmio_trace_printk(const char *fmt, va_list args)
 367 {
 368         return trace_vprintk(0, fmt, args);
 369 }