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   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 trace_mmiotrace_rw *field =
 182                 (struct trace_mmiotrace_rw *)entry;
 183         struct mmiotrace_rw *rw = &field->rw;
 184         struct trace_seq *s     = &iter->seq;
 185         unsigned long long t    = ns2usecs(iter->ts);
 186         unsigned long usec_rem  = do_div(t, 1000000ULL);
 187         unsigned secs           = (unsigned long)t;
 188         int ret = 1;
 189
 190         switch (rw->opcode) {
 191         case MMIO_READ:
 192                 ret = trace_seq_printf(s,
 193                         "R %d %lu.%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_WRITE:
 199                 ret = trace_seq_printf(s,
 200                         "W %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 201                         rw->width, secs, usec_rem, rw->map_id,
 202                         (unsigned long long)rw->phys,
 203                         rw->value, rw->pc, 0);
 204                 break;
 205         case MMIO_UNKNOWN_OP:
 206                 ret = trace_seq_printf(s,
 207                         "UNKNOWN %lu.%06lu %d 0x%llx %02x,%02x,%02x 0x%lx %d\n",
 208                         secs, usec_rem, rw->map_id,
 209                         (unsigned long long)rw->phys,
 210                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 211                         (rw->value >> 0) & 0xff, rw->pc, 0);
 212                 break;
 213         default:
 214                 ret = trace_seq_printf(s, "rw what?\n");
 215                 break;
 216         }
 217         if (ret)
 218                 return 1;
 219         return 0;
 220 }
 221
 222 static int mmio_print_map(struct trace_iterator *iter)
 223 {
 224         struct trace_entry *entry = iter->ent;
 225         struct mmiotrace_map *m = (struct mmiotrace_map *)entry;
 226         struct trace_seq *s     = &iter->seq;
 227         unsigned long long t    = ns2usecs(iter->ts);
 228         unsigned long usec_rem  = do_div(t, 1000000ULL);
 229         unsigned secs           = (unsigned long)t;
 230         int ret = 1;
 231
 232         switch (m->opcode) {
 233         case MMIO_PROBE:
 234                 ret = trace_seq_printf(s,
 235                         "MAP %lu.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 236                         secs, usec_rem, m->map_id,
 237                         (unsigned long long)m->phys, m->virt, m->len,
 238                         0UL, 0);
 239                 break;
 240         case MMIO_UNPROBE:
 241                 ret = trace_seq_printf(s,
 242                         "UNMAP %lu.%06lu %d 0x%lx %d\n",
 243                         secs, usec_rem, m->map_id, 0UL, 0);
 244                 break;
 245         default:
 246                 ret = trace_seq_printf(s, "map what?\n");
 247                 break;
 248         }
 249         if (ret)
 250                 return 1;
 251         return 0;
 252 }
 253
 254 static int mmio_print_mark(struct trace_iterator *iter)
 255 {
 256         struct trace_entry *entry = iter->ent;
 257         struct print_entry *print = (struct print_entry *)entry;
 258         const char *msg         = print->buf;
 259         struct trace_seq *s     = &iter->seq;
 260         unsigned long long t    = ns2usecs(iter->ts);
 261         unsigned long usec_rem  = do_div(t, 1000000ULL);
 262         unsigned secs           = (unsigned long)t;
 263         int ret;
 264
 265         /* The trailing newline must be in the message. */
 266         ret = trace_seq_printf(s, "MARK %lu.%06lu %s", secs, usec_rem, msg);
 267         if (!ret)
 268                 return 0;
 269
 270         if (entry->flags & TRACE_FLAG_CONT)
 271                 trace_seq_print_cont(s, iter);
 272
 273         return 1;
 274 }
 275
 276 /* return 0 to abort printing without consuming current entry in pipe mode */
 277 static int mmio_print_line(struct trace_iterator *iter)
 278 {
 279         switch (iter->ent->type) {
 280         case TRACE_MMIO_RW:
 281                 return mmio_print_rw(iter);
 282         case TRACE_MMIO_MAP:
 283                 return mmio_print_map(iter);
 284         case TRACE_PRINT:
 285                 return mmio_print_mark(iter);
 286         default:
 287                 return 1; /* ignore unknown entries */
 288         }
 289 }
 290
 291 static struct tracer mmio_tracer __read_mostly =
 292 {
 293         .name           = "mmiotrace",
 294         .init           = mmio_trace_init,
 295         .reset          = mmio_trace_reset,
 296         .pipe_open      = mmio_pipe_open,
 297         .close          = mmio_close,
 298         .read           = mmio_read,
 299         .ctrl_update    = mmio_trace_ctrl_update,
 300         .print_line     = mmio_print_line,
 301 };
 302
 303 __init static int init_mmio_trace(void)
 304 {
 305         return register_tracer(&mmio_tracer);
 306 }
 307 device_initcall(init_mmio_trace);
 308
 309 static void __trace_mmiotrace_rw(struct trace_array *tr,
 310                                 struct trace_array_cpu *data,
 311                                 struct mmiotrace_rw *rw)
 312 {
 313         struct ring_buffer_event *event;
 314         struct trace_mmiotrace_rw *entry;
 315         unsigned long irq_flags;
 316
 317         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 318                                            &irq_flags);
 319         if (!event)
 320                 return;
 321         entry   = ring_buffer_event_data(event);
 322         tracing_generic_entry_update(&entry->ent, 0);
 323         entry->ent.type                 = TRACE_MMIO_RW;
 324         entry->rw                       = *rw;
 325         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 326
 327         trace_wake_up();
 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 = tr->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 ring_buffer_event *event;
 342         struct trace_mmiotrace_map *entry;
 343         unsigned long irq_flags;
 344
 345         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 346                                            &irq_flags);
 347         if (!event)
 348                 return;
 349         entry   = ring_buffer_event_data(event);
 350         tracing_generic_entry_update(&entry->ent, 0);
 351         entry->ent.type                 = TRACE_MMIO_MAP;
 352         entry->map                      = *map;
 353         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 354
 355         trace_wake_up();
 356 }
 357
 358 void mmio_trace_mapping(struct mmiotrace_map *map)
 359 {
 360         struct trace_array *tr = mmio_trace_array;
 361         struct trace_array_cpu *data;
 362
 363         preempt_disable();
 364         data = tr->data[smp_processor_id()];
 365         __trace_mmiotrace_map(tr, data, map);
 366         preempt_enable();
 367 }
 368
 369 int mmio_trace_printk(const char *fmt, va_list args)
 370 {
 371         return trace_vprintk(0, fmt, args);
 372 }