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 #include "trace_output.h"
  15
  16 struct header_iter {
  17         struct pci_dev *dev;
  18 };
  19
  20 static struct trace_array *mmio_trace_array;
  21 static bool overrun_detected;
  22 static unsigned long prev_overruns;
  23
  24 static void mmio_reset_data(struct trace_array *tr)
  25 {
  26         overrun_detected = false;
  27         prev_overruns = 0;
  28
  29         tracing_reset_online_cpus(tr);
  30 }
  31
  32 static int mmio_trace_init(struct trace_array *tr)
  33 {
  34         pr_debug("in %s\n", __func__);
  35         mmio_trace_array = tr;
  36
  37         mmio_reset_data(tr);
  38         enable_mmiotrace();
  39         return 0;
  40 }
  41
  42 static void mmio_trace_reset(struct trace_array *tr)
  43 {
  44         pr_debug("in %s\n", __func__);
  45
  46         disable_mmiotrace();
  47         mmio_reset_data(tr);
  48         mmio_trace_array = NULL;
  49 }
  50
  51 static void mmio_trace_start(struct trace_array *tr)
  52 {
  53         pr_debug("in %s\n", __func__);
  54         mmio_reset_data(tr);
  55 }
  56
  57 static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  58 {
  59         int ret = 0;
  60         int i;
  61         resource_size_t start, end;
  62         const struct pci_driver *drv = pci_dev_driver(dev);
  63
  64         /* XXX: incomplete checks for trace_seq_printf() return value */
  65         ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  66                                 dev->bus->number, dev->devfn,
  67                                 dev->vendor, dev->device, dev->irq);
  68         /*
  69          * XXX: is pci_resource_to_user() appropriate, since we are
  70          * supposed to interpret the __ioremap() phys_addr argument based on
  71          * these printed values?
  72          */
  73         for (i = 0; i < 7; i++) {
  74                 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
  75                 ret += trace_seq_printf(s, " %llx",
  76                         (unsigned long long)(start |
  77                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  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                         dev->resource[i].start < dev->resource[i].end ?
  83                         (unsigned long long)(end - start) + 1 : 0);
  84         }
  85         if (drv)
  86                 ret += trace_seq_printf(s, " %s\n", drv->name);
  87         else
  88                 ret += trace_seq_printf(s, " \n");
  89         return ret;
  90 }
  91
  92 static void destroy_header_iter(struct header_iter *hiter)
  93 {
  94         if (!hiter)
  95                 return;
  96         pci_dev_put(hiter->dev);
  97         kfree(hiter);
  98 }
  99
 100 static void mmio_pipe_open(struct trace_iterator *iter)
 101 {
 102         struct header_iter *hiter;
 103         struct trace_seq *s = &iter->seq;
 104
 105         trace_seq_printf(s, "VERSION 20070824\n");
 106
 107         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 108         if (!hiter)
 109                 return;
 110
 111         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 112         iter->private = hiter;
 113 }
 114
 115 /* XXX: This is not called when the pipe is closed! */
 116 static void mmio_close(struct trace_iterator *iter)
 117 {
 118         struct header_iter *hiter = iter->private;
 119         destroy_header_iter(hiter);
 120         iter->private = NULL;
 121 }
 122
 123 static unsigned long count_overruns(struct trace_iterator *iter)
 124 {
 125         unsigned long cnt = 0;
 126         unsigned long over = ring_buffer_overruns(iter->tr->buffer);
 127
 128         if (over > prev_overruns)
 129                 cnt = over - prev_overruns;
 130         prev_overruns = over;
 131         return cnt;
 132 }
 133
 134 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 135                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 136 {
 137         ssize_t ret;
 138         struct header_iter *hiter = iter->private;
 139         struct trace_seq *s = &iter->seq;
 140         unsigned long n;
 141
 142         n = count_overruns(iter);
 143         if (n) {
 144                 /* XXX: This is later than where events were lost. */
 145                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 146                 if (!overrun_detected)
 147                         pr_warning("mmiotrace has lost events.\n");
 148                 overrun_detected = true;
 149                 goto print_out;
 150         }
 151
 152         if (!hiter)
 153                 return 0;
 154
 155         mmio_print_pcidev(s, hiter->dev);
 156         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 157
 158         if (!hiter->dev) {
 159                 destroy_header_iter(hiter);
 160                 iter->private = NULL;
 161         }
 162
 163 print_out:
 164         ret = trace_seq_to_user(s, ubuf, cnt);
 165         return (ret == -EBUSY) ? 0 : ret;
 166 }
 167
 168 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 169 {
 170         struct trace_entry *entry = iter->ent;
 171         struct trace_mmiotrace_rw *field;
 172         struct mmiotrace_rw *rw;
 173         struct trace_seq *s     = &iter->seq;
 174         unsigned long long t    = ns2usecs(iter->ts);
 175         unsigned long usec_rem  = do_div(t, 1000000ULL);
 176         unsigned secs           = (unsigned long)t;
 177         int ret = 1;
 178
 179         trace_assign_type(field, entry);
 180         rw = &field->rw;
 181
 182         switch (rw->opcode) {
 183         case MMIO_READ:
 184                 ret = trace_seq_printf(s,
 185                         "R %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 186                         rw->width, secs, usec_rem, rw->map_id,
 187                         (unsigned long long)rw->phys,
 188                         rw->value, rw->pc, 0);
 189                 break;
 190         case MMIO_WRITE:
 191                 ret = trace_seq_printf(s,
 192                         "W %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 193                         rw->width, secs, usec_rem, rw->map_id,
 194                         (unsigned long long)rw->phys,
 195                         rw->value, rw->pc, 0);
 196                 break;
 197         case MMIO_UNKNOWN_OP:
 198                 ret = trace_seq_printf(s,
 199                         "UNKNOWN %lu.%06lu %d 0x%llx %02x,%02x,%02x 0x%lx %d\n",
 200                         secs, usec_rem, rw->map_id,
 201                         (unsigned long long)rw->phys,
 202                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 203                         (rw->value >> 0) & 0xff, rw->pc, 0);
 204                 break;
 205         default:
 206                 ret = trace_seq_printf(s, "rw what?\n");
 207                 break;
 208         }
 209         if (ret)
 210                 return TRACE_TYPE_HANDLED;
 211         return TRACE_TYPE_PARTIAL_LINE;
 212 }
 213
 214 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 215 {
 216         struct trace_entry *entry = iter->ent;
 217         struct trace_mmiotrace_map *field;
 218         struct mmiotrace_map *m;
 219         struct trace_seq *s     = &iter->seq;
 220         unsigned long long t    = ns2usecs(iter->ts);
 221         unsigned long usec_rem  = do_div(t, 1000000ULL);
 222         unsigned secs           = (unsigned long)t;
 223         int ret;
 224
 225         trace_assign_type(field, entry);
 226         m = &field->map;
 227
 228         switch (m->opcode) {
 229         case MMIO_PROBE:
 230                 ret = trace_seq_printf(s,
 231                         "MAP %lu.%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                 ret = trace_seq_printf(s,
 238                         "UNMAP %lu.%06lu %d 0x%lx %d\n",
 239                         secs, usec_rem, m->map_id, 0UL, 0);
 240                 break;
 241         default:
 242                 ret = trace_seq_printf(s, "map what?\n");
 243                 break;
 244         }
 245         if (ret)
 246                 return TRACE_TYPE_HANDLED;
 247         return TRACE_TYPE_PARTIAL_LINE;
 248 }
 249
 250 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 251 {
 252         struct trace_entry *entry = iter->ent;
 253         struct print_entry *print = (struct print_entry *)entry;
 254         const char *msg         = print->buf;
 255         struct trace_seq *s     = &iter->seq;
 256         unsigned long long t    = ns2usecs(iter->ts);
 257         unsigned long usec_rem  = do_div(t, 1000000ULL);
 258         unsigned secs           = (unsigned long)t;
 259         int ret;
 260
 261         /* The trailing newline must be in the message. */
 262         ret = trace_seq_printf(s, "MARK %lu.%06lu %s", secs, usec_rem, msg);
 263         if (!ret)
 264                 return TRACE_TYPE_PARTIAL_LINE;
 265
 266         return TRACE_TYPE_HANDLED;
 267 }
 268
 269 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 270 {
 271         switch (iter->ent->type) {
 272         case TRACE_MMIO_RW:
 273                 return mmio_print_rw(iter);
 274         case TRACE_MMIO_MAP:
 275                 return mmio_print_map(iter);
 276         case TRACE_PRINT:
 277                 return mmio_print_mark(iter);
 278         default:
 279                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 280         }
 281 }
 282
 283 static struct tracer mmio_tracer __read_mostly =
 284 {
 285         .name           = "mmiotrace",
 286         .init           = mmio_trace_init,
 287         .reset          = mmio_trace_reset,
 288         .start          = mmio_trace_start,
 289         .pipe_open      = mmio_pipe_open,
 290         .close          = mmio_close,
 291         .read           = mmio_read,
 292         .print_line     = mmio_print_line,
 293 };
 294
 295 __init static int init_mmio_trace(void)
 296 {
 297         return register_tracer(&mmio_tracer);
 298 }
 299 device_initcall(init_mmio_trace);
 300
 301 static void __trace_mmiotrace_rw(struct trace_array *tr,
 302                                 struct trace_array_cpu *data,
 303                                 struct mmiotrace_rw *rw)
 304 {
 305         struct ring_buffer_event *event;
 306         struct trace_mmiotrace_rw *entry;
 307         unsigned long irq_flags;
 308
 309         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 310                                            &irq_flags);
 311         if (!event)
 312                 return;
 313         entry   = ring_buffer_event_data(event);
 314         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
 315         entry->ent.type                 = TRACE_MMIO_RW;
 316         entry->rw                       = *rw;
 317         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 318
 319         trace_wake_up();
 320 }
 321
 322 void mmio_trace_rw(struct mmiotrace_rw *rw)
 323 {
 324         struct trace_array *tr = mmio_trace_array;
 325         struct trace_array_cpu *data = tr->data[smp_processor_id()];
 326         __trace_mmiotrace_rw(tr, data, rw);
 327 }
 328
 329 static void __trace_mmiotrace_map(struct trace_array *tr,
 330                                 struct trace_array_cpu *data,
 331                                 struct mmiotrace_map *map)
 332 {
 333         struct ring_buffer_event *event;
 334         struct trace_mmiotrace_map *entry;
 335         unsigned long irq_flags;
 336
 337         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 338                                            &irq_flags);
 339         if (!event)
 340                 return;
 341         entry   = ring_buffer_event_data(event);
 342         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
 343         entry->ent.type                 = TRACE_MMIO_MAP;
 344         entry->map                      = *map;
 345         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 346
 347         trace_wake_up();
 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 = tr->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, -1, fmt, args);
 364 }