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->data[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         for_each_online_cpu(cpu) {
 134                 cnt += iter->overrun[cpu];
 135                 iter->overrun[cpu] = 0;
 136         }
 137         return cnt;
 138 }
 139
 140 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 141                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 142 {
 143         ssize_t ret;
 144         struct header_iter *hiter = iter->private;
 145         struct trace_seq *s = &iter->seq;
 146         unsigned long n;
 147
 148         n = count_overruns(iter);
 149         if (n) {
 150                 /* XXX: This is later than where events were lost. */
 151                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 152                 if (!overrun_detected)
 153                         pr_warning("mmiotrace has lost events.\n");
 154                 overrun_detected = true;
 155                 goto print_out;
 156         }
 157
 158         if (!hiter)
 159                 return 0;
 160
 161         mmio_print_pcidev(s, hiter->dev);
 162         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 163
 164         if (!hiter->dev) {
 165                 destroy_header_iter(hiter);
 166                 iter->private = NULL;
 167         }
 168
 169 print_out:
 170         ret = trace_seq_to_user(s, ubuf, cnt);
 171         return (ret == -EBUSY) ? 0 : ret;
 172 }
 173
 174 static int mmio_print_rw(struct trace_iterator *iter)
 175 {
 176         struct trace_entry *entry = iter->ent;
 177         struct mmiotrace_rw *rw = &entry->mmiorw;
 178         struct trace_seq *s     = &iter->seq;
 179         unsigned long long t    = ns2usecs(entry->t);
 180         unsigned long usec_rem  = do_div(t, 1000000ULL);
 181         unsigned secs           = (unsigned long)t;
 182         int ret = 1;
 183
 184         switch (entry->mmiorw.opcode) {
 185         case MMIO_READ:
 186                 ret = trace_seq_printf(s,
 187                         "R %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 188                         rw->width, secs, usec_rem, rw->map_id,
 189                         (unsigned long long)rw->phys,
 190                         rw->value, rw->pc, 0);
 191                 break;
 192         case MMIO_WRITE:
 193                 ret = trace_seq_printf(s,
 194                         "W %d %lu.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 195                         rw->width, secs, usec_rem, rw->map_id,
 196                         (unsigned long long)rw->phys,
 197                         rw->value, rw->pc, 0);
 198                 break;
 199         case MMIO_UNKNOWN_OP:
 200                 ret = trace_seq_printf(s,
 201                         "UNKNOWN %lu.%06lu %d 0x%llx %02x,%02x,%02x 0x%lx %d\n",
 202                         secs, usec_rem, rw->map_id,
 203                         (unsigned long long)rw->phys,
 204                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 205                         (rw->value >> 0) & 0xff, rw->pc, 0);
 206                 break;
 207         default:
 208                 ret = trace_seq_printf(s, "rw what?\n");
 209                 break;
 210         }
 211         if (ret)
 212                 return 1;
 213         return 0;
 214 }
 215
 216 static int mmio_print_map(struct trace_iterator *iter)
 217 {
 218         struct trace_entry *entry = iter->ent;
 219         struct mmiotrace_map *m = &entry->mmiomap;
 220         struct trace_seq *s     = &iter->seq;
 221         unsigned long long t    = ns2usecs(entry->t);
 222         unsigned long usec_rem  = do_div(t, 1000000ULL);
 223         unsigned secs           = (unsigned long)t;
 224         int ret = 1;
 225
 226         switch (entry->mmiorw.opcode) {
 227         case MMIO_PROBE:
 228                 ret = trace_seq_printf(s,
 229                         "MAP %lu.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 230                         secs, usec_rem, m->map_id,
 231                         (unsigned long long)m->phys, m->virt, m->len,
 232                         0UL, 0);
 233                 break;
 234         case MMIO_UNPROBE:
 235                 ret = trace_seq_printf(s,
 236                         "UNMAP %lu.%06lu %d 0x%lx %d\n",
 237                         secs, usec_rem, m->map_id, 0UL, 0);
 238                 break;
 239         default:
 240                 ret = trace_seq_printf(s, "map what?\n");
 241                 break;
 242         }
 243         if (ret)
 244                 return 1;
 245         return 0;
 246 }
 247
 248 /* return 0 to abort printing without consuming current entry in pipe mode */
 249 static int mmio_print_line(struct trace_iterator *iter)
 250 {
 251         switch (iter->ent->type) {
 252         case TRACE_MMIO_RW:
 253                 return mmio_print_rw(iter);
 254         case TRACE_MMIO_MAP:
 255                 return mmio_print_map(iter);
 256         default:
 257                 return 1; /* ignore unknown entries */
 258         }
 259 }
 260
 261 static struct tracer mmio_tracer __read_mostly =
 262 {
 263         .name           = "mmiotrace",
 264         .init           = mmio_trace_init,
 265         .reset          = mmio_trace_reset,
 266         .pipe_open      = mmio_pipe_open,
 267         .close          = mmio_close,
 268         .read           = mmio_read,
 269         .ctrl_update    = mmio_trace_ctrl_update,
 270         .print_line     = mmio_print_line,
 271 };
 272
 273 __init static int init_mmio_trace(void)
 274 {
 275         return register_tracer(&mmio_tracer);
 276 }
 277 device_initcall(init_mmio_trace);
 278
 279 void mmio_trace_rw(struct mmiotrace_rw *rw)
 280 {
 281         struct trace_array *tr = mmio_trace_array;
 282         struct trace_array_cpu *data = tr->data[smp_processor_id()];
 283         __trace_mmiotrace_rw(tr, data, rw);
 284 }
 285
 286 void mmio_trace_mapping(struct mmiotrace_map *map)
 287 {
 288         struct trace_array *tr = mmio_trace_array;
 289         struct trace_array_cpu *data;
 290
 291         preempt_disable();
 292         data = tr->data[smp_processor_id()];
 293         __trace_mmiotrace_map(tr, data, map);
 294         preempt_enable();
 295 }