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 #include <linux/slab.h> 13 #include <linux/time.h> 14 15 #include <linux/atomic.h> 16 17 #include "trace.h" 18 #include "trace_output.h" 19 20 struct header_iter { 21 struct pci_dev *dev; 22 }; 23 24 static struct trace_array *mmio_trace_array; 25 static bool overrun_detected; 26 static unsigned long prev_overruns; 27 static atomic_t dropped_count; 28 29 static void mmio_reset_data(struct trace_array *tr) 30 { 31 overrun_detected = false; 32 prev_overruns = 0; 33 34 tracing_reset_online_cpus(&tr->trace_buffer); 35 } 36 37 static int mmio_trace_init(struct trace_array *tr) 38 { 39 pr_debug("in %s\n", __func__); 40 mmio_trace_array = tr; 41 42 mmio_reset_data(tr); 43 enable_mmiotrace(); 44 return 0; 45 } 46 47 static void mmio_trace_reset(struct trace_array *tr) 48 { 49 pr_debug("in %s\n", __func__); 50 51 disable_mmiotrace(); 52 mmio_reset_data(tr); 53 mmio_trace_array = NULL; 54 } 55 56 static void mmio_trace_start(struct trace_array *tr) 57 { 58 pr_debug("in %s\n", __func__); 59 mmio_reset_data(tr); 60 } 61 62 static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev) 63 { 64 int ret = 0; 65 int i; 66 resource_size_t start, end; 67 const struct pci_driver *drv = pci_dev_driver(dev); 68 69 /* XXX: incomplete checks for trace_seq_printf() return value */ 70 ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x", 71 dev->bus->number, dev->devfn, 72 dev->vendor, dev->device, dev->irq); 73 /* 74 * XXX: is pci_resource_to_user() appropriate, since we are 75 * supposed to interpret the __ioremap() phys_addr argument based on 76 * these printed values? 77 */ 78 for (i = 0; i < 7; i++) { 79 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end); 80 ret += trace_seq_printf(s, " %llx", 81 (unsigned long long)(start | 82 (dev->resource[i].flags & PCI_REGION_FLAG_MASK))); 83 } 84 for (i = 0; i < 7; i++) { 85 pci_resource_to_user(dev, i, &dev->resource[i], &start, &end); 86 ret += trace_seq_printf(s, " %llx", 87 dev->resource[i].start < dev->resource[i].end ? 88 (unsigned long long)(end - start) + 1 : 0); 89 } 90 if (drv) 91 ret += trace_seq_printf(s, " %s\n", drv->name); 92 else 93 ret += trace_seq_puts(s, " \n"); 94 return ret; 95 } 96 97 static void destroy_header_iter(struct header_iter *hiter) 98 { 99 if (!hiter) 100 return; 101 pci_dev_put(hiter->dev); 102 kfree(hiter); 103 } 104 105 static void mmio_pipe_open(struct trace_iterator *iter) 106 { 107 struct header_iter *hiter; 108 struct trace_seq *s = &iter->seq; 109 110 trace_seq_puts(s, "VERSION 20070824\n"); 111 112 hiter = kzalloc(sizeof(*hiter), GFP_KERNEL); 113 if (!hiter) 114 return; 115 116 hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL); 117 iter->private = hiter; 118 } 119 120 /* XXX: This is not called when the pipe is closed! */ 121 static void mmio_close(struct trace_iterator *iter) 122 { 123 struct header_iter *hiter = iter->private; 124 destroy_header_iter(hiter); 125 iter->private = NULL; 126 } 127 128 static unsigned long count_overruns(struct trace_iterator *iter) 129 { 130 unsigned long cnt = atomic_xchg(&dropped_count, 0); 131 unsigned long over = ring_buffer_overruns(iter->trace_buffer->buffer); 132 133 if (over > prev_overruns) 134 cnt += over - prev_overruns; 135 prev_overruns = over; 136 return cnt; 137 } 138 139 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp, 140 char __user *ubuf, size_t cnt, loff_t *ppos) 141 { 142 ssize_t ret; 143 struct header_iter *hiter = iter->private; 144 struct trace_seq *s = &iter->seq; 145 unsigned long n; 146 147 n = count_overruns(iter); 148 if (n) { 149 /* XXX: This is later than where events were lost. */ 150 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n); 151 if (!overrun_detected) 152 pr_warning("mmiotrace has lost events.\n"); 153 overrun_detected = true; 154 goto print_out; 155 } 156 157 if (!hiter) 158 return 0; 159 160 mmio_print_pcidev(s, hiter->dev); 161 hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev); 162 163 if (!hiter->dev) { 164 destroy_header_iter(hiter); 165 iter->private = NULL; 166 } 167 168 print_out: 169 ret = trace_seq_to_user(s, ubuf, cnt); 170 return (ret == -EBUSY) ? 0 : ret; 171 } 172 173 static enum print_line_t mmio_print_rw(struct trace_iterator *iter) 174 { 175 struct trace_entry *entry = iter->ent; 176 struct trace_mmiotrace_rw *field; 177 struct mmiotrace_rw *rw; 178 struct trace_seq *s = &iter->seq; 179 unsigned long long t = ns2usecs(iter->ts); 180 unsigned long usec_rem = do_div(t, USEC_PER_SEC); 181 unsigned secs = (unsigned long)t; 182 int ret = 1; 183 184 trace_assign_type(field, entry); 185 rw = &field->rw; 186 187 switch (rw->opcode) { 188 case MMIO_READ: 189 ret = trace_seq_printf(s, 190 "R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n", 191 rw->width, secs, usec_rem, rw->map_id, 192 (unsigned long long)rw->phys, 193 rw->value, rw->pc, 0); 194 break; 195 case MMIO_WRITE: 196 ret = trace_seq_printf(s, 197 "W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n", 198 rw->width, secs, usec_rem, rw->map_id, 199 (unsigned long long)rw->phys, 200 rw->value, rw->pc, 0); 201 break; 202 case MMIO_UNKNOWN_OP: 203 ret = trace_seq_printf(s, 204 "UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx," 205 "%02lx 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_puts(s, "rw what?\n"); 213 break; 214 } 215 if (ret) 216 return TRACE_TYPE_HANDLED; 217 return TRACE_TYPE_PARTIAL_LINE; 218 } 219 220 static enum print_line_t mmio_print_map(struct trace_iterator *iter) 221 { 222 struct trace_entry *entry = iter->ent; 223 struct trace_mmiotrace_map *field; 224 struct mmiotrace_map *m; 225 struct trace_seq *s = &iter->seq; 226 unsigned long long t = ns2usecs(iter->ts); 227 unsigned long usec_rem = do_div(t, USEC_PER_SEC); 228 unsigned secs = (unsigned long)t; 229 int ret; 230 231 trace_assign_type(field, entry); 232 m = &field->map; 233 234 switch (m->opcode) { 235 case MMIO_PROBE: 236 ret = trace_seq_printf(s, 237 "MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n", 238 secs, usec_rem, m->map_id, 239 (unsigned long long)m->phys, m->virt, m->len, 240 0UL, 0); 241 break; 242 case MMIO_UNPROBE: 243 ret = trace_seq_printf(s, 244 "UNMAP %u.%06lu %d 0x%lx %d\n", 245 secs, usec_rem, m->map_id, 0UL, 0); 246 break; 247 default: 248 ret = trace_seq_puts(s, "map what?\n"); 249 break; 250 } 251 if (ret) 252 return TRACE_TYPE_HANDLED; 253 return TRACE_TYPE_PARTIAL_LINE; 254 } 255 256 static enum print_line_t mmio_print_mark(struct trace_iterator *iter) 257 { 258 struct trace_entry *entry = iter->ent; 259 struct print_entry *print = (struct print_entry *)entry; 260 const char *msg = print->buf; 261 struct trace_seq *s = &iter->seq; 262 unsigned long long t = ns2usecs(iter->ts); 263 unsigned long usec_rem = do_div(t, USEC_PER_SEC); 264 unsigned secs = (unsigned long)t; 265 int ret; 266 267 /* The trailing newline must be in the message. */ 268 ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg); 269 if (!ret) 270 return TRACE_TYPE_PARTIAL_LINE; 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 ftrace_event_call *call = &event_mmiotrace_rw; 312 struct ring_buffer *buffer = tr->trace_buffer.buffer; 313 struct ring_buffer_event *event; 314 struct trace_mmiotrace_rw *entry; 315 int pc = preempt_count(); 316 317 event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW, 318 sizeof(*entry), 0, pc); 319 if (!event) { 320 atomic_inc(&dropped_count); 321 return; 322 } 323 entry = ring_buffer_event_data(event); 324 entry->rw = *rw; 325 326 if (!filter_check_discard(call, entry, buffer, event)) 327 trace_buffer_unlock_commit(buffer, event, 0, pc); 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 = per_cpu_ptr(tr->trace_buffer.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 ftrace_event_call *call = &event_mmiotrace_map; 342 struct ring_buffer *buffer = tr->trace_buffer.buffer; 343 struct ring_buffer_event *event; 344 struct trace_mmiotrace_map *entry; 345 int pc = preempt_count(); 346 347 event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP, 348 sizeof(*entry), 0, pc); 349 if (!event) { 350 atomic_inc(&dropped_count); 351 return; 352 } 353 entry = ring_buffer_event_data(event); 354 entry->map = *map; 355 356 if (!filter_check_discard(call, entry, buffer, event)) 357 trace_buffer_unlock_commit(buffer, event, 0, pc); 358 } 359 360 void mmio_trace_mapping(struct mmiotrace_map *map) 361 { 362 struct trace_array *tr = mmio_trace_array; 363 struct trace_array_cpu *data; 364 365 preempt_disable(); 366 data = per_cpu_ptr(tr->trace_buffer.data, smp_processor_id()); 367 __trace_mmiotrace_map(tr, data, map); 368 preempt_enable(); 369 } 370 371 int mmio_trace_printk(const char *fmt, va_list args) 372 { 373 return trace_vprintk(0, fmt, args); 374 } 375