| 1 | /* |
| 2 | * LTTng serializing code. |
| 3 | * |
| 4 | * Copyright Mathieu Desnoyers, March 2007. |
| 5 | * |
| 6 | * Dual LGPL v2.1/GPL v2 license. |
| 7 | * |
| 8 | * See this discussion about weirdness about passing va_list and then va_list to |
| 9 | * functions. (related to array argument passing). va_list seems to be |
| 10 | * implemented as an array on x86_64, but not on i386... This is why we pass a |
| 11 | * va_list * to ltt_vtrace. |
| 12 | */ |
| 13 | |
| 14 | #include <stdarg.h> |
| 15 | #include <linux/ctype.h> |
| 16 | #include <linux/string.h> |
| 17 | #include <linux/module.h> |
| 18 | |
| 19 | #include "ltt-tracer.h" |
| 20 | #include "ltt-relay-lockless.h" |
| 21 | |
| 22 | enum ltt_type { |
| 23 | LTT_TYPE_SIGNED_INT, |
| 24 | LTT_TYPE_UNSIGNED_INT, |
| 25 | LTT_TYPE_STRING, |
| 26 | LTT_TYPE_NONE, |
| 27 | }; |
| 28 | |
| 29 | #define LTT_ATTRIBUTE_NETWORK_BYTE_ORDER (1<<1) |
| 30 | |
| 31 | /* |
| 32 | * Stack used to keep track of string length at size calculation, passed to |
| 33 | * string copy to handle racy input string updates. |
| 34 | * Can be used by any context; this is ensured by putting the stack position |
| 35 | * back to its original position after using it. |
| 36 | */ |
| 37 | #define TRACER_STACK_LEN (PAGE_SIZE / sizeof(unsigned long)) |
| 38 | static DEFINE_PER_CPU(unsigned long [TRACER_STACK_LEN], |
| 39 | tracer_stack); |
| 40 | static DEFINE_PER_CPU(unsigned int, tracer_stack_pos); |
| 41 | |
| 42 | /* |
| 43 | * Inspired from vsnprintf |
| 44 | * |
| 45 | * The serialization format string supports the basic printf format strings. |
| 46 | * In addition, it defines new formats that can be used to serialize more |
| 47 | * complex/non portable data structures. |
| 48 | * |
| 49 | * Typical use: |
| 50 | * |
| 51 | * field_name %ctype |
| 52 | * field_name #tracetype %ctype |
| 53 | * field_name #tracetype %ctype1 %ctype2 ... |
| 54 | * |
| 55 | * A conversion is performed between format string types supported by GCC and |
| 56 | * the trace type requested. GCC type is used to perform type checking on format |
| 57 | * strings. Trace type is used to specify the exact binary representation |
| 58 | * in the trace. A mapping is done between one or more GCC types to one trace |
| 59 | * type. Sign extension, if required by the conversion, is performed following |
| 60 | * the trace type. |
| 61 | * |
| 62 | * If a gcc format is not declared with a trace format, the gcc format is |
| 63 | * also used as binary representation in the trace. |
| 64 | * |
| 65 | * Strings are supported with %s. |
| 66 | * A single tracetype (sequence) can take multiple c types as parameter. |
| 67 | * |
| 68 | * c types: |
| 69 | * |
| 70 | * see printf(3). |
| 71 | * |
| 72 | * Note: to write a uint32_t in a trace, the following expression is recommended |
| 73 | * si it can be portable: |
| 74 | * |
| 75 | * ("#4u%lu", (unsigned long)var) |
| 76 | * |
| 77 | * trace types: |
| 78 | * |
| 79 | * Serialization specific formats : |
| 80 | * |
| 81 | * Fixed size integers |
| 82 | * #1u writes uint8_t |
| 83 | * #2u writes uint16_t |
| 84 | * #4u writes uint32_t |
| 85 | * #8u writes uint64_t |
| 86 | * #1d writes int8_t |
| 87 | * #2d writes int16_t |
| 88 | * #4d writes int32_t |
| 89 | * #8d writes int64_t |
| 90 | * i.e.: |
| 91 | * #1u%lu #2u%lu #4d%lu #8d%lu #llu%hu #d%lu |
| 92 | * |
| 93 | * * Attributes: |
| 94 | * |
| 95 | * n: (for network byte order) |
| 96 | * #ntracetype%ctype |
| 97 | * is written in the trace in network byte order. |
| 98 | * |
| 99 | * i.e.: #bn4u%lu, #n%lu, #b%u |
| 100 | * |
| 101 | * TODO (eventually) |
| 102 | * Variable length sequence |
| 103 | * #a #tracetype1 #tracetype2 %array_ptr %elem_size %num_elems |
| 104 | * In the trace: |
| 105 | * #a specifies that this is a sequence |
| 106 | * #tracetype1 is the type of elements in the sequence |
| 107 | * #tracetype2 is the type of the element count |
| 108 | * GCC input: |
| 109 | * array_ptr is a pointer to an array that contains members of size |
| 110 | * elem_size. |
| 111 | * num_elems is the number of elements in the array. |
| 112 | * i.e.: #a #lu #lu %p %lu %u |
| 113 | * |
| 114 | * Callback |
| 115 | * #k callback (taken from the probe data) |
| 116 | * The following % arguments are exepected by the callback |
| 117 | * |
| 118 | * i.e.: #a #lu #lu #k %p |
| 119 | * |
| 120 | * Note: No conversion is done from floats to integers, nor from integers to |
| 121 | * floats between c types and trace types. float conversion from double to float |
| 122 | * or from float to double is also not supported. |
| 123 | * |
| 124 | * REMOVE |
| 125 | * %*b expects sizeof(data), data |
| 126 | * where sizeof(data) is 1, 2, 4 or 8 |
| 127 | * |
| 128 | * Fixed length struct, union or array. |
| 129 | * FIXME: unable to extract those sizes statically. |
| 130 | * %*r expects sizeof(*ptr), ptr |
| 131 | * %*.*r expects sizeof(*ptr), __alignof__(*ptr), ptr |
| 132 | * struct and unions removed. |
| 133 | * Fixed length array: |
| 134 | * [%p]#a[len #tracetype] |
| 135 | * i.e.: [%p]#a[12 #lu] |
| 136 | * |
| 137 | * Variable length sequence |
| 138 | * %*.*:*v expects sizeof(*ptr), __alignof__(*ptr), elem_num, ptr |
| 139 | * where elem_num is the number of elements in the sequence |
| 140 | */ |
| 141 | static inline |
| 142 | const char *parse_trace_type(const char *fmt, char *trace_size, |
| 143 | enum ltt_type *trace_type, |
| 144 | unsigned long *attributes) |
| 145 | { |
| 146 | int qualifier; /* 'h', 'l', or 'L' for integer fields */ |
| 147 | /* 'z' support added 23/7/1999 S.H. */ |
| 148 | /* 'z' changed to 'Z' --davidm 1/25/99 */ |
| 149 | /* 't' added for ptrdiff_t */ |
| 150 | |
| 151 | /* parse attributes. */ |
| 152 | repeat: |
| 153 | switch (*fmt) { |
| 154 | case 'n': |
| 155 | *attributes |= LTT_ATTRIBUTE_NETWORK_BYTE_ORDER; |
| 156 | ++fmt; |
| 157 | goto repeat; |
| 158 | } |
| 159 | |
| 160 | /* get the conversion qualifier */ |
| 161 | qualifier = -1; |
| 162 | if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' || |
| 163 | *fmt == 'Z' || *fmt == 'z' || *fmt == 't' || |
| 164 | *fmt == 'S' || *fmt == '1' || *fmt == '2' || |
| 165 | *fmt == '4' || *fmt == 8) { |
| 166 | qualifier = *fmt; |
| 167 | ++fmt; |
| 168 | if (qualifier == 'l' && *fmt == 'l') { |
| 169 | qualifier = 'L'; |
| 170 | ++fmt; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | switch (*fmt) { |
| 175 | case 'c': |
| 176 | *trace_type = LTT_TYPE_UNSIGNED_INT; |
| 177 | *trace_size = sizeof(unsigned char); |
| 178 | goto parse_end; |
| 179 | case 's': |
| 180 | *trace_type = LTT_TYPE_STRING; |
| 181 | goto parse_end; |
| 182 | case 'p': |
| 183 | *trace_type = LTT_TYPE_UNSIGNED_INT; |
| 184 | *trace_size = sizeof(void *); |
| 185 | goto parse_end; |
| 186 | case 'd': |
| 187 | case 'i': |
| 188 | *trace_type = LTT_TYPE_SIGNED_INT; |
| 189 | break; |
| 190 | case 'o': |
| 191 | case 'u': |
| 192 | case 'x': |
| 193 | case 'X': |
| 194 | *trace_type = LTT_TYPE_UNSIGNED_INT; |
| 195 | break; |
| 196 | default: |
| 197 | if (!*fmt) |
| 198 | --fmt; |
| 199 | goto parse_end; |
| 200 | } |
| 201 | switch (qualifier) { |
| 202 | case 'L': |
| 203 | *trace_size = sizeof(long long); |
| 204 | break; |
| 205 | case 'l': |
| 206 | *trace_size = sizeof(long); |
| 207 | break; |
| 208 | case 'Z': |
| 209 | case 'z': |
| 210 | *trace_size = sizeof(size_t); |
| 211 | break; |
| 212 | case 't': |
| 213 | *trace_size = sizeof(ptrdiff_t); |
| 214 | break; |
| 215 | case 'h': |
| 216 | *trace_size = sizeof(short); |
| 217 | break; |
| 218 | case '1': |
| 219 | *trace_size = sizeof(uint8_t); |
| 220 | break; |
| 221 | case '2': |
| 222 | *trace_size = sizeof(uint16_t); |
| 223 | break; |
| 224 | case '4': |
| 225 | *trace_size = sizeof(uint32_t); |
| 226 | break; |
| 227 | case '8': |
| 228 | *trace_size = sizeof(uint64_t); |
| 229 | break; |
| 230 | default: |
| 231 | *trace_size = sizeof(int); |
| 232 | } |
| 233 | |
| 234 | parse_end: |
| 235 | return fmt; |
| 236 | } |
| 237 | |
| 238 | /* |
| 239 | * Restrictions: |
| 240 | * Field width and precision are *not* supported. |
| 241 | * %n not supported. |
| 242 | */ |
| 243 | static inline |
| 244 | const char *parse_c_type(const char *fmt, char *c_size, enum ltt_type *c_type, |
| 245 | char *outfmt) |
| 246 | { |
| 247 | int qualifier; /* 'h', 'l', or 'L' for integer fields */ |
| 248 | /* 'z' support added 23/7/1999 S.H. */ |
| 249 | /* 'z' changed to 'Z' --davidm 1/25/99 */ |
| 250 | /* 't' added for ptrdiff_t */ |
| 251 | |
| 252 | /* process flags : ignore standard print formats for now. */ |
| 253 | repeat: |
| 254 | switch (*fmt) { |
| 255 | case '-': |
| 256 | case '+': |
| 257 | case ' ': |
| 258 | case '#': |
| 259 | case '0': |
| 260 | ++fmt; |
| 261 | goto repeat; |
| 262 | } |
| 263 | |
| 264 | /* get the conversion qualifier */ |
| 265 | qualifier = -1; |
| 266 | if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' || |
| 267 | *fmt == 'Z' || *fmt == 'z' || *fmt == 't' || |
| 268 | *fmt == 'S') { |
| 269 | qualifier = *fmt; |
| 270 | ++fmt; |
| 271 | if (qualifier == 'l' && *fmt == 'l') { |
| 272 | qualifier = 'L'; |
| 273 | ++fmt; |
| 274 | } |
| 275 | } |
| 276 | |
| 277 | if (outfmt) { |
| 278 | if (qualifier != -1) |
| 279 | *outfmt++ = (char)qualifier; |
| 280 | *outfmt++ = *fmt; |
| 281 | *outfmt = 0; |
| 282 | } |
| 283 | |
| 284 | switch (*fmt) { |
| 285 | case 'c': |
| 286 | *c_type = LTT_TYPE_UNSIGNED_INT; |
| 287 | *c_size = sizeof(unsigned char); |
| 288 | goto parse_end; |
| 289 | case 's': |
| 290 | *c_type = LTT_TYPE_STRING; |
| 291 | goto parse_end; |
| 292 | case 'p': |
| 293 | *c_type = LTT_TYPE_UNSIGNED_INT; |
| 294 | *c_size = sizeof(void *); |
| 295 | goto parse_end; |
| 296 | case 'd': |
| 297 | case 'i': |
| 298 | *c_type = LTT_TYPE_SIGNED_INT; |
| 299 | break; |
| 300 | case 'o': |
| 301 | case 'u': |
| 302 | case 'x': |
| 303 | case 'X': |
| 304 | *c_type = LTT_TYPE_UNSIGNED_INT; |
| 305 | break; |
| 306 | default: |
| 307 | if (!*fmt) |
| 308 | --fmt; |
| 309 | goto parse_end; |
| 310 | } |
| 311 | switch (qualifier) { |
| 312 | case 'L': |
| 313 | *c_size = sizeof(long long); |
| 314 | break; |
| 315 | case 'l': |
| 316 | *c_size = sizeof(long); |
| 317 | break; |
| 318 | case 'Z': |
| 319 | case 'z': |
| 320 | *c_size = sizeof(size_t); |
| 321 | break; |
| 322 | case 't': |
| 323 | *c_size = sizeof(ptrdiff_t); |
| 324 | break; |
| 325 | case 'h': |
| 326 | *c_size = sizeof(short); |
| 327 | break; |
| 328 | default: |
| 329 | *c_size = sizeof(int); |
| 330 | } |
| 331 | |
| 332 | parse_end: |
| 333 | return fmt; |
| 334 | } |
| 335 | |
| 336 | static inline |
| 337 | size_t serialize_trace_data(struct ltt_chanbuf *buf, size_t buf_offset, |
| 338 | char trace_size, enum ltt_type trace_type, |
| 339 | char c_size, enum ltt_type c_type, |
| 340 | unsigned int *stack_pos_ctx, |
| 341 | int *largest_align, |
| 342 | va_list *args) |
| 343 | { |
| 344 | union { |
| 345 | unsigned long v_ulong; |
| 346 | uint64_t v_uint64; |
| 347 | struct { |
| 348 | const char *s; |
| 349 | size_t len; |
| 350 | } v_string; |
| 351 | } tmp; |
| 352 | |
| 353 | /* |
| 354 | * Be careful about sign extension here. |
| 355 | * Sign extension is done with the destination (trace) type. |
| 356 | */ |
| 357 | switch (trace_type) { |
| 358 | case LTT_TYPE_SIGNED_INT: |
| 359 | switch (c_size) { |
| 360 | case 1: |
| 361 | tmp.v_ulong = (long)(int8_t)va_arg(*args, int); |
| 362 | break; |
| 363 | case 2: |
| 364 | tmp.v_ulong = (long)(int16_t)va_arg(*args, int); |
| 365 | break; |
| 366 | case 4: |
| 367 | tmp.v_ulong = (long)(int32_t)va_arg(*args, int); |
| 368 | break; |
| 369 | case 8: |
| 370 | tmp.v_uint64 = va_arg(*args, int64_t); |
| 371 | break; |
| 372 | default: |
| 373 | BUG(); |
| 374 | } |
| 375 | break; |
| 376 | case LTT_TYPE_UNSIGNED_INT: |
| 377 | switch (c_size) { |
| 378 | case 1: |
| 379 | tmp.v_ulong = (unsigned long)(uint8_t)va_arg(*args, unsigned int); |
| 380 | break; |
| 381 | case 2: |
| 382 | tmp.v_ulong = (unsigned long)(uint16_t)va_arg(*args, unsigned int); |
| 383 | break; |
| 384 | case 4: |
| 385 | tmp.v_ulong = (unsigned long)(uint32_t)va_arg(*args, unsigned int); |
| 386 | break; |
| 387 | case 8: |
| 388 | tmp.v_uint64 = va_arg(*args, uint64_t); |
| 389 | break; |
| 390 | default: |
| 391 | BUG(); |
| 392 | } |
| 393 | break; |
| 394 | case LTT_TYPE_STRING: |
| 395 | tmp.v_string.s = va_arg(*args, const char *); |
| 396 | if ((unsigned long)tmp.v_string.s < PAGE_SIZE) |
| 397 | tmp.v_string.s = "<NULL>"; |
| 398 | if (!buf) { |
| 399 | /* |
| 400 | * Reserve tracer stack entry. |
| 401 | */ |
| 402 | __get_cpu_var(tracer_stack_pos)++; |
| 403 | WARN_ON_ONCE(__get_cpu_var(tracer_stack_pos) |
| 404 | > TRACER_STACK_LEN); |
| 405 | barrier(); |
| 406 | __get_cpu_var(tracer_stack)[*stack_pos_ctx] = |
| 407 | strlen(tmp.v_string.s) + 1; |
| 408 | } |
| 409 | tmp.v_string.len = __get_cpu_var(tracer_stack) |
| 410 | [(*stack_pos_ctx)++]; |
| 411 | if (buf) |
| 412 | ltt_relay_strncpy(&buf->a, buf->a.chan, buf_offset, |
| 413 | tmp.v_string.s, tmp.v_string.len); |
| 414 | buf_offset += tmp.v_string.len; |
| 415 | goto copydone; |
| 416 | default: |
| 417 | BUG(); |
| 418 | } |
| 419 | |
| 420 | /* |
| 421 | * If trace_size is lower or equal to 4 bytes, there is no sign |
| 422 | * extension to do because we are already encoded in a long. Therefore, |
| 423 | * we can combine signed and unsigned ops. 4 bytes float also works |
| 424 | * with this, because we do a simple copy of 4 bytes into 4 bytes |
| 425 | * without manipulation (and we do not support conversion from integers |
| 426 | * to floats). |
| 427 | * It is also the case if c_size is 8 bytes, which is the largest |
| 428 | * possible integer. |
| 429 | */ |
| 430 | if (ltt_get_alignment()) { |
| 431 | buf_offset += ltt_align(buf_offset, trace_size); |
| 432 | if (largest_align) |
| 433 | *largest_align = max_t(int, *largest_align, trace_size); |
| 434 | } |
| 435 | if (trace_size <= 4 || c_size == 8) { |
| 436 | if (buf) { |
| 437 | switch (trace_size) { |
| 438 | case 1: |
| 439 | if (c_size == 8) |
| 440 | ltt_relay_write(&buf->a, buf->a.chan, |
| 441 | buf_offset, |
| 442 | (uint8_t[]){ (uint8_t)tmp.v_uint64 }, |
| 443 | sizeof(uint8_t)); |
| 444 | else |
| 445 | ltt_relay_write(&buf->a, buf->a.chan, |
| 446 | buf_offset, |
| 447 | (uint8_t[]){ (uint8_t)tmp.v_ulong }, |
| 448 | sizeof(uint8_t)); |
| 449 | break; |
| 450 | case 2: |
| 451 | if (c_size == 8) |
| 452 | ltt_relay_write(&buf->a, buf->a.chan, |
| 453 | buf_offset, |
| 454 | (uint16_t[]){ (uint16_t)tmp.v_uint64 }, |
| 455 | sizeof(uint16_t)); |
| 456 | else |
| 457 | ltt_relay_write(&buf->a, buf->a.chan, |
| 458 | buf_offset, |
| 459 | (uint16_t[]){ (uint16_t)tmp.v_ulong }, |
| 460 | sizeof(uint16_t)); |
| 461 | break; |
| 462 | case 4: |
| 463 | if (c_size == 8) |
| 464 | ltt_relay_write(&buf->a, buf->a.chan, |
| 465 | buf_offset, |
| 466 | (uint32_t[]){ (uint32_t)tmp.v_uint64 }, |
| 467 | sizeof(uint32_t)); |
| 468 | else |
| 469 | ltt_relay_write(&buf->a, buf->a.chan, |
| 470 | buf_offset, |
| 471 | (uint32_t[]){ (uint32_t)tmp.v_ulong }, |
| 472 | sizeof(uint32_t)); |
| 473 | break; |
| 474 | case 8: |
| 475 | /* |
| 476 | * c_size cannot be other than 8 here because |
| 477 | * trace_size > 4. |
| 478 | */ |
| 479 | ltt_relay_write(&buf->a, buf->a.chan, buf_offset, |
| 480 | (uint64_t[]){ (uint64_t)tmp.v_uint64 }, |
| 481 | sizeof(uint64_t)); |
| 482 | break; |
| 483 | default: |
| 484 | BUG(); |
| 485 | } |
| 486 | } |
| 487 | buf_offset += trace_size; |
| 488 | goto copydone; |
| 489 | } else { |
| 490 | /* |
| 491 | * Perform sign extension. |
| 492 | */ |
| 493 | if (buf) { |
| 494 | switch (trace_type) { |
| 495 | case LTT_TYPE_SIGNED_INT: |
| 496 | ltt_relay_write(&buf->a, buf->a.chan, buf_offset, |
| 497 | (int64_t[]){ (int64_t)tmp.v_ulong }, |
| 498 | sizeof(int64_t)); |
| 499 | break; |
| 500 | case LTT_TYPE_UNSIGNED_INT: |
| 501 | ltt_relay_write(&buf->a, buf->a.chan, buf_offset, |
| 502 | (uint64_t[]){ (uint64_t)tmp.v_ulong }, |
| 503 | sizeof(uint64_t)); |
| 504 | break; |
| 505 | default: |
| 506 | BUG(); |
| 507 | } |
| 508 | } |
| 509 | buf_offset += trace_size; |
| 510 | goto copydone; |
| 511 | } |
| 512 | |
| 513 | copydone: |
| 514 | return buf_offset; |
| 515 | } |
| 516 | |
| 517 | notrace size_t |
| 518 | ltt_serialize_data(struct ltt_chanbuf *buf, size_t buf_offset, |
| 519 | struct ltt_serialize_closure *closure, |
| 520 | void *serialize_private, unsigned int stack_pos_ctx, |
| 521 | int *largest_align, const char *fmt, va_list *args) |
| 522 | { |
| 523 | char trace_size = 0, c_size = 0; /* |
| 524 | * 0 (unset), 1, 2, 4, 8 bytes. |
| 525 | */ |
| 526 | enum ltt_type trace_type = LTT_TYPE_NONE, c_type = LTT_TYPE_NONE; |
| 527 | unsigned long attributes = 0; |
| 528 | |
| 529 | for (; *fmt ; ++fmt) { |
| 530 | switch (*fmt) { |
| 531 | case '#': |
| 532 | /* tracetypes (#) */ |
| 533 | ++fmt; /* skip first '#' */ |
| 534 | if (*fmt == '#') /* Escaped ## */ |
| 535 | break; |
| 536 | attributes = 0; |
| 537 | fmt = parse_trace_type(fmt, &trace_size, &trace_type, |
| 538 | &attributes); |
| 539 | break; |
| 540 | case '%': |
| 541 | /* c types (%) */ |
| 542 | ++fmt; /* skip first '%' */ |
| 543 | if (*fmt == '%') /* Escaped %% */ |
| 544 | break; |
| 545 | fmt = parse_c_type(fmt, &c_size, &c_type, NULL); |
| 546 | /* |
| 547 | * Output c types if no trace types has been |
| 548 | * specified. |
| 549 | */ |
| 550 | if (!trace_size) |
| 551 | trace_size = c_size; |
| 552 | if (trace_type == LTT_TYPE_NONE) |
| 553 | trace_type = c_type; |
| 554 | if (c_type == LTT_TYPE_STRING) |
| 555 | trace_type = LTT_TYPE_STRING; |
| 556 | /* perform trace write */ |
| 557 | buf_offset = serialize_trace_data(buf, buf_offset, |
| 558 | trace_size, |
| 559 | trace_type, c_size, |
| 560 | c_type, |
| 561 | &stack_pos_ctx, |
| 562 | largest_align, |
| 563 | args); |
| 564 | trace_size = 0; |
| 565 | c_size = 0; |
| 566 | trace_type = LTT_TYPE_NONE; |
| 567 | c_size = LTT_TYPE_NONE; |
| 568 | attributes = 0; |
| 569 | break; |
| 570 | /* default is to skip the text, doing nothing */ |
| 571 | } |
| 572 | } |
| 573 | return buf_offset; |
| 574 | } |
| 575 | EXPORT_SYMBOL_GPL(ltt_serialize_data); |
| 576 | |
| 577 | static inline |
| 578 | uint64_t unserialize_base_type(struct ltt_chanbuf *buf, |
| 579 | size_t *ppos, char trace_size, |
| 580 | enum ltt_type trace_type) |
| 581 | { |
| 582 | uint64_t tmp; |
| 583 | |
| 584 | *ppos += ltt_align(*ppos, trace_size); |
| 585 | ltt_relay_read(&buf->a, *ppos, &tmp, trace_size); |
| 586 | *ppos += trace_size; |
| 587 | |
| 588 | switch (trace_type) { |
| 589 | case LTT_TYPE_SIGNED_INT: |
| 590 | switch (trace_size) { |
| 591 | case 1: |
| 592 | return (uint64_t)*(int8_t *)&tmp; |
| 593 | case 2: |
| 594 | return (uint64_t)*(int16_t *)&tmp; |
| 595 | case 4: |
| 596 | return (uint64_t)*(int32_t *)&tmp; |
| 597 | case 8: |
| 598 | return tmp; |
| 599 | } |
| 600 | break; |
| 601 | case LTT_TYPE_UNSIGNED_INT: |
| 602 | switch (trace_size) { |
| 603 | case 1: |
| 604 | return (uint64_t)*(uint8_t *)&tmp; |
| 605 | case 2: |
| 606 | return (uint64_t)*(uint16_t *)&tmp; |
| 607 | case 4: |
| 608 | return (uint64_t)*(uint32_t *)&tmp; |
| 609 | case 8: |
| 610 | return tmp; |
| 611 | } |
| 612 | break; |
| 613 | default: |
| 614 | break; |
| 615 | } |
| 616 | |
| 617 | BUG(); |
| 618 | return 0; |
| 619 | } |
| 620 | |
| 621 | static |
| 622 | int serialize_printf_data(struct ltt_chanbuf *buf, size_t *ppos, |
| 623 | char trace_size, enum ltt_type trace_type, |
| 624 | char c_size, enum ltt_type c_type, char *output, |
| 625 | ssize_t outlen, const char *outfmt) |
| 626 | { |
| 627 | u64 value; |
| 628 | outlen = outlen < 0 ? 0 : outlen; |
| 629 | |
| 630 | if (trace_type == LTT_TYPE_STRING) { |
| 631 | size_t len = ltt_relay_read_cstr(&buf->a, *ppos, output, |
| 632 | outlen); |
| 633 | *ppos += len + 1; |
| 634 | return len; |
| 635 | } |
| 636 | |
| 637 | value = unserialize_base_type(buf, ppos, trace_size, trace_type); |
| 638 | |
| 639 | if (c_size == 8) |
| 640 | return snprintf(output, outlen, outfmt, value); |
| 641 | else |
| 642 | return snprintf(output, outlen, outfmt, (unsigned int)value); |
| 643 | } |
| 644 | |
| 645 | /** |
| 646 | * ltt_serialize_printf - Format a string and place it in a buffer |
| 647 | * @buf: The ltt-relay buffer that store binary data |
| 648 | * @buf_offset: binary data's offset in @buf (should be masked to use as offset) |
| 649 | * @msg_size: return message's length |
| 650 | * @output: The buffer to place the result into |
| 651 | * @outlen: The size of the buffer, including the trailing '\0' |
| 652 | * @fmt: The format string to use |
| 653 | * |
| 654 | * The return value is the number of characters which would |
| 655 | * be generated for the given input, excluding the trailing |
| 656 | * '\0', as per ISO C99. If the return is greater than or equal to @outlen, |
| 657 | * the resulting string is truncated. |
| 658 | */ |
| 659 | size_t ltt_serialize_printf(struct ltt_chanbuf *buf, unsigned long buf_offset, |
| 660 | size_t *msg_size, char *output, size_t outlen, |
| 661 | const char *fmt) |
| 662 | { |
| 663 | char trace_size = 0, c_size = 0; /* |
| 664 | * 0 (unset), 1, 2, 4, 8 bytes. |
| 665 | */ |
| 666 | enum ltt_type trace_type = LTT_TYPE_NONE, c_type = LTT_TYPE_NONE; |
| 667 | unsigned long attributes = 0; |
| 668 | char outfmt[4] = "%"; |
| 669 | size_t outpos = 0; |
| 670 | size_t len; |
| 671 | size_t msgpos = buf_offset; |
| 672 | |
| 673 | for (; *fmt ; ++fmt) { |
| 674 | switch (*fmt) { |
| 675 | case '#': |
| 676 | /* tracetypes (#) */ |
| 677 | ++fmt; /* skip first '#' */ |
| 678 | if (*fmt == '#') { /* Escaped ## */ |
| 679 | if (outpos < outlen) |
| 680 | output[outpos] = '#'; |
| 681 | outpos++; |
| 682 | break; |
| 683 | } |
| 684 | attributes = 0; |
| 685 | fmt = parse_trace_type(fmt, &trace_size, &trace_type, |
| 686 | &attributes); |
| 687 | break; |
| 688 | case '%': |
| 689 | /* c types (%) */ |
| 690 | ++fmt; /* skip first '%' */ |
| 691 | if (*fmt == '%') { /* Escaped %% */ |
| 692 | if (outpos < outlen) |
| 693 | output[outpos] = '%'; |
| 694 | outpos++; |
| 695 | break; |
| 696 | } |
| 697 | fmt = parse_c_type(fmt, &c_size, &c_type, outfmt + 1); |
| 698 | /* |
| 699 | * Output c types if no trace types has been |
| 700 | * specified. |
| 701 | */ |
| 702 | if (!trace_size) |
| 703 | trace_size = c_size; |
| 704 | if (trace_type == LTT_TYPE_NONE) |
| 705 | trace_type = c_type; |
| 706 | if (c_type == LTT_TYPE_STRING) |
| 707 | trace_type = LTT_TYPE_STRING; |
| 708 | |
| 709 | /* perform trace printf */ |
| 710 | len = serialize_printf_data(buf, &msgpos, trace_size, |
| 711 | trace_type, c_size, c_type, |
| 712 | output + outpos, |
| 713 | outlen - outpos, outfmt); |
| 714 | outpos += len; |
| 715 | trace_size = 0; |
| 716 | c_size = 0; |
| 717 | trace_type = LTT_TYPE_NONE; |
| 718 | c_size = LTT_TYPE_NONE; |
| 719 | attributes = 0; |
| 720 | break; |
| 721 | default: |
| 722 | if (outpos < outlen) |
| 723 | output[outpos] = *fmt; |
| 724 | outpos++; |
| 725 | break; |
| 726 | } |
| 727 | } |
| 728 | if (msg_size) |
| 729 | *msg_size = (size_t)(msgpos - buf_offset); |
| 730 | /* |
| 731 | * Make sure we end output with terminating \0 when truncated. |
| 732 | */ |
| 733 | if (outpos >= outlen + 1) |
| 734 | output[outlen] = '\0'; |
| 735 | return outpos; |
| 736 | } |
| 737 | EXPORT_SYMBOL_GPL(ltt_serialize_printf); |
| 738 | |
| 739 | #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS |
| 740 | |
| 741 | unsigned int ltt_fmt_largest_align(size_t align_drift, const char *fmt) |
| 742 | { |
| 743 | char trace_size = 0, c_size = 0; |
| 744 | enum ltt_type trace_type = LTT_TYPE_NONE, c_type = LTT_TYPE_NONE; |
| 745 | unsigned long attributes = 0; |
| 746 | int largest_align = 1; |
| 747 | |
| 748 | for (; *fmt ; ++fmt) { |
| 749 | switch (*fmt) { |
| 750 | case '#': |
| 751 | /* tracetypes (#) */ |
| 752 | ++fmt; /* skip first '#' */ |
| 753 | if (*fmt == '#') /* Escaped ## */ |
| 754 | break; |
| 755 | attributes = 0; |
| 756 | fmt = parse_trace_type(fmt, &trace_size, &trace_type, |
| 757 | &attributes); |
| 758 | |
| 759 | largest_align = max_t(int, largest_align, trace_size); |
| 760 | if (largest_align >= ltt_get_alignment()) |
| 761 | goto exit; |
| 762 | break; |
| 763 | case '%': |
| 764 | /* c types (%) */ |
| 765 | ++fmt; /* skip first '%' */ |
| 766 | if (*fmt == '%') /* Escaped %% */ |
| 767 | break; |
| 768 | fmt = parse_c_type(fmt, &c_size, &c_type, NULL); |
| 769 | /* |
| 770 | * Output c types if no trace types has been |
| 771 | * specified. |
| 772 | */ |
| 773 | if (!trace_size) |
| 774 | trace_size = c_size; |
| 775 | if (trace_type == LTT_TYPE_NONE) |
| 776 | trace_type = c_type; |
| 777 | if (c_type == LTT_TYPE_STRING) |
| 778 | trace_type = LTT_TYPE_STRING; |
| 779 | |
| 780 | largest_align = max_t(int, largest_align, trace_size); |
| 781 | if (largest_align >= ltt_get_alignment()) |
| 782 | goto exit; |
| 783 | |
| 784 | trace_size = 0; |
| 785 | c_size = 0; |
| 786 | trace_type = LTT_TYPE_NONE; |
| 787 | c_size = LTT_TYPE_NONE; |
| 788 | break; |
| 789 | } |
| 790 | } |
| 791 | |
| 792 | exit: |
| 793 | largest_align = min_t(int, largest_align, ltt_get_alignment()); |
| 794 | return (largest_align - align_drift) & (largest_align - 1); |
| 795 | } |
| 796 | EXPORT_SYMBOL_GPL(ltt_fmt_largest_align); |
| 797 | |
| 798 | #endif |
| 799 | |
| 800 | /* |
| 801 | * Calculate data size |
| 802 | * Assume that the padding for alignment starts at a sizeof(void *) address. |
| 803 | */ |
| 804 | static notrace |
| 805 | size_t ltt_get_data_size(struct ltt_serialize_closure *closure, |
| 806 | void *serialize_private, unsigned int stack_pos_ctx, |
| 807 | int *largest_align, const char *fmt, va_list *args) |
| 808 | { |
| 809 | ltt_serialize_cb cb = closure->callbacks[0]; |
| 810 | closure->cb_idx = 0; |
| 811 | return (size_t)cb(NULL, 0, closure, serialize_private, stack_pos_ctx, |
| 812 | largest_align, fmt, args); |
| 813 | } |
| 814 | |
| 815 | static notrace |
| 816 | void ltt_write_event_data(struct ltt_chanbuf *buf, size_t buf_offset, |
| 817 | struct ltt_serialize_closure *closure, |
| 818 | void *serialize_private, unsigned int stack_pos_ctx, |
| 819 | int largest_align, const char *fmt, va_list *args) |
| 820 | { |
| 821 | ltt_serialize_cb cb = closure->callbacks[0]; |
| 822 | closure->cb_idx = 0; |
| 823 | buf_offset += ltt_align(buf_offset, largest_align); |
| 824 | cb(buf, buf_offset, closure, serialize_private, stack_pos_ctx, NULL, |
| 825 | fmt, args); |
| 826 | } |
| 827 | |
| 828 | |
| 829 | notrace |
| 830 | void ltt_vtrace(const struct marker *mdata, void *probe_data, void *call_data, |
| 831 | const char *fmt, va_list *args) |
| 832 | { |
| 833 | int largest_align, ret; |
| 834 | struct ltt_active_marker *pdata; |
| 835 | uint16_t eID; |
| 836 | size_t data_size, slot_size; |
| 837 | unsigned int chan_index; |
| 838 | struct ltt_chanbuf *buf; |
| 839 | struct ltt_chan *chan; |
| 840 | struct ltt_trace *trace, *dest_trace = NULL; |
| 841 | uint64_t tsc; |
| 842 | long buf_offset; |
| 843 | va_list args_copy; |
| 844 | struct ltt_serialize_closure closure; |
| 845 | struct ltt_probe_private_data *private_data = call_data; |
| 846 | void *serialize_private = NULL; |
| 847 | int cpu; |
| 848 | unsigned int rflags; |
| 849 | unsigned int stack_pos_ctx; |
| 850 | |
| 851 | /* |
| 852 | * This test is useful for quickly exiting static tracing when no trace |
| 853 | * is active. We expect to have an active trace when we get here. |
| 854 | */ |
| 855 | if (unlikely(ltt_traces.num_active_traces == 0)) |
| 856 | return; |
| 857 | |
| 858 | rcu_read_lock_sched_notrace(); |
| 859 | cpu = smp_processor_id(); |
| 860 | __get_cpu_var(ltt_nesting)++; |
| 861 | stack_pos_ctx = __get_cpu_var(tracer_stack_pos); |
| 862 | /* |
| 863 | * asm volatile and "memory" clobber prevent the compiler from moving |
| 864 | * instructions out of the ltt nesting count. This is required to ensure |
| 865 | * that probe side-effects which can cause recursion (e.g. unforeseen |
| 866 | * traps, divisions by 0, ...) are triggered within the incremented |
| 867 | * nesting count section. |
| 868 | */ |
| 869 | barrier(); |
| 870 | pdata = (struct ltt_active_marker *)probe_data; |
| 871 | eID = mdata->event_id; |
| 872 | chan_index = mdata->channel_id; |
| 873 | closure.callbacks = pdata->probe->callbacks; |
| 874 | |
| 875 | if (unlikely(private_data)) { |
| 876 | dest_trace = private_data->trace; |
| 877 | if (private_data->serializer) |
| 878 | closure.callbacks = &private_data->serializer; |
| 879 | serialize_private = private_data->serialize_private; |
| 880 | } |
| 881 | |
| 882 | va_copy(args_copy, *args); |
| 883 | /* |
| 884 | * Assumes event payload to start on largest_align alignment. |
| 885 | */ |
| 886 | largest_align = 1; /* must be non-zero for ltt_align */ |
| 887 | data_size = ltt_get_data_size(&closure, serialize_private, |
| 888 | stack_pos_ctx, &largest_align, |
| 889 | fmt, &args_copy); |
| 890 | largest_align = min_t(int, largest_align, sizeof(void *)); |
| 891 | va_end(args_copy); |
| 892 | |
| 893 | /* Iterate on each trace */ |
| 894 | list_for_each_entry_rcu(trace, <t_traces.head, list) { |
| 895 | /* |
| 896 | * Expect the filter to filter out events. If we get here, |
| 897 | * we went through tracepoint activation as a first step. |
| 898 | */ |
| 899 | if (unlikely(dest_trace && trace != dest_trace)) |
| 900 | continue; |
| 901 | if (unlikely(!trace->active)) |
| 902 | continue; |
| 903 | if (unlikely(!ltt_run_filter(trace, eID))) |
| 904 | continue; |
| 905 | #ifdef LTT_DEBUG_EVENT_SIZE |
| 906 | rflags = LTT_RFLAG_ID_SIZE; |
| 907 | #else |
| 908 | if (unlikely(eID >= LTT_FREE_EVENTS)) |
| 909 | rflags = LTT_RFLAG_ID; |
| 910 | else |
| 911 | rflags = 0; |
| 912 | #endif |
| 913 | /* |
| 914 | * Skip channels added after trace creation. |
| 915 | */ |
| 916 | if (unlikely(chan_index >= trace->nr_channels)) |
| 917 | continue; |
| 918 | chan = &trace->channels[chan_index]; |
| 919 | if (!chan->active) |
| 920 | continue; |
| 921 | |
| 922 | /* reserve space : header and data */ |
| 923 | ret = ltt_reserve_slot(chan, trace, data_size, largest_align, |
| 924 | cpu, &buf, &slot_size, &buf_offset, |
| 925 | &tsc, &rflags); |
| 926 | if (unlikely(ret < 0)) |
| 927 | continue; /* buffer full */ |
| 928 | |
| 929 | va_copy(args_copy, *args); |
| 930 | /* Out-of-order write : header and data */ |
| 931 | buf_offset = ltt_write_event_header(&buf->a, &chan->a, |
| 932 | buf_offset, eID, data_size, |
| 933 | tsc, rflags); |
| 934 | ltt_write_event_data(buf, buf_offset, &closure, |
| 935 | serialize_private, stack_pos_ctx, |
| 936 | largest_align, fmt, &args_copy); |
| 937 | va_end(args_copy); |
| 938 | /* Out-of-order commit */ |
| 939 | ltt_commit_slot(buf, chan, buf_offset, data_size, slot_size); |
| 940 | } |
| 941 | /* |
| 942 | * asm volatile and "memory" clobber prevent the compiler from moving |
| 943 | * instructions out of the ltt nesting count. This is required to ensure |
| 944 | * that probe side-effects which can cause recursion (e.g. unforeseen |
| 945 | * traps, divisions by 0, ...) are triggered within the incremented |
| 946 | * nesting count section. |
| 947 | */ |
| 948 | barrier(); |
| 949 | __get_cpu_var(tracer_stack_pos) = stack_pos_ctx; |
| 950 | __get_cpu_var(ltt_nesting)--; |
| 951 | rcu_read_unlock_sched_notrace(); |
| 952 | } |
| 953 | EXPORT_SYMBOL_GPL(ltt_vtrace); |
| 954 | |
| 955 | notrace |
| 956 | void ltt_trace(const struct marker *mdata, void *probe_data, void *call_data, |
| 957 | const char *fmt, ...) |
| 958 | { |
| 959 | va_list args; |
| 960 | |
| 961 | va_start(args, fmt); |
| 962 | ltt_vtrace(mdata, probe_data, call_data, fmt, &args); |
| 963 | va_end(args); |
| 964 | } |
| 965 | EXPORT_SYMBOL_GPL(ltt_trace); |
| 966 | |
| 967 | MODULE_LICENSE("GPL and additional rights"); |
| 968 | MODULE_AUTHOR("Mathieu Desnoyers"); |
| 969 | MODULE_DESCRIPTION("Linux Trace Toolkit Next Generation Serializer"); |