tools/perf/jvmti/jvmti_agent.c

   1 /*
   2  * jvmti_agent.c: JVMTI agent interface
   3  *
   4  * Adapted from the Oprofile code in opagent.c:
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  *
  19  * Copyright 2007 OProfile authors
  20  * Jens Wilke
  21  * Daniel Hansel
  22  * Copyright IBM Corporation 2007
  23  */
  24 #include <sys/types.h>
  25 #include <sys/stat.h> /* for mkdir() */
  26 #include <stdio.h>
  27 #include <errno.h>
  28 #include <string.h>
  29 #include <stdlib.h>
  30 #include <stdint.h>
  31 #include <limits.h>
  32 #include <fcntl.h>
  33 #include <unistd.h>
  34 #include <time.h>
  35 #include <sys/mman.h>
  36 #include <syscall.h> /* for gettid() */
  37 #include <err.h>
  38 #include <linux/kernel.h>
  39
  40 #include "jvmti_agent.h"
  41 #include "../util/jitdump.h"
  42
  43 #define JIT_LANG "java"
  44
  45 static char jit_path[PATH_MAX];
  46 static void *marker_addr;
  47
  48 static inline pid_t gettid(void)
  49 {
  50         return (pid_t)syscall(__NR_gettid);
  51 }
  52
  53 static int get_e_machine(struct jitheader *hdr)
  54 {
  55         ssize_t sret;
  56         char id[16];
  57         int fd, ret = -1;
  58         struct {
  59                 uint16_t e_type;
  60                 uint16_t e_machine;
  61         } info;
  62
  63         fd = open("/proc/self/exe", O_RDONLY);
  64         if (fd == -1)
  65                 return -1;
  66
  67         sret = read(fd, id, sizeof(id));
  68         if (sret != sizeof(id))
  69                 goto error;
  70
  71         /* check ELF signature */
  72         if (id[0] != 0x7f || id[1] != 'E' || id[2] != 'L' || id[3] != 'F')
  73                 goto error;
  74
  75         sret = read(fd, &info, sizeof(info));
  76         if (sret != sizeof(info))
  77                 goto error;
  78
  79         hdr->elf_mach = info.e_machine;
  80         ret = 0;
  81 error:
  82         close(fd);
  83         return ret;
  84 }
  85
  86 static int use_arch_timestamp;
  87
  88 static inline uint64_t
  89 get_arch_timestamp(void)
  90 {
  91 #if defined(__i386__) || defined(__x86_64__)
  92         unsigned int low, high;
  93
  94         asm volatile("rdtsc" : "=a" (low), "=d" (high));
  95
  96         return low | ((uint64_t)high) << 32;
  97 #else
  98         return 0;
  99 #endif
 100 }
 101
 102 #define NSEC_PER_SEC    1000000000
 103 static int perf_clk_id = CLOCK_MONOTONIC;
 104
 105 static inline uint64_t
 106 timespec_to_ns(const struct timespec *ts)
 107 {
 108         return ((uint64_t) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
 109 }
 110
 111 static inline uint64_t
 112 perf_get_timestamp(void)
 113 {
 114         struct timespec ts;
 115         int ret;
 116
 117         if (use_arch_timestamp)
 118                 return get_arch_timestamp();
 119
 120         ret = clock_gettime(perf_clk_id, &ts);
 121         if (ret)
 122                 return 0;
 123
 124         return timespec_to_ns(&ts);
 125 }
 126
 127 static int
 128 debug_cache_init(void)
 129 {
 130         char str[32];
 131         char *base, *p;
 132         struct tm tm;
 133         time_t t;
 134         int ret;
 135
 136         time(&t);
 137         localtime_r(&t, &tm);
 138
 139         base = getenv("JITDUMPDIR");
 140         if (!base)
 141                 base = getenv("HOME");
 142         if (!base)
 143                 base = ".";
 144
 145         strftime(str, sizeof(str), JIT_LANG"-jit-%Y%m%d", &tm);
 146
 147         snprintf(jit_path, PATH_MAX - 1, "%s/.debug/", base);
 148
 149         ret = mkdir(jit_path, 0755);
 150         if (ret == -1) {
 151                 if (errno != EEXIST) {
 152                         warn("jvmti: cannot create jit cache dir %s", jit_path);
 153                         return -1;
 154                 }
 155         }
 156
 157         snprintf(jit_path, PATH_MAX - 1, "%s/.debug/jit", base);
 158         ret = mkdir(jit_path, 0755);
 159         if (ret == -1) {
 160                 if (errno != EEXIST) {
 161                         warn("cannot create jit cache dir %s", jit_path);
 162                         return -1;
 163                 }
 164         }
 165
 166         snprintf(jit_path, PATH_MAX - 1, "%s/.debug/jit/%s.XXXXXXXX", base, str);
 167
 168         p = mkdtemp(jit_path);
 169         if (p != jit_path) {
 170                 warn("cannot create jit cache dir %s", jit_path);
 171                 return -1;
 172         }
 173
 174         return 0;
 175 }
 176
 177 static int
 178 perf_open_marker_file(int fd)
 179 {
 180         long pgsz;
 181
 182         pgsz = sysconf(_SC_PAGESIZE);
 183         if (pgsz == -1)
 184                 return -1;
 185
 186         /*
 187          * we mmap the jitdump to create an MMAP RECORD in perf.data file.
 188          * The mmap is captured either live (perf record running when we mmap)
 189          * or  in deferred mode, via /proc/PID/maps
 190          * the MMAP record is used as a marker of a jitdump file for more meta
 191          * data info about the jitted code. Perf report/annotate detect this
 192          * special filename and process the jitdump file.
 193          *
 194          * mapping must be PROT_EXEC to ensure it is captured by perf record
 195          * even when not using -d option
 196          */
 197         marker_addr = mmap(NULL, pgsz, PROT_READ|PROT_EXEC, MAP_PRIVATE, fd, 0);
 198         return (marker_addr == MAP_FAILED) ? -1 : 0;
 199 }
 200
 201 static void
 202 perf_close_marker_file(void)
 203 {
 204         long pgsz;
 205
 206         if (!marker_addr)
 207                 return;
 208
 209         pgsz = sysconf(_SC_PAGESIZE);
 210         if (pgsz == -1)
 211                 return;
 212
 213         munmap(marker_addr, pgsz);
 214 }
 215
 216 static void
 217 init_arch_timestamp(void)
 218 {
 219         char *str = getenv("JITDUMP_USE_ARCH_TIMESTAMP");
 220
 221         if (!str || !*str || !strcmp(str, "0"))
 222                 return;
 223
 224         use_arch_timestamp = 1;
 225 }
 226
 227 void *jvmti_open(void)
 228 {
 229         char dump_path[PATH_MAX];
 230         struct jitheader header;
 231         int fd;
 232         FILE *fp;
 233
 234         init_arch_timestamp();
 235
 236         /*
 237          * check if clockid is supported
 238          */
 239         if (!perf_get_timestamp()) {
 240                 if (use_arch_timestamp)
 241                         warnx("jvmti: arch timestamp not supported");
 242                 else
 243                         warnx("jvmti: kernel does not support %d clock id", perf_clk_id);
 244         }
 245
 246         memset(&header, 0, sizeof(header));
 247
 248         debug_cache_init();
 249
 250         /*
 251          * jitdump file name
 252          */
 253         scnprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", jit_path, getpid());
 254
 255         fd = open(dump_path, O_CREAT|O_TRUNC|O_RDWR, 0666);
 256         if (fd == -1)
 257                 return NULL;
 258
 259         /*
 260          * create perf.data maker for the jitdump file
 261          */
 262         if (perf_open_marker_file(fd)) {
 263                 warnx("jvmti: failed to create marker file");
 264                 return NULL;
 265         }
 266
 267         fp = fdopen(fd, "w+");
 268         if (!fp) {
 269                 warn("jvmti: cannot create %s", dump_path);
 270                 close(fd);
 271                 goto error;
 272         }
 273
 274         warnx("jvmti: jitdump in %s", dump_path);
 275
 276         if (get_e_machine(&header)) {
 277                 warn("get_e_machine failed\n");
 278                 goto error;
 279         }
 280
 281         header.magic      = JITHEADER_MAGIC;
 282         header.version    = JITHEADER_VERSION;
 283         header.total_size = sizeof(header);
 284         header.pid        = getpid();
 285
 286         header.timestamp = perf_get_timestamp();
 287
 288         if (use_arch_timestamp)
 289                 header.flags |= JITDUMP_FLAGS_ARCH_TIMESTAMP;
 290
 291         if (!fwrite(&header, sizeof(header), 1, fp)) {
 292                 warn("jvmti: cannot write dumpfile header");
 293                 goto error;
 294         }
 295         return fp;
 296 error:
 297         fclose(fp);
 298         return NULL;
 299 }
 300
 301 int
 302 jvmti_close(void *agent)
 303 {
 304         struct jr_code_close rec;
 305         FILE *fp = agent;
 306
 307         if (!fp) {
 308                 warnx("jvmti: invalid fd in close_agent");
 309                 return -1;
 310         }
 311
 312         rec.p.id = JIT_CODE_CLOSE;
 313         rec.p.total_size = sizeof(rec);
 314
 315         rec.p.timestamp = perf_get_timestamp();
 316
 317         if (!fwrite(&rec, sizeof(rec), 1, fp))
 318                 return -1;
 319
 320         fclose(fp);
 321
 322         fp = NULL;
 323
 324         perf_close_marker_file();
 325
 326         return 0;
 327 }
 328
 329 int
 330 jvmti_write_code(void *agent, char const *sym,
 331         uint64_t vma, void const *code, unsigned int const size)
 332 {
 333         static int code_generation = 1;
 334         struct jr_code_load rec;
 335         size_t sym_len;
 336         FILE *fp = agent;
 337         int ret = -1;
 338
 339         /* don't care about 0 length function, no samples */
 340         if (size == 0)
 341                 return 0;
 342
 343         if (!fp) {
 344                 warnx("jvmti: invalid fd in write_native_code");
 345                 return -1;
 346         }
 347
 348         sym_len = strlen(sym) + 1;
 349
 350         rec.p.id           = JIT_CODE_LOAD;
 351         rec.p.total_size   = sizeof(rec) + sym_len;
 352         rec.p.timestamp    = perf_get_timestamp();
 353
 354         rec.code_size  = size;
 355         rec.vma        = vma;
 356         rec.code_addr  = vma;
 357         rec.pid        = getpid();
 358         rec.tid        = gettid();
 359
 360         if (code)
 361                 rec.p.total_size += size;
 362
 363         /*
 364          * If JVM is multi-threaded, nultiple concurrent calls to agent
 365          * may be possible, so protect file writes
 366          */
 367         flockfile(fp);
 368
 369         /*
 370          * get code index inside lock to avoid race condition
 371          */
 372         rec.code_index = code_generation++;
 373
 374         ret = fwrite_unlocked(&rec, sizeof(rec), 1, fp);
 375         fwrite_unlocked(sym, sym_len, 1, fp);
 376
 377         if (code)
 378                 fwrite_unlocked(code, size, 1, fp);
 379
 380         funlockfile(fp);
 381
 382         ret = 0;
 383
 384         return ret;
 385 }
 386
 387 int
 388 jvmti_write_debug_info(void *agent, uint64_t code,
 389     int nr_lines, jvmti_line_info_t *li,
 390     const char * const * file_names)
 391 {
 392         struct jr_code_debug_info rec;
 393         size_t sret, len, size, flen = 0;
 394         uint64_t addr;
 395         FILE *fp = agent;
 396         int i;
 397
 398         /*
 399          * no entry to write
 400          */
 401         if (!nr_lines)
 402                 return 0;
 403
 404         if (!fp) {
 405                 warnx("jvmti: invalid fd in write_debug_info");
 406                 return -1;
 407         }
 408
 409         for (i = 0; i < nr_lines; ++i) {
 410             flen += strlen(file_names[i]) + 1;
 411         }
 412
 413         rec.p.id        = JIT_CODE_DEBUG_INFO;
 414         size            = sizeof(rec);
 415         rec.p.timestamp = perf_get_timestamp();
 416         rec.code_addr   = (uint64_t)(uintptr_t)code;
 417         rec.nr_entry    = nr_lines;
 418
 419         /*
 420          * on disk source line info layout:
 421          * uint64_t : addr
 422          * int      : line number
 423          * int      : column discriminator
 424          * file[]   : source file name
 425          */
 426         size += nr_lines * sizeof(struct debug_entry);
 427         size += flen;
 428         rec.p.total_size = size;
 429
 430         /*
 431          * If JVM is multi-threaded, nultiple concurrent calls to agent
 432          * may be possible, so protect file writes
 433          */
 434         flockfile(fp);
 435
 436         sret = fwrite_unlocked(&rec, sizeof(rec), 1, fp);
 437         if (sret != 1)
 438                 goto error;
 439
 440         for (i = 0; i < nr_lines; i++) {
 441
 442                 addr = (uint64_t)li[i].pc;
 443                 len  = sizeof(addr);
 444                 sret = fwrite_unlocked(&addr, len, 1, fp);
 445                 if (sret != 1)
 446                         goto error;
 447
 448                 len  = sizeof(li[0].line_number);
 449                 sret = fwrite_unlocked(&li[i].line_number, len, 1, fp);
 450                 if (sret != 1)
 451                         goto error;
 452
 453                 len  = sizeof(li[0].discrim);
 454                 sret = fwrite_unlocked(&li[i].discrim, len, 1, fp);
 455                 if (sret != 1)
 456                         goto error;
 457
 458                 sret = fwrite_unlocked(file_names[i], strlen(file_names[i]) + 1, 1, fp);
 459                 if (sret != 1)
 460                         goto error;
 461         }
 462         funlockfile(fp);
 463         return 0;
 464 error:
 465         funlockfile(fp);
 466         return -1;
 467 }