tools/testing/selftests/vm/userfaultfd.c

   1 /*
   2  * Stress userfaultfd syscall.
   3  *
   4  *  Copyright (C) 2015  Red Hat, Inc.
   5  *
   6  *  This work is licensed under the terms of the GNU GPL, version 2. See
   7  *  the COPYING file in the top-level directory.
   8  *
   9  * This test allocates two virtual areas and bounces the physical
  10  * memory across the two virtual areas (from area_src to area_dst)
  11  * using userfaultfd.
  12  *
  13  * There are three threads running per CPU:
  14  *
  15  * 1) one per-CPU thread takes a per-page pthread_mutex in a random
  16  *    page of the area_dst (while the physical page may still be in
  17  *    area_src), and increments a per-page counter in the same page,
  18  *    and checks its value against a verification region.
  19  *
  20  * 2) another per-CPU thread handles the userfaults generated by
  21  *    thread 1 above. userfaultfd blocking reads or poll() modes are
  22  *    exercised interleaved.
  23  *
  24  * 3) one last per-CPU thread transfers the memory in the background
  25  *    at maximum bandwidth (if not already transferred by thread
  26  *    2). Each cpu thread takes cares of transferring a portion of the
  27  *    area.
  28  *
  29  * When all threads of type 3 completed the transfer, one bounce is
  30  * complete. area_src and area_dst are then swapped. All threads are
  31  * respawned and so the bounce is immediately restarted in the
  32  * opposite direction.
  33  *
  34  * per-CPU threads 1 by triggering userfaults inside
  35  * pthread_mutex_lock will also verify the atomicity of the memory
  36  * transfer (UFFDIO_COPY).
  37  *
  38  * The program takes two parameters: the amounts of physical memory in
  39  * megabytes (MiB) of the area and the number of bounces to execute.
  40  *
  41  * # 100MiB 99999 bounces
  42  * ./userfaultfd 100 99999
  43  *
  44  * # 1GiB 99 bounces
  45  * ./userfaultfd 1000 99
  46  *
  47  * # 10MiB-~6GiB 999 bounces, continue forever unless an error triggers
  48  * while ./userfaultfd $[RANDOM % 6000 + 10] 999; do true; done
  49  */
  50
  51 #define _GNU_SOURCE
  52 #include <stdio.h>
  53 #include <errno.h>
  54 #include <unistd.h>
  55 #include <stdlib.h>
  56 #include <sys/types.h>
  57 #include <sys/stat.h>
  58 #include <fcntl.h>
  59 #include <time.h>
  60 #include <signal.h>
  61 #include <poll.h>
  62 #include <string.h>
  63 #include <sys/mman.h>
  64 #include <sys/syscall.h>
  65 #include <sys/ioctl.h>
  66 #include <sys/wait.h>
  67 #include <pthread.h>
  68 #include <linux/userfaultfd.h>
  69 #include <setjmp.h>
  70 #include <stdbool.h>
  71
  72 #include "../kselftest.h"
  73
  74 #ifdef __NR_userfaultfd
  75
  76 static unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size;
  77
  78 #define BOUNCE_RANDOM           (1<<0)
  79 #define BOUNCE_RACINGFAULTS     (1<<1)
  80 #define BOUNCE_VERIFY           (1<<2)
  81 #define BOUNCE_POLL             (1<<3)
  82 static int bounces;
  83
  84 #define TEST_ANON       1
  85 #define TEST_HUGETLB    2
  86 #define TEST_SHMEM      3
  87 static int test_type;
  88
  89 /* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */
  90 #define ALARM_INTERVAL_SECS 10
  91 static volatile bool test_uffdio_copy_eexist = true;
  92 static volatile bool test_uffdio_zeropage_eexist = true;
  93
  94 static bool map_shared;
  95 static int huge_fd;
  96 static char *huge_fd_off0;
  97 static unsigned long long *count_verify;
  98 static int uffd, uffd_flags, finished, *pipefd;
  99 static char *area_src, *area_src_alias, *area_dst, *area_dst_alias;
 100 static char *zeropage;
 101 pthread_attr_t attr;
 102
 103 /* pthread_mutex_t starts at page offset 0 */
 104 #define area_mutex(___area, ___nr)                                      \
 105         ((pthread_mutex_t *) ((___area) + (___nr)*page_size))
 106 /*
 107  * count is placed in the page after pthread_mutex_t naturally aligned
 108  * to avoid non alignment faults on non-x86 archs.
 109  */
 110 #define area_count(___area, ___nr)                                      \
 111         ((volatile unsigned long long *) ((unsigned long)               \
 112                                  ((___area) + (___nr)*page_size +       \
 113                                   sizeof(pthread_mutex_t) +             \
 114                                   sizeof(unsigned long long) - 1) &     \
 115                                  ~(unsigned long)(sizeof(unsigned long long) \
 116                                                   -  1)))
 117
 118 static int anon_release_pages(char *rel_area)
 119 {
 120         int ret = 0;
 121
 122         if (madvise(rel_area, nr_pages * page_size, MADV_DONTNEED)) {
 123                 perror("madvise");
 124                 ret = 1;
 125         }
 126
 127         return ret;
 128 }
 129
 130 static void anon_allocate_area(void **alloc_area)
 131 {
 132         if (posix_memalign(alloc_area, page_size, nr_pages * page_size)) {
 133                 fprintf(stderr, "out of memory\n");
 134                 *alloc_area = NULL;
 135         }
 136 }
 137
 138 static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset)
 139 {
 140 }
 141
 142 /* HugeTLB memory */
 143 static int hugetlb_release_pages(char *rel_area)
 144 {
 145         int ret = 0;
 146
 147         if (fallocate(huge_fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
 148                                 rel_area == huge_fd_off0 ? 0 :
 149                                 nr_pages * page_size,
 150                                 nr_pages * page_size)) {
 151                 perror("fallocate");
 152                 ret = 1;
 153         }
 154
 155         return ret;
 156 }
 157
 158
 159 static void hugetlb_allocate_area(void **alloc_area)
 160 {
 161         void *area_alias = NULL;
 162         char **alloc_area_alias;
 163         *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 164                            (map_shared ? MAP_SHARED : MAP_PRIVATE) |
 165                            MAP_HUGETLB,
 166                            huge_fd, *alloc_area == area_src ? 0 :
 167                            nr_pages * page_size);
 168         if (*alloc_area == MAP_FAILED) {
 169                 fprintf(stderr, "mmap of hugetlbfs file failed\n");
 170                 *alloc_area = NULL;
 171         }
 172
 173         if (map_shared) {
 174                 area_alias = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 175                                   MAP_SHARED | MAP_HUGETLB,
 176                                   huge_fd, *alloc_area == area_src ? 0 :
 177                                   nr_pages * page_size);
 178                 if (area_alias == MAP_FAILED) {
 179                         if (munmap(*alloc_area, nr_pages * page_size) < 0)
 180                                 perror("hugetlb munmap"), exit(1);
 181                         *alloc_area = NULL;
 182                         return;
 183                 }
 184         }
 185         if (*alloc_area == area_src) {
 186                 huge_fd_off0 = *alloc_area;
 187                 alloc_area_alias = &area_src_alias;
 188         } else {
 189                 alloc_area_alias = &area_dst_alias;
 190         }
 191         if (area_alias)
 192                 *alloc_area_alias = area_alias;
 193 }
 194
 195 static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset)
 196 {
 197         if (!map_shared)
 198                 return;
 199         /*
 200          * We can't zap just the pagetable with hugetlbfs because
 201          * MADV_DONTEED won't work. So exercise -EEXIST on a alias
 202          * mapping where the pagetables are not established initially,
 203          * this way we'll exercise the -EEXEC at the fs level.
 204          */
 205         *start = (unsigned long) area_dst_alias + offset;
 206 }
 207
 208 /* Shared memory */
 209 static int shmem_release_pages(char *rel_area)
 210 {
 211         int ret = 0;
 212
 213         if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE)) {
 214                 perror("madvise");
 215                 ret = 1;
 216         }
 217
 218         return ret;
 219 }
 220
 221 static void shmem_allocate_area(void **alloc_area)
 222 {
 223         *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 224                            MAP_ANONYMOUS | MAP_SHARED, -1, 0);
 225         if (*alloc_area == MAP_FAILED) {
 226                 fprintf(stderr, "shared memory mmap failed\n");
 227                 *alloc_area = NULL;
 228         }
 229 }
 230
 231 struct uffd_test_ops {
 232         unsigned long expected_ioctls;
 233         void (*allocate_area)(void **alloc_area);
 234         int (*release_pages)(char *rel_area);
 235         void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset);
 236 };
 237
 238 #define ANON_EXPECTED_IOCTLS            ((1 << _UFFDIO_WAKE) | \
 239                                          (1 << _UFFDIO_COPY) | \
 240                                          (1 << _UFFDIO_ZEROPAGE))
 241
 242 static struct uffd_test_ops anon_uffd_test_ops = {
 243         .expected_ioctls = ANON_EXPECTED_IOCTLS,
 244         .allocate_area  = anon_allocate_area,
 245         .release_pages  = anon_release_pages,
 246         .alias_mapping = noop_alias_mapping,
 247 };
 248
 249 static struct uffd_test_ops shmem_uffd_test_ops = {
 250         .expected_ioctls = ANON_EXPECTED_IOCTLS,
 251         .allocate_area  = shmem_allocate_area,
 252         .release_pages  = shmem_release_pages,
 253         .alias_mapping = noop_alias_mapping,
 254 };
 255
 256 static struct uffd_test_ops hugetlb_uffd_test_ops = {
 257         .expected_ioctls = UFFD_API_RANGE_IOCTLS_BASIC,
 258         .allocate_area  = hugetlb_allocate_area,
 259         .release_pages  = hugetlb_release_pages,
 260         .alias_mapping = hugetlb_alias_mapping,
 261 };
 262
 263 static struct uffd_test_ops *uffd_test_ops;
 264
 265 static int my_bcmp(char *str1, char *str2, size_t n)
 266 {
 267         unsigned long i;
 268         for (i = 0; i < n; i++)
 269                 if (str1[i] != str2[i])
 270                         return 1;
 271         return 0;
 272 }
 273
 274 static void *locking_thread(void *arg)
 275 {
 276         unsigned long cpu = (unsigned long) arg;
 277         struct random_data rand;
 278         unsigned long page_nr = *(&(page_nr)); /* uninitialized warning */
 279         int32_t rand_nr;
 280         unsigned long long count;
 281         char randstate[64];
 282         unsigned int seed;
 283         time_t start;
 284
 285         if (bounces & BOUNCE_RANDOM) {
 286                 seed = (unsigned int) time(NULL) - bounces;
 287                 if (!(bounces & BOUNCE_RACINGFAULTS))
 288                         seed += cpu;
 289                 bzero(&rand, sizeof(rand));
 290                 bzero(&randstate, sizeof(randstate));
 291                 if (initstate_r(seed, randstate, sizeof(randstate), &rand))
 292                         fprintf(stderr, "srandom_r error\n"), exit(1);
 293         } else {
 294                 page_nr = -bounces;
 295                 if (!(bounces & BOUNCE_RACINGFAULTS))
 296                         page_nr += cpu * nr_pages_per_cpu;
 297         }
 298
 299         while (!finished) {
 300                 if (bounces & BOUNCE_RANDOM) {
 301                         if (random_r(&rand, &rand_nr))
 302                                 fprintf(stderr, "random_r 1 error\n"), exit(1);
 303                         page_nr = rand_nr;
 304                         if (sizeof(page_nr) > sizeof(rand_nr)) {
 305                                 if (random_r(&rand, &rand_nr))
 306                                         fprintf(stderr, "random_r 2 error\n"), exit(1);
 307                                 page_nr |= (((unsigned long) rand_nr) << 16) <<
 308                                            16;
 309                         }
 310                 } else
 311                         page_nr += 1;
 312                 page_nr %= nr_pages;
 313
 314                 start = time(NULL);
 315                 if (bounces & BOUNCE_VERIFY) {
 316                         count = *area_count(area_dst, page_nr);
 317                         if (!count)
 318                                 fprintf(stderr,
 319                                         "page_nr %lu wrong count %Lu %Lu\n",
 320                                         page_nr, count,
 321                                         count_verify[page_nr]), exit(1);
 322
 323
 324                         /*
 325                          * We can't use bcmp (or memcmp) because that
 326                          * returns 0 erroneously if the memory is
 327                          * changing under it (even if the end of the
 328                          * page is never changing and always
 329                          * different).
 330                          */
 331 #if 1
 332                         if (!my_bcmp(area_dst + page_nr * page_size, zeropage,
 333                                      page_size))
 334                                 fprintf(stderr,
 335                                         "my_bcmp page_nr %lu wrong count %Lu %Lu\n",
 336                                         page_nr, count,
 337                                         count_verify[page_nr]), exit(1);
 338 #else
 339                         unsigned long loops;
 340
 341                         loops = 0;
 342                         /* uncomment the below line to test with mutex */
 343                         /* pthread_mutex_lock(area_mutex(area_dst, page_nr)); */
 344                         while (!bcmp(area_dst + page_nr * page_size, zeropage,
 345                                      page_size)) {
 346                                 loops += 1;
 347                                 if (loops > 10)
 348                                         break;
 349                         }
 350                         /* uncomment below line to test with mutex */
 351                         /* pthread_mutex_unlock(area_mutex(area_dst, page_nr)); */
 352                         if (loops) {
 353                                 fprintf(stderr,
 354                                         "page_nr %lu all zero thread %lu %p %lu\n",
 355                                         page_nr, cpu, area_dst + page_nr * page_size,
 356                                         loops);
 357                                 if (loops > 10)
 358                                         exit(1);
 359                         }
 360 #endif
 361                 }
 362
 363                 pthread_mutex_lock(area_mutex(area_dst, page_nr));
 364                 count = *area_count(area_dst, page_nr);
 365                 if (count != count_verify[page_nr]) {
 366                         fprintf(stderr,
 367                                 "page_nr %lu memory corruption %Lu %Lu\n",
 368                                 page_nr, count,
 369                                 count_verify[page_nr]), exit(1);
 370                 }
 371                 count++;
 372                 *area_count(area_dst, page_nr) = count_verify[page_nr] = count;
 373                 pthread_mutex_unlock(area_mutex(area_dst, page_nr));
 374
 375                 if (time(NULL) - start > 1)
 376                         fprintf(stderr,
 377                                 "userfault too slow %ld "
 378                                 "possible false positive with overcommit\n",
 379                                 time(NULL) - start);
 380         }
 381
 382         return NULL;
 383 }
 384
 385 static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
 386                             unsigned long offset)
 387 {
 388         uffd_test_ops->alias_mapping(&uffdio_copy->dst,
 389                                      uffdio_copy->len,
 390                                      offset);
 391         if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) {
 392                 /* real retval in ufdio_copy.copy */
 393                 if (uffdio_copy->copy != -EEXIST)
 394                         fprintf(stderr, "UFFDIO_COPY retry error %Ld\n",
 395                                 uffdio_copy->copy), exit(1);
 396         } else {
 397                 fprintf(stderr, "UFFDIO_COPY retry unexpected %Ld\n",
 398                         uffdio_copy->copy), exit(1);
 399         }
 400 }
 401
 402 static int __copy_page(int ufd, unsigned long offset, bool retry)
 403 {
 404         struct uffdio_copy uffdio_copy;
 405
 406         if (offset >= nr_pages * page_size)
 407                 fprintf(stderr, "unexpected offset %lu\n",
 408                         offset), exit(1);
 409         uffdio_copy.dst = (unsigned long) area_dst + offset;
 410         uffdio_copy.src = (unsigned long) area_src + offset;
 411         uffdio_copy.len = page_size;
 412         uffdio_copy.mode = 0;
 413         uffdio_copy.copy = 0;
 414         if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
 415                 /* real retval in ufdio_copy.copy */
 416                 if (uffdio_copy.copy != -EEXIST)
 417                         fprintf(stderr, "UFFDIO_COPY error %Ld\n",
 418                                 uffdio_copy.copy), exit(1);
 419         } else if (uffdio_copy.copy != page_size) {
 420                 fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n",
 421                         uffdio_copy.copy), exit(1);
 422         } else {
 423                 if (test_uffdio_copy_eexist && retry) {
 424                         test_uffdio_copy_eexist = false;
 425                         retry_copy_page(ufd, &uffdio_copy, offset);
 426                 }
 427                 return 1;
 428         }
 429         return 0;
 430 }
 431
 432 static int copy_page_retry(int ufd, unsigned long offset)
 433 {
 434         return __copy_page(ufd, offset, true);
 435 }
 436
 437 static int copy_page(int ufd, unsigned long offset)
 438 {
 439         return __copy_page(ufd, offset, false);
 440 }
 441
 442 static void *uffd_poll_thread(void *arg)
 443 {
 444         unsigned long cpu = (unsigned long) arg;
 445         struct pollfd pollfd[2];
 446         struct uffd_msg msg;
 447         struct uffdio_register uffd_reg;
 448         int ret;
 449         unsigned long offset;
 450         char tmp_chr;
 451         unsigned long userfaults = 0;
 452
 453         pollfd[0].fd = uffd;
 454         pollfd[0].events = POLLIN;
 455         pollfd[1].fd = pipefd[cpu*2];
 456         pollfd[1].events = POLLIN;
 457
 458         for (;;) {
 459                 ret = poll(pollfd, 2, -1);
 460                 if (!ret)
 461                         fprintf(stderr, "poll error %d\n", ret), exit(1);
 462                 if (ret < 0)
 463                         perror("poll"), exit(1);
 464                 if (pollfd[1].revents & POLLIN) {
 465                         if (read(pollfd[1].fd, &tmp_chr, 1) != 1)
 466                                 fprintf(stderr, "read pipefd error\n"),
 467                                         exit(1);
 468                         break;
 469                 }
 470                 if (!(pollfd[0].revents & POLLIN))
 471                         fprintf(stderr, "pollfd[0].revents %d\n",
 472                                 pollfd[0].revents), exit(1);
 473                 ret = read(uffd, &msg, sizeof(msg));
 474                 if (ret < 0) {
 475                         if (errno == EAGAIN)
 476                                 continue;
 477                         perror("nonblocking read error"), exit(1);
 478                 }
 479                 switch (msg.event) {
 480                 default:
 481                         fprintf(stderr, "unexpected msg event %u\n",
 482                                 msg.event), exit(1);
 483                         break;
 484                 case UFFD_EVENT_PAGEFAULT:
 485                         if (msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
 486                                 fprintf(stderr, "unexpected write fault\n"), exit(1);
 487                         offset = (char *)(unsigned long)msg.arg.pagefault.address -
 488                                 area_dst;
 489                         offset &= ~(page_size-1);
 490                         if (copy_page(uffd, offset))
 491                                 userfaults++;
 492                         break;
 493                 case UFFD_EVENT_FORK:
 494                         close(uffd);
 495                         uffd = msg.arg.fork.ufd;
 496                         pollfd[0].fd = uffd;
 497                         break;
 498                 case UFFD_EVENT_REMOVE:
 499                         uffd_reg.range.start = msg.arg.remove.start;
 500                         uffd_reg.range.len = msg.arg.remove.end -
 501                                 msg.arg.remove.start;
 502                         if (ioctl(uffd, UFFDIO_UNREGISTER, &uffd_reg.range))
 503                                 fprintf(stderr, "remove failure\n"), exit(1);
 504                         break;
 505                 case UFFD_EVENT_REMAP:
 506                         area_dst = (char *)(unsigned long)msg.arg.remap.to;
 507                         break;
 508                 }
 509         }
 510         return (void *)userfaults;
 511 }
 512
 513 pthread_mutex_t uffd_read_mutex = PTHREAD_MUTEX_INITIALIZER;
 514
 515 static void *uffd_read_thread(void *arg)
 516 {
 517         unsigned long *this_cpu_userfaults;
 518         struct uffd_msg msg;
 519         unsigned long offset;
 520         int ret;
 521
 522         this_cpu_userfaults = (unsigned long *) arg;
 523         *this_cpu_userfaults = 0;
 524
 525         pthread_mutex_unlock(&uffd_read_mutex);
 526         /* from here cancellation is ok */
 527
 528         for (;;) {
 529                 ret = read(uffd, &msg, sizeof(msg));
 530                 if (ret != sizeof(msg)) {
 531                         if (ret < 0)
 532                                 perror("blocking read error"), exit(1);
 533                         else
 534                                 fprintf(stderr, "short read\n"), exit(1);
 535                 }
 536                 if (msg.event != UFFD_EVENT_PAGEFAULT)
 537                         fprintf(stderr, "unexpected msg event %u\n",
 538                                 msg.event), exit(1);
 539                 if (bounces & BOUNCE_VERIFY &&
 540                     msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
 541                         fprintf(stderr, "unexpected write fault\n"), exit(1);
 542                 offset = (char *)(unsigned long)msg.arg.pagefault.address -
 543                          area_dst;
 544                 offset &= ~(page_size-1);
 545                 if (copy_page(uffd, offset))
 546                         (*this_cpu_userfaults)++;
 547         }
 548         return (void *)NULL;
 549 }
 550
 551 static void *background_thread(void *arg)
 552 {
 553         unsigned long cpu = (unsigned long) arg;
 554         unsigned long page_nr;
 555
 556         for (page_nr = cpu * nr_pages_per_cpu;
 557              page_nr < (cpu+1) * nr_pages_per_cpu;
 558              page_nr++)
 559                 copy_page_retry(uffd, page_nr * page_size);
 560
 561         return NULL;
 562 }
 563
 564 static int stress(unsigned long *userfaults)
 565 {
 566         unsigned long cpu;
 567         pthread_t locking_threads[nr_cpus];
 568         pthread_t uffd_threads[nr_cpus];
 569         pthread_t background_threads[nr_cpus];
 570         void **_userfaults = (void **) userfaults;
 571
 572         finished = 0;
 573         for (cpu = 0; cpu < nr_cpus; cpu++) {
 574                 if (pthread_create(&locking_threads[cpu], &attr,
 575                                    locking_thread, (void *)cpu))
 576                         return 1;
 577                 if (bounces & BOUNCE_POLL) {
 578                         if (pthread_create(&uffd_threads[cpu], &attr,
 579                                            uffd_poll_thread, (void *)cpu))
 580                                 return 1;
 581                 } else {
 582                         if (pthread_create(&uffd_threads[cpu], &attr,
 583                                            uffd_read_thread,
 584                                            &_userfaults[cpu]))
 585                                 return 1;
 586                         pthread_mutex_lock(&uffd_read_mutex);
 587                 }
 588                 if (pthread_create(&background_threads[cpu], &attr,
 589                                    background_thread, (void *)cpu))
 590                         return 1;
 591         }
 592         for (cpu = 0; cpu < nr_cpus; cpu++)
 593                 if (pthread_join(background_threads[cpu], NULL))
 594                         return 1;
 595
 596         /*
 597          * Be strict and immediately zap area_src, the whole area has
 598          * been transferred already by the background treads. The
 599          * area_src could then be faulted in in a racy way by still
 600          * running uffdio_threads reading zeropages after we zapped
 601          * area_src (but they're guaranteed to get -EEXIST from
 602          * UFFDIO_COPY without writing zero pages into area_dst
 603          * because the background threads already completed).
 604          */
 605         if (uffd_test_ops->release_pages(area_src))
 606                 return 1;
 607
 608         for (cpu = 0; cpu < nr_cpus; cpu++) {
 609                 char c;
 610                 if (bounces & BOUNCE_POLL) {
 611                         if (write(pipefd[cpu*2+1], &c, 1) != 1) {
 612                                 fprintf(stderr, "pipefd write error\n");
 613                                 return 1;
 614                         }
 615                         if (pthread_join(uffd_threads[cpu], &_userfaults[cpu]))
 616                                 return 1;
 617                 } else {
 618                         if (pthread_cancel(uffd_threads[cpu]))
 619                                 return 1;
 620                         if (pthread_join(uffd_threads[cpu], NULL))
 621                                 return 1;
 622                 }
 623         }
 624
 625         finished = 1;
 626         for (cpu = 0; cpu < nr_cpus; cpu++)
 627                 if (pthread_join(locking_threads[cpu], NULL))
 628                         return 1;
 629
 630         return 0;
 631 }
 632
 633 static int userfaultfd_open(int features)
 634 {
 635         struct uffdio_api uffdio_api;
 636
 637         uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
 638         if (uffd < 0) {
 639                 fprintf(stderr,
 640                         "userfaultfd syscall not available in this kernel\n");
 641                 return 1;
 642         }
 643         uffd_flags = fcntl(uffd, F_GETFD, NULL);
 644
 645         uffdio_api.api = UFFD_API;
 646         uffdio_api.features = features;
 647         if (ioctl(uffd, UFFDIO_API, &uffdio_api)) {
 648                 fprintf(stderr, "UFFDIO_API\n");
 649                 return 1;
 650         }
 651         if (uffdio_api.api != UFFD_API) {
 652                 fprintf(stderr, "UFFDIO_API error %Lu\n", uffdio_api.api);
 653                 return 1;
 654         }
 655
 656         return 0;
 657 }
 658
 659 sigjmp_buf jbuf, *sigbuf;
 660
 661 static void sighndl(int sig, siginfo_t *siginfo, void *ptr)
 662 {
 663         if (sig == SIGBUS) {
 664                 if (sigbuf)
 665                         siglongjmp(*sigbuf, 1);
 666                 abort();
 667         }
 668 }
 669
 670 /*
 671  * For non-cooperative userfaultfd test we fork() a process that will
 672  * generate pagefaults, will mremap the area monitored by the
 673  * userfaultfd and at last this process will release the monitored
 674  * area.
 675  * For the anonymous and shared memory the area is divided into two
 676  * parts, the first part is accessed before mremap, and the second
 677  * part is accessed after mremap. Since hugetlbfs does not support
 678  * mremap, the entire monitored area is accessed in a single pass for
 679  * HUGETLB_TEST.
 680  * The release of the pages currently generates event for shmem and
 681  * anonymous memory (UFFD_EVENT_REMOVE), hence it is not checked
 682  * for hugetlb.
 683  * For signal test(UFFD_FEATURE_SIGBUS), signal_test = 1, we register
 684  * monitored area, generate pagefaults and test that signal is delivered.
 685  * Use UFFDIO_COPY to allocate missing page and retry. For signal_test = 2
 686  * test robustness use case - we release monitored area, fork a process
 687  * that will generate pagefaults and verify signal is generated.
 688  * This also tests UFFD_FEATURE_EVENT_FORK event along with the signal
 689  * feature. Using monitor thread, verify no userfault events are generated.
 690  */
 691 static int faulting_process(int signal_test)
 692 {
 693         unsigned long nr;
 694         unsigned long long count;
 695         unsigned long split_nr_pages;
 696         unsigned long lastnr;
 697         struct sigaction act;
 698         unsigned long signalled = 0;
 699
 700         if (test_type != TEST_HUGETLB)
 701                 split_nr_pages = (nr_pages + 1) / 2;
 702         else
 703                 split_nr_pages = nr_pages;
 704
 705         if (signal_test) {
 706                 sigbuf = &jbuf;
 707                 memset(&act, 0, sizeof(act));
 708                 act.sa_sigaction = sighndl;
 709                 act.sa_flags = SA_SIGINFO;
 710                 if (sigaction(SIGBUS, &act, 0)) {
 711                         perror("sigaction");
 712                         return 1;
 713                 }
 714                 lastnr = (unsigned long)-1;
 715         }
 716
 717         for (nr = 0; nr < split_nr_pages; nr++) {
 718                 if (signal_test) {
 719                         if (sigsetjmp(*sigbuf, 1) != 0) {
 720                                 if (nr == lastnr) {
 721                                         fprintf(stderr, "Signal repeated\n");
 722                                         return 1;
 723                                 }
 724
 725                                 lastnr = nr;
 726                                 if (signal_test == 1) {
 727                                         if (copy_page(uffd, nr * page_size))
 728                                                 signalled++;
 729                                 } else {
 730                                         signalled++;
 731                                         continue;
 732                                 }
 733                         }
 734                 }
 735
 736                 count = *area_count(area_dst, nr);
 737                 if (count != count_verify[nr]) {
 738                         fprintf(stderr,
 739                                 "nr %lu memory corruption %Lu %Lu\n",
 740                                 nr, count,
 741                                 count_verify[nr]), exit(1);
 742                 }
 743         }
 744
 745         if (signal_test)
 746                 return signalled != split_nr_pages;
 747
 748         if (test_type == TEST_HUGETLB)
 749                 return 0;
 750
 751         area_dst = mremap(area_dst, nr_pages * page_size,  nr_pages * page_size,
 752                           MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
 753         if (area_dst == MAP_FAILED)
 754                 perror("mremap"), exit(1);
 755
 756         for (; nr < nr_pages; nr++) {
 757                 count = *area_count(area_dst, nr);
 758                 if (count != count_verify[nr]) {
 759                         fprintf(stderr,
 760                                 "nr %lu memory corruption %Lu %Lu\n",
 761                                 nr, count,
 762                                 count_verify[nr]), exit(1);
 763                 }
 764         }
 765
 766         if (uffd_test_ops->release_pages(area_dst))
 767                 return 1;
 768
 769         for (nr = 0; nr < nr_pages; nr++) {
 770                 if (my_bcmp(area_dst + nr * page_size, zeropage, page_size))
 771                         fprintf(stderr, "nr %lu is not zero\n", nr), exit(1);
 772         }
 773
 774         return 0;
 775 }
 776
 777 static void retry_uffdio_zeropage(int ufd,
 778                                   struct uffdio_zeropage *uffdio_zeropage,
 779                                   unsigned long offset)
 780 {
 781         uffd_test_ops->alias_mapping(&uffdio_zeropage->range.start,
 782                                      uffdio_zeropage->range.len,
 783                                      offset);
 784         if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
 785                 if (uffdio_zeropage->zeropage != -EEXIST)
 786                         fprintf(stderr, "UFFDIO_ZEROPAGE retry error %Ld\n",
 787                                 uffdio_zeropage->zeropage), exit(1);
 788         } else {
 789                 fprintf(stderr, "UFFDIO_ZEROPAGE retry unexpected %Ld\n",
 790                         uffdio_zeropage->zeropage), exit(1);
 791         }
 792 }
 793
 794 static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
 795 {
 796         struct uffdio_zeropage uffdio_zeropage;
 797         int ret;
 798         unsigned long has_zeropage;
 799
 800         has_zeropage = uffd_test_ops->expected_ioctls & (1 << _UFFDIO_ZEROPAGE);
 801
 802         if (offset >= nr_pages * page_size)
 803                 fprintf(stderr, "unexpected offset %lu\n",
 804                         offset), exit(1);
 805         uffdio_zeropage.range.start = (unsigned long) area_dst + offset;
 806         uffdio_zeropage.range.len = page_size;
 807         uffdio_zeropage.mode = 0;
 808         ret = ioctl(ufd, UFFDIO_ZEROPAGE, &uffdio_zeropage);
 809         if (ret) {
 810                 /* real retval in ufdio_zeropage.zeropage */
 811                 if (has_zeropage) {
 812                         if (uffdio_zeropage.zeropage == -EEXIST)
 813                                 fprintf(stderr, "UFFDIO_ZEROPAGE -EEXIST\n"),
 814                                         exit(1);
 815                         else
 816                                 fprintf(stderr, "UFFDIO_ZEROPAGE error %Ld\n",
 817                                         uffdio_zeropage.zeropage), exit(1);
 818                 } else {
 819                         if (uffdio_zeropage.zeropage != -EINVAL)
 820                                 fprintf(stderr,
 821                                         "UFFDIO_ZEROPAGE not -EINVAL %Ld\n",
 822                                         uffdio_zeropage.zeropage), exit(1);
 823                 }
 824         } else if (has_zeropage) {
 825                 if (uffdio_zeropage.zeropage != page_size) {
 826                         fprintf(stderr, "UFFDIO_ZEROPAGE unexpected %Ld\n",
 827                                 uffdio_zeropage.zeropage), exit(1);
 828                 } else {
 829                         if (test_uffdio_zeropage_eexist && retry) {
 830                                 test_uffdio_zeropage_eexist = false;
 831                                 retry_uffdio_zeropage(ufd, &uffdio_zeropage,
 832                                                       offset);
 833                         }
 834                         return 1;
 835                 }
 836         } else {
 837                 fprintf(stderr,
 838                         "UFFDIO_ZEROPAGE succeeded %Ld\n",
 839                         uffdio_zeropage.zeropage), exit(1);
 840         }
 841
 842         return 0;
 843 }
 844
 845 static int uffdio_zeropage(int ufd, unsigned long offset)
 846 {
 847         return __uffdio_zeropage(ufd, offset, false);
 848 }
 849
 850 /* exercise UFFDIO_ZEROPAGE */
 851 static int userfaultfd_zeropage_test(void)
 852 {
 853         struct uffdio_register uffdio_register;
 854         unsigned long expected_ioctls;
 855
 856         printf("testing UFFDIO_ZEROPAGE: ");
 857         fflush(stdout);
 858
 859         if (uffd_test_ops->release_pages(area_dst))
 860                 return 1;
 861
 862         if (userfaultfd_open(0) < 0)
 863                 return 1;
 864         uffdio_register.range.start = (unsigned long) area_dst;
 865         uffdio_register.range.len = nr_pages * page_size;
 866         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 867         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
 868                 fprintf(stderr, "register failure\n"), exit(1);
 869
 870         expected_ioctls = uffd_test_ops->expected_ioctls;
 871         if ((uffdio_register.ioctls & expected_ioctls) !=
 872             expected_ioctls)
 873                 fprintf(stderr,
 874                         "unexpected missing ioctl for anon memory\n"),
 875                         exit(1);
 876
 877         if (uffdio_zeropage(uffd, 0)) {
 878                 if (my_bcmp(area_dst, zeropage, page_size))
 879                         fprintf(stderr, "zeropage is not zero\n"), exit(1);
 880         }
 881
 882         close(uffd);
 883         printf("done.\n");
 884         return 0;
 885 }
 886
 887 static int userfaultfd_events_test(void)
 888 {
 889         struct uffdio_register uffdio_register;
 890         unsigned long expected_ioctls;
 891         unsigned long userfaults;
 892         pthread_t uffd_mon;
 893         int err, features;
 894         pid_t pid;
 895         char c;
 896
 897         printf("testing events (fork, remap, remove): ");
 898         fflush(stdout);
 899
 900         if (uffd_test_ops->release_pages(area_dst))
 901                 return 1;
 902
 903         features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
 904                 UFFD_FEATURE_EVENT_REMOVE;
 905         if (userfaultfd_open(features) < 0)
 906                 return 1;
 907         fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
 908
 909         uffdio_register.range.start = (unsigned long) area_dst;
 910         uffdio_register.range.len = nr_pages * page_size;
 911         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 912         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
 913                 fprintf(stderr, "register failure\n"), exit(1);
 914
 915         expected_ioctls = uffd_test_ops->expected_ioctls;
 916         if ((uffdio_register.ioctls & expected_ioctls) !=
 917             expected_ioctls)
 918                 fprintf(stderr,
 919                         "unexpected missing ioctl for anon memory\n"),
 920                         exit(1);
 921
 922         if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, NULL))
 923                 perror("uffd_poll_thread create"), exit(1);
 924
 925         pid = fork();
 926         if (pid < 0)
 927                 perror("fork"), exit(1);
 928
 929         if (!pid)
 930                 return faulting_process(0);
 931
 932         waitpid(pid, &err, 0);
 933         if (err)
 934                 fprintf(stderr, "faulting process failed\n"), exit(1);
 935
 936         if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
 937                 perror("pipe write"), exit(1);
 938         if (pthread_join(uffd_mon, (void **)&userfaults))
 939                 return 1;
 940
 941         close(uffd);
 942         printf("userfaults: %ld\n", userfaults);
 943
 944         return userfaults != nr_pages;
 945 }
 946
 947 static int userfaultfd_sig_test(void)
 948 {
 949         struct uffdio_register uffdio_register;
 950         unsigned long expected_ioctls;
 951         unsigned long userfaults;
 952         pthread_t uffd_mon;
 953         int err, features;
 954         pid_t pid;
 955         char c;
 956
 957         printf("testing signal delivery: ");
 958         fflush(stdout);
 959
 960         if (uffd_test_ops->release_pages(area_dst))
 961                 return 1;
 962
 963         features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
 964         if (userfaultfd_open(features) < 0)
 965                 return 1;
 966         fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
 967
 968         uffdio_register.range.start = (unsigned long) area_dst;
 969         uffdio_register.range.len = nr_pages * page_size;
 970         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 971         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
 972                 fprintf(stderr, "register failure\n"), exit(1);
 973
 974         expected_ioctls = uffd_test_ops->expected_ioctls;
 975         if ((uffdio_register.ioctls & expected_ioctls) !=
 976             expected_ioctls)
 977                 fprintf(stderr,
 978                         "unexpected missing ioctl for anon memory\n"),
 979                         exit(1);
 980
 981         if (faulting_process(1))
 982                 fprintf(stderr, "faulting process failed\n"), exit(1);
 983
 984         if (uffd_test_ops->release_pages(area_dst))
 985                 return 1;
 986
 987         if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, NULL))
 988                 perror("uffd_poll_thread create"), exit(1);
 989
 990         pid = fork();
 991         if (pid < 0)
 992                 perror("fork"), exit(1);
 993
 994         if (!pid)
 995                 exit(faulting_process(2));
 996
 997         waitpid(pid, &err, 0);
 998         if (err)
 999                 fprintf(stderr, "faulting process failed\n"), exit(1);
1000
1001         if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
1002                 perror("pipe write"), exit(1);
1003         if (pthread_join(uffd_mon, (void **)&userfaults))
1004                 return 1;
1005
1006         printf("done.\n");
1007         if (userfaults)
1008                 fprintf(stderr, "Signal test failed, userfaults: %ld\n",
1009                         userfaults);
1010         close(uffd);
1011         return userfaults != 0;
1012 }
1013 static int userfaultfd_stress(void)
1014 {
1015         void *area;
1016         char *tmp_area;
1017         unsigned long nr;
1018         struct uffdio_register uffdio_register;
1019         unsigned long cpu;
1020         int err;
1021         unsigned long userfaults[nr_cpus];
1022
1023         uffd_test_ops->allocate_area((void **)&area_src);
1024         if (!area_src)
1025                 return 1;
1026         uffd_test_ops->allocate_area((void **)&area_dst);
1027         if (!area_dst)
1028                 return 1;
1029
1030         if (userfaultfd_open(0) < 0)
1031                 return 1;
1032
1033         count_verify = malloc(nr_pages * sizeof(unsigned long long));
1034         if (!count_verify) {
1035                 perror("count_verify");
1036                 return 1;
1037         }
1038
1039         for (nr = 0; nr < nr_pages; nr++) {
1040                 *area_mutex(area_src, nr) = (pthread_mutex_t)
1041                         PTHREAD_MUTEX_INITIALIZER;
1042                 count_verify[nr] = *area_count(area_src, nr) = 1;
1043                 /*
1044                  * In the transition between 255 to 256, powerpc will
1045                  * read out of order in my_bcmp and see both bytes as
1046                  * zero, so leave a placeholder below always non-zero
1047                  * after the count, to avoid my_bcmp to trigger false
1048                  * positives.
1049                  */
1050                 *(area_count(area_src, nr) + 1) = 1;
1051         }
1052
1053         pipefd = malloc(sizeof(int) * nr_cpus * 2);
1054         if (!pipefd) {
1055                 perror("pipefd");
1056                 return 1;
1057         }
1058         for (cpu = 0; cpu < nr_cpus; cpu++) {
1059                 if (pipe2(&pipefd[cpu*2], O_CLOEXEC | O_NONBLOCK)) {
1060                         perror("pipe");
1061                         return 1;
1062                 }
1063         }
1064
1065         if (posix_memalign(&area, page_size, page_size)) {
1066                 fprintf(stderr, "out of memory\n");
1067                 return 1;
1068         }
1069         zeropage = area;
1070         bzero(zeropage, page_size);
1071
1072         pthread_mutex_lock(&uffd_read_mutex);
1073
1074         pthread_attr_init(&attr);
1075         pthread_attr_setstacksize(&attr, 16*1024*1024);
1076
1077         err = 0;
1078         while (bounces--) {
1079                 unsigned long expected_ioctls;
1080
1081                 printf("bounces: %d, mode:", bounces);
1082                 if (bounces & BOUNCE_RANDOM)
1083                         printf(" rnd");
1084                 if (bounces & BOUNCE_RACINGFAULTS)
1085                         printf(" racing");
1086                 if (bounces & BOUNCE_VERIFY)
1087                         printf(" ver");
1088                 if (bounces & BOUNCE_POLL)
1089                         printf(" poll");
1090                 printf(", ");
1091                 fflush(stdout);
1092
1093                 if (bounces & BOUNCE_POLL)
1094                         fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
1095                 else
1096                         fcntl(uffd, F_SETFL, uffd_flags & ~O_NONBLOCK);
1097
1098                 /* register */
1099                 uffdio_register.range.start = (unsigned long) area_dst;
1100                 uffdio_register.range.len = nr_pages * page_size;
1101                 uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
1102                 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
1103                         fprintf(stderr, "register failure\n");
1104                         return 1;
1105                 }
1106                 expected_ioctls = uffd_test_ops->expected_ioctls;
1107                 if ((uffdio_register.ioctls & expected_ioctls) !=
1108                     expected_ioctls) {
1109                         fprintf(stderr,
1110                                 "unexpected missing ioctl for anon memory\n");
1111                         return 1;
1112                 }
1113
1114                 if (area_dst_alias) {
1115                         uffdio_register.range.start = (unsigned long)
1116                                 area_dst_alias;
1117                         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
1118                                 fprintf(stderr, "register failure alias\n");
1119                                 return 1;
1120                         }
1121                 }
1122
1123                 /*
1124                  * The madvise done previously isn't enough: some
1125                  * uffd_thread could have read userfaults (one of
1126                  * those already resolved by the background thread)
1127                  * and it may be in the process of calling
1128                  * UFFDIO_COPY. UFFDIO_COPY will read the zapped
1129                  * area_src and it would map a zero page in it (of
1130                  * course such a UFFDIO_COPY is perfectly safe as it'd
1131                  * return -EEXIST). The problem comes at the next
1132                  * bounce though: that racing UFFDIO_COPY would
1133                  * generate zeropages in the area_src, so invalidating
1134                  * the previous MADV_DONTNEED. Without this additional
1135                  * MADV_DONTNEED those zeropages leftovers in the
1136                  * area_src would lead to -EEXIST failure during the
1137                  * next bounce, effectively leaving a zeropage in the
1138                  * area_dst.
1139                  *
1140                  * Try to comment this out madvise to see the memory
1141                  * corruption being caught pretty quick.
1142                  *
1143                  * khugepaged is also inhibited to collapse THP after
1144                  * MADV_DONTNEED only after the UFFDIO_REGISTER, so it's
1145                  * required to MADV_DONTNEED here.
1146                  */
1147                 if (uffd_test_ops->release_pages(area_dst))
1148                         return 1;
1149
1150                 /* bounce pass */
1151                 if (stress(userfaults))
1152                         return 1;
1153
1154                 /* unregister */
1155                 if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range)) {
1156                         fprintf(stderr, "unregister failure\n");
1157                         return 1;
1158                 }
1159                 if (area_dst_alias) {
1160                         uffdio_register.range.start = (unsigned long) area_dst;
1161                         if (ioctl(uffd, UFFDIO_UNREGISTER,
1162                                   &uffdio_register.range)) {
1163                                 fprintf(stderr, "unregister failure alias\n");
1164                                 return 1;
1165                         }
1166                 }
1167
1168                 /* verification */
1169                 if (bounces & BOUNCE_VERIFY) {
1170                         for (nr = 0; nr < nr_pages; nr++) {
1171                                 if (*area_count(area_dst, nr) != count_verify[nr]) {
1172                                         fprintf(stderr,
1173                                                 "error area_count %Lu %Lu %lu\n",
1174                                                 *area_count(area_src, nr),
1175                                                 count_verify[nr],
1176                                                 nr);
1177                                         err = 1;
1178                                         bounces = 0;
1179                                 }
1180                         }
1181                 }
1182
1183                 /* prepare next bounce */
1184                 tmp_area = area_src;
1185                 area_src = area_dst;
1186                 area_dst = tmp_area;
1187
1188                 tmp_area = area_src_alias;
1189                 area_src_alias = area_dst_alias;
1190                 area_dst_alias = tmp_area;
1191
1192                 printf("userfaults:");
1193                 for (cpu = 0; cpu < nr_cpus; cpu++)
1194                         printf(" %lu", userfaults[cpu]);
1195                 printf("\n");
1196         }
1197
1198         if (err)
1199                 return err;
1200
1201         close(uffd);
1202         return userfaultfd_zeropage_test() || userfaultfd_sig_test()
1203                 || userfaultfd_events_test();
1204 }
1205
1206 /*
1207  * Copied from mlock2-tests.c
1208  */
1209 unsigned long default_huge_page_size(void)
1210 {
1211         unsigned long hps = 0;
1212         char *line = NULL;
1213         size_t linelen = 0;
1214         FILE *f = fopen("/proc/meminfo", "r");
1215
1216         if (!f)
1217                 return 0;
1218         while (getline(&line, &linelen, f) > 0) {
1219                 if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
1220                         hps <<= 10;
1221                         break;
1222                 }
1223         }
1224
1225         free(line);
1226         fclose(f);
1227         return hps;
1228 }
1229
1230 static void set_test_type(const char *type)
1231 {
1232         if (!strcmp(type, "anon")) {
1233                 test_type = TEST_ANON;
1234                 uffd_test_ops = &anon_uffd_test_ops;
1235         } else if (!strcmp(type, "hugetlb")) {
1236                 test_type = TEST_HUGETLB;
1237                 uffd_test_ops = &hugetlb_uffd_test_ops;
1238         } else if (!strcmp(type, "hugetlb_shared")) {
1239                 map_shared = true;
1240                 test_type = TEST_HUGETLB;
1241                 uffd_test_ops = &hugetlb_uffd_test_ops;
1242         } else if (!strcmp(type, "shmem")) {
1243                 map_shared = true;
1244                 test_type = TEST_SHMEM;
1245                 uffd_test_ops = &shmem_uffd_test_ops;
1246         } else {
1247                 fprintf(stderr, "Unknown test type: %s\n", type), exit(1);
1248         }
1249
1250         if (test_type == TEST_HUGETLB)
1251                 page_size = default_huge_page_size();
1252         else
1253                 page_size = sysconf(_SC_PAGE_SIZE);
1254
1255         if (!page_size)
1256                 fprintf(stderr, "Unable to determine page size\n"),
1257                                 exit(2);
1258         if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) * 2
1259             > page_size)
1260                 fprintf(stderr, "Impossible to run this test\n"), exit(2);
1261 }
1262
1263 static void sigalrm(int sig)
1264 {
1265         if (sig != SIGALRM)
1266                 abort();
1267         test_uffdio_copy_eexist = true;
1268         test_uffdio_zeropage_eexist = true;
1269         alarm(ALARM_INTERVAL_SECS);
1270 }
1271
1272 int main(int argc, char **argv)
1273 {
1274         if (argc < 4)
1275                 fprintf(stderr, "Usage: <test type> <MiB> <bounces> [hugetlbfs_file]\n"),
1276                                 exit(1);
1277
1278         if (signal(SIGALRM, sigalrm) == SIG_ERR)
1279                 fprintf(stderr, "failed to arm SIGALRM"), exit(1);
1280         alarm(ALARM_INTERVAL_SECS);
1281
1282         set_test_type(argv[1]);
1283
1284         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
1285         nr_pages_per_cpu = atol(argv[2]) * 1024*1024 / page_size /
1286                 nr_cpus;
1287         if (!nr_pages_per_cpu) {
1288                 fprintf(stderr, "invalid MiB\n");
1289                 fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
1290         }
1291
1292         bounces = atoi(argv[3]);
1293         if (bounces <= 0) {
1294                 fprintf(stderr, "invalid bounces\n");
1295                 fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
1296         }
1297         nr_pages = nr_pages_per_cpu * nr_cpus;
1298
1299         if (test_type == TEST_HUGETLB) {
1300                 if (argc < 5)
1301                         fprintf(stderr, "Usage: hugetlb <MiB> <bounces> <hugetlbfs_file>\n"),
1302                                 exit(1);
1303                 huge_fd = open(argv[4], O_CREAT | O_RDWR, 0755);
1304                 if (huge_fd < 0) {
1305                         fprintf(stderr, "Open of %s failed", argv[3]);
1306                         perror("open");
1307                         exit(1);
1308                 }
1309                 if (ftruncate(huge_fd, 0)) {
1310                         fprintf(stderr, "ftruncate %s to size 0 failed", argv[3]);
1311                         perror("ftruncate");
1312                         exit(1);
1313                 }
1314         }
1315         printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
1316                nr_pages, nr_pages_per_cpu);
1317         return userfaultfd_stress();
1318 }
1319
1320 #else /* __NR_userfaultfd */
1321
1322 #warning "missing __NR_userfaultfd definition"
1323
1324 int main(void)
1325 {
1326         printf("skip: Skipping userfaultfd test (missing __NR_userfaultfd)\n");
1327         return KSFT_SKIP;
1328 }
1329
1330 #endif /* __NR_userfaultfd */