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         *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 133                            MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 134         if (*alloc_area == MAP_FAILED) {
 135                 fprintf(stderr, "mmap of anonymous memory failed");
 136                 *alloc_area = NULL;
 137         }
 138 }
 139
 140 static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset)
 141 {
 142 }
 143
 144 /* HugeTLB memory */
 145 static int hugetlb_release_pages(char *rel_area)
 146 {
 147         int ret = 0;
 148
 149         if (fallocate(huge_fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
 150                                 rel_area == huge_fd_off0 ? 0 :
 151                                 nr_pages * page_size,
 152                                 nr_pages * page_size)) {
 153                 perror("fallocate");
 154                 ret = 1;
 155         }
 156
 157         return ret;
 158 }
 159
 160
 161 static void hugetlb_allocate_area(void **alloc_area)
 162 {
 163         void *area_alias = NULL;
 164         char **alloc_area_alias;
 165         *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 166                            (map_shared ? MAP_SHARED : MAP_PRIVATE) |
 167                            MAP_HUGETLB,
 168                            huge_fd, *alloc_area == area_src ? 0 :
 169                            nr_pages * page_size);
 170         if (*alloc_area == MAP_FAILED) {
 171                 fprintf(stderr, "mmap of hugetlbfs file failed\n");
 172                 *alloc_area = NULL;
 173         }
 174
 175         if (map_shared) {
 176                 area_alias = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 177                                   MAP_SHARED | MAP_HUGETLB,
 178                                   huge_fd, *alloc_area == area_src ? 0 :
 179                                   nr_pages * page_size);
 180                 if (area_alias == MAP_FAILED) {
 181                         if (munmap(*alloc_area, nr_pages * page_size) < 0)
 182                                 perror("hugetlb munmap"), exit(1);
 183                         *alloc_area = NULL;
 184                         return;
 185                 }
 186         }
 187         if (*alloc_area == area_src) {
 188                 huge_fd_off0 = *alloc_area;
 189                 alloc_area_alias = &area_src_alias;
 190         } else {
 191                 alloc_area_alias = &area_dst_alias;
 192         }
 193         if (area_alias)
 194                 *alloc_area_alias = area_alias;
 195 }
 196
 197 static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset)
 198 {
 199         if (!map_shared)
 200                 return;
 201         /*
 202          * We can't zap just the pagetable with hugetlbfs because
 203          * MADV_DONTEED won't work. So exercise -EEXIST on a alias
 204          * mapping where the pagetables are not established initially,
 205          * this way we'll exercise the -EEXEC at the fs level.
 206          */
 207         *start = (unsigned long) area_dst_alias + offset;
 208 }
 209
 210 /* Shared memory */
 211 static int shmem_release_pages(char *rel_area)
 212 {
 213         int ret = 0;
 214
 215         if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE)) {
 216                 perror("madvise");
 217                 ret = 1;
 218         }
 219
 220         return ret;
 221 }
 222
 223 static void shmem_allocate_area(void **alloc_area)
 224 {
 225         *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 226                            MAP_ANONYMOUS | MAP_SHARED, -1, 0);
 227         if (*alloc_area == MAP_FAILED) {
 228                 fprintf(stderr, "shared memory mmap failed\n");
 229                 *alloc_area = NULL;
 230         }
 231 }
 232
 233 struct uffd_test_ops {
 234         unsigned long expected_ioctls;
 235         void (*allocate_area)(void **alloc_area);
 236         int (*release_pages)(char *rel_area);
 237         void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset);
 238 };
 239
 240 #define ANON_EXPECTED_IOCTLS            ((1 << _UFFDIO_WAKE) | \
 241                                          (1 << _UFFDIO_COPY) | \
 242                                          (1 << _UFFDIO_ZEROPAGE))
 243
 244 static struct uffd_test_ops anon_uffd_test_ops = {
 245         .expected_ioctls = ANON_EXPECTED_IOCTLS,
 246         .allocate_area  = anon_allocate_area,
 247         .release_pages  = anon_release_pages,
 248         .alias_mapping = noop_alias_mapping,
 249 };
 250
 251 static struct uffd_test_ops shmem_uffd_test_ops = {
 252         .expected_ioctls = ANON_EXPECTED_IOCTLS,
 253         .allocate_area  = shmem_allocate_area,
 254         .release_pages  = shmem_release_pages,
 255         .alias_mapping = noop_alias_mapping,
 256 };
 257
 258 static struct uffd_test_ops hugetlb_uffd_test_ops = {
 259         .expected_ioctls = UFFD_API_RANGE_IOCTLS_BASIC,
 260         .allocate_area  = hugetlb_allocate_area,
 261         .release_pages  = hugetlb_release_pages,
 262         .alias_mapping = hugetlb_alias_mapping,
 263 };
 264
 265 static struct uffd_test_ops *uffd_test_ops;
 266
 267 static int my_bcmp(char *str1, char *str2, size_t n)
 268 {
 269         unsigned long i;
 270         for (i = 0; i < n; i++)
 271                 if (str1[i] != str2[i])
 272                         return 1;
 273         return 0;
 274 }
 275
 276 static void *locking_thread(void *arg)
 277 {
 278         unsigned long cpu = (unsigned long) arg;
 279         struct random_data rand;
 280         unsigned long page_nr = *(&(page_nr)); /* uninitialized warning */
 281         int32_t rand_nr;
 282         unsigned long long count;
 283         char randstate[64];
 284         unsigned int seed;
 285         time_t start;
 286
 287         if (bounces & BOUNCE_RANDOM) {
 288                 seed = (unsigned int) time(NULL) - bounces;
 289                 if (!(bounces & BOUNCE_RACINGFAULTS))
 290                         seed += cpu;
 291                 bzero(&rand, sizeof(rand));
 292                 bzero(&randstate, sizeof(randstate));
 293                 if (initstate_r(seed, randstate, sizeof(randstate), &rand))
 294                         fprintf(stderr, "srandom_r error\n"), exit(1);
 295         } else {
 296                 page_nr = -bounces;
 297                 if (!(bounces & BOUNCE_RACINGFAULTS))
 298                         page_nr += cpu * nr_pages_per_cpu;
 299         }
 300
 301         while (!finished) {
 302                 if (bounces & BOUNCE_RANDOM) {
 303                         if (random_r(&rand, &rand_nr))
 304                                 fprintf(stderr, "random_r 1 error\n"), exit(1);
 305                         page_nr = rand_nr;
 306                         if (sizeof(page_nr) > sizeof(rand_nr)) {
 307                                 if (random_r(&rand, &rand_nr))
 308                                         fprintf(stderr, "random_r 2 error\n"), exit(1);
 309                                 page_nr |= (((unsigned long) rand_nr) << 16) <<
 310                                            16;
 311                         }
 312                 } else
 313                         page_nr += 1;
 314                 page_nr %= nr_pages;
 315
 316                 start = time(NULL);
 317                 if (bounces & BOUNCE_VERIFY) {
 318                         count = *area_count(area_dst, page_nr);
 319                         if (!count)
 320                                 fprintf(stderr,
 321                                         "page_nr %lu wrong count %Lu %Lu\n",
 322                                         page_nr, count,
 323                                         count_verify[page_nr]), exit(1);
 324
 325
 326                         /*
 327                          * We can't use bcmp (or memcmp) because that
 328                          * returns 0 erroneously if the memory is
 329                          * changing under it (even if the end of the
 330                          * page is never changing and always
 331                          * different).
 332                          */
 333 #if 1
 334                         if (!my_bcmp(area_dst + page_nr * page_size, zeropage,
 335                                      page_size))
 336                                 fprintf(stderr,
 337                                         "my_bcmp page_nr %lu wrong count %Lu %Lu\n",
 338                                         page_nr, count,
 339                                         count_verify[page_nr]), exit(1);
 340 #else
 341                         unsigned long loops;
 342
 343                         loops = 0;
 344                         /* uncomment the below line to test with mutex */
 345                         /* pthread_mutex_lock(area_mutex(area_dst, page_nr)); */
 346                         while (!bcmp(area_dst + page_nr * page_size, zeropage,
 347                                      page_size)) {
 348                                 loops += 1;
 349                                 if (loops > 10)
 350                                         break;
 351                         }
 352                         /* uncomment below line to test with mutex */
 353                         /* pthread_mutex_unlock(area_mutex(area_dst, page_nr)); */
 354                         if (loops) {
 355                                 fprintf(stderr,
 356                                         "page_nr %lu all zero thread %lu %p %lu\n",
 357                                         page_nr, cpu, area_dst + page_nr * page_size,
 358                                         loops);
 359                                 if (loops > 10)
 360                                         exit(1);
 361                         }
 362 #endif
 363                 }
 364
 365                 pthread_mutex_lock(area_mutex(area_dst, page_nr));
 366                 count = *area_count(area_dst, page_nr);
 367                 if (count != count_verify[page_nr]) {
 368                         fprintf(stderr,
 369                                 "page_nr %lu memory corruption %Lu %Lu\n",
 370                                 page_nr, count,
 371                                 count_verify[page_nr]), exit(1);
 372                 }
 373                 count++;
 374                 *area_count(area_dst, page_nr) = count_verify[page_nr] = count;
 375                 pthread_mutex_unlock(area_mutex(area_dst, page_nr));
 376
 377                 if (time(NULL) - start > 1)
 378                         fprintf(stderr,
 379                                 "userfault too slow %ld "
 380                                 "possible false positive with overcommit\n",
 381                                 time(NULL) - start);
 382         }
 383
 384         return NULL;
 385 }
 386
 387 static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
 388                             unsigned long offset)
 389 {
 390         uffd_test_ops->alias_mapping(&uffdio_copy->dst,
 391                                      uffdio_copy->len,
 392                                      offset);
 393         if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) {
 394                 /* real retval in ufdio_copy.copy */
 395                 if (uffdio_copy->copy != -EEXIST)
 396                         fprintf(stderr, "UFFDIO_COPY retry error %Ld\n",
 397                                 uffdio_copy->copy), exit(1);
 398         } else {
 399                 fprintf(stderr, "UFFDIO_COPY retry unexpected %Ld\n",
 400                         uffdio_copy->copy), exit(1);
 401         }
 402 }
 403
 404 static int __copy_page(int ufd, unsigned long offset, bool retry)
 405 {
 406         struct uffdio_copy uffdio_copy;
 407
 408         if (offset >= nr_pages * page_size)
 409                 fprintf(stderr, "unexpected offset %lu\n",
 410                         offset), exit(1);
 411         uffdio_copy.dst = (unsigned long) area_dst + offset;
 412         uffdio_copy.src = (unsigned long) area_src + offset;
 413         uffdio_copy.len = page_size;
 414         uffdio_copy.mode = 0;
 415         uffdio_copy.copy = 0;
 416         if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
 417                 /* real retval in ufdio_copy.copy */
 418                 if (uffdio_copy.copy != -EEXIST)
 419                         fprintf(stderr, "UFFDIO_COPY error %Ld\n",
 420                                 uffdio_copy.copy), exit(1);
 421         } else if (uffdio_copy.copy != page_size) {
 422                 fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n",
 423                         uffdio_copy.copy), exit(1);
 424         } else {
 425                 if (test_uffdio_copy_eexist && retry) {
 426                         test_uffdio_copy_eexist = false;
 427                         retry_copy_page(ufd, &uffdio_copy, offset);
 428                 }
 429                 return 1;
 430         }
 431         return 0;
 432 }
 433
 434 static int copy_page_retry(int ufd, unsigned long offset)
 435 {
 436         return __copy_page(ufd, offset, true);
 437 }
 438
 439 static int copy_page(int ufd, unsigned long offset)
 440 {
 441         return __copy_page(ufd, offset, false);
 442 }
 443
 444 static void *uffd_poll_thread(void *arg)
 445 {
 446         unsigned long cpu = (unsigned long) arg;
 447         struct pollfd pollfd[2];
 448         struct uffd_msg msg;
 449         struct uffdio_register uffd_reg;
 450         int ret;
 451         unsigned long offset;
 452         char tmp_chr;
 453         unsigned long userfaults = 0;
 454
 455         pollfd[0].fd = uffd;
 456         pollfd[0].events = POLLIN;
 457         pollfd[1].fd = pipefd[cpu*2];
 458         pollfd[1].events = POLLIN;
 459
 460         for (;;) {
 461                 ret = poll(pollfd, 2, -1);
 462                 if (!ret)
 463                         fprintf(stderr, "poll error %d\n", ret), exit(1);
 464                 if (ret < 0)
 465                         perror("poll"), exit(1);
 466                 if (pollfd[1].revents & POLLIN) {
 467                         if (read(pollfd[1].fd, &tmp_chr, 1) != 1)
 468                                 fprintf(stderr, "read pipefd error\n"),
 469                                         exit(1);
 470                         break;
 471                 }
 472                 if (!(pollfd[0].revents & POLLIN))
 473                         fprintf(stderr, "pollfd[0].revents %d\n",
 474                                 pollfd[0].revents), exit(1);
 475                 ret = read(uffd, &msg, sizeof(msg));
 476                 if (ret < 0) {
 477                         if (errno == EAGAIN)
 478                                 continue;
 479                         perror("nonblocking read error"), exit(1);
 480                 }
 481                 switch (msg.event) {
 482                 default:
 483                         fprintf(stderr, "unexpected msg event %u\n",
 484                                 msg.event), exit(1);
 485                         break;
 486                 case UFFD_EVENT_PAGEFAULT:
 487                         if (msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
 488                                 fprintf(stderr, "unexpected write fault\n"), exit(1);
 489                         offset = (char *)(unsigned long)msg.arg.pagefault.address -
 490                                 area_dst;
 491                         offset &= ~(page_size-1);
 492                         if (copy_page(uffd, offset))
 493                                 userfaults++;
 494                         break;
 495                 case UFFD_EVENT_FORK:
 496                         close(uffd);
 497                         uffd = msg.arg.fork.ufd;
 498                         pollfd[0].fd = uffd;
 499                         break;
 500                 case UFFD_EVENT_REMOVE:
 501                         uffd_reg.range.start = msg.arg.remove.start;
 502                         uffd_reg.range.len = msg.arg.remove.end -
 503                                 msg.arg.remove.start;
 504                         if (ioctl(uffd, UFFDIO_UNREGISTER, &uffd_reg.range))
 505                                 fprintf(stderr, "remove failure\n"), exit(1);
 506                         break;
 507                 case UFFD_EVENT_REMAP:
 508                         area_dst = (char *)(unsigned long)msg.arg.remap.to;
 509                         break;
 510                 }
 511         }
 512         return (void *)userfaults;
 513 }
 514
 515 pthread_mutex_t uffd_read_mutex = PTHREAD_MUTEX_INITIALIZER;
 516
 517 static void *uffd_read_thread(void *arg)
 518 {
 519         unsigned long *this_cpu_userfaults;
 520         struct uffd_msg msg;
 521         unsigned long offset;
 522         int ret;
 523
 524         this_cpu_userfaults = (unsigned long *) arg;
 525         *this_cpu_userfaults = 0;
 526
 527         pthread_mutex_unlock(&uffd_read_mutex);
 528         /* from here cancellation is ok */
 529
 530         for (;;) {
 531                 ret = read(uffd, &msg, sizeof(msg));
 532                 if (ret != sizeof(msg)) {
 533                         if (ret < 0)
 534                                 perror("blocking read error"), exit(1);
 535                         else
 536                                 fprintf(stderr, "short read\n"), exit(1);
 537                 }
 538                 if (msg.event != UFFD_EVENT_PAGEFAULT)
 539                         fprintf(stderr, "unexpected msg event %u\n",
 540                                 msg.event), exit(1);
 541                 if (bounces & BOUNCE_VERIFY &&
 542                     msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
 543                         fprintf(stderr, "unexpected write fault\n"), exit(1);
 544                 offset = (char *)(unsigned long)msg.arg.pagefault.address -
 545                          area_dst;
 546                 offset &= ~(page_size-1);
 547                 if (copy_page(uffd, offset))
 548                         (*this_cpu_userfaults)++;
 549         }
 550         return (void *)NULL;
 551 }
 552
 553 static void *background_thread(void *arg)
 554 {
 555         unsigned long cpu = (unsigned long) arg;
 556         unsigned long page_nr;
 557
 558         for (page_nr = cpu * nr_pages_per_cpu;
 559              page_nr < (cpu+1) * nr_pages_per_cpu;
 560              page_nr++)
 561                 copy_page_retry(uffd, page_nr * page_size);
 562
 563         return NULL;
 564 }
 565
 566 static int stress(unsigned long *userfaults)
 567 {
 568         unsigned long cpu;
 569         pthread_t locking_threads[nr_cpus];
 570         pthread_t uffd_threads[nr_cpus];
 571         pthread_t background_threads[nr_cpus];
 572         void **_userfaults = (void **) userfaults;
 573
 574         finished = 0;
 575         for (cpu = 0; cpu < nr_cpus; cpu++) {
 576                 if (pthread_create(&locking_threads[cpu], &attr,
 577                                    locking_thread, (void *)cpu))
 578                         return 1;
 579                 if (bounces & BOUNCE_POLL) {
 580                         if (pthread_create(&uffd_threads[cpu], &attr,
 581                                            uffd_poll_thread, (void *)cpu))
 582                                 return 1;
 583                 } else {
 584                         if (pthread_create(&uffd_threads[cpu], &attr,
 585                                            uffd_read_thread,
 586                                            &_userfaults[cpu]))
 587                                 return 1;
 588                         pthread_mutex_lock(&uffd_read_mutex);
 589                 }
 590                 if (pthread_create(&background_threads[cpu], &attr,
 591                                    background_thread, (void *)cpu))
 592                         return 1;
 593         }
 594         for (cpu = 0; cpu < nr_cpus; cpu++)
 595                 if (pthread_join(background_threads[cpu], NULL))
 596                         return 1;
 597
 598         /*
 599          * Be strict and immediately zap area_src, the whole area has
 600          * been transferred already by the background treads. The
 601          * area_src could then be faulted in in a racy way by still
 602          * running uffdio_threads reading zeropages after we zapped
 603          * area_src (but they're guaranteed to get -EEXIST from
 604          * UFFDIO_COPY without writing zero pages into area_dst
 605          * because the background threads already completed).
 606          */
 607         if (uffd_test_ops->release_pages(area_src))
 608                 return 1;
 609
 610         for (cpu = 0; cpu < nr_cpus; cpu++) {
 611                 char c;
 612                 if (bounces & BOUNCE_POLL) {
 613                         if (write(pipefd[cpu*2+1], &c, 1) != 1) {
 614                                 fprintf(stderr, "pipefd write error\n");
 615                                 return 1;
 616                         }
 617                         if (pthread_join(uffd_threads[cpu], &_userfaults[cpu]))
 618                                 return 1;
 619                 } else {
 620                         if (pthread_cancel(uffd_threads[cpu]))
 621                                 return 1;
 622                         if (pthread_join(uffd_threads[cpu], NULL))
 623                                 return 1;
 624                 }
 625         }
 626
 627         finished = 1;
 628         for (cpu = 0; cpu < nr_cpus; cpu++)
 629                 if (pthread_join(locking_threads[cpu], NULL))
 630                         return 1;
 631
 632         return 0;
 633 }
 634
 635 static int userfaultfd_open(int features)
 636 {
 637         struct uffdio_api uffdio_api;
 638
 639         uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
 640         if (uffd < 0) {
 641                 fprintf(stderr,
 642                         "userfaultfd syscall not available in this kernel\n");
 643                 return 1;
 644         }
 645         uffd_flags = fcntl(uffd, F_GETFD, NULL);
 646
 647         uffdio_api.api = UFFD_API;
 648         uffdio_api.features = features;
 649         if (ioctl(uffd, UFFDIO_API, &uffdio_api)) {
 650                 fprintf(stderr, "UFFDIO_API\n");
 651                 return 1;
 652         }
 653         if (uffdio_api.api != UFFD_API) {
 654                 fprintf(stderr, "UFFDIO_API error %Lu\n", uffdio_api.api);
 655                 return 1;
 656         }
 657
 658         return 0;
 659 }
 660
 661 sigjmp_buf jbuf, *sigbuf;
 662
 663 static void sighndl(int sig, siginfo_t *siginfo, void *ptr)
 664 {
 665         if (sig == SIGBUS) {
 666                 if (sigbuf)
 667                         siglongjmp(*sigbuf, 1);
 668                 abort();
 669         }
 670 }
 671
 672 /*
 673  * For non-cooperative userfaultfd test we fork() a process that will
 674  * generate pagefaults, will mremap the area monitored by the
 675  * userfaultfd and at last this process will release the monitored
 676  * area.
 677  * For the anonymous and shared memory the area is divided into two
 678  * parts, the first part is accessed before mremap, and the second
 679  * part is accessed after mremap. Since hugetlbfs does not support
 680  * mremap, the entire monitored area is accessed in a single pass for
 681  * HUGETLB_TEST.
 682  * The release of the pages currently generates event for shmem and
 683  * anonymous memory (UFFD_EVENT_REMOVE), hence it is not checked
 684  * for hugetlb.
 685  * For signal test(UFFD_FEATURE_SIGBUS), signal_test = 1, we register
 686  * monitored area, generate pagefaults and test that signal is delivered.
 687  * Use UFFDIO_COPY to allocate missing page and retry. For signal_test = 2
 688  * test robustness use case - we release monitored area, fork a process
 689  * that will generate pagefaults and verify signal is generated.
 690  * This also tests UFFD_FEATURE_EVENT_FORK event along with the signal
 691  * feature. Using monitor thread, verify no userfault events are generated.
 692  */
 693 static int faulting_process(int signal_test)
 694 {
 695         unsigned long nr;
 696         unsigned long long count;
 697         unsigned long split_nr_pages;
 698         unsigned long lastnr;
 699         struct sigaction act;
 700         unsigned long signalled = 0;
 701
 702         if (test_type != TEST_HUGETLB)
 703                 split_nr_pages = (nr_pages + 1) / 2;
 704         else
 705                 split_nr_pages = nr_pages;
 706
 707         if (signal_test) {
 708                 sigbuf = &jbuf;
 709                 memset(&act, 0, sizeof(act));
 710                 act.sa_sigaction = sighndl;
 711                 act.sa_flags = SA_SIGINFO;
 712                 if (sigaction(SIGBUS, &act, 0)) {
 713                         perror("sigaction");
 714                         return 1;
 715                 }
 716                 lastnr = (unsigned long)-1;
 717         }
 718
 719         for (nr = 0; nr < split_nr_pages; nr++) {
 720                 if (signal_test) {
 721                         if (sigsetjmp(*sigbuf, 1) != 0) {
 722                                 if (nr == lastnr) {
 723                                         fprintf(stderr, "Signal repeated\n");
 724                                         return 1;
 725                                 }
 726
 727                                 lastnr = nr;
 728                                 if (signal_test == 1) {
 729                                         if (copy_page(uffd, nr * page_size))
 730                                                 signalled++;
 731                                 } else {
 732                                         signalled++;
 733                                         continue;
 734                                 }
 735                         }
 736                 }
 737
 738                 count = *area_count(area_dst, nr);
 739                 if (count != count_verify[nr]) {
 740                         fprintf(stderr,
 741                                 "nr %lu memory corruption %Lu %Lu\n",
 742                                 nr, count,
 743                                 count_verify[nr]), exit(1);
 744                 }
 745         }
 746
 747         if (signal_test)
 748                 return signalled != split_nr_pages;
 749
 750         if (test_type == TEST_HUGETLB)
 751                 return 0;
 752
 753         area_dst = mremap(area_dst, nr_pages * page_size,  nr_pages * page_size,
 754                           MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
 755         if (area_dst == MAP_FAILED)
 756                 perror("mremap"), exit(1);
 757
 758         for (; nr < nr_pages; nr++) {
 759                 count = *area_count(area_dst, nr);
 760                 if (count != count_verify[nr]) {
 761                         fprintf(stderr,
 762                                 "nr %lu memory corruption %Lu %Lu\n",
 763                                 nr, count,
 764                                 count_verify[nr]), exit(1);
 765                 }
 766         }
 767
 768         if (uffd_test_ops->release_pages(area_dst))
 769                 return 1;
 770
 771         for (nr = 0; nr < nr_pages; nr++) {
 772                 if (my_bcmp(area_dst + nr * page_size, zeropage, page_size))
 773                         fprintf(stderr, "nr %lu is not zero\n", nr), exit(1);
 774         }
 775
 776         return 0;
 777 }
 778
 779 static void retry_uffdio_zeropage(int ufd,
 780                                   struct uffdio_zeropage *uffdio_zeropage,
 781                                   unsigned long offset)
 782 {
 783         uffd_test_ops->alias_mapping(&uffdio_zeropage->range.start,
 784                                      uffdio_zeropage->range.len,
 785                                      offset);
 786         if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
 787                 if (uffdio_zeropage->zeropage != -EEXIST)
 788                         fprintf(stderr, "UFFDIO_ZEROPAGE retry error %Ld\n",
 789                                 uffdio_zeropage->zeropage), exit(1);
 790         } else {
 791                 fprintf(stderr, "UFFDIO_ZEROPAGE retry unexpected %Ld\n",
 792                         uffdio_zeropage->zeropage), exit(1);
 793         }
 794 }
 795
 796 static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
 797 {
 798         struct uffdio_zeropage uffdio_zeropage;
 799         int ret;
 800         unsigned long has_zeropage;
 801
 802         has_zeropage = uffd_test_ops->expected_ioctls & (1 << _UFFDIO_ZEROPAGE);
 803
 804         if (offset >= nr_pages * page_size)
 805                 fprintf(stderr, "unexpected offset %lu\n",
 806                         offset), exit(1);
 807         uffdio_zeropage.range.start = (unsigned long) area_dst + offset;
 808         uffdio_zeropage.range.len = page_size;
 809         uffdio_zeropage.mode = 0;
 810         ret = ioctl(ufd, UFFDIO_ZEROPAGE, &uffdio_zeropage);
 811         if (ret) {
 812                 /* real retval in ufdio_zeropage.zeropage */
 813                 if (has_zeropage) {
 814                         if (uffdio_zeropage.zeropage == -EEXIST)
 815                                 fprintf(stderr, "UFFDIO_ZEROPAGE -EEXIST\n"),
 816                                         exit(1);
 817                         else
 818                                 fprintf(stderr, "UFFDIO_ZEROPAGE error %Ld\n",
 819                                         uffdio_zeropage.zeropage), exit(1);
 820                 } else {
 821                         if (uffdio_zeropage.zeropage != -EINVAL)
 822                                 fprintf(stderr,
 823                                         "UFFDIO_ZEROPAGE not -EINVAL %Ld\n",
 824                                         uffdio_zeropage.zeropage), exit(1);
 825                 }
 826         } else if (has_zeropage) {
 827                 if (uffdio_zeropage.zeropage != page_size) {
 828                         fprintf(stderr, "UFFDIO_ZEROPAGE unexpected %Ld\n",
 829                                 uffdio_zeropage.zeropage), exit(1);
 830                 } else {
 831                         if (test_uffdio_zeropage_eexist && retry) {
 832                                 test_uffdio_zeropage_eexist = false;
 833                                 retry_uffdio_zeropage(ufd, &uffdio_zeropage,
 834                                                       offset);
 835                         }
 836                         return 1;
 837                 }
 838         } else {
 839                 fprintf(stderr,
 840                         "UFFDIO_ZEROPAGE succeeded %Ld\n",
 841                         uffdio_zeropage.zeropage), exit(1);
 842         }
 843
 844         return 0;
 845 }
 846
 847 static int uffdio_zeropage(int ufd, unsigned long offset)
 848 {
 849         return __uffdio_zeropage(ufd, offset, false);
 850 }
 851
 852 /* exercise UFFDIO_ZEROPAGE */
 853 static int userfaultfd_zeropage_test(void)
 854 {
 855         struct uffdio_register uffdio_register;
 856         unsigned long expected_ioctls;
 857
 858         printf("testing UFFDIO_ZEROPAGE: ");
 859         fflush(stdout);
 860
 861         if (uffd_test_ops->release_pages(area_dst))
 862                 return 1;
 863
 864         if (userfaultfd_open(0) < 0)
 865                 return 1;
 866         uffdio_register.range.start = (unsigned long) area_dst;
 867         uffdio_register.range.len = nr_pages * page_size;
 868         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 869         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
 870                 fprintf(stderr, "register failure\n"), exit(1);
 871
 872         expected_ioctls = uffd_test_ops->expected_ioctls;
 873         if ((uffdio_register.ioctls & expected_ioctls) !=
 874             expected_ioctls)
 875                 fprintf(stderr,
 876                         "unexpected missing ioctl for anon memory\n"),
 877                         exit(1);
 878
 879         if (uffdio_zeropage(uffd, 0)) {
 880                 if (my_bcmp(area_dst, zeropage, page_size))
 881                         fprintf(stderr, "zeropage is not zero\n"), exit(1);
 882         }
 883
 884         close(uffd);
 885         printf("done.\n");
 886         return 0;
 887 }
 888
 889 static int userfaultfd_events_test(void)
 890 {
 891         struct uffdio_register uffdio_register;
 892         unsigned long expected_ioctls;
 893         unsigned long userfaults;
 894         pthread_t uffd_mon;
 895         int err, features;
 896         pid_t pid;
 897         char c;
 898
 899         printf("testing events (fork, remap, remove): ");
 900         fflush(stdout);
 901
 902         if (uffd_test_ops->release_pages(area_dst))
 903                 return 1;
 904
 905         features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
 906                 UFFD_FEATURE_EVENT_REMOVE;
 907         if (userfaultfd_open(features) < 0)
 908                 return 1;
 909         fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
 910
 911         uffdio_register.range.start = (unsigned long) area_dst;
 912         uffdio_register.range.len = nr_pages * page_size;
 913         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 914         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
 915                 fprintf(stderr, "register failure\n"), exit(1);
 916
 917         expected_ioctls = uffd_test_ops->expected_ioctls;
 918         if ((uffdio_register.ioctls & expected_ioctls) !=
 919             expected_ioctls)
 920                 fprintf(stderr,
 921                         "unexpected missing ioctl for anon memory\n"),
 922                         exit(1);
 923
 924         if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, NULL))
 925                 perror("uffd_poll_thread create"), exit(1);
 926
 927         pid = fork();
 928         if (pid < 0)
 929                 perror("fork"), exit(1);
 930
 931         if (!pid)
 932                 return faulting_process(0);
 933
 934         waitpid(pid, &err, 0);
 935         if (err)
 936                 fprintf(stderr, "faulting process failed\n"), exit(1);
 937
 938         if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
 939                 perror("pipe write"), exit(1);
 940         if (pthread_join(uffd_mon, (void **)&userfaults))
 941                 return 1;
 942
 943         close(uffd);
 944         printf("userfaults: %ld\n", userfaults);
 945
 946         return userfaults != nr_pages;
 947 }
 948
 949 static int userfaultfd_sig_test(void)
 950 {
 951         struct uffdio_register uffdio_register;
 952         unsigned long expected_ioctls;
 953         unsigned long userfaults;
 954         pthread_t uffd_mon;
 955         int err, features;
 956         pid_t pid;
 957         char c;
 958
 959         printf("testing signal delivery: ");
 960         fflush(stdout);
 961
 962         if (uffd_test_ops->release_pages(area_dst))
 963                 return 1;
 964
 965         features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
 966         if (userfaultfd_open(features) < 0)
 967                 return 1;
 968         fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
 969
 970         uffdio_register.range.start = (unsigned long) area_dst;
 971         uffdio_register.range.len = nr_pages * page_size;
 972         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 973         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
 974                 fprintf(stderr, "register failure\n"), exit(1);
 975
 976         expected_ioctls = uffd_test_ops->expected_ioctls;
 977         if ((uffdio_register.ioctls & expected_ioctls) !=
 978             expected_ioctls)
 979                 fprintf(stderr,
 980                         "unexpected missing ioctl for anon memory\n"),
 981                         exit(1);
 982
 983         if (faulting_process(1))
 984                 fprintf(stderr, "faulting process failed\n"), exit(1);
 985
 986         if (uffd_test_ops->release_pages(area_dst))
 987                 return 1;
 988
 989         if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, NULL))
 990                 perror("uffd_poll_thread create"), exit(1);
 991
 992         pid = fork();
 993         if (pid < 0)
 994                 perror("fork"), exit(1);
 995
 996         if (!pid)
 997                 exit(faulting_process(2));
 998
 999         waitpid(pid, &err, 0);
1000         if (err)
1001                 fprintf(stderr, "faulting process failed\n"), exit(1);
1002
1003         if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
1004                 perror("pipe write"), exit(1);
1005         if (pthread_join(uffd_mon, (void **)&userfaults))
1006                 return 1;
1007
1008         printf("done.\n");
1009         if (userfaults)
1010                 fprintf(stderr, "Signal test failed, userfaults: %ld\n",
1011                         userfaults);
1012         close(uffd);
1013         return userfaults != 0;
1014 }
1015 static int userfaultfd_stress(void)
1016 {
1017         void *area;
1018         char *tmp_area;
1019         unsigned long nr;
1020         struct uffdio_register uffdio_register;
1021         unsigned long cpu;
1022         int err;
1023         unsigned long userfaults[nr_cpus];
1024
1025         uffd_test_ops->allocate_area((void **)&area_src);
1026         if (!area_src)
1027                 return 1;
1028         uffd_test_ops->allocate_area((void **)&area_dst);
1029         if (!area_dst)
1030                 return 1;
1031
1032         if (userfaultfd_open(0) < 0)
1033                 return 1;
1034
1035         count_verify = malloc(nr_pages * sizeof(unsigned long long));
1036         if (!count_verify) {
1037                 perror("count_verify");
1038                 return 1;
1039         }
1040
1041         for (nr = 0; nr < nr_pages; nr++) {
1042                 *area_mutex(area_src, nr) = (pthread_mutex_t)
1043                         PTHREAD_MUTEX_INITIALIZER;
1044                 count_verify[nr] = *area_count(area_src, nr) = 1;
1045                 /*
1046                  * In the transition between 255 to 256, powerpc will
1047                  * read out of order in my_bcmp and see both bytes as
1048                  * zero, so leave a placeholder below always non-zero
1049                  * after the count, to avoid my_bcmp to trigger false
1050                  * positives.
1051                  */
1052                 *(area_count(area_src, nr) + 1) = 1;
1053         }
1054
1055         pipefd = malloc(sizeof(int) * nr_cpus * 2);
1056         if (!pipefd) {
1057                 perror("pipefd");
1058                 return 1;
1059         }
1060         for (cpu = 0; cpu < nr_cpus; cpu++) {
1061                 if (pipe2(&pipefd[cpu*2], O_CLOEXEC | O_NONBLOCK)) {
1062                         perror("pipe");
1063                         return 1;
1064                 }
1065         }
1066
1067         if (posix_memalign(&area, page_size, page_size)) {
1068                 fprintf(stderr, "out of memory\n");
1069                 return 1;
1070         }
1071         zeropage = area;
1072         bzero(zeropage, page_size);
1073
1074         pthread_mutex_lock(&uffd_read_mutex);
1075
1076         pthread_attr_init(&attr);
1077         pthread_attr_setstacksize(&attr, 16*1024*1024);
1078
1079         err = 0;
1080         while (bounces--) {
1081                 unsigned long expected_ioctls;
1082
1083                 printf("bounces: %d, mode:", bounces);
1084                 if (bounces & BOUNCE_RANDOM)
1085                         printf(" rnd");
1086                 if (bounces & BOUNCE_RACINGFAULTS)
1087                         printf(" racing");
1088                 if (bounces & BOUNCE_VERIFY)
1089                         printf(" ver");
1090                 if (bounces & BOUNCE_POLL)
1091                         printf(" poll");
1092                 printf(", ");
1093                 fflush(stdout);
1094
1095                 if (bounces & BOUNCE_POLL)
1096                         fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
1097                 else
1098                         fcntl(uffd, F_SETFL, uffd_flags & ~O_NONBLOCK);
1099
1100                 /* register */
1101                 uffdio_register.range.start = (unsigned long) area_dst;
1102                 uffdio_register.range.len = nr_pages * page_size;
1103                 uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
1104                 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
1105                         fprintf(stderr, "register failure\n");
1106                         return 1;
1107                 }
1108                 expected_ioctls = uffd_test_ops->expected_ioctls;
1109                 if ((uffdio_register.ioctls & expected_ioctls) !=
1110                     expected_ioctls) {
1111                         fprintf(stderr,
1112                                 "unexpected missing ioctl for anon memory\n");
1113                         return 1;
1114                 }
1115
1116                 if (area_dst_alias) {
1117                         uffdio_register.range.start = (unsigned long)
1118                                 area_dst_alias;
1119                         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
1120                                 fprintf(stderr, "register failure alias\n");
1121                                 return 1;
1122                         }
1123                 }
1124
1125                 /*
1126                  * The madvise done previously isn't enough: some
1127                  * uffd_thread could have read userfaults (one of
1128                  * those already resolved by the background thread)
1129                  * and it may be in the process of calling
1130                  * UFFDIO_COPY. UFFDIO_COPY will read the zapped
1131                  * area_src and it would map a zero page in it (of
1132                  * course such a UFFDIO_COPY is perfectly safe as it'd
1133                  * return -EEXIST). The problem comes at the next
1134                  * bounce though: that racing UFFDIO_COPY would
1135                  * generate zeropages in the area_src, so invalidating
1136                  * the previous MADV_DONTNEED. Without this additional
1137                  * MADV_DONTNEED those zeropages leftovers in the
1138                  * area_src would lead to -EEXIST failure during the
1139                  * next bounce, effectively leaving a zeropage in the
1140                  * area_dst.
1141                  *
1142                  * Try to comment this out madvise to see the memory
1143                  * corruption being caught pretty quick.
1144                  *
1145                  * khugepaged is also inhibited to collapse THP after
1146                  * MADV_DONTNEED only after the UFFDIO_REGISTER, so it's
1147                  * required to MADV_DONTNEED here.
1148                  */
1149                 if (uffd_test_ops->release_pages(area_dst))
1150                         return 1;
1151
1152                 /* bounce pass */
1153                 if (stress(userfaults))
1154                         return 1;
1155
1156                 /* unregister */
1157                 if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range)) {
1158                         fprintf(stderr, "unregister failure\n");
1159                         return 1;
1160                 }
1161                 if (area_dst_alias) {
1162                         uffdio_register.range.start = (unsigned long) area_dst;
1163                         if (ioctl(uffd, UFFDIO_UNREGISTER,
1164                                   &uffdio_register.range)) {
1165                                 fprintf(stderr, "unregister failure alias\n");
1166                                 return 1;
1167                         }
1168                 }
1169
1170                 /* verification */
1171                 if (bounces & BOUNCE_VERIFY) {
1172                         for (nr = 0; nr < nr_pages; nr++) {
1173                                 if (*area_count(area_dst, nr) != count_verify[nr]) {
1174                                         fprintf(stderr,
1175                                                 "error area_count %Lu %Lu %lu\n",
1176                                                 *area_count(area_src, nr),
1177                                                 count_verify[nr],
1178                                                 nr);
1179                                         err = 1;
1180                                         bounces = 0;
1181                                 }
1182                         }
1183                 }
1184
1185                 /* prepare next bounce */
1186                 tmp_area = area_src;
1187                 area_src = area_dst;
1188                 area_dst = tmp_area;
1189
1190                 tmp_area = area_src_alias;
1191                 area_src_alias = area_dst_alias;
1192                 area_dst_alias = tmp_area;
1193
1194                 printf("userfaults:");
1195                 for (cpu = 0; cpu < nr_cpus; cpu++)
1196                         printf(" %lu", userfaults[cpu]);
1197                 printf("\n");
1198         }
1199
1200         if (err)
1201                 return err;
1202
1203         close(uffd);
1204         return userfaultfd_zeropage_test() || userfaultfd_sig_test()
1205                 || userfaultfd_events_test();
1206 }
1207
1208 /*
1209  * Copied from mlock2-tests.c
1210  */
1211 unsigned long default_huge_page_size(void)
1212 {
1213         unsigned long hps = 0;
1214         char *line = NULL;
1215         size_t linelen = 0;
1216         FILE *f = fopen("/proc/meminfo", "r");
1217
1218         if (!f)
1219                 return 0;
1220         while (getline(&line, &linelen, f) > 0) {
1221                 if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
1222                         hps <<= 10;
1223                         break;
1224                 }
1225         }
1226
1227         free(line);
1228         fclose(f);
1229         return hps;
1230 }
1231
1232 static void set_test_type(const char *type)
1233 {
1234         if (!strcmp(type, "anon")) {
1235                 test_type = TEST_ANON;
1236                 uffd_test_ops = &anon_uffd_test_ops;
1237         } else if (!strcmp(type, "hugetlb")) {
1238                 test_type = TEST_HUGETLB;
1239                 uffd_test_ops = &hugetlb_uffd_test_ops;
1240         } else if (!strcmp(type, "hugetlb_shared")) {
1241                 map_shared = true;
1242                 test_type = TEST_HUGETLB;
1243                 uffd_test_ops = &hugetlb_uffd_test_ops;
1244         } else if (!strcmp(type, "shmem")) {
1245                 map_shared = true;
1246                 test_type = TEST_SHMEM;
1247                 uffd_test_ops = &shmem_uffd_test_ops;
1248         } else {
1249                 fprintf(stderr, "Unknown test type: %s\n", type), exit(1);
1250         }
1251
1252         if (test_type == TEST_HUGETLB)
1253                 page_size = default_huge_page_size();
1254         else
1255                 page_size = sysconf(_SC_PAGE_SIZE);
1256
1257         if (!page_size)
1258                 fprintf(stderr, "Unable to determine page size\n"),
1259                                 exit(2);
1260         if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) * 2
1261             > page_size)
1262                 fprintf(stderr, "Impossible to run this test\n"), exit(2);
1263 }
1264
1265 static void sigalrm(int sig)
1266 {
1267         if (sig != SIGALRM)
1268                 abort();
1269         test_uffdio_copy_eexist = true;
1270         test_uffdio_zeropage_eexist = true;
1271         alarm(ALARM_INTERVAL_SECS);
1272 }
1273
1274 int main(int argc, char **argv)
1275 {
1276         if (argc < 4)
1277                 fprintf(stderr, "Usage: <test type> <MiB> <bounces> [hugetlbfs_file]\n"),
1278                                 exit(1);
1279
1280         if (signal(SIGALRM, sigalrm) == SIG_ERR)
1281                 fprintf(stderr, "failed to arm SIGALRM"), exit(1);
1282         alarm(ALARM_INTERVAL_SECS);
1283
1284         set_test_type(argv[1]);
1285
1286         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
1287         nr_pages_per_cpu = atol(argv[2]) * 1024*1024 / page_size /
1288                 nr_cpus;
1289         if (!nr_pages_per_cpu) {
1290                 fprintf(stderr, "invalid MiB\n");
1291                 fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
1292         }
1293
1294         bounces = atoi(argv[3]);
1295         if (bounces <= 0) {
1296                 fprintf(stderr, "invalid bounces\n");
1297                 fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
1298         }
1299         nr_pages = nr_pages_per_cpu * nr_cpus;
1300
1301         if (test_type == TEST_HUGETLB) {
1302                 if (argc < 5)
1303                         fprintf(stderr, "Usage: hugetlb <MiB> <bounces> <hugetlbfs_file>\n"),
1304                                 exit(1);
1305                 huge_fd = open(argv[4], O_CREAT | O_RDWR, 0755);
1306                 if (huge_fd < 0) {
1307                         fprintf(stderr, "Open of %s failed", argv[3]);
1308                         perror("open");
1309                         exit(1);
1310                 }
1311                 if (ftruncate(huge_fd, 0)) {
1312                         fprintf(stderr, "ftruncate %s to size 0 failed", argv[3]);
1313                         perror("ftruncate");
1314                         exit(1);
1315                 }
1316         }
1317         printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
1318                nr_pages, nr_pages_per_cpu);
1319         return userfaultfd_stress();
1320 }
1321
1322 #else /* __NR_userfaultfd */
1323
1324 #warning "missing __NR_userfaultfd definition"
1325
1326 int main(void)
1327 {
1328         printf("skip: Skipping userfaultfd test (missing __NR_userfaultfd)\n");
1329         return KSFT_SKIP;
1330 }
1331
1332 #endif /* __NR_userfaultfd */