tools/testing/selftests/vm/userfaultfd.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
usage
anon_release_pages
anon_allocate_area
noop_alias_mapping
hugetlb_release_pages
hugetlb_allocate_area
hugetlb_alias_mapping
shmem_release_pages
shmem_allocate_area
my_bcmp
locking_thread
retry_copy_page
__copy_page
copy_page_retry
copy_page
uffd_read_msg
uffd_handle_page_fault
uffd_poll_thread
uffd_read_thread
background_thread
stress
userfaultfd_open
sighndl
faulting_process
retry_uffdio_zeropage
__uffdio_zeropage
uffdio_zeropage
userfaultfd_zeropage_test
userfaultfd_events_test
userfaultfd_sig_test
userfaultfd_stress
default_huge_page_size
set_test_type
sigalrm
main
main
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Stress userfaultfd syscall.
   4  *
   5  *  Copyright (C) 2015  Red Hat, Inc.
   6  *
   7  * This test allocates two virtual areas and bounces the physical
   8  * memory across the two virtual areas (from area_src to area_dst)
   9  * using userfaultfd.
  10  *
  11  * There are three threads running per CPU:
  12  *
  13  * 1) one per-CPU thread takes a per-page pthread_mutex in a random
  14  *    page of the area_dst (while the physical page may still be in
  15  *    area_src), and increments a per-page counter in the same page,
  16  *    and checks its value against a verification region.
  17  *
  18  * 2) another per-CPU thread handles the userfaults generated by
  19  *    thread 1 above. userfaultfd blocking reads or poll() modes are
  20  *    exercised interleaved.
  21  *
  22  * 3) one last per-CPU thread transfers the memory in the background
  23  *    at maximum bandwidth (if not already transferred by thread
  24  *    2). Each cpu thread takes cares of transferring a portion of the
  25  *    area.
  26  *
  27  * When all threads of type 3 completed the transfer, one bounce is
  28  * complete. area_src and area_dst are then swapped. All threads are
  29  * respawned and so the bounce is immediately restarted in the
  30  * opposite direction.
  31  *
  32  * per-CPU threads 1 by triggering userfaults inside
  33  * pthread_mutex_lock will also verify the atomicity of the memory
  34  * transfer (UFFDIO_COPY).
  35  */
  36 
  37 #define _GNU_SOURCE
  38 #include <stdio.h>
  39 #include <errno.h>
  40 #include <unistd.h>
  41 #include <stdlib.h>
  42 #include <sys/types.h>
  43 #include <sys/stat.h>
  44 #include <fcntl.h>
  45 #include <time.h>
  46 #include <signal.h>
  47 #include <poll.h>
  48 #include <string.h>
  49 #include <sys/mman.h>
  50 #include <sys/syscall.h>
  51 #include <sys/ioctl.h>
  52 #include <sys/wait.h>
  53 #include <pthread.h>
  54 #include <linux/userfaultfd.h>
  55 #include <setjmp.h>
  56 #include <stdbool.h>
  57 
  58 #include "../kselftest.h"
  59 
  60 #ifdef __NR_userfaultfd
  61 
  62 static unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size;
  63 
  64 #define BOUNCE_RANDOM           (1<<0)
  65 #define BOUNCE_RACINGFAULTS     (1<<1)
  66 #define BOUNCE_VERIFY           (1<<2)
  67 #define BOUNCE_POLL             (1<<3)
  68 static int bounces;
  69 
  70 #define TEST_ANON       1
  71 #define TEST_HUGETLB    2
  72 #define TEST_SHMEM      3
  73 static int test_type;
  74 
  75 /* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */
  76 #define ALARM_INTERVAL_SECS 10
  77 static volatile bool test_uffdio_copy_eexist = true;
  78 static volatile bool test_uffdio_zeropage_eexist = true;
  79 
  80 static bool map_shared;
  81 static int huge_fd;
  82 static char *huge_fd_off0;
  83 static unsigned long long *count_verify;
  84 static int uffd, uffd_flags, finished, *pipefd;
  85 static char *area_src, *area_src_alias, *area_dst, *area_dst_alias;
  86 static char *zeropage;
  87 pthread_attr_t attr;
  88 
  89 /* pthread_mutex_t starts at page offset 0 */
  90 #define area_mutex(___area, ___nr)                                      \
  91         ((pthread_mutex_t *) ((___area) + (___nr)*page_size))
  92 /*
  93  * count is placed in the page after pthread_mutex_t naturally aligned
  94  * to avoid non alignment faults on non-x86 archs.
  95  */
  96 #define area_count(___area, ___nr)                                      \
  97         ((volatile unsigned long long *) ((unsigned long)               \
  98                                  ((___area) + (___nr)*page_size +       \
  99                                   sizeof(pthread_mutex_t) +             \
 100                                   sizeof(unsigned long long) - 1) &     \
 101                                  ~(unsigned long)(sizeof(unsigned long long) \
 102                                                   -  1)))
 103 
 104 const char *examples =
 105     "# Run anonymous memory test on 100MiB region with 99999 bounces:\n"
 106     "./userfaultfd anon 100 99999\n\n"
 107     "# Run share memory test on 1GiB region with 99 bounces:\n"
 108     "./userfaultfd shmem 1000 99\n\n"
 109     "# Run hugetlb memory test on 256MiB region with 50 bounces (using /dev/hugepages/hugefile):\n"
 110     "./userfaultfd hugetlb 256 50 /dev/hugepages/hugefile\n\n"
 111     "# Run the same hugetlb test but using shmem:\n"
 112     "./userfaultfd hugetlb_shared 256 50 /dev/hugepages/hugefile\n\n"
 113     "# 10MiB-~6GiB 999 bounces anonymous test, "
 114     "continue forever unless an error triggers\n"
 115     "while ./userfaultfd anon $[RANDOM % 6000 + 10] 999; do true; done\n\n";
 116 
 117 static void usage(void)
 118 {
 119         fprintf(stderr, "\nUsage: ./userfaultfd <test type> <MiB> <bounces> "
 120                 "[hugetlbfs_file]\n\n");
 121         fprintf(stderr, "Supported <test type>: anon, hugetlb, "
 122                 "hugetlb_shared, shmem\n\n");
 123         fprintf(stderr, "Examples:\n\n");
 124         fprintf(stderr, "%s", examples);
 125         exit(1);
 126 }
 127 
 128 static int anon_release_pages(char *rel_area)
 129 {
 130         int ret = 0;
 131 
 132         if (madvise(rel_area, nr_pages * page_size, MADV_DONTNEED)) {
 133                 perror("madvise");
 134                 ret = 1;
 135         }
 136 
 137         return ret;
 138 }
 139 
 140 static void anon_allocate_area(void **alloc_area)
 141 {
 142         if (posix_memalign(alloc_area, page_size, nr_pages * page_size)) {
 143                 fprintf(stderr, "out of memory\n");
 144                 *alloc_area = NULL;
 145         }
 146 }
 147 
 148 static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset)
 149 {
 150 }
 151 
 152 /* HugeTLB memory */
 153 static int hugetlb_release_pages(char *rel_area)
 154 {
 155         int ret = 0;
 156 
 157         if (fallocate(huge_fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
 158                                 rel_area == huge_fd_off0 ? 0 :
 159                                 nr_pages * page_size,
 160                                 nr_pages * page_size)) {
 161                 perror("fallocate");
 162                 ret = 1;
 163         }
 164 
 165         return ret;
 166 }
 167 
 168 
 169 static void hugetlb_allocate_area(void **alloc_area)
 170 {
 171         void *area_alias = NULL;
 172         char **alloc_area_alias;
 173         *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 174                            (map_shared ? MAP_SHARED : MAP_PRIVATE) |
 175                            MAP_HUGETLB,
 176                            huge_fd, *alloc_area == area_src ? 0 :
 177                            nr_pages * page_size);
 178         if (*alloc_area == MAP_FAILED) {
 179                 fprintf(stderr, "mmap of hugetlbfs file failed\n");
 180                 *alloc_area = NULL;
 181         }
 182 
 183         if (map_shared) {
 184                 area_alias = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 185                                   MAP_SHARED | MAP_HUGETLB,
 186                                   huge_fd, *alloc_area == area_src ? 0 :
 187                                   nr_pages * page_size);
 188                 if (area_alias == MAP_FAILED) {
 189                         if (munmap(*alloc_area, nr_pages * page_size) < 0)
 190                                 perror("hugetlb munmap"), exit(1);
 191                         *alloc_area = NULL;
 192                         return;
 193                 }
 194         }
 195         if (*alloc_area == area_src) {
 196                 huge_fd_off0 = *alloc_area;
 197                 alloc_area_alias = &area_src_alias;
 198         } else {
 199                 alloc_area_alias = &area_dst_alias;
 200         }
 201         if (area_alias)
 202                 *alloc_area_alias = area_alias;
 203 }
 204 
 205 static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset)
 206 {
 207         if (!map_shared)
 208                 return;
 209         /*
 210          * We can't zap just the pagetable with hugetlbfs because
 211          * MADV_DONTEED won't work. So exercise -EEXIST on a alias
 212          * mapping where the pagetables are not established initially,
 213          * this way we'll exercise the -EEXEC at the fs level.
 214          */
 215         *start = (unsigned long) area_dst_alias + offset;
 216 }
 217 
 218 /* Shared memory */
 219 static int shmem_release_pages(char *rel_area)
 220 {
 221         int ret = 0;
 222 
 223         if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE)) {
 224                 perror("madvise");
 225                 ret = 1;
 226         }
 227 
 228         return ret;
 229 }
 230 
 231 static void shmem_allocate_area(void **alloc_area)
 232 {
 233         *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
 234                            MAP_ANONYMOUS | MAP_SHARED, -1, 0);
 235         if (*alloc_area == MAP_FAILED) {
 236                 fprintf(stderr, "shared memory mmap failed\n");
 237                 *alloc_area = NULL;
 238         }
 239 }
 240 
 241 struct uffd_test_ops {
 242         unsigned long expected_ioctls;
 243         void (*allocate_area)(void **alloc_area);
 244         int (*release_pages)(char *rel_area);
 245         void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset);
 246 };
 247 
 248 #define ANON_EXPECTED_IOCTLS            ((1 << _UFFDIO_WAKE) | \
 249                                          (1 << _UFFDIO_COPY) | \
 250                                          (1 << _UFFDIO_ZEROPAGE))
 251 
 252 static struct uffd_test_ops anon_uffd_test_ops = {
 253         .expected_ioctls = ANON_EXPECTED_IOCTLS,
 254         .allocate_area  = anon_allocate_area,
 255         .release_pages  = anon_release_pages,
 256         .alias_mapping = noop_alias_mapping,
 257 };
 258 
 259 static struct uffd_test_ops shmem_uffd_test_ops = {
 260         .expected_ioctls = ANON_EXPECTED_IOCTLS,
 261         .allocate_area  = shmem_allocate_area,
 262         .release_pages  = shmem_release_pages,
 263         .alias_mapping = noop_alias_mapping,
 264 };
 265 
 266 static struct uffd_test_ops hugetlb_uffd_test_ops = {
 267         .expected_ioctls = UFFD_API_RANGE_IOCTLS_BASIC,
 268         .allocate_area  = hugetlb_allocate_area,
 269         .release_pages  = hugetlb_release_pages,
 270         .alias_mapping = hugetlb_alias_mapping,
 271 };
 272 
 273 static struct uffd_test_ops *uffd_test_ops;
 274 
 275 static int my_bcmp(char *str1, char *str2, size_t n)
 276 {
 277         unsigned long i;
 278         for (i = 0; i < n; i++)
 279                 if (str1[i] != str2[i])
 280                         return 1;
 281         return 0;
 282 }
 283 
 284 static void *locking_thread(void *arg)
 285 {
 286         unsigned long cpu = (unsigned long) arg;
 287         struct random_data rand;
 288         unsigned long page_nr = *(&(page_nr)); /* uninitialized warning */
 289         int32_t rand_nr;
 290         unsigned long long count;
 291         char randstate[64];
 292         unsigned int seed;
 293         time_t start;
 294 
 295         if (bounces & BOUNCE_RANDOM) {
 296                 seed = (unsigned int) time(NULL) - bounces;
 297                 if (!(bounces & BOUNCE_RACINGFAULTS))
 298                         seed += cpu;
 299                 bzero(&rand, sizeof(rand));
 300                 bzero(&randstate, sizeof(randstate));
 301                 if (initstate_r(seed, randstate, sizeof(randstate), &rand))
 302                         fprintf(stderr, "srandom_r error\n"), exit(1);
 303         } else {
 304                 page_nr = -bounces;
 305                 if (!(bounces & BOUNCE_RACINGFAULTS))
 306                         page_nr += cpu * nr_pages_per_cpu;
 307         }
 308 
 309         while (!finished) {
 310                 if (bounces & BOUNCE_RANDOM) {
 311                         if (random_r(&rand, &rand_nr))
 312                                 fprintf(stderr, "random_r 1 error\n"), exit(1);
 313                         page_nr = rand_nr;
 314                         if (sizeof(page_nr) > sizeof(rand_nr)) {
 315                                 if (random_r(&rand, &rand_nr))
 316                                         fprintf(stderr, "random_r 2 error\n"), exit(1);
 317                                 page_nr |= (((unsigned long) rand_nr) << 16) <<
 318                                            16;
 319                         }
 320                 } else
 321                         page_nr += 1;
 322                 page_nr %= nr_pages;
 323 
 324                 start = time(NULL);
 325                 if (bounces & BOUNCE_VERIFY) {
 326                         count = *area_count(area_dst, page_nr);
 327                         if (!count)
 328                                 fprintf(stderr,
 329                                         "page_nr %lu wrong count %Lu %Lu\n",
 330                                         page_nr, count,
 331                                         count_verify[page_nr]), exit(1);
 332 
 333 
 334                         /*
 335                          * We can't use bcmp (or memcmp) because that
 336                          * returns 0 erroneously if the memory is
 337                          * changing under it (even if the end of the
 338                          * page is never changing and always
 339                          * different).
 340                          */
 341 #if 1
 342                         if (!my_bcmp(area_dst + page_nr * page_size, zeropage,
 343                                      page_size))
 344                                 fprintf(stderr,
 345                                         "my_bcmp page_nr %lu wrong count %Lu %Lu\n",
 346                                         page_nr, count,
 347                                         count_verify[page_nr]), exit(1);
 348 #else
 349                         unsigned long loops;
 350 
 351                         loops = 0;
 352                         /* uncomment the below line to test with mutex */
 353                         /* pthread_mutex_lock(area_mutex(area_dst, page_nr)); */
 354                         while (!bcmp(area_dst + page_nr * page_size, zeropage,
 355                                      page_size)) {
 356                                 loops += 1;
 357                                 if (loops > 10)
 358                                         break;
 359                         }
 360                         /* uncomment below line to test with mutex */
 361                         /* pthread_mutex_unlock(area_mutex(area_dst, page_nr)); */
 362                         if (loops) {
 363                                 fprintf(stderr,
 364                                         "page_nr %lu all zero thread %lu %p %lu\n",
 365                                         page_nr, cpu, area_dst + page_nr * page_size,
 366                                         loops);
 367                                 if (loops > 10)
 368                                         exit(1);
 369                         }
 370 #endif
 371                 }
 372 
 373                 pthread_mutex_lock(area_mutex(area_dst, page_nr));
 374                 count = *area_count(area_dst, page_nr);
 375                 if (count != count_verify[page_nr]) {
 376                         fprintf(stderr,
 377                                 "page_nr %lu memory corruption %Lu %Lu\n",
 378                                 page_nr, count,
 379                                 count_verify[page_nr]), exit(1);
 380                 }
 381                 count++;
 382                 *area_count(area_dst, page_nr) = count_verify[page_nr] = count;
 383                 pthread_mutex_unlock(area_mutex(area_dst, page_nr));
 384 
 385                 if (time(NULL) - start > 1)
 386                         fprintf(stderr,
 387                                 "userfault too slow %ld "
 388                                 "possible false positive with overcommit\n",
 389                                 time(NULL) - start);
 390         }
 391 
 392         return NULL;
 393 }
 394 
 395 static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
 396                             unsigned long offset)
 397 {
 398         uffd_test_ops->alias_mapping(&uffdio_copy->dst,
 399                                      uffdio_copy->len,
 400                                      offset);
 401         if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) {
 402                 /* real retval in ufdio_copy.copy */
 403                 if (uffdio_copy->copy != -EEXIST)
 404                         fprintf(stderr, "UFFDIO_COPY retry error %Ld\n",
 405                                 uffdio_copy->copy), exit(1);
 406         } else {
 407                 fprintf(stderr, "UFFDIO_COPY retry unexpected %Ld\n",
 408                         uffdio_copy->copy), exit(1);
 409         }
 410 }
 411 
 412 static int __copy_page(int ufd, unsigned long offset, bool retry)
 413 {
 414         struct uffdio_copy uffdio_copy;
 415 
 416         if (offset >= nr_pages * page_size)
 417                 fprintf(stderr, "unexpected offset %lu\n",
 418                         offset), exit(1);
 419         uffdio_copy.dst = (unsigned long) area_dst + offset;
 420         uffdio_copy.src = (unsigned long) area_src + offset;
 421         uffdio_copy.len = page_size;
 422         uffdio_copy.mode = 0;
 423         uffdio_copy.copy = 0;
 424         if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
 425                 /* real retval in ufdio_copy.copy */
 426                 if (uffdio_copy.copy != -EEXIST)
 427                         fprintf(stderr, "UFFDIO_COPY error %Ld\n",
 428                                 uffdio_copy.copy), exit(1);
 429         } else if (uffdio_copy.copy != page_size) {
 430                 fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n",
 431                         uffdio_copy.copy), exit(1);
 432         } else {
 433                 if (test_uffdio_copy_eexist && retry) {
 434                         test_uffdio_copy_eexist = false;
 435                         retry_copy_page(ufd, &uffdio_copy, offset);
 436                 }
 437                 return 1;
 438         }
 439         return 0;
 440 }
 441 
 442 static int copy_page_retry(int ufd, unsigned long offset)
 443 {
 444         return __copy_page(ufd, offset, true);
 445 }
 446 
 447 static int copy_page(int ufd, unsigned long offset)
 448 {
 449         return __copy_page(ufd, offset, false);
 450 }
 451 
 452 static int uffd_read_msg(int ufd, struct uffd_msg *msg)
 453 {
 454         int ret = read(uffd, msg, sizeof(*msg));
 455 
 456         if (ret != sizeof(*msg)) {
 457                 if (ret < 0) {
 458                         if (errno == EAGAIN)
 459                                 return 1;
 460                         else
 461                                 perror("blocking read error"), exit(1);
 462                 } else {
 463                         fprintf(stderr, "short read\n"), exit(1);
 464                 }
 465         }
 466 
 467         return 0;
 468 }
 469 
 470 /* Return 1 if page fault handled by us; otherwise 0 */
 471 static int uffd_handle_page_fault(struct uffd_msg *msg)
 472 {
 473         unsigned long offset;
 474 
 475         if (msg->event != UFFD_EVENT_PAGEFAULT)
 476                 fprintf(stderr, "unexpected msg event %u\n",
 477                         msg->event), exit(1);
 478 
 479         if (bounces & BOUNCE_VERIFY &&
 480             msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
 481                 fprintf(stderr, "unexpected write fault\n"), exit(1);
 482 
 483         offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst;
 484         offset &= ~(page_size-1);
 485 
 486         return copy_page(uffd, offset);
 487 }
 488 
 489 static void *uffd_poll_thread(void *arg)
 490 {
 491         unsigned long cpu = (unsigned long) arg;
 492         struct pollfd pollfd[2];
 493         struct uffd_msg msg;
 494         struct uffdio_register uffd_reg;
 495         int ret;
 496         char tmp_chr;
 497         unsigned long userfaults = 0;
 498 
 499         pollfd[0].fd = uffd;
 500         pollfd[0].events = POLLIN;
 501         pollfd[1].fd = pipefd[cpu*2];
 502         pollfd[1].events = POLLIN;
 503 
 504         for (;;) {
 505                 ret = poll(pollfd, 2, -1);
 506                 if (!ret)
 507                         fprintf(stderr, "poll error %d\n", ret), exit(1);
 508                 if (ret < 0)
 509                         perror("poll"), exit(1);
 510                 if (pollfd[1].revents & POLLIN) {
 511                         if (read(pollfd[1].fd, &tmp_chr, 1) != 1)
 512                                 fprintf(stderr, "read pipefd error\n"),
 513                                         exit(1);
 514                         break;
 515                 }
 516                 if (!(pollfd[0].revents & POLLIN))
 517                         fprintf(stderr, "pollfd[0].revents %d\n",
 518                                 pollfd[0].revents), exit(1);
 519                 if (uffd_read_msg(uffd, &msg))
 520                         continue;
 521                 switch (msg.event) {
 522                 default:
 523                         fprintf(stderr, "unexpected msg event %u\n",
 524                                 msg.event), exit(1);
 525                         break;
 526                 case UFFD_EVENT_PAGEFAULT:
 527                         userfaults += uffd_handle_page_fault(&msg);
 528                         break;
 529                 case UFFD_EVENT_FORK:
 530                         close(uffd);
 531                         uffd = msg.arg.fork.ufd;
 532                         pollfd[0].fd = uffd;
 533                         break;
 534                 case UFFD_EVENT_REMOVE:
 535                         uffd_reg.range.start = msg.arg.remove.start;
 536                         uffd_reg.range.len = msg.arg.remove.end -
 537                                 msg.arg.remove.start;
 538                         if (ioctl(uffd, UFFDIO_UNREGISTER, &uffd_reg.range))
 539                                 fprintf(stderr, "remove failure\n"), exit(1);
 540                         break;
 541                 case UFFD_EVENT_REMAP:
 542                         area_dst = (char *)(unsigned long)msg.arg.remap.to;
 543                         break;
 544                 }
 545         }
 546         return (void *)userfaults;
 547 }
 548 
 549 pthread_mutex_t uffd_read_mutex = PTHREAD_MUTEX_INITIALIZER;
 550 
 551 static void *uffd_read_thread(void *arg)
 552 {
 553         unsigned long *this_cpu_userfaults;
 554         struct uffd_msg msg;
 555 
 556         this_cpu_userfaults = (unsigned long *) arg;
 557         *this_cpu_userfaults = 0;
 558 
 559         pthread_mutex_unlock(&uffd_read_mutex);
 560         /* from here cancellation is ok */
 561 
 562         for (;;) {
 563                 if (uffd_read_msg(uffd, &msg))
 564                         continue;
 565                 (*this_cpu_userfaults) += uffd_handle_page_fault(&msg);
 566         }
 567         return (void *)NULL;
 568 }
 569 
 570 static void *background_thread(void *arg)
 571 {
 572         unsigned long cpu = (unsigned long) arg;
 573         unsigned long page_nr;
 574 
 575         for (page_nr = cpu * nr_pages_per_cpu;
 576              page_nr < (cpu+1) * nr_pages_per_cpu;
 577              page_nr++)
 578                 copy_page_retry(uffd, page_nr * page_size);
 579 
 580         return NULL;
 581 }
 582 
 583 static int stress(unsigned long *userfaults)
 584 {
 585         unsigned long cpu;
 586         pthread_t locking_threads[nr_cpus];
 587         pthread_t uffd_threads[nr_cpus];
 588         pthread_t background_threads[nr_cpus];
 589         void **_userfaults = (void **) userfaults;
 590 
 591         finished = 0;
 592         for (cpu = 0; cpu < nr_cpus; cpu++) {
 593                 if (pthread_create(&locking_threads[cpu], &attr,
 594                                    locking_thread, (void *)cpu))
 595                         return 1;
 596                 if (bounces & BOUNCE_POLL) {
 597                         if (pthread_create(&uffd_threads[cpu], &attr,
 598                                            uffd_poll_thread, (void *)cpu))
 599                                 return 1;
 600                 } else {
 601                         if (pthread_create(&uffd_threads[cpu], &attr,
 602                                            uffd_read_thread,
 603                                            &_userfaults[cpu]))
 604                                 return 1;
 605                         pthread_mutex_lock(&uffd_read_mutex);
 606                 }
 607                 if (pthread_create(&background_threads[cpu], &attr,
 608                                    background_thread, (void *)cpu))
 609                         return 1;
 610         }
 611         for (cpu = 0; cpu < nr_cpus; cpu++)
 612                 if (pthread_join(background_threads[cpu], NULL))
 613                         return 1;
 614 
 615         /*
 616          * Be strict and immediately zap area_src, the whole area has
 617          * been transferred already by the background treads. The
 618          * area_src could then be faulted in in a racy way by still
 619          * running uffdio_threads reading zeropages after we zapped
 620          * area_src (but they're guaranteed to get -EEXIST from
 621          * UFFDIO_COPY without writing zero pages into area_dst
 622          * because the background threads already completed).
 623          */
 624         if (uffd_test_ops->release_pages(area_src))
 625                 return 1;
 626 
 627 
 628         finished = 1;
 629         for (cpu = 0; cpu < nr_cpus; cpu++)
 630                 if (pthread_join(locking_threads[cpu], NULL))
 631                         return 1;
 632 
 633         for (cpu = 0; cpu < nr_cpus; cpu++) {
 634                 char c;
 635                 if (bounces & BOUNCE_POLL) {
 636                         if (write(pipefd[cpu*2+1], &c, 1) != 1) {
 637                                 fprintf(stderr, "pipefd write error\n");
 638                                 return 1;
 639                         }
 640                         if (pthread_join(uffd_threads[cpu], &_userfaults[cpu]))
 641                                 return 1;
 642                 } else {
 643                         if (pthread_cancel(uffd_threads[cpu]))
 644                                 return 1;
 645                         if (pthread_join(uffd_threads[cpu], NULL))
 646                                 return 1;
 647                 }
 648         }
 649 
 650         return 0;
 651 }
 652 
 653 static int userfaultfd_open(int features)
 654 {
 655         struct uffdio_api uffdio_api;
 656 
 657         uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
 658         if (uffd < 0) {
 659                 fprintf(stderr,
 660                         "userfaultfd syscall not available in this kernel\n");
 661                 return 1;
 662         }
 663         uffd_flags = fcntl(uffd, F_GETFD, NULL);
 664 
 665         uffdio_api.api = UFFD_API;
 666         uffdio_api.features = features;
 667         if (ioctl(uffd, UFFDIO_API, &uffdio_api)) {
 668                 fprintf(stderr, "UFFDIO_API\n");
 669                 return 1;
 670         }
 671         if (uffdio_api.api != UFFD_API) {
 672                 fprintf(stderr, "UFFDIO_API error %Lu\n", uffdio_api.api);
 673                 return 1;
 674         }
 675 
 676         return 0;
 677 }
 678 
 679 sigjmp_buf jbuf, *sigbuf;
 680 
 681 static void sighndl(int sig, siginfo_t *siginfo, void *ptr)
 682 {
 683         if (sig == SIGBUS) {
 684                 if (sigbuf)
 685                         siglongjmp(*sigbuf, 1);
 686                 abort();
 687         }
 688 }
 689 
 690 /*
 691  * For non-cooperative userfaultfd test we fork() a process that will
 692  * generate pagefaults, will mremap the area monitored by the
 693  * userfaultfd and at last this process will release the monitored
 694  * area.
 695  * For the anonymous and shared memory the area is divided into two
 696  * parts, the first part is accessed before mremap, and the second
 697  * part is accessed after mremap. Since hugetlbfs does not support
 698  * mremap, the entire monitored area is accessed in a single pass for
 699  * HUGETLB_TEST.
 700  * The release of the pages currently generates event for shmem and
 701  * anonymous memory (UFFD_EVENT_REMOVE), hence it is not checked
 702  * for hugetlb.
 703  * For signal test(UFFD_FEATURE_SIGBUS), signal_test = 1, we register
 704  * monitored area, generate pagefaults and test that signal is delivered.
 705  * Use UFFDIO_COPY to allocate missing page and retry. For signal_test = 2
 706  * test robustness use case - we release monitored area, fork a process
 707  * that will generate pagefaults and verify signal is generated.
 708  * This also tests UFFD_FEATURE_EVENT_FORK event along with the signal
 709  * feature. Using monitor thread, verify no userfault events are generated.
 710  */
 711 static int faulting_process(int signal_test)
 712 {
 713         unsigned long nr;
 714         unsigned long long count;
 715         unsigned long split_nr_pages;
 716         unsigned long lastnr;
 717         struct sigaction act;
 718         unsigned long signalled = 0;
 719 
 720         if (test_type != TEST_HUGETLB)
 721                 split_nr_pages = (nr_pages + 1) / 2;
 722         else
 723                 split_nr_pages = nr_pages;
 724 
 725         if (signal_test) {
 726                 sigbuf = &jbuf;
 727                 memset(&act, 0, sizeof(act));
 728                 act.sa_sigaction = sighndl;
 729                 act.sa_flags = SA_SIGINFO;
 730                 if (sigaction(SIGBUS, &act, 0)) {
 731                         perror("sigaction");
 732                         return 1;
 733                 }
 734                 lastnr = (unsigned long)-1;
 735         }
 736 
 737         for (nr = 0; nr < split_nr_pages; nr++) {
 738                 if (signal_test) {
 739                         if (sigsetjmp(*sigbuf, 1) != 0) {
 740                                 if (nr == lastnr) {
 741                                         fprintf(stderr, "Signal repeated\n");
 742                                         return 1;
 743                                 }
 744 
 745                                 lastnr = nr;
 746                                 if (signal_test == 1) {
 747                                         if (copy_page(uffd, nr * page_size))
 748                                                 signalled++;
 749                                 } else {
 750                                         signalled++;
 751                                         continue;
 752                                 }
 753                         }
 754                 }
 755 
 756                 count = *area_count(area_dst, nr);
 757                 if (count != count_verify[nr]) {
 758                         fprintf(stderr,
 759                                 "nr %lu memory corruption %Lu %Lu\n",
 760                                 nr, count,
 761                                 count_verify[nr]), exit(1);
 762                 }
 763         }
 764 
 765         if (signal_test)
 766                 return signalled != split_nr_pages;
 767 
 768         if (test_type == TEST_HUGETLB)
 769                 return 0;
 770 
 771         area_dst = mremap(area_dst, nr_pages * page_size,  nr_pages * page_size,
 772                           MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
 773         if (area_dst == MAP_FAILED)
 774                 perror("mremap"), exit(1);
 775 
 776         for (; nr < nr_pages; nr++) {
 777                 count = *area_count(area_dst, nr);
 778                 if (count != count_verify[nr]) {
 779                         fprintf(stderr,
 780                                 "nr %lu memory corruption %Lu %Lu\n",
 781                                 nr, count,
 782                                 count_verify[nr]), exit(1);
 783                 }
 784         }
 785 
 786         if (uffd_test_ops->release_pages(area_dst))
 787                 return 1;
 788 
 789         for (nr = 0; nr < nr_pages; nr++) {
 790                 if (my_bcmp(area_dst + nr * page_size, zeropage, page_size))
 791                         fprintf(stderr, "nr %lu is not zero\n", nr), exit(1);
 792         }
 793 
 794         return 0;
 795 }
 796 
 797 static void retry_uffdio_zeropage(int ufd,
 798                                   struct uffdio_zeropage *uffdio_zeropage,
 799                                   unsigned long offset)
 800 {
 801         uffd_test_ops->alias_mapping(&uffdio_zeropage->range.start,
 802                                      uffdio_zeropage->range.len,
 803                                      offset);
 804         if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
 805                 if (uffdio_zeropage->zeropage != -EEXIST)
 806                         fprintf(stderr, "UFFDIO_ZEROPAGE retry error %Ld\n",
 807                                 uffdio_zeropage->zeropage), exit(1);
 808         } else {
 809                 fprintf(stderr, "UFFDIO_ZEROPAGE retry unexpected %Ld\n",
 810                         uffdio_zeropage->zeropage), exit(1);
 811         }
 812 }
 813 
 814 static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
 815 {
 816         struct uffdio_zeropage uffdio_zeropage;
 817         int ret;
 818         unsigned long has_zeropage;
 819 
 820         has_zeropage = uffd_test_ops->expected_ioctls & (1 << _UFFDIO_ZEROPAGE);
 821 
 822         if (offset >= nr_pages * page_size)
 823                 fprintf(stderr, "unexpected offset %lu\n",
 824                         offset), exit(1);
 825         uffdio_zeropage.range.start = (unsigned long) area_dst + offset;
 826         uffdio_zeropage.range.len = page_size;
 827         uffdio_zeropage.mode = 0;
 828         ret = ioctl(ufd, UFFDIO_ZEROPAGE, &uffdio_zeropage);
 829         if (ret) {
 830                 /* real retval in ufdio_zeropage.zeropage */
 831                 if (has_zeropage) {
 832                         if (uffdio_zeropage.zeropage == -EEXIST)
 833                                 fprintf(stderr, "UFFDIO_ZEROPAGE -EEXIST\n"),
 834                                         exit(1);
 835                         else
 836                                 fprintf(stderr, "UFFDIO_ZEROPAGE error %Ld\n",
 837                                         uffdio_zeropage.zeropage), exit(1);
 838                 } else {
 839                         if (uffdio_zeropage.zeropage != -EINVAL)
 840                                 fprintf(stderr,
 841                                         "UFFDIO_ZEROPAGE not -EINVAL %Ld\n",
 842                                         uffdio_zeropage.zeropage), exit(1);
 843                 }
 844         } else if (has_zeropage) {
 845                 if (uffdio_zeropage.zeropage != page_size) {
 846                         fprintf(stderr, "UFFDIO_ZEROPAGE unexpected %Ld\n",
 847                                 uffdio_zeropage.zeropage), exit(1);
 848                 } else {
 849                         if (test_uffdio_zeropage_eexist && retry) {
 850                                 test_uffdio_zeropage_eexist = false;
 851                                 retry_uffdio_zeropage(ufd, &uffdio_zeropage,
 852                                                       offset);
 853                         }
 854                         return 1;
 855                 }
 856         } else {
 857                 fprintf(stderr,
 858                         "UFFDIO_ZEROPAGE succeeded %Ld\n",
 859                         uffdio_zeropage.zeropage), exit(1);
 860         }
 861 
 862         return 0;
 863 }
 864 
 865 static int uffdio_zeropage(int ufd, unsigned long offset)
 866 {
 867         return __uffdio_zeropage(ufd, offset, false);
 868 }
 869 
 870 /* exercise UFFDIO_ZEROPAGE */
 871 static int userfaultfd_zeropage_test(void)
 872 {
 873         struct uffdio_register uffdio_register;
 874         unsigned long expected_ioctls;
 875 
 876         printf("testing UFFDIO_ZEROPAGE: ");
 877         fflush(stdout);
 878 
 879         if (uffd_test_ops->release_pages(area_dst))
 880                 return 1;
 881 
 882         if (userfaultfd_open(0) < 0)
 883                 return 1;
 884         uffdio_register.range.start = (unsigned long) area_dst;
 885         uffdio_register.range.len = nr_pages * page_size;
 886         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 887         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
 888                 fprintf(stderr, "register failure\n"), exit(1);
 889 
 890         expected_ioctls = uffd_test_ops->expected_ioctls;
 891         if ((uffdio_register.ioctls & expected_ioctls) !=
 892             expected_ioctls)
 893                 fprintf(stderr,
 894                         "unexpected missing ioctl for anon memory\n"),
 895                         exit(1);
 896 
 897         if (uffdio_zeropage(uffd, 0)) {
 898                 if (my_bcmp(area_dst, zeropage, page_size))
 899                         fprintf(stderr, "zeropage is not zero\n"), exit(1);
 900         }
 901 
 902         close(uffd);
 903         printf("done.\n");
 904         return 0;
 905 }
 906 
 907 static int userfaultfd_events_test(void)
 908 {
 909         struct uffdio_register uffdio_register;
 910         unsigned long expected_ioctls;
 911         unsigned long userfaults;
 912         pthread_t uffd_mon;
 913         int err, features;
 914         pid_t pid;
 915         char c;
 916 
 917         printf("testing events (fork, remap, remove): ");
 918         fflush(stdout);
 919 
 920         if (uffd_test_ops->release_pages(area_dst))
 921                 return 1;
 922 
 923         features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
 924                 UFFD_FEATURE_EVENT_REMOVE;
 925         if (userfaultfd_open(features) < 0)
 926                 return 1;
 927         fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
 928 
 929         uffdio_register.range.start = (unsigned long) area_dst;
 930         uffdio_register.range.len = nr_pages * page_size;
 931         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 932         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
 933                 fprintf(stderr, "register failure\n"), exit(1);
 934 
 935         expected_ioctls = uffd_test_ops->expected_ioctls;
 936         if ((uffdio_register.ioctls & expected_ioctls) !=
 937             expected_ioctls)
 938                 fprintf(stderr,
 939                         "unexpected missing ioctl for anon memory\n"),
 940                         exit(1);
 941 
 942         if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, NULL))
 943                 perror("uffd_poll_thread create"), exit(1);
 944 
 945         pid = fork();
 946         if (pid < 0)
 947                 perror("fork"), exit(1);
 948 
 949         if (!pid)
 950                 return faulting_process(0);
 951 
 952         waitpid(pid, &err, 0);
 953         if (err)
 954                 fprintf(stderr, "faulting process failed\n"), exit(1);
 955 
 956         if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
 957                 perror("pipe write"), exit(1);
 958         if (pthread_join(uffd_mon, (void **)&userfaults))
 959                 return 1;
 960 
 961         close(uffd);
 962         printf("userfaults: %ld\n", userfaults);
 963 
 964         return userfaults != nr_pages;
 965 }
 966 
 967 static int userfaultfd_sig_test(void)
 968 {
 969         struct uffdio_register uffdio_register;
 970         unsigned long expected_ioctls;
 971         unsigned long userfaults;
 972         pthread_t uffd_mon;
 973         int err, features;
 974         pid_t pid;
 975         char c;
 976 
 977         printf("testing signal delivery: ");
 978         fflush(stdout);
 979 
 980         if (uffd_test_ops->release_pages(area_dst))
 981                 return 1;
 982 
 983         features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
 984         if (userfaultfd_open(features) < 0)
 985                 return 1;
 986         fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
 987 
 988         uffdio_register.range.start = (unsigned long) area_dst;
 989         uffdio_register.range.len = nr_pages * page_size;
 990         uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
 991         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
 992                 fprintf(stderr, "register failure\n"), exit(1);
 993 
 994         expected_ioctls = uffd_test_ops->expected_ioctls;
 995         if ((uffdio_register.ioctls & expected_ioctls) !=
 996             expected_ioctls)
 997                 fprintf(stderr,
 998                         "unexpected missing ioctl for anon memory\n"),
 999                         exit(1);
1000 
1001         if (faulting_process(1))
1002                 fprintf(stderr, "faulting process failed\n"), exit(1);
1003 
1004         if (uffd_test_ops->release_pages(area_dst))
1005                 return 1;
1006 
1007         if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, NULL))
1008                 perror("uffd_poll_thread create"), exit(1);
1009 
1010         pid = fork();
1011         if (pid < 0)
1012                 perror("fork"), exit(1);
1013 
1014         if (!pid)
1015                 exit(faulting_process(2));
1016 
1017         waitpid(pid, &err, 0);
1018         if (err)
1019                 fprintf(stderr, "faulting process failed\n"), exit(1);
1020 
1021         if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
1022                 perror("pipe write"), exit(1);
1023         if (pthread_join(uffd_mon, (void **)&userfaults))
1024                 return 1;
1025 
1026         printf("done.\n");
1027         if (userfaults)
1028                 fprintf(stderr, "Signal test failed, userfaults: %ld\n",
1029                         userfaults);
1030         close(uffd);
1031         return userfaults != 0;
1032 }
1033 static int userfaultfd_stress(void)
1034 {
1035         void *area;
1036         char *tmp_area;
1037         unsigned long nr;
1038         struct uffdio_register uffdio_register;
1039         unsigned long cpu;
1040         int err;
1041         unsigned long userfaults[nr_cpus];
1042 
1043         uffd_test_ops->allocate_area((void **)&area_src);
1044         if (!area_src)
1045                 return 1;
1046         uffd_test_ops->allocate_area((void **)&area_dst);
1047         if (!area_dst)
1048                 return 1;
1049 
1050         if (userfaultfd_open(0) < 0)
1051                 return 1;
1052 
1053         count_verify = malloc(nr_pages * sizeof(unsigned long long));
1054         if (!count_verify) {
1055                 perror("count_verify");
1056                 return 1;
1057         }
1058 
1059         for (nr = 0; nr < nr_pages; nr++) {
1060                 *area_mutex(area_src, nr) = (pthread_mutex_t)
1061                         PTHREAD_MUTEX_INITIALIZER;
1062                 count_verify[nr] = *area_count(area_src, nr) = 1;
1063                 /*
1064                  * In the transition between 255 to 256, powerpc will
1065                  * read out of order in my_bcmp and see both bytes as
1066                  * zero, so leave a placeholder below always non-zero
1067                  * after the count, to avoid my_bcmp to trigger false
1068                  * positives.
1069                  */
1070                 *(area_count(area_src, nr) + 1) = 1;
1071         }
1072 
1073         pipefd = malloc(sizeof(int) * nr_cpus * 2);
1074         if (!pipefd) {
1075                 perror("pipefd");
1076                 return 1;
1077         }
1078         for (cpu = 0; cpu < nr_cpus; cpu++) {
1079                 if (pipe2(&pipefd[cpu*2], O_CLOEXEC | O_NONBLOCK)) {
1080                         perror("pipe");
1081                         return 1;
1082                 }
1083         }
1084 
1085         if (posix_memalign(&area, page_size, page_size)) {
1086                 fprintf(stderr, "out of memory\n");
1087                 return 1;
1088         }
1089         zeropage = area;
1090         bzero(zeropage, page_size);
1091 
1092         pthread_mutex_lock(&uffd_read_mutex);
1093 
1094         pthread_attr_init(&attr);
1095         pthread_attr_setstacksize(&attr, 16*1024*1024);
1096 
1097         err = 0;
1098         while (bounces--) {
1099                 unsigned long expected_ioctls;
1100 
1101                 printf("bounces: %d, mode:", bounces);
1102                 if (bounces & BOUNCE_RANDOM)
1103                         printf(" rnd");
1104                 if (bounces & BOUNCE_RACINGFAULTS)
1105                         printf(" racing");
1106                 if (bounces & BOUNCE_VERIFY)
1107                         printf(" ver");
1108                 if (bounces & BOUNCE_POLL)
1109                         printf(" poll");
1110                 printf(", ");
1111                 fflush(stdout);
1112 
1113                 if (bounces & BOUNCE_POLL)
1114                         fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
1115                 else
1116                         fcntl(uffd, F_SETFL, uffd_flags & ~O_NONBLOCK);
1117 
1118                 /* register */
1119                 uffdio_register.range.start = (unsigned long) area_dst;
1120                 uffdio_register.range.len = nr_pages * page_size;
1121                 uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
1122                 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
1123                         fprintf(stderr, "register failure\n");
1124                         return 1;
1125                 }
1126                 expected_ioctls = uffd_test_ops->expected_ioctls;
1127                 if ((uffdio_register.ioctls & expected_ioctls) !=
1128                     expected_ioctls) {
1129                         fprintf(stderr,
1130                                 "unexpected missing ioctl for anon memory\n");
1131                         return 1;
1132                 }
1133 
1134                 if (area_dst_alias) {
1135                         uffdio_register.range.start = (unsigned long)
1136                                 area_dst_alias;
1137                         if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
1138                                 fprintf(stderr, "register failure alias\n");
1139                                 return 1;
1140                         }
1141                 }
1142 
1143                 /*
1144                  * The madvise done previously isn't enough: some
1145                  * uffd_thread could have read userfaults (one of
1146                  * those already resolved by the background thread)
1147                  * and it may be in the process of calling
1148                  * UFFDIO_COPY. UFFDIO_COPY will read the zapped
1149                  * area_src and it would map a zero page in it (of
1150                  * course such a UFFDIO_COPY is perfectly safe as it'd
1151                  * return -EEXIST). The problem comes at the next
1152                  * bounce though: that racing UFFDIO_COPY would
1153                  * generate zeropages in the area_src, so invalidating
1154                  * the previous MADV_DONTNEED. Without this additional
1155                  * MADV_DONTNEED those zeropages leftovers in the
1156                  * area_src would lead to -EEXIST failure during the
1157                  * next bounce, effectively leaving a zeropage in the
1158                  * area_dst.
1159                  *
1160                  * Try to comment this out madvise to see the memory
1161                  * corruption being caught pretty quick.
1162                  *
1163                  * khugepaged is also inhibited to collapse THP after
1164                  * MADV_DONTNEED only after the UFFDIO_REGISTER, so it's
1165                  * required to MADV_DONTNEED here.
1166                  */
1167                 if (uffd_test_ops->release_pages(area_dst))
1168                         return 1;
1169 
1170                 /* bounce pass */
1171                 if (stress(userfaults))
1172                         return 1;
1173 
1174                 /* unregister */
1175                 if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range)) {
1176                         fprintf(stderr, "unregister failure\n");
1177                         return 1;
1178                 }
1179                 if (area_dst_alias) {
1180                         uffdio_register.range.start = (unsigned long) area_dst;
1181                         if (ioctl(uffd, UFFDIO_UNREGISTER,
1182                                   &uffdio_register.range)) {
1183                                 fprintf(stderr, "unregister failure alias\n");
1184                                 return 1;
1185                         }
1186                 }
1187 
1188                 /* verification */
1189                 if (bounces & BOUNCE_VERIFY) {
1190                         for (nr = 0; nr < nr_pages; nr++) {
1191                                 if (*area_count(area_dst, nr) != count_verify[nr]) {
1192                                         fprintf(stderr,
1193                                                 "error area_count %Lu %Lu %lu\n",
1194                                                 *area_count(area_src, nr),
1195                                                 count_verify[nr],
1196                                                 nr);
1197                                         err = 1;
1198                                         bounces = 0;
1199                                 }
1200                         }
1201                 }
1202 
1203                 /* prepare next bounce */
1204                 tmp_area = area_src;
1205                 area_src = area_dst;
1206                 area_dst = tmp_area;
1207 
1208                 tmp_area = area_src_alias;
1209                 area_src_alias = area_dst_alias;
1210                 area_dst_alias = tmp_area;
1211 
1212                 printf("userfaults:");
1213                 for (cpu = 0; cpu < nr_cpus; cpu++)
1214                         printf(" %lu", userfaults[cpu]);
1215                 printf("\n");
1216         }
1217 
1218         if (err)
1219                 return err;
1220 
1221         close(uffd);
1222         return userfaultfd_zeropage_test() || userfaultfd_sig_test()
1223                 || userfaultfd_events_test();
1224 }
1225 
1226 /*
1227  * Copied from mlock2-tests.c
1228  */
1229 unsigned long default_huge_page_size(void)
1230 {
1231         unsigned long hps = 0;
1232         char *line = NULL;
1233         size_t linelen = 0;
1234         FILE *f = fopen("/proc/meminfo", "r");
1235 
1236         if (!f)
1237                 return 0;
1238         while (getline(&line, &linelen, f) > 0) {
1239                 if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
1240                         hps <<= 10;
1241                         break;
1242                 }
1243         }
1244 
1245         free(line);
1246         fclose(f);
1247         return hps;
1248 }
1249 
1250 static void set_test_type(const char *type)
1251 {
1252         if (!strcmp(type, "anon")) {
1253                 test_type = TEST_ANON;
1254                 uffd_test_ops = &anon_uffd_test_ops;
1255         } else if (!strcmp(type, "hugetlb")) {
1256                 test_type = TEST_HUGETLB;
1257                 uffd_test_ops = &hugetlb_uffd_test_ops;
1258         } else if (!strcmp(type, "hugetlb_shared")) {
1259                 map_shared = true;
1260                 test_type = TEST_HUGETLB;
1261                 uffd_test_ops = &hugetlb_uffd_test_ops;
1262         } else if (!strcmp(type, "shmem")) {
1263                 map_shared = true;
1264                 test_type = TEST_SHMEM;
1265                 uffd_test_ops = &shmem_uffd_test_ops;
1266         } else {
1267                 fprintf(stderr, "Unknown test type: %s\n", type), exit(1);
1268         }
1269 
1270         if (test_type == TEST_HUGETLB)
1271                 page_size = default_huge_page_size();
1272         else
1273                 page_size = sysconf(_SC_PAGE_SIZE);
1274 
1275         if (!page_size)
1276                 fprintf(stderr, "Unable to determine page size\n"),
1277                                 exit(2);
1278         if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) * 2
1279             > page_size)
1280                 fprintf(stderr, "Impossible to run this test\n"), exit(2);
1281 }
1282 
1283 static void sigalrm(int sig)
1284 {
1285         if (sig != SIGALRM)
1286                 abort();
1287         test_uffdio_copy_eexist = true;
1288         test_uffdio_zeropage_eexist = true;
1289         alarm(ALARM_INTERVAL_SECS);
1290 }
1291 
1292 int main(int argc, char **argv)
1293 {
1294         if (argc < 4)
1295                 usage();
1296 
1297         if (signal(SIGALRM, sigalrm) == SIG_ERR)
1298                 fprintf(stderr, "failed to arm SIGALRM"), exit(1);
1299         alarm(ALARM_INTERVAL_SECS);
1300 
1301         set_test_type(argv[1]);
1302 
1303         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
1304         nr_pages_per_cpu = atol(argv[2]) * 1024*1024 / page_size /
1305                 nr_cpus;
1306         if (!nr_pages_per_cpu) {
1307                 fprintf(stderr, "invalid MiB\n");
1308                 usage();
1309         }
1310 
1311         bounces = atoi(argv[3]);
1312         if (bounces <= 0) {
1313                 fprintf(stderr, "invalid bounces\n");
1314                 usage();
1315         }
1316         nr_pages = nr_pages_per_cpu * nr_cpus;
1317 
1318         if (test_type == TEST_HUGETLB) {
1319                 if (argc < 5)
1320                         usage();
1321                 huge_fd = open(argv[4], O_CREAT | O_RDWR, 0755);
1322                 if (huge_fd < 0) {
1323                         fprintf(stderr, "Open of %s failed", argv[3]);
1324                         perror("open");
1325                         exit(1);
1326                 }
1327                 if (ftruncate(huge_fd, 0)) {
1328                         fprintf(stderr, "ftruncate %s to size 0 failed", argv[3]);
1329                         perror("ftruncate");
1330                         exit(1);
1331                 }
1332         }
1333         printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
1334                nr_pages, nr_pages_per_cpu);
1335         return userfaultfd_stress();
1336 }
1337 
1338 #else /* __NR_userfaultfd */
1339 
1340 #warning "missing __NR_userfaultfd definition"
1341 
1342 int main(void)
1343 {
1344         printf("skip: Skipping userfaultfd test (missing __NR_userfaultfd)\n");
1345         return KSFT_SKIP;
1346 }
1347 
1348 #endif /* __NR_userfaultfd */
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root/tools/testing/selftests/vm/userfaultfd.c

DEFINITIONS
