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Linux/tools/testing/selftests/vm/userfaultfd.c

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  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 */
1349 

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