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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#include <assert.h>
58#include <inttypes.h>
59#include <stdint.h>
60
61#include "../kselftest.h"
62
63#ifdef __NR_userfaultfd
64
65static unsigned long nr_cpus, nr_pages, nr_pages_per_cpu, page_size;
66
67#define BOUNCE_RANDOM (1<<0)
68#define BOUNCE_RACINGFAULTS (1<<1)
69#define BOUNCE_VERIFY (1<<2)
70#define BOUNCE_POLL (1<<3)
71static int bounces;
72
73#define TEST_ANON 1
74#define TEST_HUGETLB 2
75#define TEST_SHMEM 3
76static int test_type;
77
78/* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */
79#define ALARM_INTERVAL_SECS 10
80static volatile bool test_uffdio_copy_eexist = true;
81static volatile bool test_uffdio_zeropage_eexist = true;
82/* Whether to test uffd write-protection */
83static bool test_uffdio_wp = false;
84/* Whether to test uffd minor faults */
85static bool test_uffdio_minor = false;
86
87static bool map_shared;
88static int shm_fd;
89static int huge_fd;
90static char *huge_fd_off0;
91static unsigned long long *count_verify;
92static int uffd = -1;
93static int uffd_flags, finished, *pipefd;
94static char *area_src, *area_src_alias, *area_dst, *area_dst_alias;
95static char *zeropage;
96pthread_attr_t attr;
97
98/* Userfaultfd test statistics */
99struct uffd_stats {
100 int cpu;
101 unsigned long missing_faults;
102 unsigned long wp_faults;
103 unsigned long minor_faults;
104};
105
106/* pthread_mutex_t starts at page offset 0 */
107#define area_mutex(___area, ___nr) \
108 ((pthread_mutex_t *) ((___area) + (___nr)*page_size))
109/*
110 * count is placed in the page after pthread_mutex_t naturally aligned
111 * to avoid non alignment faults on non-x86 archs.
112 */
113#define area_count(___area, ___nr) \
114 ((volatile unsigned long long *) ((unsigned long) \
115 ((___area) + (___nr)*page_size + \
116 sizeof(pthread_mutex_t) + \
117 sizeof(unsigned long long) - 1) & \
118 ~(unsigned long)(sizeof(unsigned long long) \
119 - 1)))
120
121const char *examples =
122 "# Run anonymous memory test on 100MiB region with 99999 bounces:\n"
123 "./userfaultfd anon 100 99999\n\n"
124 "# Run share memory test on 1GiB region with 99 bounces:\n"
125 "./userfaultfd shmem 1000 99\n\n"
126 "# Run hugetlb memory test on 256MiB region with 50 bounces (using /dev/hugepages/hugefile):\n"
127 "./userfaultfd hugetlb 256 50 /dev/hugepages/hugefile\n\n"
128 "# Run the same hugetlb test but using shmem:\n"
129 "./userfaultfd hugetlb_shared 256 50 /dev/hugepages/hugefile\n\n"
130 "# 10MiB-~6GiB 999 bounces anonymous test, "
131 "continue forever unless an error triggers\n"
132 "while ./userfaultfd anon $[RANDOM % 6000 + 10] 999; do true; done\n\n";
133
134static void usage(void)
135{
136 fprintf(stderr, "\nUsage: ./userfaultfd <test type> <MiB> <bounces> "
137 "[hugetlbfs_file]\n\n");
138 fprintf(stderr, "Supported <test type>: anon, hugetlb, "
139 "hugetlb_shared, shmem\n\n");
140 fprintf(stderr, "Examples:\n\n");
141 fprintf(stderr, "%s", examples);
142 exit(1);
143}
144
145#define _err(fmt, ...) \
146 do { \
147 int ret = errno; \
148 fprintf(stderr, "ERROR: " fmt, ##__VA_ARGS__); \
149 fprintf(stderr, " (errno=%d, line=%d)\n", \
150 ret, __LINE__); \
151 } while (0)
152
153#define err(fmt, ...) \
154 do { \
155 _err(fmt, ##__VA_ARGS__); \
156 exit(1); \
157 } while (0)
158
159static void uffd_stats_reset(struct uffd_stats *uffd_stats,
160 unsigned long n_cpus)
161{
162 int i;
163
164 for (i = 0; i < n_cpus; i++) {
165 uffd_stats[i].cpu = i;
166 uffd_stats[i].missing_faults = 0;
167 uffd_stats[i].wp_faults = 0;
168 uffd_stats[i].minor_faults = 0;
169 }
170}
171
172static void uffd_stats_report(struct uffd_stats *stats, int n_cpus)
173{
174 int i;
175 unsigned long long miss_total = 0, wp_total = 0, minor_total = 0;
176
177 for (i = 0; i < n_cpus; i++) {
178 miss_total += stats[i].missing_faults;
179 wp_total += stats[i].wp_faults;
180 minor_total += stats[i].minor_faults;
181 }
182
183 printf("userfaults: ");
184 if (miss_total) {
185 printf("%llu missing (", miss_total);
186 for (i = 0; i < n_cpus; i++)
187 printf("%lu+", stats[i].missing_faults);
188 printf("\b) ");
189 }
190 if (wp_total) {
191 printf("%llu wp (", wp_total);
192 for (i = 0; i < n_cpus; i++)
193 printf("%lu+", stats[i].wp_faults);
194 printf("\b) ");
195 }
196 if (minor_total) {
197 printf("%llu minor (", minor_total);
198 for (i = 0; i < n_cpus; i++)
199 printf("%lu+", stats[i].minor_faults);
200 printf("\b)");
201 }
202 printf("\n");
203}
204
205static void anon_release_pages(char *rel_area)
206{
207 if (madvise(rel_area, nr_pages * page_size, MADV_DONTNEED))
208 err("madvise(MADV_DONTNEED) failed");
209}
210
211static void anon_allocate_area(void **alloc_area)
212{
213 *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
214 MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
215 if (*alloc_area == MAP_FAILED)
216 err("mmap of anonymous memory failed");
217}
218
219static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset)
220{
221}
222
223static void hugetlb_release_pages(char *rel_area)
224{
225 if (fallocate(huge_fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
226 rel_area == huge_fd_off0 ? 0 : nr_pages * page_size,
227 nr_pages * page_size))
228 err("fallocate() failed");
229}
230
231static void hugetlb_allocate_area(void **alloc_area)
232{
233 void *area_alias = NULL;
234 char **alloc_area_alias;
235
236 *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
237 (map_shared ? MAP_SHARED : MAP_PRIVATE) |
238 MAP_HUGETLB,
239 huge_fd, *alloc_area == area_src ? 0 :
240 nr_pages * page_size);
241 if (*alloc_area == MAP_FAILED)
242 err("mmap of hugetlbfs file failed");
243
244 if (map_shared) {
245 area_alias = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
246 MAP_SHARED | MAP_HUGETLB,
247 huge_fd, *alloc_area == area_src ? 0 :
248 nr_pages * page_size);
249 if (area_alias == MAP_FAILED)
250 err("mmap of hugetlb file alias failed");
251 }
252
253 if (*alloc_area == area_src) {
254 huge_fd_off0 = *alloc_area;
255 alloc_area_alias = &area_src_alias;
256 } else {
257 alloc_area_alias = &area_dst_alias;
258 }
259 if (area_alias)
260 *alloc_area_alias = area_alias;
261}
262
263static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset)
264{
265 if (!map_shared)
266 return;
267 /*
268 * We can't zap just the pagetable with hugetlbfs because
269 * MADV_DONTEED won't work. So exercise -EEXIST on a alias
270 * mapping where the pagetables are not established initially,
271 * this way we'll exercise the -EEXEC at the fs level.
272 */
273 *start = (unsigned long) area_dst_alias + offset;
274}
275
276static void shmem_release_pages(char *rel_area)
277{
278 if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE))
279 err("madvise(MADV_REMOVE) failed");
280}
281
282static void shmem_allocate_area(void **alloc_area)
283{
284 void *area_alias = NULL;
285 bool is_src = alloc_area == (void **)&area_src;
286 unsigned long offset = is_src ? 0 : nr_pages * page_size;
287
288 *alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
289 MAP_SHARED, shm_fd, offset);
290 if (*alloc_area == MAP_FAILED)
291 err("mmap of memfd failed");
292
293 area_alias = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
294 MAP_SHARED, shm_fd, offset);
295 if (area_alias == MAP_FAILED)
296 err("mmap of memfd alias failed");
297
298 if (is_src)
299 area_src_alias = area_alias;
300 else
301 area_dst_alias = area_alias;
302}
303
304static void shmem_alias_mapping(__u64 *start, size_t len, unsigned long offset)
305{
306 *start = (unsigned long)area_dst_alias + offset;
307}
308
309struct uffd_test_ops {
310 unsigned long expected_ioctls;
311 void (*allocate_area)(void **alloc_area);
312 void (*release_pages)(char *rel_area);
313 void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset);
314};
315
316#define SHMEM_EXPECTED_IOCTLS ((1 << _UFFDIO_WAKE) | \
317 (1 << _UFFDIO_COPY) | \
318 (1 << _UFFDIO_ZEROPAGE))
319
320#define ANON_EXPECTED_IOCTLS ((1 << _UFFDIO_WAKE) | \
321 (1 << _UFFDIO_COPY) | \
322 (1 << _UFFDIO_ZEROPAGE) | \
323 (1 << _UFFDIO_WRITEPROTECT))
324
325static struct uffd_test_ops anon_uffd_test_ops = {
326 .expected_ioctls = ANON_EXPECTED_IOCTLS,
327 .allocate_area = anon_allocate_area,
328 .release_pages = anon_release_pages,
329 .alias_mapping = noop_alias_mapping,
330};
331
332static struct uffd_test_ops shmem_uffd_test_ops = {
333 .expected_ioctls = SHMEM_EXPECTED_IOCTLS,
334 .allocate_area = shmem_allocate_area,
335 .release_pages = shmem_release_pages,
336 .alias_mapping = shmem_alias_mapping,
337};
338
339static struct uffd_test_ops hugetlb_uffd_test_ops = {
340 .expected_ioctls = UFFD_API_RANGE_IOCTLS_BASIC & ~(1 << _UFFDIO_CONTINUE),
341 .allocate_area = hugetlb_allocate_area,
342 .release_pages = hugetlb_release_pages,
343 .alias_mapping = hugetlb_alias_mapping,
344};
345
346static struct uffd_test_ops *uffd_test_ops;
347
348static void userfaultfd_open(uint64_t *features)
349{
350 struct uffdio_api uffdio_api;
351
352 uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK | UFFD_USER_MODE_ONLY);
353 if (uffd < 0)
354 err("userfaultfd syscall not available in this kernel");
355 uffd_flags = fcntl(uffd, F_GETFD, NULL);
356
357 uffdio_api.api = UFFD_API;
358 uffdio_api.features = *features;
359 if (ioctl(uffd, UFFDIO_API, &uffdio_api))
360 err("UFFDIO_API failed.\nPlease make sure to "
361 "run with either root or ptrace capability.");
362 if (uffdio_api.api != UFFD_API)
363 err("UFFDIO_API error: %" PRIu64, (uint64_t)uffdio_api.api);
364
365 *features = uffdio_api.features;
366}
367
368static inline void munmap_area(void **area)
369{
370 if (*area)
371 if (munmap(*area, nr_pages * page_size))
372 err("munmap");
373
374 *area = NULL;
375}
376
377static void uffd_test_ctx_clear(void)
378{
379 size_t i;
380
381 if (pipefd) {
382 for (i = 0; i < nr_cpus * 2; ++i) {
383 if (close(pipefd[i]))
384 err("close pipefd");
385 }
386 free(pipefd);
387 pipefd = NULL;
388 }
389
390 if (count_verify) {
391 free(count_verify);
392 count_verify = NULL;
393 }
394
395 if (uffd != -1) {
396 if (close(uffd))
397 err("close uffd");
398 uffd = -1;
399 }
400
401 huge_fd_off0 = NULL;
402 munmap_area((void **)&area_src);
403 munmap_area((void **)&area_src_alias);
404 munmap_area((void **)&area_dst);
405 munmap_area((void **)&area_dst_alias);
406}
407
408static void uffd_test_ctx_init_ext(uint64_t *features)
409{
410 unsigned long nr, cpu;
411
412 uffd_test_ctx_clear();
413
414 uffd_test_ops->allocate_area((void **)&area_src);
415 uffd_test_ops->allocate_area((void **)&area_dst);
416
417 userfaultfd_open(features);
418
419 count_verify = malloc(nr_pages * sizeof(unsigned long long));
420 if (!count_verify)
421 err("count_verify");
422
423 for (nr = 0; nr < nr_pages; nr++) {
424 *area_mutex(area_src, nr) =
425 (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
426 count_verify[nr] = *area_count(area_src, nr) = 1;
427 /*
428 * In the transition between 255 to 256, powerpc will
429 * read out of order in my_bcmp and see both bytes as
430 * zero, so leave a placeholder below always non-zero
431 * after the count, to avoid my_bcmp to trigger false
432 * positives.
433 */
434 *(area_count(area_src, nr) + 1) = 1;
435 }
436
437 /*
438 * After initialization of area_src, we must explicitly release pages
439 * for area_dst to make sure it's fully empty. Otherwise we could have
440 * some area_dst pages be errornously initialized with zero pages,
441 * hence we could hit memory corruption later in the test.
442 *
443 * One example is when THP is globally enabled, above allocate_area()
444 * calls could have the two areas merged into a single VMA (as they
445 * will have the same VMA flags so they're mergeable). When we
446 * initialize the area_src above, it's possible that some part of
447 * area_dst could have been faulted in via one huge THP that will be
448 * shared between area_src and area_dst. It could cause some of the
449 * area_dst won't be trapped by missing userfaults.
450 *
451 * This release_pages() will guarantee even if that happened, we'll
452 * proactively split the thp and drop any accidentally initialized
453 * pages within area_dst.
454 */
455 uffd_test_ops->release_pages(area_dst);
456
457 pipefd = malloc(sizeof(int) * nr_cpus * 2);
458 if (!pipefd)
459 err("pipefd");
460 for (cpu = 0; cpu < nr_cpus; cpu++)
461 if (pipe2(&pipefd[cpu * 2], O_CLOEXEC | O_NONBLOCK))
462 err("pipe");
463}
464
465static inline void uffd_test_ctx_init(uint64_t features)
466{
467 uffd_test_ctx_init_ext(&features);
468}
469
470static int my_bcmp(char *str1, char *str2, size_t n)
471{
472 unsigned long i;
473 for (i = 0; i < n; i++)
474 if (str1[i] != str2[i])
475 return 1;
476 return 0;
477}
478
479static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
480{
481 struct uffdio_writeprotect prms;
482
483 /* Write protection page faults */
484 prms.range.start = start;
485 prms.range.len = len;
486 /* Undo write-protect, do wakeup after that */
487 prms.mode = wp ? UFFDIO_WRITEPROTECT_MODE_WP : 0;
488
489 if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms))
490 err("clear WP failed: address=0x%"PRIx64, (uint64_t)start);
491}
492
493static void continue_range(int ufd, __u64 start, __u64 len)
494{
495 struct uffdio_continue req;
496 int ret;
497
498 req.range.start = start;
499 req.range.len = len;
500 req.mode = 0;
501
502 if (ioctl(ufd, UFFDIO_CONTINUE, &req))
503 err("UFFDIO_CONTINUE failed for address 0x%" PRIx64,
504 (uint64_t)start);
505
506 /*
507 * Error handling within the kernel for continue is subtly different
508 * from copy or zeropage, so it may be a source of bugs. Trigger an
509 * error (-EEXIST) on purpose, to verify doing so doesn't cause a BUG.
510 */
511 req.mapped = 0;
512 ret = ioctl(ufd, UFFDIO_CONTINUE, &req);
513 if (ret >= 0 || req.mapped != -EEXIST)
514 err("failed to exercise UFFDIO_CONTINUE error handling, ret=%d, mapped=%" PRId64,
515 ret, (int64_t) req.mapped);
516}
517
518static void *locking_thread(void *arg)
519{
520 unsigned long cpu = (unsigned long) arg;
521 struct random_data rand;
522 unsigned long page_nr = *(&(page_nr)); /* uninitialized warning */
523 int32_t rand_nr;
524 unsigned long long count;
525 char randstate[64];
526 unsigned int seed;
527
528 if (bounces & BOUNCE_RANDOM) {
529 seed = (unsigned int) time(NULL) - bounces;
530 if (!(bounces & BOUNCE_RACINGFAULTS))
531 seed += cpu;
532 bzero(&rand, sizeof(rand));
533 bzero(&randstate, sizeof(randstate));
534 if (initstate_r(seed, randstate, sizeof(randstate), &rand))
535 err("initstate_r failed");
536 } else {
537 page_nr = -bounces;
538 if (!(bounces & BOUNCE_RACINGFAULTS))
539 page_nr += cpu * nr_pages_per_cpu;
540 }
541
542 while (!finished) {
543 if (bounces & BOUNCE_RANDOM) {
544 if (random_r(&rand, &rand_nr))
545 err("random_r failed");
546 page_nr = rand_nr;
547 if (sizeof(page_nr) > sizeof(rand_nr)) {
548 if (random_r(&rand, &rand_nr))
549 err("random_r failed");
550 page_nr |= (((unsigned long) rand_nr) << 16) <<
551 16;
552 }
553 } else
554 page_nr += 1;
555 page_nr %= nr_pages;
556 pthread_mutex_lock(area_mutex(area_dst, page_nr));
557 count = *area_count(area_dst, page_nr);
558 if (count != count_verify[page_nr])
559 err("page_nr %lu memory corruption %llu %llu",
560 page_nr, count, count_verify[page_nr]);
561 count++;
562 *area_count(area_dst, page_nr) = count_verify[page_nr] = count;
563 pthread_mutex_unlock(area_mutex(area_dst, page_nr));
564 }
565
566 return NULL;
567}
568
569static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
570 unsigned long offset)
571{
572 uffd_test_ops->alias_mapping(&uffdio_copy->dst,
573 uffdio_copy->len,
574 offset);
575 if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) {
576 /* real retval in ufdio_copy.copy */
577 if (uffdio_copy->copy != -EEXIST)
578 err("UFFDIO_COPY retry error: %"PRId64,
579 (int64_t)uffdio_copy->copy);
580 } else {
581 err("UFFDIO_COPY retry unexpected: %"PRId64,
582 (int64_t)uffdio_copy->copy);
583 }
584}
585
586static int __copy_page(int ufd, unsigned long offset, bool retry)
587{
588 struct uffdio_copy uffdio_copy;
589
590 if (offset >= nr_pages * page_size)
591 err("unexpected offset %lu\n", offset);
592 uffdio_copy.dst = (unsigned long) area_dst + offset;
593 uffdio_copy.src = (unsigned long) area_src + offset;
594 uffdio_copy.len = page_size;
595 if (test_uffdio_wp)
596 uffdio_copy.mode = UFFDIO_COPY_MODE_WP;
597 else
598 uffdio_copy.mode = 0;
599 uffdio_copy.copy = 0;
600 if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
601 /* real retval in ufdio_copy.copy */
602 if (uffdio_copy.copy != -EEXIST)
603 err("UFFDIO_COPY error: %"PRId64,
604 (int64_t)uffdio_copy.copy);
605 } else if (uffdio_copy.copy != page_size) {
606 err("UFFDIO_COPY error: %"PRId64, (int64_t)uffdio_copy.copy);
607 } else {
608 if (test_uffdio_copy_eexist && retry) {
609 test_uffdio_copy_eexist = false;
610 retry_copy_page(ufd, &uffdio_copy, offset);
611 }
612 return 1;
613 }
614 return 0;
615}
616
617static int copy_page_retry(int ufd, unsigned long offset)
618{
619 return __copy_page(ufd, offset, true);
620}
621
622static int copy_page(int ufd, unsigned long offset)
623{
624 return __copy_page(ufd, offset, false);
625}
626
627static int uffd_read_msg(int ufd, struct uffd_msg *msg)
628{
629 int ret = read(uffd, msg, sizeof(*msg));
630
631 if (ret != sizeof(*msg)) {
632 if (ret < 0) {
633 if (errno == EAGAIN)
634 return 1;
635 err("blocking read error");
636 } else {
637 err("short read");
638 }
639 }
640
641 return 0;
642}
643
644static void uffd_handle_page_fault(struct uffd_msg *msg,
645 struct uffd_stats *stats)
646{
647 unsigned long offset;
648
649 if (msg->event != UFFD_EVENT_PAGEFAULT)
650 err("unexpected msg event %u", msg->event);
651
652 if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WP) {
653 /* Write protect page faults */
654 wp_range(uffd, msg->arg.pagefault.address, page_size, false);
655 stats->wp_faults++;
656 } else if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_MINOR) {
657 uint8_t *area;
658 int b;
659
660 /*
661 * Minor page faults
662 *
663 * To prove we can modify the original range for testing
664 * purposes, we're going to bit flip this range before
665 * continuing.
666 *
667 * Note that this requires all minor page fault tests operate on
668 * area_dst (non-UFFD-registered) and area_dst_alias
669 * (UFFD-registered).
670 */
671
672 area = (uint8_t *)(area_dst +
673 ((char *)msg->arg.pagefault.address -
674 area_dst_alias));
675 for (b = 0; b < page_size; ++b)
676 area[b] = ~area[b];
677 continue_range(uffd, msg->arg.pagefault.address, page_size);
678 stats->minor_faults++;
679 } else {
680 /* Missing page faults */
681 if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
682 err("unexpected write fault");
683
684 offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst;
685 offset &= ~(page_size-1);
686
687 if (copy_page(uffd, offset))
688 stats->missing_faults++;
689 }
690}
691
692static void *uffd_poll_thread(void *arg)
693{
694 struct uffd_stats *stats = (struct uffd_stats *)arg;
695 unsigned long cpu = stats->cpu;
696 struct pollfd pollfd[2];
697 struct uffd_msg msg;
698 struct uffdio_register uffd_reg;
699 int ret;
700 char tmp_chr;
701
702 pollfd[0].fd = uffd;
703 pollfd[0].events = POLLIN;
704 pollfd[1].fd = pipefd[cpu*2];
705 pollfd[1].events = POLLIN;
706
707 for (;;) {
708 ret = poll(pollfd, 2, -1);
709 if (ret <= 0)
710 err("poll error: %d", ret);
711 if (pollfd[1].revents & POLLIN) {
712 if (read(pollfd[1].fd, &tmp_chr, 1) != 1)
713 err("read pipefd error");
714 break;
715 }
716 if (!(pollfd[0].revents & POLLIN))
717 err("pollfd[0].revents %d", pollfd[0].revents);
718 if (uffd_read_msg(uffd, &msg))
719 continue;
720 switch (msg.event) {
721 default:
722 err("unexpected msg event %u\n", msg.event);
723 break;
724 case UFFD_EVENT_PAGEFAULT:
725 uffd_handle_page_fault(&msg, stats);
726 break;
727 case UFFD_EVENT_FORK:
728 close(uffd);
729 uffd = msg.arg.fork.ufd;
730 pollfd[0].fd = uffd;
731 break;
732 case UFFD_EVENT_REMOVE:
733 uffd_reg.range.start = msg.arg.remove.start;
734 uffd_reg.range.len = msg.arg.remove.end -
735 msg.arg.remove.start;
736 if (ioctl(uffd, UFFDIO_UNREGISTER, &uffd_reg.range))
737 err("remove failure");
738 break;
739 case UFFD_EVENT_REMAP:
740 area_dst = (char *)(unsigned long)msg.arg.remap.to;
741 break;
742 }
743 }
744
745 return NULL;
746}
747
748pthread_mutex_t uffd_read_mutex = PTHREAD_MUTEX_INITIALIZER;
749
750static void *uffd_read_thread(void *arg)
751{
752 struct uffd_stats *stats = (struct uffd_stats *)arg;
753 struct uffd_msg msg;
754
755 pthread_mutex_unlock(&uffd_read_mutex);
756 /* from here cancellation is ok */
757
758 for (;;) {
759 if (uffd_read_msg(uffd, &msg))
760 continue;
761 uffd_handle_page_fault(&msg, stats);
762 }
763
764 return NULL;
765}
766
767static void *background_thread(void *arg)
768{
769 unsigned long cpu = (unsigned long) arg;
770 unsigned long page_nr, start_nr, mid_nr, end_nr;
771
772 start_nr = cpu * nr_pages_per_cpu;
773 end_nr = (cpu+1) * nr_pages_per_cpu;
774 mid_nr = (start_nr + end_nr) / 2;
775
776 /* Copy the first half of the pages */
777 for (page_nr = start_nr; page_nr < mid_nr; page_nr++)
778 copy_page_retry(uffd, page_nr * page_size);
779
780 /*
781 * If we need to test uffd-wp, set it up now. Then we'll have
782 * at least the first half of the pages mapped already which
783 * can be write-protected for testing
784 */
785 if (test_uffdio_wp)
786 wp_range(uffd, (unsigned long)area_dst + start_nr * page_size,
787 nr_pages_per_cpu * page_size, true);
788
789 /*
790 * Continue the 2nd half of the page copying, handling write
791 * protection faults if any
792 */
793 for (page_nr = mid_nr; page_nr < end_nr; page_nr++)
794 copy_page_retry(uffd, page_nr * page_size);
795
796 return NULL;
797}
798
799static int stress(struct uffd_stats *uffd_stats)
800{
801 unsigned long cpu;
802 pthread_t locking_threads[nr_cpus];
803 pthread_t uffd_threads[nr_cpus];
804 pthread_t background_threads[nr_cpus];
805
806 finished = 0;
807 for (cpu = 0; cpu < nr_cpus; cpu++) {
808 if (pthread_create(&locking_threads[cpu], &attr,
809 locking_thread, (void *)cpu))
810 return 1;
811 if (bounces & BOUNCE_POLL) {
812 if (pthread_create(&uffd_threads[cpu], &attr,
813 uffd_poll_thread,
814 (void *)&uffd_stats[cpu]))
815 return 1;
816 } else {
817 if (pthread_create(&uffd_threads[cpu], &attr,
818 uffd_read_thread,
819 (void *)&uffd_stats[cpu]))
820 return 1;
821 pthread_mutex_lock(&uffd_read_mutex);
822 }
823 if (pthread_create(&background_threads[cpu], &attr,
824 background_thread, (void *)cpu))
825 return 1;
826 }
827 for (cpu = 0; cpu < nr_cpus; cpu++)
828 if (pthread_join(background_threads[cpu], NULL))
829 return 1;
830
831 /*
832 * Be strict and immediately zap area_src, the whole area has
833 * been transferred already by the background treads. The
834 * area_src could then be faulted in in a racy way by still
835 * running uffdio_threads reading zeropages after we zapped
836 * area_src (but they're guaranteed to get -EEXIST from
837 * UFFDIO_COPY without writing zero pages into area_dst
838 * because the background threads already completed).
839 */
840 uffd_test_ops->release_pages(area_src);
841
842 finished = 1;
843 for (cpu = 0; cpu < nr_cpus; cpu++)
844 if (pthread_join(locking_threads[cpu], NULL))
845 return 1;
846
847 for (cpu = 0; cpu < nr_cpus; cpu++) {
848 char c;
849 if (bounces & BOUNCE_POLL) {
850 if (write(pipefd[cpu*2+1], &c, 1) != 1)
851 err("pipefd write error");
852 if (pthread_join(uffd_threads[cpu],
853 (void *)&uffd_stats[cpu]))
854 return 1;
855 } else {
856 if (pthread_cancel(uffd_threads[cpu]))
857 return 1;
858 if (pthread_join(uffd_threads[cpu], NULL))
859 return 1;
860 }
861 }
862
863 return 0;
864}
865
866sigjmp_buf jbuf, *sigbuf;
867
868static void sighndl(int sig, siginfo_t *siginfo, void *ptr)
869{
870 if (sig == SIGBUS) {
871 if (sigbuf)
872 siglongjmp(*sigbuf, 1);
873 abort();
874 }
875}
876
877/*
878 * For non-cooperative userfaultfd test we fork() a process that will
879 * generate pagefaults, will mremap the area monitored by the
880 * userfaultfd and at last this process will release the monitored
881 * area.
882 * For the anonymous and shared memory the area is divided into two
883 * parts, the first part is accessed before mremap, and the second
884 * part is accessed after mremap. Since hugetlbfs does not support
885 * mremap, the entire monitored area is accessed in a single pass for
886 * HUGETLB_TEST.
887 * The release of the pages currently generates event for shmem and
888 * anonymous memory (UFFD_EVENT_REMOVE), hence it is not checked
889 * for hugetlb.
890 * For signal test(UFFD_FEATURE_SIGBUS), signal_test = 1, we register
891 * monitored area, generate pagefaults and test that signal is delivered.
892 * Use UFFDIO_COPY to allocate missing page and retry. For signal_test = 2
893 * test robustness use case - we release monitored area, fork a process
894 * that will generate pagefaults and verify signal is generated.
895 * This also tests UFFD_FEATURE_EVENT_FORK event along with the signal
896 * feature. Using monitor thread, verify no userfault events are generated.
897 */
898static int faulting_process(int signal_test)
899{
900 unsigned long nr;
901 unsigned long long count;
902 unsigned long split_nr_pages;
903 unsigned long lastnr;
904 struct sigaction act;
905 unsigned long signalled = 0;
906
907 if (test_type != TEST_HUGETLB)
908 split_nr_pages = (nr_pages + 1) / 2;
909 else
910 split_nr_pages = nr_pages;
911
912 if (signal_test) {
913 sigbuf = &jbuf;
914 memset(&act, 0, sizeof(act));
915 act.sa_sigaction = sighndl;
916 act.sa_flags = SA_SIGINFO;
917 if (sigaction(SIGBUS, &act, 0))
918 err("sigaction");
919 lastnr = (unsigned long)-1;
920 }
921
922 for (nr = 0; nr < split_nr_pages; nr++) {
923 int steps = 1;
924 unsigned long offset = nr * page_size;
925
926 if (signal_test) {
927 if (sigsetjmp(*sigbuf, 1) != 0) {
928 if (steps == 1 && nr == lastnr)
929 err("Signal repeated");
930
931 lastnr = nr;
932 if (signal_test == 1) {
933 if (steps == 1) {
934 /* This is a MISSING request */
935 steps++;
936 if (copy_page(uffd, offset))
937 signalled++;
938 } else {
939 /* This is a WP request */
940 assert(steps == 2);
941 wp_range(uffd,
942 (__u64)area_dst +
943 offset,
944 page_size, false);
945 }
946 } else {
947 signalled++;
948 continue;
949 }
950 }
951 }
952
953 count = *area_count(area_dst, nr);
954 if (count != count_verify[nr])
955 err("nr %lu memory corruption %llu %llu\n",
956 nr, count, count_verify[nr]);
957 /*
958 * Trigger write protection if there is by writing
959 * the same value back.
960 */
961 *area_count(area_dst, nr) = count;
962 }
963
964 if (signal_test)
965 return signalled != split_nr_pages;
966
967 if (test_type == TEST_HUGETLB)
968 return 0;
969
970 area_dst = mremap(area_dst, nr_pages * page_size, nr_pages * page_size,
971 MREMAP_MAYMOVE | MREMAP_FIXED, area_src);
972 if (area_dst == MAP_FAILED)
973 err("mremap");
974 /* Reset area_src since we just clobbered it */
975 area_src = NULL;
976
977 for (; nr < nr_pages; nr++) {
978 count = *area_count(area_dst, nr);
979 if (count != count_verify[nr]) {
980 err("nr %lu memory corruption %llu %llu\n",
981 nr, count, count_verify[nr]);
982 }
983 /*
984 * Trigger write protection if there is by writing
985 * the same value back.
986 */
987 *area_count(area_dst, nr) = count;
988 }
989
990 uffd_test_ops->release_pages(area_dst);
991
992 for (nr = 0; nr < nr_pages; nr++)
993 if (my_bcmp(area_dst + nr * page_size, zeropage, page_size))
994 err("nr %lu is not zero", nr);
995
996 return 0;
997}
998
999static void retry_uffdio_zeropage(int ufd,
1000 struct uffdio_zeropage *uffdio_zeropage,
1001 unsigned long offset)
1002{
1003 uffd_test_ops->alias_mapping(&uffdio_zeropage->range.start,
1004 uffdio_zeropage->range.len,
1005 offset);
1006 if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
1007 if (uffdio_zeropage->zeropage != -EEXIST)
1008 err("UFFDIO_ZEROPAGE error: %"PRId64,
1009 (int64_t)uffdio_zeropage->zeropage);
1010 } else {
1011 err("UFFDIO_ZEROPAGE error: %"PRId64,
1012 (int64_t)uffdio_zeropage->zeropage);
1013 }
1014}
1015
1016static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
1017{
1018 struct uffdio_zeropage uffdio_zeropage;
1019 int ret;
1020 unsigned long has_zeropage;
1021 __s64 res;
1022
1023 has_zeropage = uffd_test_ops->expected_ioctls & (1 << _UFFDIO_ZEROPAGE);
1024
1025 if (offset >= nr_pages * page_size)
1026 err("unexpected offset %lu", offset);
1027 uffdio_zeropage.range.start = (unsigned long) area_dst + offset;
1028 uffdio_zeropage.range.len = page_size;
1029 uffdio_zeropage.mode = 0;
1030 ret = ioctl(ufd, UFFDIO_ZEROPAGE, &uffdio_zeropage);
1031 res = uffdio_zeropage.zeropage;
1032 if (ret) {
1033 /* real retval in ufdio_zeropage.zeropage */
1034 if (has_zeropage)
1035 err("UFFDIO_ZEROPAGE error: %"PRId64, (int64_t)res);
1036 else if (res != -EINVAL)
1037 err("UFFDIO_ZEROPAGE not -EINVAL");
1038 } else if (has_zeropage) {
1039 if (res != page_size) {
1040 err("UFFDIO_ZEROPAGE unexpected size");
1041 } else {
1042 if (test_uffdio_zeropage_eexist && retry) {
1043 test_uffdio_zeropage_eexist = false;
1044 retry_uffdio_zeropage(ufd, &uffdio_zeropage,
1045 offset);
1046 }
1047 return 1;
1048 }
1049 } else
1050 err("UFFDIO_ZEROPAGE succeeded");
1051
1052 return 0;
1053}
1054
1055static int uffdio_zeropage(int ufd, unsigned long offset)
1056{
1057 return __uffdio_zeropage(ufd, offset, false);
1058}
1059
1060/* exercise UFFDIO_ZEROPAGE */
1061static int userfaultfd_zeropage_test(void)
1062{
1063 struct uffdio_register uffdio_register;
1064 unsigned long expected_ioctls;
1065
1066 printf("testing UFFDIO_ZEROPAGE: ");
1067 fflush(stdout);
1068
1069 uffd_test_ctx_init(0);
1070
1071 uffdio_register.range.start = (unsigned long) area_dst;
1072 uffdio_register.range.len = nr_pages * page_size;
1073 uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
1074 if (test_uffdio_wp)
1075 uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
1076 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
1077 err("register failure");
1078
1079 expected_ioctls = uffd_test_ops->expected_ioctls;
1080 if ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls)
1081 err("unexpected missing ioctl for anon memory");
1082
1083 if (uffdio_zeropage(uffd, 0))
1084 if (my_bcmp(area_dst, zeropage, page_size))
1085 err("zeropage is not zero");
1086
1087 printf("done.\n");
1088 return 0;
1089}
1090
1091static int userfaultfd_events_test(void)
1092{
1093 struct uffdio_register uffdio_register;
1094 unsigned long expected_ioctls;
1095 pthread_t uffd_mon;
1096 int err, features;
1097 pid_t pid;
1098 char c;
1099 struct uffd_stats stats = { 0 };
1100
1101 printf("testing events (fork, remap, remove): ");
1102 fflush(stdout);
1103
1104 features = UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP |
1105 UFFD_FEATURE_EVENT_REMOVE;
1106 uffd_test_ctx_init(features);
1107
1108 fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
1109
1110 uffdio_register.range.start = (unsigned long) area_dst;
1111 uffdio_register.range.len = nr_pages * page_size;
1112 uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
1113 if (test_uffdio_wp)
1114 uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
1115 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
1116 err("register failure");
1117
1118 expected_ioctls = uffd_test_ops->expected_ioctls;
1119 if ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls)
1120 err("unexpected missing ioctl for anon memory");
1121
1122 if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
1123 err("uffd_poll_thread create");
1124
1125 pid = fork();
1126 if (pid < 0)
1127 err("fork");
1128
1129 if (!pid)
1130 exit(faulting_process(0));
1131
1132 waitpid(pid, &err, 0);
1133 if (err)
1134 err("faulting process failed");
1135 if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
1136 err("pipe write");
1137 if (pthread_join(uffd_mon, NULL))
1138 return 1;
1139
1140 uffd_stats_report(&stats, 1);
1141
1142 return stats.missing_faults != nr_pages;
1143}
1144
1145static int userfaultfd_sig_test(void)
1146{
1147 struct uffdio_register uffdio_register;
1148 unsigned long expected_ioctls;
1149 unsigned long userfaults;
1150 pthread_t uffd_mon;
1151 int err, features;
1152 pid_t pid;
1153 char c;
1154 struct uffd_stats stats = { 0 };
1155
1156 printf("testing signal delivery: ");
1157 fflush(stdout);
1158
1159 features = UFFD_FEATURE_EVENT_FORK|UFFD_FEATURE_SIGBUS;
1160 uffd_test_ctx_init(features);
1161
1162 fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
1163
1164 uffdio_register.range.start = (unsigned long) area_dst;
1165 uffdio_register.range.len = nr_pages * page_size;
1166 uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
1167 if (test_uffdio_wp)
1168 uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
1169 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
1170 err("register failure");
1171
1172 expected_ioctls = uffd_test_ops->expected_ioctls;
1173 if ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls)
1174 err("unexpected missing ioctl for anon memory");
1175
1176 if (faulting_process(1))
1177 err("faulting process failed");
1178
1179 uffd_test_ops->release_pages(area_dst);
1180
1181 if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
1182 err("uffd_poll_thread create");
1183
1184 pid = fork();
1185 if (pid < 0)
1186 err("fork");
1187
1188 if (!pid)
1189 exit(faulting_process(2));
1190
1191 waitpid(pid, &err, 0);
1192 if (err)
1193 err("faulting process failed");
1194 if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
1195 err("pipe write");
1196 if (pthread_join(uffd_mon, (void **)&userfaults))
1197 return 1;
1198
1199 printf("done.\n");
1200 if (userfaults)
1201 err("Signal test failed, userfaults: %ld", userfaults);
1202
1203 return userfaults != 0;
1204}
1205
1206static int userfaultfd_minor_test(void)
1207{
1208 struct uffdio_register uffdio_register;
1209 unsigned long expected_ioctls;
1210 unsigned long p;
1211 pthread_t uffd_mon;
1212 uint8_t expected_byte;
1213 void *expected_page;
1214 char c;
1215 struct uffd_stats stats = { 0 };
1216 uint64_t req_features, features_out;
1217
1218 if (!test_uffdio_minor)
1219 return 0;
1220
1221 printf("testing minor faults: ");
1222 fflush(stdout);
1223
1224 if (test_type == TEST_HUGETLB)
1225 req_features = UFFD_FEATURE_MINOR_HUGETLBFS;
1226 else if (test_type == TEST_SHMEM)
1227 req_features = UFFD_FEATURE_MINOR_SHMEM;
1228 else
1229 return 1;
1230
1231 features_out = req_features;
1232 uffd_test_ctx_init_ext(&features_out);
1233 /* If kernel reports required features aren't supported, skip test. */
1234 if ((features_out & req_features) != req_features) {
1235 printf("skipping test due to lack of feature support\n");
1236 fflush(stdout);
1237 return 0;
1238 }
1239
1240 uffdio_register.range.start = (unsigned long)area_dst_alias;
1241 uffdio_register.range.len = nr_pages * page_size;
1242 uffdio_register.mode = UFFDIO_REGISTER_MODE_MINOR;
1243 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
1244 err("register failure");
1245
1246 expected_ioctls = uffd_test_ops->expected_ioctls;
1247 expected_ioctls |= 1 << _UFFDIO_CONTINUE;
1248 if ((uffdio_register.ioctls & expected_ioctls) != expected_ioctls)
1249 err("unexpected missing ioctl(s)");
1250
1251 /*
1252 * After registering with UFFD, populate the non-UFFD-registered side of
1253 * the shared mapping. This should *not* trigger any UFFD minor faults.
1254 */
1255 for (p = 0; p < nr_pages; ++p) {
1256 memset(area_dst + (p * page_size), p % ((uint8_t)-1),
1257 page_size);
1258 }
1259
1260 if (pthread_create(&uffd_mon, &attr, uffd_poll_thread, &stats))
1261 err("uffd_poll_thread create");
1262
1263 /*
1264 * Read each of the pages back using the UFFD-registered mapping. We
1265 * expect that the first time we touch a page, it will result in a minor
1266 * fault. uffd_poll_thread will resolve the fault by bit-flipping the
1267 * page's contents, and then issuing a CONTINUE ioctl.
1268 */
1269
1270 if (posix_memalign(&expected_page, page_size, page_size))
1271 err("out of memory");
1272
1273 for (p = 0; p < nr_pages; ++p) {
1274 expected_byte = ~((uint8_t)(p % ((uint8_t)-1)));
1275 memset(expected_page, expected_byte, page_size);
1276 if (my_bcmp(expected_page, area_dst_alias + (p * page_size),
1277 page_size))
1278 err("unexpected page contents after minor fault");
1279 }
1280
1281 if (write(pipefd[1], &c, sizeof(c)) != sizeof(c))
1282 err("pipe write");
1283 if (pthread_join(uffd_mon, NULL))
1284 return 1;
1285
1286 uffd_stats_report(&stats, 1);
1287
1288 return stats.missing_faults != 0 || stats.minor_faults != nr_pages;
1289}
1290
1291#define BIT_ULL(nr) (1ULL << (nr))
1292#define PM_SOFT_DIRTY BIT_ULL(55)
1293#define PM_MMAP_EXCLUSIVE BIT_ULL(56)
1294#define PM_UFFD_WP BIT_ULL(57)
1295#define PM_FILE BIT_ULL(61)
1296#define PM_SWAP BIT_ULL(62)
1297#define PM_PRESENT BIT_ULL(63)
1298
1299static int pagemap_open(void)
1300{
1301 int fd = open("/proc/self/pagemap", O_RDONLY);
1302
1303 if (fd < 0)
1304 err("open pagemap");
1305
1306 return fd;
1307}
1308
1309static uint64_t pagemap_read_vaddr(int fd, void *vaddr)
1310{
1311 uint64_t value;
1312 int ret;
1313
1314 ret = pread(fd, &value, sizeof(uint64_t),
1315 ((uint64_t)vaddr >> 12) * sizeof(uint64_t));
1316 if (ret != sizeof(uint64_t))
1317 err("pread() on pagemap failed");
1318
1319 return value;
1320}
1321
1322/* This macro let __LINE__ works in err() */
1323#define pagemap_check_wp(value, wp) do { \
1324 if (!!(value & PM_UFFD_WP) != wp) \
1325 err("pagemap uffd-wp bit error: 0x%"PRIx64, value); \
1326 } while (0)
1327
1328static int pagemap_test_fork(bool present)
1329{
1330 pid_t child = fork();
1331 uint64_t value;
1332 int fd, result;
1333
1334 if (!child) {
1335 /* Open the pagemap fd of the child itself */
1336 fd = pagemap_open();
1337 value = pagemap_read_vaddr(fd, area_dst);
1338 /*
1339 * After fork() uffd-wp bit should be gone as long as we're
1340 * without UFFD_FEATURE_EVENT_FORK
1341 */
1342 pagemap_check_wp(value, false);
1343 /* Succeed */
1344 exit(0);
1345 }
1346 waitpid(child, &result, 0);
1347 return result;
1348}
1349
1350static void userfaultfd_pagemap_test(unsigned int test_pgsize)
1351{
1352 struct uffdio_register uffdio_register;
1353 int pagemap_fd;
1354 uint64_t value;
1355
1356 /* Pagemap tests uffd-wp only */
1357 if (!test_uffdio_wp)
1358 return;
1359
1360 /* Not enough memory to test this page size */
1361 if (test_pgsize > nr_pages * page_size)
1362 return;
1363
1364 printf("testing uffd-wp with pagemap (pgsize=%u): ", test_pgsize);
1365 /* Flush so it doesn't flush twice in parent/child later */
1366 fflush(stdout);
1367
1368 uffd_test_ctx_init(0);
1369
1370 if (test_pgsize > page_size) {
1371 /* This is a thp test */
1372 if (madvise(area_dst, nr_pages * page_size, MADV_HUGEPAGE))
1373 err("madvise(MADV_HUGEPAGE) failed");
1374 } else if (test_pgsize == page_size) {
1375 /* This is normal page test; force no thp */
1376 if (madvise(area_dst, nr_pages * page_size, MADV_NOHUGEPAGE))
1377 err("madvise(MADV_NOHUGEPAGE) failed");
1378 }
1379
1380 uffdio_register.range.start = (unsigned long) area_dst;
1381 uffdio_register.range.len = nr_pages * page_size;
1382 uffdio_register.mode = UFFDIO_REGISTER_MODE_WP;
1383 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
1384 err("register failed");
1385
1386 pagemap_fd = pagemap_open();
1387
1388 /* Touch the page */
1389 *area_dst = 1;
1390 wp_range(uffd, (uint64_t)area_dst, test_pgsize, true);
1391 value = pagemap_read_vaddr(pagemap_fd, area_dst);
1392 pagemap_check_wp(value, true);
1393 /* Make sure uffd-wp bit dropped when fork */
1394 if (pagemap_test_fork(true))
1395 err("Detected stall uffd-wp bit in child");
1396
1397 /* Exclusive required or PAGEOUT won't work */
1398 if (!(value & PM_MMAP_EXCLUSIVE))
1399 err("multiple mapping detected: 0x%"PRIx64, value);
1400
1401 if (madvise(area_dst, test_pgsize, MADV_PAGEOUT))
1402 err("madvise(MADV_PAGEOUT) failed");
1403
1404 /* Uffd-wp should persist even swapped out */
1405 value = pagemap_read_vaddr(pagemap_fd, area_dst);
1406 pagemap_check_wp(value, true);
1407 /* Make sure uffd-wp bit dropped when fork */
1408 if (pagemap_test_fork(false))
1409 err("Detected stall uffd-wp bit in child");
1410
1411 /* Unprotect; this tests swap pte modifications */
1412 wp_range(uffd, (uint64_t)area_dst, page_size, false);
1413 value = pagemap_read_vaddr(pagemap_fd, area_dst);
1414 pagemap_check_wp(value, false);
1415
1416 /* Fault in the page from disk */
1417 *area_dst = 2;
1418 value = pagemap_read_vaddr(pagemap_fd, area_dst);
1419 pagemap_check_wp(value, false);
1420
1421 close(pagemap_fd);
1422 printf("done\n");
1423}
1424
1425static int userfaultfd_stress(void)
1426{
1427 void *area;
1428 char *tmp_area;
1429 unsigned long nr;
1430 struct uffdio_register uffdio_register;
1431 struct uffd_stats uffd_stats[nr_cpus];
1432
1433 uffd_test_ctx_init(0);
1434
1435 if (posix_memalign(&area, page_size, page_size))
1436 err("out of memory");
1437 zeropage = area;
1438 bzero(zeropage, page_size);
1439
1440 pthread_mutex_lock(&uffd_read_mutex);
1441
1442 pthread_attr_init(&attr);
1443 pthread_attr_setstacksize(&attr, 16*1024*1024);
1444
1445 while (bounces--) {
1446 unsigned long expected_ioctls;
1447
1448 printf("bounces: %d, mode:", bounces);
1449 if (bounces & BOUNCE_RANDOM)
1450 printf(" rnd");
1451 if (bounces & BOUNCE_RACINGFAULTS)
1452 printf(" racing");
1453 if (bounces & BOUNCE_VERIFY)
1454 printf(" ver");
1455 if (bounces & BOUNCE_POLL)
1456 printf(" poll");
1457 else
1458 printf(" read");
1459 printf(", ");
1460 fflush(stdout);
1461
1462 if (bounces & BOUNCE_POLL)
1463 fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
1464 else
1465 fcntl(uffd, F_SETFL, uffd_flags & ~O_NONBLOCK);
1466
1467 /* register */
1468 uffdio_register.range.start = (unsigned long) area_dst;
1469 uffdio_register.range.len = nr_pages * page_size;
1470 uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
1471 if (test_uffdio_wp)
1472 uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
1473 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
1474 err("register failure");
1475 expected_ioctls = uffd_test_ops->expected_ioctls;
1476 if ((uffdio_register.ioctls & expected_ioctls) !=
1477 expected_ioctls)
1478 err("unexpected missing ioctl for anon memory");
1479
1480 if (area_dst_alias) {
1481 uffdio_register.range.start = (unsigned long)
1482 area_dst_alias;
1483 if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
1484 err("register failure alias");
1485 }
1486
1487 /*
1488 * The madvise done previously isn't enough: some
1489 * uffd_thread could have read userfaults (one of
1490 * those already resolved by the background thread)
1491 * and it may be in the process of calling
1492 * UFFDIO_COPY. UFFDIO_COPY will read the zapped
1493 * area_src and it would map a zero page in it (of
1494 * course such a UFFDIO_COPY is perfectly safe as it'd
1495 * return -EEXIST). The problem comes at the next
1496 * bounce though: that racing UFFDIO_COPY would
1497 * generate zeropages in the area_src, so invalidating
1498 * the previous MADV_DONTNEED. Without this additional
1499 * MADV_DONTNEED those zeropages leftovers in the
1500 * area_src would lead to -EEXIST failure during the
1501 * next bounce, effectively leaving a zeropage in the
1502 * area_dst.
1503 *
1504 * Try to comment this out madvise to see the memory
1505 * corruption being caught pretty quick.
1506 *
1507 * khugepaged is also inhibited to collapse THP after
1508 * MADV_DONTNEED only after the UFFDIO_REGISTER, so it's
1509 * required to MADV_DONTNEED here.
1510 */
1511 uffd_test_ops->release_pages(area_dst);
1512
1513 uffd_stats_reset(uffd_stats, nr_cpus);
1514
1515 /* bounce pass */
1516 if (stress(uffd_stats))
1517 return 1;
1518
1519 /* Clear all the write protections if there is any */
1520 if (test_uffdio_wp)
1521 wp_range(uffd, (unsigned long)area_dst,
1522 nr_pages * page_size, false);
1523
1524 /* unregister */
1525 if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range))
1526 err("unregister failure");
1527 if (area_dst_alias) {
1528 uffdio_register.range.start = (unsigned long) area_dst;
1529 if (ioctl(uffd, UFFDIO_UNREGISTER,
1530 &uffdio_register.range))
1531 err("unregister failure alias");
1532 }
1533
1534 /* verification */
1535 if (bounces & BOUNCE_VERIFY)
1536 for (nr = 0; nr < nr_pages; nr++)
1537 if (*area_count(area_dst, nr) != count_verify[nr])
1538 err("error area_count %llu %llu %lu\n",
1539 *area_count(area_src, nr),
1540 count_verify[nr], nr);
1541
1542 /* prepare next bounce */
1543 tmp_area = area_src;
1544 area_src = area_dst;
1545 area_dst = tmp_area;
1546
1547 tmp_area = area_src_alias;
1548 area_src_alias = area_dst_alias;
1549 area_dst_alias = tmp_area;
1550
1551 uffd_stats_report(uffd_stats, nr_cpus);
1552 }
1553
1554 if (test_type == TEST_ANON) {
1555 /*
1556 * shmem/hugetlb won't be able to run since they have different
1557 * behavior on fork() (file-backed memory normally drops ptes
1558 * directly when fork), meanwhile the pagemap test will verify
1559 * pgtable entry of fork()ed child.
1560 */
1561 userfaultfd_pagemap_test(page_size);
1562 /*
1563 * Hard-code for x86_64 for now for 2M THP, as x86_64 is
1564 * currently the only one that supports uffd-wp
1565 */
1566 userfaultfd_pagemap_test(page_size * 512);
1567 }
1568
1569 return userfaultfd_zeropage_test() || userfaultfd_sig_test()
1570 || userfaultfd_events_test() || userfaultfd_minor_test();
1571}
1572
1573/*
1574 * Copied from mlock2-tests.c
1575 */
1576unsigned long default_huge_page_size(void)
1577{
1578 unsigned long hps = 0;
1579 char *line = NULL;
1580 size_t linelen = 0;
1581 FILE *f = fopen("/proc/meminfo", "r");
1582
1583 if (!f)
1584 return 0;
1585 while (getline(&line, &linelen, f) > 0) {
1586 if (sscanf(line, "Hugepagesize: %lu kB", &hps) == 1) {
1587 hps <<= 10;
1588 break;
1589 }
1590 }
1591
1592 free(line);
1593 fclose(f);
1594 return hps;
1595}
1596
1597static void set_test_type(const char *type)
1598{
1599 if (!strcmp(type, "anon")) {
1600 test_type = TEST_ANON;
1601 uffd_test_ops = &anon_uffd_test_ops;
1602 /* Only enable write-protect test for anonymous test */
1603 test_uffdio_wp = true;
1604 } else if (!strcmp(type, "hugetlb")) {
1605 test_type = TEST_HUGETLB;
1606 uffd_test_ops = &hugetlb_uffd_test_ops;
1607 } else if (!strcmp(type, "hugetlb_shared")) {
1608 map_shared = true;
1609 test_type = TEST_HUGETLB;
1610 uffd_test_ops = &hugetlb_uffd_test_ops;
1611 /* Minor faults require shared hugetlb; only enable here. */
1612 test_uffdio_minor = true;
1613 } else if (!strcmp(type, "shmem")) {
1614 map_shared = true;
1615 test_type = TEST_SHMEM;
1616 uffd_test_ops = &shmem_uffd_test_ops;
1617 test_uffdio_minor = true;
1618 } else {
1619 err("Unknown test type: %s", type);
1620 }
1621
1622 if (test_type == TEST_HUGETLB)
1623 page_size = default_huge_page_size();
1624 else
1625 page_size = sysconf(_SC_PAGE_SIZE);
1626
1627 if (!page_size)
1628 err("Unable to determine page size");
1629 if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) * 2
1630 > page_size)
1631 err("Impossible to run this test");
1632}
1633
1634static void sigalrm(int sig)
1635{
1636 if (sig != SIGALRM)
1637 abort();
1638 test_uffdio_copy_eexist = true;
1639 test_uffdio_zeropage_eexist = true;
1640 alarm(ALARM_INTERVAL_SECS);
1641}
1642
1643int main(int argc, char **argv)
1644{
1645 if (argc < 4)
1646 usage();
1647
1648 if (signal(SIGALRM, sigalrm) == SIG_ERR)
1649 err("failed to arm SIGALRM");
1650 alarm(ALARM_INTERVAL_SECS);
1651
1652 set_test_type(argv[1]);
1653
1654 nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
1655 nr_pages_per_cpu = atol(argv[2]) * 1024*1024 / page_size /
1656 nr_cpus;
1657 if (!nr_pages_per_cpu) {
1658 _err("invalid MiB");
1659 usage();
1660 }
1661
1662 bounces = atoi(argv[3]);
1663 if (bounces <= 0) {
1664 _err("invalid bounces");
1665 usage();
1666 }
1667 nr_pages = nr_pages_per_cpu * nr_cpus;
1668
1669 if (test_type == TEST_HUGETLB) {
1670 if (argc < 5)
1671 usage();
1672 huge_fd = open(argv[4], O_CREAT | O_RDWR, 0755);
1673 if (huge_fd < 0)
1674 err("Open of %s failed", argv[4]);
1675 if (ftruncate(huge_fd, 0))
1676 err("ftruncate %s to size 0 failed", argv[4]);
1677 } else if (test_type == TEST_SHMEM) {
1678 shm_fd = memfd_create(argv[0], 0);
1679 if (shm_fd < 0)
1680 err("memfd_create");
1681 if (ftruncate(shm_fd, nr_pages * page_size * 2))
1682 err("ftruncate");
1683 if (fallocate(shm_fd,
1684 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0,
1685 nr_pages * page_size * 2))
1686 err("fallocate");
1687 }
1688 printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
1689 nr_pages, nr_pages_per_cpu);
1690 return userfaultfd_stress();
1691}
1692
1693#else /* __NR_userfaultfd */
1694
1695#warning "missing __NR_userfaultfd definition"
1696
1697int main(void)
1698{
1699 printf("skip: Skipping userfaultfd test (missing __NR_userfaultfd)\n");
1700 return KSFT_SKIP;
1701}
1702
1703#endif /* __NR_userfaultfd */