selftests/mm/uffd: refactor non-composite global vars into struct

Refactor macros and non-composite global variable definitions into a struct that is defined at the start of a test and is passed around instead of relying on global vars. Link: https://lkml.kernel.org/r/20250829155600.2000-1-ujwal.kundur@gmail.com Signed-off-by: Ujwal Kundur <ujwal.kundur@gmail.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Brendan Jackman <jackmanb@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-12-01 07:26:02 +07:00 · 2025-08-29 21:26:00 +05:30
parent 2f5bd89ba9
commit 4dfd4bba85
5 changed files with 615 additions and 541 deletions
--- a/tools/testing/selftests/mm/uffd-common.c
+++ b/tools/testing/selftests/mm/uffd-common.c
@@ -7,18 +7,29 @@

 #include "uffd-common.h"

-#define BASE_PMD_ADDR ((void *)(1UL << 30))
-
-volatile bool test_uffdio_copy_eexist = true;
-unsigned long nr_parallel, nr_pages, nr_pages_per_cpu, page_size;
-char *area_src, *area_src_alias, *area_dst, *area_dst_alias, *area_remap;
-int uffd = -1, uffd_flags, finished, *pipefd, test_type;
-bool map_shared;
-bool test_uffdio_wp = true;
-unsigned long long *count_verify;
 uffd_test_ops_t *uffd_test_ops;
 uffd_test_case_ops_t *uffd_test_case_ops;
-atomic_bool ready_for_fork;
+
+#define BASE_PMD_ADDR ((void *)(1UL << 30))
+
+/* pthread_mutex_t starts at page offset 0 */
+pthread_mutex_t *area_mutex(char *area, unsigned long nr, uffd_global_test_opts_t *gopts)
+{
+	return (pthread_mutex_t *) (area + nr * gopts->page_size);
+}
+
+/*
+ * count is placed in the page after pthread_mutex_t naturally aligned
+ * to avoid non alignment faults on non-x86 archs.
+ */
+volatile unsigned long long *area_count(char *area, unsigned long nr,
+					uffd_global_test_opts_t *gopts)
+{
+	return (volatile unsigned long long *)
+	       ((unsigned long)(area + nr * gopts->page_size +
+	       sizeof(pthread_mutex_t) + sizeof(unsigned long long) - 1) &
+	       ~(unsigned long)(sizeof(unsigned long long) - 1));
+}

 static int uffd_mem_fd_create(off_t mem_size, bool hugetlb)
 {
@@ -40,15 +51,15 @@ static int uffd_mem_fd_create(off_t mem_size, bool hugetlb)
 	return mem_fd;
 }

-static void anon_release_pages(char *rel_area)
+static void anon_release_pages(uffd_global_test_opts_t *gopts, char *rel_area)
 {
-	if (madvise(rel_area, nr_pages * page_size, MADV_DONTNEED))
+	if (madvise(rel_area, gopts->nr_pages * gopts->page_size, MADV_DONTNEED))
 		err("madvise(MADV_DONTNEED) failed");
 }

-static int anon_allocate_area(void **alloc_area, bool is_src)
+static int anon_allocate_area(uffd_global_test_opts_t *gopts, void **alloc_area, bool is_src)
 {
-	*alloc_area = mmap(NULL, nr_pages * page_size, PROT_READ | PROT_WRITE,
+	*alloc_area = mmap(NULL, gopts->nr_pages * gopts->page_size, PROT_READ | PROT_WRITE,
 			   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 	if (*alloc_area == MAP_FAILED) {
 		*alloc_area = NULL;
@@ -57,31 +68,32 @@ static int anon_allocate_area(void **alloc_area, bool is_src)
 	return 0;
 }

-static void noop_alias_mapping(__u64 *start, size_t len, unsigned long offset)
+static void noop_alias_mapping(uffd_global_test_opts_t *gopts, __u64 *start,
+			       size_t len, unsigned long offset)
 {
 }

-static void hugetlb_release_pages(char *rel_area)
+static void hugetlb_release_pages(uffd_global_test_opts_t *gopts, char *rel_area)
 {
-	if (!map_shared) {
-		if (madvise(rel_area, nr_pages * page_size, MADV_DONTNEED))
+	if (!gopts->map_shared) {
+		if (madvise(rel_area, gopts->nr_pages * gopts->page_size, MADV_DONTNEED))
 			err("madvise(MADV_DONTNEED) failed");
 	} else {
-		if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE))
+		if (madvise(rel_area, gopts->nr_pages * gopts->page_size, MADV_REMOVE))
 			err("madvise(MADV_REMOVE) failed");
 	}
 }

-static int hugetlb_allocate_area(void **alloc_area, bool is_src)
+static int hugetlb_allocate_area(uffd_global_test_opts_t *gopts, void **alloc_area, bool is_src)
 {
-	off_t size = nr_pages * page_size;
+	off_t size = gopts->nr_pages * gopts->page_size;
 	off_t offset = is_src ? 0 : size;
 	void *area_alias = NULL;
 	char **alloc_area_alias;
 	int mem_fd = uffd_mem_fd_create(size * 2, true);

 	*alloc_area = mmap(NULL, size, PROT_READ | PROT_WRITE,
-			   (map_shared ? MAP_SHARED : MAP_PRIVATE) |
+			   (gopts->map_shared ? MAP_SHARED : MAP_PRIVATE) |
 			   (is_src ? 0 : MAP_NORESERVE),
 			   mem_fd, offset);
 	if (*alloc_area == MAP_FAILED) {
@@ -89,7 +101,7 @@ static int hugetlb_allocate_area(void **alloc_area, bool is_src)
 		return -errno;
 	}

-	if (map_shared) {
+	if (gopts->map_shared) {
 		area_alias = mmap(NULL, size, PROT_READ | PROT_WRITE,
 				  MAP_SHARED, mem_fd, offset);
 		if (area_alias == MAP_FAILED)
@@ -97,9 +109,9 @@ static int hugetlb_allocate_area(void **alloc_area, bool is_src)
 	}

 	if (is_src) {
-		alloc_area_alias = &area_src_alias;
+		alloc_area_alias = &gopts->area_src_alias;
 	} else {
-		alloc_area_alias = &area_dst_alias;
+		alloc_area_alias = &gopts->area_dst_alias;
 	}
 	if (area_alias)
 		*alloc_area_alias = area_alias;
@@ -108,24 +120,25 @@ static int hugetlb_allocate_area(void **alloc_area, bool is_src)
 	return 0;
 }

-static void hugetlb_alias_mapping(__u64 *start, size_t len, unsigned long offset)
+static void hugetlb_alias_mapping(uffd_global_test_opts_t *gopts, __u64 *start,
+				  size_t len, unsigned long offset)
 {
-	if (!map_shared)
+	if (!gopts->map_shared)
 		return;

-	*start = (unsigned long) area_dst_alias + offset;
+	*start = (unsigned long) gopts->area_dst_alias + offset;
 }

-static void shmem_release_pages(char *rel_area)
+static void shmem_release_pages(uffd_global_test_opts_t *gopts, char *rel_area)
 {
-	if (madvise(rel_area, nr_pages * page_size, MADV_REMOVE))
+	if (madvise(rel_area, gopts->nr_pages * gopts->page_size, MADV_REMOVE))
 		err("madvise(MADV_REMOVE) failed");
 }

-static int shmem_allocate_area(void **alloc_area, bool is_src)
+static int shmem_allocate_area(uffd_global_test_opts_t *gopts, void **alloc_area, bool is_src)
 {
 	void *area_alias = NULL;
-	size_t bytes = nr_pages * page_size, hpage_size = read_pmd_pagesize();
+	size_t bytes = gopts->nr_pages * gopts->page_size, hpage_size = read_pmd_pagesize();
 	unsigned long offset = is_src ? 0 : bytes;
 	char *p = NULL, *p_alias = NULL;
 	int mem_fd = uffd_mem_fd_create(bytes * 2, false);
@@ -159,22 +172,23 @@ static int shmem_allocate_area(void **alloc_area, bool is_src)
 		err("mmap of anonymous memory failed at %p", p_alias);

 	if (is_src)
-		area_src_alias = area_alias;
+		gopts->area_src_alias = area_alias;
 	else
-		area_dst_alias = area_alias;
+		gopts->area_dst_alias = area_alias;

 	close(mem_fd);
 	return 0;
 }

-static void shmem_alias_mapping(__u64 *start, size_t len, unsigned long offset)
+static void shmem_alias_mapping(uffd_global_test_opts_t *gopts, __u64 *start,
+				size_t len, unsigned long offset)
 {
-	*start = (unsigned long)area_dst_alias + offset;
+	*start = (unsigned long)gopts->area_dst_alias + offset;
 }

-static void shmem_check_pmd_mapping(void *p, int expect_nr_hpages)
+static void shmem_check_pmd_mapping(uffd_global_test_opts_t *gopts, void *p, int expect_nr_hpages)
 {
-	if (!check_huge_shmem(area_dst_alias, expect_nr_hpages,
+	if (!check_huge_shmem(gopts->area_dst_alias, expect_nr_hpages,
 			      read_pmd_pagesize()))
 		err("Did not find expected %d number of hugepages",
 		    expect_nr_hpages);
@@ -234,18 +248,18 @@ void uffd_stats_report(struct uffd_args *args, int n_cpus)
 	printf("\n");
 }

-int userfaultfd_open(uint64_t *features)
+int userfaultfd_open(uffd_global_test_opts_t *gopts, uint64_t *features)
 {
 	struct uffdio_api uffdio_api;

-	uffd = uffd_open(UFFD_FLAGS);
-	if (uffd < 0)
+	gopts->uffd = uffd_open(UFFD_FLAGS);
+	if (gopts->uffd < 0)
 		return -1;
-	uffd_flags = fcntl(uffd, F_GETFD, NULL);
+	gopts->uffd_flags = fcntl(gopts->uffd, F_GETFD, NULL);

 	uffdio_api.api = UFFD_API;
 	uffdio_api.features = *features;
-	if (ioctl(uffd, UFFDIO_API, &uffdio_api))
+	if (ioctl(gopts->uffd, UFFDIO_API, &uffdio_api))
 		/* Probably lack of CAP_PTRACE? */
 		return -1;
 	if (uffdio_api.api != UFFD_API)
@@ -255,59 +269,63 @@ int userfaultfd_open(uint64_t *features)
 	return 0;
 }

-static inline void munmap_area(void **area)
+static inline void munmap_area(uffd_global_test_opts_t *gopts, void **area)
 {
 	if (*area)
-		if (munmap(*area, nr_pages * page_size))
+		if (munmap(*area, gopts->nr_pages * gopts->page_size))
 			err("munmap");

 	*area = NULL;
 }

-void uffd_test_ctx_clear(void)
+void uffd_test_ctx_clear(uffd_global_test_opts_t *gopts)
 {
 	size_t i;

-	if (pipefd) {
-		for (i = 0; i < nr_parallel * 2; ++i) {
-			if (close(pipefd[i]))
+	if (gopts->pipefd) {
+		for (i = 0; i < gopts->nr_parallel * 2; ++i) {
+			if (close(gopts->pipefd[i]))
 				err("close pipefd");
 		}
-		free(pipefd);
-		pipefd = NULL;
+		free(gopts->pipefd);
+		gopts->pipefd = NULL;
 	}

-	if (count_verify) {
-		free(count_verify);
-		count_verify = NULL;
+	if (gopts->count_verify) {
+		free(gopts->count_verify);
+		gopts->count_verify = NULL;
 	}

-	if (uffd != -1) {
-		if (close(uffd))
+	if (gopts->uffd != -1) {
+		if (close(gopts->uffd))
 			err("close uffd");
-		uffd = -1;
+		gopts->uffd = -1;
 	}

-	munmap_area((void **)&area_src);
-	munmap_area((void **)&area_src_alias);
-	munmap_area((void **)&area_dst);
-	munmap_area((void **)&area_dst_alias);
-	munmap_area((void **)&area_remap);
+	munmap_area(gopts, (void **)&gopts->area_src);
+	munmap_area(gopts, (void **)&gopts->area_src_alias);
+	munmap_area(gopts, (void **)&gopts->area_dst);
+	munmap_area(gopts, (void **)&gopts->area_dst_alias);
+	munmap_area(gopts, (void **)&gopts->area_remap);
 }

-int uffd_test_ctx_init(uint64_t features, const char **errmsg)
+int uffd_test_ctx_init(uffd_global_test_opts_t *gopts, uint64_t features, const char **errmsg)
 {
 	unsigned long nr, cpu;
 	int ret;

+	gopts->area_src_alias = NULL;
+	gopts->area_dst_alias = NULL;
+	gopts->area_remap = NULL;
+
 	if (uffd_test_case_ops && uffd_test_case_ops->pre_alloc) {
-		ret = uffd_test_case_ops->pre_alloc(errmsg);
+		ret = uffd_test_case_ops->pre_alloc(gopts, errmsg);
 		if (ret)
 			return ret;
 	}

-	ret = uffd_test_ops->allocate_area((void **)&area_src, true);
-	ret |= uffd_test_ops->allocate_area((void **)&area_dst, false);
+	ret = uffd_test_ops->allocate_area(gopts, (void **) &gopts->area_src, true);
+	ret |= uffd_test_ops->allocate_area(gopts, (void **) &gopts->area_dst, false);
 	if (ret) {
 		if (errmsg)
 			*errmsg = "memory allocation failed";
@@ -315,26 +333,26 @@ int uffd_test_ctx_init(uint64_t features, const char **errmsg)
 	}

 	if (uffd_test_case_ops && uffd_test_case_ops->post_alloc) {
-		ret = uffd_test_case_ops->post_alloc(errmsg);
+		ret = uffd_test_case_ops->post_alloc(gopts, errmsg);
 		if (ret)
 			return ret;
 	}

-	ret = userfaultfd_open(&features);
+	ret = userfaultfd_open(gopts, &features);
 	if (ret) {
 		if (errmsg)
 			*errmsg = "possible lack of privilege";
 		return ret;
 	}

-	count_verify = malloc(nr_pages * sizeof(unsigned long long));
-	if (!count_verify)
+	gopts->count_verify = malloc(gopts->nr_pages * sizeof(unsigned long long));
+	if (!gopts->count_verify)
 		err("count_verify");

-	for (nr = 0; nr < nr_pages; nr++) {
-		*area_mutex(area_src, nr) =
+	for (nr = 0; nr < gopts->nr_pages; nr++) {
+		*area_mutex(gopts->area_src, nr, gopts) =
 			(pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
-		count_verify[nr] = *area_count(area_src, nr) = 1;
+		gopts->count_verify[nr] = *area_count(gopts->area_src, nr, gopts) = 1;
 		/*
 		 * In the transition between 255 to 256, powerpc will
 		 * read out of order in my_bcmp and see both bytes as
@@ -342,7 +360,7 @@ int uffd_test_ctx_init(uint64_t features, const char **errmsg)
 		 * after the count, to avoid my_bcmp to trigger false
 		 * positives.
 		 */
-		*(area_count(area_src, nr) + 1) = 1;
+		*(area_count(gopts->area_src, nr, gopts) + 1) = 1;
 	}

 	/*
@@ -363,13 +381,13 @@ int uffd_test_ctx_init(uint64_t features, const char **errmsg)
 	 * proactively split the thp and drop any accidentally initialized
 	 * pages within area_dst.
 	 */
-	uffd_test_ops->release_pages(area_dst);
+	uffd_test_ops->release_pages(gopts, gopts->area_dst);

-	pipefd = malloc(sizeof(int) * nr_parallel * 2);
-	if (!pipefd)
+	gopts->pipefd = malloc(sizeof(int) * gopts->nr_parallel * 2);
+	if (!gopts->pipefd)
 		err("pipefd");
-	for (cpu = 0; cpu < nr_parallel; cpu++)
-		if (pipe2(&pipefd[cpu * 2], O_CLOEXEC | O_NONBLOCK))
+	for (cpu = 0; cpu < gopts->nr_parallel; cpu++)
+		if (pipe2(&gopts->pipefd[cpu * 2], O_CLOEXEC | O_NONBLOCK))
 			err("pipe");

 	return 0;
@@ -416,9 +434,9 @@ static void continue_range(int ufd, __u64 start, __u64 len, bool wp)
 		    ret, (int64_t) req.mapped);
 }

-int uffd_read_msg(int ufd, struct uffd_msg *msg)
+int uffd_read_msg(uffd_global_test_opts_t *gopts, struct uffd_msg *msg)
 {
-	int ret = read(uffd, msg, sizeof(*msg));
+	int ret = read(gopts->uffd, msg, sizeof(*msg));

 	if (ret != sizeof(*msg)) {
 		if (ret < 0) {
@@ -433,7 +451,8 @@ int uffd_read_msg(int ufd, struct uffd_msg *msg)
 	return 0;
 }

-void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args)
+void uffd_handle_page_fault(uffd_global_test_opts_t *gopts, struct uffd_msg *msg,
+			    struct uffd_args *args)
 {
 	unsigned long offset;

@@ -442,7 +461,7 @@ void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args)

 	if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WP) {
 		/* Write protect page faults */
-		wp_range(uffd, msg->arg.pagefault.address, page_size, false);
+		wp_range(gopts->uffd, msg->arg.pagefault.address, gopts->page_size, false);
 		args->wp_faults++;
 	} else if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_MINOR) {
 		uint8_t *area;
@@ -460,12 +479,12 @@ void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args)
 		 * (UFFD-registered).
 		 */

-		area = (uint8_t *)(area_dst +
-				   ((char *)msg->arg.pagefault.address -
-				    area_dst_alias));
-		for (b = 0; b < page_size; ++b)
+		area = (uint8_t *)(gopts->area_dst +
+		       ((char *)msg->arg.pagefault.address -
+		       gopts->area_dst_alias));
+		for (b = 0; b < gopts->page_size; ++b)
 			area[b] = ~area[b];
-		continue_range(uffd, msg->arg.pagefault.address, page_size,
+		continue_range(gopts->uffd, msg->arg.pagefault.address, gopts->page_size,
 			       args->apply_wp);
 		args->minor_faults++;
 	} else {
@@ -493,10 +512,10 @@ void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args)
 		if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
 			err("unexpected write fault");

-		offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst;
-		offset &= ~(page_size-1);
+		offset = (char *)(unsigned long)msg->arg.pagefault.address - gopts->area_dst;
+		offset &= ~(gopts->page_size-1);

-		if (copy_page(uffd, offset, args->apply_wp))
+		if (copy_page(gopts, offset, args->apply_wp))
 			args->missing_faults++;
 	}
 }
@@ -504,6 +523,7 @@ void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args)
 void *uffd_poll_thread(void *arg)
 {
 	struct uffd_args *args = (struct uffd_args *)arg;
+	uffd_global_test_opts_t *gopts = args->gopts;
 	unsigned long cpu = args->cpu;
 	struct pollfd pollfd[2];
 	struct uffd_msg msg;
@@ -514,12 +534,12 @@ void *uffd_poll_thread(void *arg)
 	if (!args->handle_fault)
 		args->handle_fault = uffd_handle_page_fault;

-	pollfd[0].fd = uffd;
+	pollfd[0].fd = gopts->uffd;
 	pollfd[0].events = POLLIN;
-	pollfd[1].fd = pipefd[cpu*2];
+	pollfd[1].fd = gopts->pipefd[cpu*2];
 	pollfd[1].events = POLLIN;

-	ready_for_fork = true;
+	gopts->ready_for_fork = true;

 	for (;;) {
 		ret = poll(pollfd, 2, -1);
@@ -537,30 +557,30 @@ void *uffd_poll_thread(void *arg)
 		}
 		if (!(pollfd[0].revents & POLLIN))
 			err("pollfd[0].revents %d", pollfd[0].revents);
-		if (uffd_read_msg(uffd, &msg))
+		if (uffd_read_msg(gopts, &msg))
 			continue;
 		switch (msg.event) {
 		default:
 			err("unexpected msg event %u\n", msg.event);
 			break;
 		case UFFD_EVENT_PAGEFAULT:
-			args->handle_fault(&msg, args);
+			args->handle_fault(gopts, &msg, args);
 			break;
 		case UFFD_EVENT_FORK:
-			close(uffd);
-			uffd = msg.arg.fork.ufd;
-			pollfd[0].fd = uffd;
+			close(gopts->uffd);
+			gopts->uffd = msg.arg.fork.ufd;
+			pollfd[0].fd = gopts->uffd;
 			break;
 		case UFFD_EVENT_REMOVE:
 			uffd_reg.range.start = msg.arg.remove.start;
 			uffd_reg.range.len = msg.arg.remove.end -
 				msg.arg.remove.start;
-			if (ioctl(uffd, UFFDIO_UNREGISTER, &uffd_reg.range))
+			if (ioctl(gopts->uffd, UFFDIO_UNREGISTER, &uffd_reg.range))
 				err("remove failure");
 			break;
 		case UFFD_EVENT_REMAP:
-			area_remap = area_dst;  /* save for later unmap */
-			area_dst = (char *)(unsigned long)msg.arg.remap.to;
+			gopts->area_remap = gopts->area_dst;  /* save for later unmap */
+			gopts->area_dst = (char *)(unsigned long)msg.arg.remap.to;
 			break;
 		}
 	}
@@ -568,17 +588,18 @@ void *uffd_poll_thread(void *arg)
 	return NULL;
 }

-static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
+static void retry_copy_page(uffd_global_test_opts_t *gopts, struct uffdio_copy *uffdio_copy,
 			    unsigned long offset)
 {
-	uffd_test_ops->alias_mapping(&uffdio_copy->dst,
+	uffd_test_ops->alias_mapping(gopts,
+				     &uffdio_copy->dst,
 				     uffdio_copy->len,
 				     offset);
-	if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) {
+	if (ioctl(gopts->uffd, UFFDIO_COPY, uffdio_copy)) {
 		/* real retval in ufdio_copy.copy */
 		if (uffdio_copy->copy != -EEXIST)
 			err("UFFDIO_COPY retry error: %"PRId64,
-			    (int64_t)uffdio_copy->copy);
+			(int64_t)uffdio_copy->copy);
 	} else {
 		err("UFFDIO_COPY retry unexpected: %"PRId64,
 		    (int64_t)uffdio_copy->copy);
@@ -597,60 +618,60 @@ static void wake_range(int ufd, unsigned long addr, unsigned long len)
 			addr), exit(1);
 }

-int __copy_page(int ufd, unsigned long offset, bool retry, bool wp)
+int __copy_page(uffd_global_test_opts_t *gopts, unsigned long offset, bool retry, bool wp)
 {
 	struct uffdio_copy uffdio_copy;

-	if (offset >= nr_pages * page_size)
+	if (offset >= gopts->nr_pages * gopts->page_size)
 		err("unexpected offset %lu\n", offset);
-	uffdio_copy.dst = (unsigned long) area_dst + offset;
-	uffdio_copy.src = (unsigned long) area_src + offset;
-	uffdio_copy.len = page_size;
+	uffdio_copy.dst = (unsigned long) gopts->area_dst + offset;
+	uffdio_copy.src = (unsigned long) gopts->area_src + offset;
+	uffdio_copy.len = gopts->page_size;
 	if (wp)
 		uffdio_copy.mode = UFFDIO_COPY_MODE_WP;
 	else
 		uffdio_copy.mode = 0;
 	uffdio_copy.copy = 0;
-	if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
+	if (ioctl(gopts->uffd, UFFDIO_COPY, &uffdio_copy)) {
 		/* real retval in ufdio_copy.copy */
 		if (uffdio_copy.copy != -EEXIST)
 			err("UFFDIO_COPY error: %"PRId64,
 			    (int64_t)uffdio_copy.copy);
-		wake_range(ufd, uffdio_copy.dst, page_size);
-	} else if (uffdio_copy.copy != page_size) {
+		wake_range(gopts->uffd, uffdio_copy.dst, gopts->page_size);
+	} else if (uffdio_copy.copy != gopts->page_size) {
 		err("UFFDIO_COPY error: %"PRId64, (int64_t)uffdio_copy.copy);
 	} else {
-		if (test_uffdio_copy_eexist && retry) {
-			test_uffdio_copy_eexist = false;
-			retry_copy_page(ufd, &uffdio_copy, offset);
+		if (gopts->test_uffdio_copy_eexist && retry) {
+			gopts->test_uffdio_copy_eexist = false;
+			retry_copy_page(gopts, &uffdio_copy, offset);
 		}
 		return 1;
 	}
 	return 0;
 }

-int copy_page(int ufd, unsigned long offset, bool wp)
+int copy_page(uffd_global_test_opts_t *gopts, unsigned long offset, bool wp)
 {
-	return __copy_page(ufd, offset, false, wp);
+	return __copy_page(gopts, offset, false, wp);
 }

-int move_page(int ufd, unsigned long offset, unsigned long len)
+int move_page(uffd_global_test_opts_t *gopts, unsigned long offset, unsigned long len)
 {
 	struct uffdio_move uffdio_move;

-	if (offset + len > nr_pages * page_size)
+	if (offset + len > gopts->nr_pages * gopts->page_size)
 		err("unexpected offset %lu and length %lu\n", offset, len);
-	uffdio_move.dst = (unsigned long) area_dst + offset;
-	uffdio_move.src = (unsigned long) area_src + offset;
+	uffdio_move.dst = (unsigned long) gopts->area_dst + offset;
+	uffdio_move.src = (unsigned long) gopts->area_src + offset;
 	uffdio_move.len = len;
 	uffdio_move.mode = UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES;
 	uffdio_move.move = 0;
-	if (ioctl(ufd, UFFDIO_MOVE, &uffdio_move)) {
+	if (ioctl(gopts->uffd, UFFDIO_MOVE, &uffdio_move)) {
 		/* real retval in uffdio_move.move */
 		if (uffdio_move.move != -EEXIST)
 			err("UFFDIO_MOVE error: %"PRId64,
 			    (int64_t)uffdio_move.move);
-		wake_range(ufd, uffdio_move.dst, len);
+		wake_range(gopts->uffd, uffdio_move.dst, len);
 	} else if (uffdio_move.move != len) {
 		err("UFFDIO_MOVE error: %"PRId64, (int64_t)uffdio_move.move);
 	} else
--- a/tools/testing/selftests/mm/uffd-common.h
+++ b/tools/testing/selftests/mm/uffd-common.h
@@ -56,20 +56,17 @@

 #define err(fmt, ...) errexit(1, fmt, ##__VA_ARGS__)

-/* pthread_mutex_t starts at page offset 0 */
-#define area_mutex(___area, ___nr)					\
-	((pthread_mutex_t *) ((___area) + (___nr)*page_size))
-/*
- * count is placed in the page after pthread_mutex_t naturally aligned
- * to avoid non alignment faults on non-x86 archs.
- */
-#define area_count(___area, ___nr)					\
-	((volatile unsigned long long *) ((unsigned long)		\
-				 ((___area) + (___nr)*page_size +	\
-				  sizeof(pthread_mutex_t) +		\
-				  sizeof(unsigned long long) - 1) &	\
-				 ~(unsigned long)(sizeof(unsigned long long) \
-						  -  1)))
+struct uffd_global_test_opts {
+	unsigned long nr_parallel, nr_pages, nr_pages_per_cpu, page_size;
+	char *area_src, *area_src_alias, *area_dst, *area_dst_alias, *area_remap;
+	int uffd, uffd_flags, finished, *pipefd, test_type;
+	bool map_shared;
+	bool test_uffdio_wp;
+	unsigned long long *count_verify;
+	volatile bool test_uffdio_copy_eexist;
+	atomic_bool ready_for_fork;
+};
+typedef struct uffd_global_test_opts uffd_global_test_opts_t;

 /* Userfaultfd test statistics */
 struct uffd_args {
@@ -79,50 +76,55 @@ struct uffd_args {
 	unsigned long missing_faults;
 	unsigned long wp_faults;
 	unsigned long minor_faults;
+	struct uffd_global_test_opts *gopts;

 	/* A custom fault handler; defaults to uffd_handle_page_fault. */
-	void (*handle_fault)(struct uffd_msg *msg, struct uffd_args *args);
+	void (*handle_fault)(struct uffd_global_test_opts *gopts,
+			     struct uffd_msg *msg,
+			     struct uffd_args *args);
 };

 struct uffd_test_ops {
-	int (*allocate_area)(void **alloc_area, bool is_src);
-	void (*release_pages)(char *rel_area);
-	void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset);
-	void (*check_pmd_mapping)(void *p, int expect_nr_hpages);
+	int (*allocate_area)(uffd_global_test_opts_t *gopts, void **alloc_area, bool is_src);
+	void (*release_pages)(uffd_global_test_opts_t *gopts, char *rel_area);
+	void (*alias_mapping)(uffd_global_test_opts_t *gopts,
+			      __u64 *start,
+			      size_t len,
+			      unsigned long offset);
+	void (*check_pmd_mapping)(uffd_global_test_opts_t *gopts, void *p, int expect_nr_hpages);
 };
 typedef struct uffd_test_ops uffd_test_ops_t;

 struct uffd_test_case_ops {
-	int (*pre_alloc)(const char **errmsg);
-	int (*post_alloc)(const char **errmsg);
+	int (*pre_alloc)(uffd_global_test_opts_t *gopts, const char **errmsg);
+	int (*post_alloc)(uffd_global_test_opts_t *gopts, const char **errmsg);
 };
 typedef struct uffd_test_case_ops uffd_test_case_ops_t;

-extern unsigned long nr_parallel, nr_pages, nr_pages_per_cpu, page_size;
-extern char *area_src, *area_src_alias, *area_dst, *area_dst_alias, *area_remap;
-extern int uffd, uffd_flags, finished, *pipefd, test_type;
-extern bool map_shared;
-extern bool test_uffdio_wp;
-extern unsigned long long *count_verify;
-extern volatile bool test_uffdio_copy_eexist;
-extern atomic_bool ready_for_fork;
-
+extern uffd_global_test_opts_t *uffd_gtest_opts;
 extern uffd_test_ops_t anon_uffd_test_ops;
 extern uffd_test_ops_t shmem_uffd_test_ops;
 extern uffd_test_ops_t hugetlb_uffd_test_ops;
 extern uffd_test_ops_t *uffd_test_ops;
 extern uffd_test_case_ops_t *uffd_test_case_ops;

+pthread_mutex_t *area_mutex(char *area, unsigned long nr, uffd_global_test_opts_t *gopts);
+volatile unsigned long long *area_count(char *area,
+					unsigned long nr,
+					uffd_global_test_opts_t *gopts);
+
 void uffd_stats_report(struct uffd_args *args, int n_cpus);
-int uffd_test_ctx_init(uint64_t features, const char **errmsg);
-void uffd_test_ctx_clear(void);
-int userfaultfd_open(uint64_t *features);
-int uffd_read_msg(int ufd, struct uffd_msg *msg);
+int uffd_test_ctx_init(uffd_global_test_opts_t *gopts, uint64_t features, const char **errmsg);
+void uffd_test_ctx_clear(uffd_global_test_opts_t *gopts);
+int userfaultfd_open(uffd_global_test_opts_t *gopts, uint64_t *features);
+int uffd_read_msg(uffd_global_test_opts_t *gopts, struct uffd_msg *msg);
 void wp_range(int ufd, __u64 start, __u64 len, bool wp);
-void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args);
-int __copy_page(int ufd, unsigned long offset, bool retry, bool wp);
-int copy_page(int ufd, unsigned long offset, bool wp);
-int move_page(int ufd, unsigned long offset, unsigned long len);
+void uffd_handle_page_fault(uffd_global_test_opts_t *gopts,
+			    struct uffd_msg *msg,
+			    struct uffd_args *args);
+int __copy_page(uffd_global_test_opts_t *gopts, unsigned long offset, bool retry, bool wp);
+int copy_page(uffd_global_test_opts_t *gopts, unsigned long offset, bool wp);
+int move_page(uffd_global_test_opts_t *gopts, unsigned long offset, unsigned long len);
 void *uffd_poll_thread(void *arg);

 int uffd_open_dev(unsigned int flags);
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -44,6 +44,12 @@ uint64_t features;
 #define BOUNCE_VERIFY		(1<<2)
 #define BOUNCE_POLL		(1<<3)
 static int bounces;
+/* defined globally for this particular test as the sigalrm handler
+ * depends on test_uffdio_*_eexist.
+ * XXX: define gopts in main() when we figure out a way to deal with
+ * test_uffdio_*_eexist.
+ */
+static uffd_global_test_opts_t *gopts;

 /* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */
 #define ALARM_INTERVAL_SECS 10
@@ -76,54 +82,58 @@ static void usage(void)
 	exit(1);
 }

-static void uffd_stats_reset(struct uffd_args *args, unsigned long n_cpus)
+static void uffd_stats_reset(uffd_global_test_opts_t *gopts, struct uffd_args *args,
+			     unsigned long n_cpus)
 {
 	int i;

 	for (i = 0; i < n_cpus; i++) {
 		args[i].cpu = i;
-		args[i].apply_wp = test_uffdio_wp;
+		args[i].apply_wp = gopts->test_uffdio_wp;
 		args[i].missing_faults = 0;
 		args[i].wp_faults = 0;
 		args[i].minor_faults = 0;
+		args[i].gopts = gopts;
 	}
 }

 static void *locking_thread(void *arg)
 {
-	unsigned long cpu = (unsigned long) arg;
+	struct uffd_args *args = (struct uffd_args *) arg;
+	uffd_global_test_opts_t *gopts = args->gopts;
+	unsigned long cpu = (unsigned long) args->cpu;
 	unsigned long page_nr;
 	unsigned long long count;

 	if (!(bounces & BOUNCE_RANDOM)) {
 		page_nr = -bounces;
 		if (!(bounces & BOUNCE_RACINGFAULTS))
-			page_nr += cpu * nr_pages_per_cpu;
+			page_nr += cpu * gopts->nr_pages_per_cpu;
 	}

-	while (!finished) {
+	while (!gopts->finished) {
 		if (bounces & BOUNCE_RANDOM) {
 			if (getrandom(&page_nr, sizeof(page_nr), 0) != sizeof(page_nr))
 				err("getrandom failed");
 		} else
 			page_nr += 1;
-		page_nr %= nr_pages;
-		pthread_mutex_lock(area_mutex(area_dst, page_nr));
-		count = *area_count(area_dst, page_nr);
-		if (count != count_verify[page_nr])
+		page_nr %= gopts->nr_pages;
+		pthread_mutex_lock(area_mutex(gopts->area_dst, page_nr, gopts));
+		count = *area_count(gopts->area_dst, page_nr, gopts);
+		if (count != gopts->count_verify[page_nr])
 			err("page_nr %lu memory corruption %llu %llu",
-			    page_nr, count, count_verify[page_nr]);
+			    page_nr, count, gopts->count_verify[page_nr]);
 		count++;
-		*area_count(area_dst, page_nr) = count_verify[page_nr] = count;
-		pthread_mutex_unlock(area_mutex(area_dst, page_nr));
+		*area_count(gopts->area_dst, page_nr, gopts) = gopts->count_verify[page_nr] = count;
+		pthread_mutex_unlock(area_mutex(gopts->area_dst, page_nr, gopts));
 	}

 	return NULL;
 }

-static int copy_page_retry(int ufd, unsigned long offset)
+static int copy_page_retry(uffd_global_test_opts_t *gopts, unsigned long offset)
 {
-	return __copy_page(ufd, offset, true, test_uffdio_wp);
+	return __copy_page(gopts, offset, true, gopts->test_uffdio_wp);
 }

 pthread_mutex_t uffd_read_mutex = PTHREAD_MUTEX_INITIALIZER;
@@ -131,15 +141,16 @@ pthread_mutex_t uffd_read_mutex = PTHREAD_MUTEX_INITIALIZER;
 static void *uffd_read_thread(void *arg)
 {
 	struct uffd_args *args = (struct uffd_args *)arg;
+	uffd_global_test_opts_t *gopts = args->gopts;
 	struct uffd_msg msg;

 	pthread_mutex_unlock(&uffd_read_mutex);
 	/* from here cancellation is ok */

 	for (;;) {
-		if (uffd_read_msg(uffd, &msg))
+		if (uffd_read_msg(gopts, &msg))
 			continue;
-		uffd_handle_page_fault(&msg, args);
+		uffd_handle_page_fault(gopts, &msg, args);
 	}

 	return NULL;
@@ -147,32 +158,34 @@ static void *uffd_read_thread(void *arg)

 static void *background_thread(void *arg)
 {
-	unsigned long cpu = (unsigned long) arg;
+	struct uffd_args *args = (struct uffd_args *) arg;
+	uffd_global_test_opts_t *gopts = args->gopts;
+	unsigned long cpu = (unsigned long) args->cpu;
 	unsigned long page_nr, start_nr, mid_nr, end_nr;

-	start_nr = cpu * nr_pages_per_cpu;
-	end_nr = (cpu+1) * nr_pages_per_cpu;
+	start_nr = cpu * gopts->nr_pages_per_cpu;
+	end_nr = (cpu+1) * gopts->nr_pages_per_cpu;
 	mid_nr = (start_nr + end_nr) / 2;

 	/* Copy the first half of the pages */
 	for (page_nr = start_nr; page_nr < mid_nr; page_nr++)
-		copy_page_retry(uffd, page_nr * page_size);
+		copy_page_retry(gopts, page_nr * gopts->page_size);

 	/*
 	 * If we need to test uffd-wp, set it up now.  Then we'll have
 	 * at least the first half of the pages mapped already which
 	 * can be write-protected for testing
 	 */
-	if (test_uffdio_wp)
-		wp_range(uffd, (unsigned long)area_dst + start_nr * page_size,
-			nr_pages_per_cpu * page_size, true);
+	if (gopts->test_uffdio_wp)
+		wp_range(gopts->uffd, (unsigned long)gopts->area_dst + start_nr * gopts->page_size,
+			gopts->nr_pages_per_cpu * gopts->page_size, true);

 	/*
 	 * Continue the 2nd half of the page copying, handling write
 	 * protection faults if any
 	 */
 	for (page_nr = mid_nr; page_nr < end_nr; page_nr++)
-		copy_page_retry(uffd, page_nr * page_size);
+		copy_page_retry(gopts, page_nr * gopts->page_size);

 	return NULL;
 }
@@ -180,17 +193,21 @@ static void *background_thread(void *arg)
 static int stress(struct uffd_args *args)
 {
 	unsigned long cpu;
-	pthread_t locking_threads[nr_parallel];
-	pthread_t uffd_threads[nr_parallel];
-	pthread_t background_threads[nr_parallel];
+	uffd_global_test_opts_t *gopts = args->gopts;
+	pthread_t locking_threads[gopts->nr_parallel];
+	pthread_t uffd_threads[gopts->nr_parallel];
+	pthread_t background_threads[gopts->nr_parallel];

-	finished = 0;
-	for (cpu = 0; cpu < nr_parallel; cpu++) {
+	gopts->finished = 0;
+	for (cpu = 0; cpu < gopts->nr_parallel; cpu++) {
 		if (pthread_create(&locking_threads[cpu], &attr,
-				   locking_thread, (void *)cpu))
+				   locking_thread, (void *)&args[cpu]))
 			return 1;
 		if (bounces & BOUNCE_POLL) {
-			if (pthread_create(&uffd_threads[cpu], &attr, uffd_poll_thread, &args[cpu]))
+			if (pthread_create(&uffd_threads[cpu],
+					   &attr,
+					   uffd_poll_thread,
+					   (void *) &args[cpu]))
 				err("uffd_poll_thread create");
 		} else {
 			if (pthread_create(&uffd_threads[cpu], &attr,
@@ -200,10 +217,10 @@ static int stress(struct uffd_args *args)
 			pthread_mutex_lock(&uffd_read_mutex);
 		}
 		if (pthread_create(&background_threads[cpu], &attr,
-				   background_thread, (void *)cpu))
+				   background_thread, (void *)&args[cpu]))
 			return 1;
 	}
-	for (cpu = 0; cpu < nr_parallel; cpu++)
+	for (cpu = 0; cpu < gopts->nr_parallel; cpu++)
 		if (pthread_join(background_threads[cpu], NULL))
 			return 1;

@@ -216,17 +233,17 @@ static int stress(struct uffd_args *args)
 	 * UFFDIO_COPY without writing zero pages into area_dst
 	 * because the background threads already completed).
 	 */
-	uffd_test_ops->release_pages(area_src);
+	uffd_test_ops->release_pages(gopts, gopts->area_src);

-	finished = 1;
-	for (cpu = 0; cpu < nr_parallel; cpu++)
+	gopts->finished = 1;
+	for (cpu = 0; cpu < gopts->nr_parallel; cpu++)
 		if (pthread_join(locking_threads[cpu], NULL))
 			return 1;

-	for (cpu = 0; cpu < nr_parallel; cpu++) {
+	for (cpu = 0; cpu < gopts->nr_parallel; cpu++) {
 		char c;
 		if (bounces & BOUNCE_POLL) {
-			if (write(pipefd[cpu*2+1], &c, 1) != 1)
+			if (write(gopts->pipefd[cpu*2+1], &c, 1) != 1)
 				err("pipefd write error");
 			if (pthread_join(uffd_threads[cpu],
 					 (void *)&args[cpu]))
@@ -242,26 +259,26 @@ static int stress(struct uffd_args *args)
 	return 0;
 }

-static int userfaultfd_stress(void)
+static int userfaultfd_stress(uffd_global_test_opts_t *gopts)
 {
 	void *area;
 	unsigned long nr;
-	struct uffd_args args[nr_parallel];
-	uint64_t mem_size = nr_pages * page_size;
+	struct uffd_args args[gopts->nr_parallel];
+	uint64_t mem_size = gopts->nr_pages * gopts->page_size;
 	int flags = 0;

-	memset(args, 0, sizeof(struct uffd_args) * nr_parallel);
+	memset(args, 0, sizeof(struct uffd_args) * gopts->nr_parallel);

-	if (features & UFFD_FEATURE_WP_UNPOPULATED && test_type == TEST_ANON)
+	if (features & UFFD_FEATURE_WP_UNPOPULATED && gopts->test_type == TEST_ANON)
 		flags = UFFD_FEATURE_WP_UNPOPULATED;

-	if (uffd_test_ctx_init(flags, NULL))
+	if (uffd_test_ctx_init(gopts, flags, NULL))
 		err("context init failed");

-	if (posix_memalign(&area, page_size, page_size))
+	if (posix_memalign(&area, gopts->page_size, gopts->page_size))
 		err("out of memory");
 	zeropage = area;
-	bzero(zeropage, page_size);
+	bzero(zeropage, gopts->page_size);

 	pthread_mutex_lock(&uffd_read_mutex);

@@ -284,18 +301,18 @@ static int userfaultfd_stress(void)
 		fflush(stdout);

 		if (bounces & BOUNCE_POLL)
-			fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
+			fcntl(gopts->uffd, F_SETFL, gopts->uffd_flags | O_NONBLOCK);
 		else
-			fcntl(uffd, F_SETFL, uffd_flags & ~O_NONBLOCK);
+			fcntl(gopts->uffd, F_SETFL, gopts->uffd_flags & ~O_NONBLOCK);

 		/* register */
-		if (uffd_register(uffd, area_dst, mem_size,
-				  true, test_uffdio_wp, false))
+		if (uffd_register(gopts->uffd, gopts->area_dst, mem_size,
+				  true, gopts->test_uffdio_wp, false))
 			err("register failure");

-		if (area_dst_alias) {
-			if (uffd_register(uffd, area_dst_alias, mem_size,
-					  true, test_uffdio_wp, false))
+		if (gopts->area_dst_alias) {
+			if (uffd_register(gopts->uffd, gopts->area_dst_alias, mem_size,
+					  true, gopts->test_uffdio_wp, false))
 				err("register failure alias");
 		}

@@ -323,87 +340,88 @@ static int userfaultfd_stress(void)
 		 * MADV_DONTNEED only after the UFFDIO_REGISTER, so it's
 		 * required to MADV_DONTNEED here.
 		 */
-		uffd_test_ops->release_pages(area_dst);
+		uffd_test_ops->release_pages(gopts, gopts->area_dst);

-		uffd_stats_reset(args, nr_parallel);
+		uffd_stats_reset(gopts, args, gopts->nr_parallel);

 		/* bounce pass */
 		if (stress(args)) {
-			uffd_test_ctx_clear();
+			uffd_test_ctx_clear(gopts);
 			return 1;
 		}

 		/* Clear all the write protections if there is any */
-		if (test_uffdio_wp)
-			wp_range(uffd, (unsigned long)area_dst,
-				 nr_pages * page_size, false);
+		if (gopts->test_uffdio_wp)
+			wp_range(gopts->uffd, (unsigned long)gopts->area_dst,
+				 gopts->nr_pages * gopts->page_size, false);

 		/* unregister */
-		if (uffd_unregister(uffd, area_dst, mem_size))
+		if (uffd_unregister(gopts->uffd, gopts->area_dst, mem_size))
 			err("unregister failure");
-		if (area_dst_alias) {
-			if (uffd_unregister(uffd, area_dst_alias, mem_size))
+		if (gopts->area_dst_alias) {
+			if (uffd_unregister(gopts->uffd, gopts->area_dst_alias, mem_size))
 				err("unregister failure alias");
 		}

 		/* verification */
 		if (bounces & BOUNCE_VERIFY)
-			for (nr = 0; nr < nr_pages; nr++)
-				if (*area_count(area_dst, nr) != count_verify[nr])
+			for (nr = 0; nr < gopts->nr_pages; nr++)
+				if (*area_count(gopts->area_dst, nr, gopts) !=
+						gopts->count_verify[nr])
 					err("error area_count %llu %llu %lu\n",
-					    *area_count(area_src, nr),
-					    count_verify[nr], nr);
+					    *area_count(gopts->area_src, nr, gopts),
+					    gopts->count_verify[nr], nr);

 		/* prepare next bounce */
-		swap(area_src, area_dst);
+		swap(gopts->area_src, gopts->area_dst);

-		swap(area_src_alias, area_dst_alias);
+		swap(gopts->area_src_alias, gopts->area_dst_alias);

-		uffd_stats_report(args, nr_parallel);
+		uffd_stats_report(args, gopts->nr_parallel);
 	}
-	uffd_test_ctx_clear();
+	uffd_test_ctx_clear(gopts);

 	return 0;
 }

-static void set_test_type(const char *type)
+static void set_test_type(uffd_global_test_opts_t *gopts, const char *type)
 {
 	if (!strcmp(type, "anon")) {
-		test_type = TEST_ANON;
+		gopts->test_type = TEST_ANON;
 		uffd_test_ops = &anon_uffd_test_ops;
 	} else if (!strcmp(type, "hugetlb")) {
-		test_type = TEST_HUGETLB;
+		gopts->test_type = TEST_HUGETLB;
 		uffd_test_ops = &hugetlb_uffd_test_ops;
-		map_shared = true;
+		gopts->map_shared = true;
 	} else if (!strcmp(type, "hugetlb-private")) {
-		test_type = TEST_HUGETLB;
+		gopts->test_type = TEST_HUGETLB;
 		uffd_test_ops = &hugetlb_uffd_test_ops;
 	} else if (!strcmp(type, "shmem")) {
-		map_shared = true;
-		test_type = TEST_SHMEM;
+		gopts->map_shared = true;
+		gopts->test_type = TEST_SHMEM;
 		uffd_test_ops = &shmem_uffd_test_ops;
 	} else if (!strcmp(type, "shmem-private")) {
-		test_type = TEST_SHMEM;
+		gopts->test_type = TEST_SHMEM;
 		uffd_test_ops = &shmem_uffd_test_ops;
 	}
 }

-static void parse_test_type_arg(const char *raw_type)
+static void parse_test_type_arg(uffd_global_test_opts_t *gopts, const char *raw_type)
 {
-	set_test_type(raw_type);
+	set_test_type(gopts, raw_type);

-	if (!test_type)
+	if (!gopts->test_type)
 		err("failed to parse test type argument: '%s'", raw_type);

-	if (test_type == TEST_HUGETLB)
-		page_size = default_huge_page_size();
+	if (gopts->test_type == TEST_HUGETLB)
+		gopts->page_size = default_huge_page_size();
 	else
-		page_size = sysconf(_SC_PAGE_SIZE);
+		gopts->page_size = sysconf(_SC_PAGE_SIZE);

-	if (!page_size)
+	if (!gopts->page_size)
 		err("Unable to determine page size");
-	if ((unsigned long) area_count(NULL, 0) + sizeof(unsigned long long) * 2
-	    > page_size)
+	if ((unsigned long) area_count(NULL, 0, gopts) + sizeof(unsigned long long) * 2
+	    > gopts->page_size)
 		err("Impossible to run this test");

 	/*
@@ -415,21 +433,21 @@ static void parse_test_type_arg(const char *raw_type)
 	if (uffd_get_features(&features) && errno == ENOENT)
 		ksft_exit_skip("failed to get available features (%d)\n", errno);

-	test_uffdio_wp = test_uffdio_wp &&
+	gopts->test_uffdio_wp = gopts->test_uffdio_wp &&
 		(features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);

-	if (test_type != TEST_ANON && !(features & UFFD_FEATURE_WP_HUGETLBFS_SHMEM))
-		test_uffdio_wp = false;
+	if (gopts->test_type != TEST_ANON && !(features & UFFD_FEATURE_WP_HUGETLBFS_SHMEM))
+		gopts->test_uffdio_wp = false;

-	close(uffd);
-	uffd = -1;
+	close(gopts->uffd);
+	gopts->uffd = -1;
 }

 static void sigalrm(int sig)
 {
 	if (sig != SIGALRM)
 		abort();
-	test_uffdio_copy_eexist = true;
+	gopts->test_uffdio_copy_eexist = true;
 	alarm(ALARM_INTERVAL_SECS);
 }

@@ -438,6 +456,8 @@ int main(int argc, char **argv)
 	unsigned long nr_cpus;
 	size_t bytes;

+	gopts = (uffd_global_test_opts_t *) malloc(sizeof(uffd_global_test_opts_t));
+
 	if (argc < 4)
 		usage();

@@ -445,7 +465,7 @@ int main(int argc, char **argv)
 		err("failed to arm SIGALRM");
 	alarm(ALARM_INTERVAL_SECS);

-	parse_test_type_arg(argv[1]);
+	parse_test_type_arg(gopts, argv[1]);
 	bytes = atol(argv[2]) * 1024 * 1024;

 	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
@@ -453,9 +473,9 @@ int main(int argc, char **argv)
 		/* Don't let calculation below go to zero. */
 		ksft_print_msg("_SC_NPROCESSORS_ONLN (%lu) too large, capping nr_threads to 32\n",
 			       nr_cpus);
-		nr_parallel = 32;
+		gopts->nr_parallel = 32;
 	} else {
-		nr_parallel = nr_cpus;
+		gopts->nr_parallel = nr_cpus;
 	}

 	/*
@@ -463,16 +483,16 @@ int main(int argc, char **argv)
 	 * Ensure nr_parallel - 1 hugepages on top of that to account
 	 * for racy extra reservation of hugepages.
 	 */
-	if (test_type == TEST_HUGETLB &&
-	   get_free_hugepages() < 2 * (bytes / page_size) + nr_parallel - 1) {
+	if (gopts->test_type == TEST_HUGETLB &&
+	   get_free_hugepages() < 2 * (bytes / gopts->page_size) + gopts->nr_parallel - 1) {
 		printf("skip: Skipping userfaultfd... not enough hugepages\n");
 		return KSFT_SKIP;
 	}

-	nr_pages_per_cpu = bytes / page_size / nr_parallel;
-	if (!nr_pages_per_cpu) {
+	gopts->nr_pages_per_cpu = bytes / gopts->page_size / gopts->nr_parallel;
+	if (!gopts->nr_pages_per_cpu) {
 		_err("pages_per_cpu = 0, cannot test (%lu / %lu / %lu)",
-			bytes, page_size, nr_parallel);
+			bytes, gopts->page_size, gopts->nr_parallel);
 		usage();
 	}

@@ -481,11 +501,11 @@ int main(int argc, char **argv)
 		_err("invalid bounces");
 		usage();
 	}
-	nr_pages = nr_pages_per_cpu * nr_parallel;
+	gopts->nr_pages = gopts->nr_pages_per_cpu * gopts->nr_parallel;

 	printf("nr_pages: %lu, nr_pages_per_cpu: %lu\n",
-	       nr_pages, nr_pages_per_cpu);
-	return userfaultfd_stress();
+	       gopts->nr_pages, gopts->nr_pages_per_cpu);
+	return userfaultfd_stress(gopts);
 }

 #else /* __NR_userfaultfd */
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/tools/testing/selftests/mm/uffd-unit-tests.c
--- a/tools/testing/selftests/mm/uffd-wp-mremap.c
+++ b/tools/testing/selftests/mm/uffd-wp-mremap.c
@@ -152,7 +152,8 @@ static bool range_is_swapped(void *addr, size_t size)
 	return true;
 }

-static void test_one_folio(size_t size, bool private, bool swapout, bool hugetlb)
+static void test_one_folio(uffd_global_test_opts_t *gopts, size_t size, bool private,
+			   bool swapout, bool hugetlb)
 {
 	struct uffdio_writeprotect wp_prms;
 	uint64_t features = 0;
@@ -176,21 +177,21 @@ static void test_one_folio(size_t size, bool private, bool swapout, bool hugetlb
 	}

 	/* Register range for uffd-wp. */
-	if (userfaultfd_open(&features)) {
+	if (userfaultfd_open(gopts, &features)) {
 		if (errno == ENOENT)
 			ksft_test_result_skip("userfaultfd not available\n");
 		else
 			ksft_test_result_fail("userfaultfd_open() failed\n");
 		goto out;
 	}
-	if (uffd_register(uffd, mem, size, false, true, false)) {
+	if (uffd_register(gopts->uffd, mem, size, false, true, false)) {
 		ksft_test_result_fail("uffd_register() failed\n");
 		goto out;
 	}
 	wp_prms.mode = UFFDIO_WRITEPROTECT_MODE_WP;
 	wp_prms.range.start = (uintptr_t)mem;
 	wp_prms.range.len = size;
-	if (ioctl(uffd, UFFDIO_WRITEPROTECT, &wp_prms)) {
+	if (ioctl(gopts->uffd, UFFDIO_WRITEPROTECT, &wp_prms)) {
 		ksft_test_result_fail("ioctl(UFFDIO_WRITEPROTECT) failed\n");
 		goto out;
 	}
@@ -237,9 +238,9 @@ static void test_one_folio(size_t size, bool private, bool swapout, bool hugetlb
 out:
 	if (mem)
 		munmap(mem, size);
-	if (uffd >= 0) {
-		close(uffd);
-		uffd = -1;
+	if (gopts->uffd >= 0) {
+		close(gopts->uffd);
+		gopts->uffd = -1;
 	}
 }

@@ -331,6 +332,7 @@ static const struct testcase testcases[] = {

 int main(int argc, char **argv)
 {
+	uffd_global_test_opts_t gopts = { 0 };
 	struct thp_settings settings;
 	int i, j, plan = 0;

@@ -362,8 +364,8 @@ int main(int argc, char **argv)
 		const struct testcase *tc = &testcases[i];

 		for (j = 0; j < *tc->nr_sizes; j++)
-			test_one_folio(tc->sizes[j], tc->private, tc->swapout,
-				       tc->hugetlb);
+			test_one_folio(&gopts, tc->sizes[j], tc->private,
+				       tc->swapout, tc->hugetlb);
 	}

 	/* If THP is supported, restore original THP settings. */