1 files changed, 380 insertions, 0 deletions
diff --git a/tools/testing/selftests/mm/uffd-wp-mremap.c b/tools/testing/selftests/mm/uffd-wp-mremap.c
new file mode 100644
index 000000000000..2c4f984bd73c
--- /dev/null
+++ b/tools/testing/selftests/mm/uffd-wp-mremap.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define _GNU_SOURCE
+#include <stdbool.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <linux/mman.h>
+#include <sys/mman.h>
+#include "../kselftest.h"
+#include "thp_settings.h"
+#include "uffd-common.h"
+
+static int pagemap_fd;
+static size_t pagesize;
+static int nr_pagesizes = 1;
+static int nr_thpsizes;
+static size_t thpsizes[20];
+static int nr_hugetlbsizes;
+static size_t hugetlbsizes[10];
+
+static int sz2ord(size_t size)
+{
+	return __builtin_ctzll(size / pagesize);
+}
+
+static int detect_thp_sizes(size_t sizes[], int max)
+{
+	int count = 0;
+	unsigned long orders;
+	size_t kb;
+	int i;
+
+	/* thp not supported at all. */
+	if (!read_pmd_pagesize())
+		return 0;
+
+	orders = thp_supported_orders();
+
+	for (i = 0; orders && count < max; i++) {
+		if (!(orders & (1UL << i)))
+			continue;
+		orders &= ~(1UL << i);
+		kb = (pagesize >> 10) << i;
+		sizes[count++] = kb * 1024;
+		ksft_print_msg("[INFO] detected THP size: %zu KiB\n", kb);
+	}
+
+	return count;
+}
+
+static void *mmap_aligned(size_t size, int prot, int flags)
+{
+	size_t mmap_size = size * 2;
+	char *mmap_mem, *mem;
+
+	mmap_mem = mmap(NULL, mmap_size, prot, flags, -1, 0);
+	if (mmap_mem == MAP_FAILED)
+		return mmap_mem;
+
+	mem = (char *)(((uintptr_t)mmap_mem + size - 1) & ~(size - 1));
+	munmap(mmap_mem, mem - mmap_mem);
+	munmap(mem + size, mmap_mem + mmap_size - mem - size);
+
+	return mem;
+}
+
+static void *alloc_one_folio(size_t size, bool private, bool hugetlb)
+{
+	bool thp = !hugetlb && size > pagesize;
+	int flags = MAP_ANONYMOUS;
+	int prot = PROT_READ | PROT_WRITE;
+	char *mem, *addr;
+
+	assert((size & (size - 1)) == 0);
+
+	if (private)
+		flags |= MAP_PRIVATE;
+	else
+		flags |= MAP_SHARED;
+
+	/*
+	 * For THP, we must explicitly enable the THP size, allocate twice the
+	 * required space then manually align.
+	 */
+	if (thp) {
+		struct thp_settings settings = *thp_current_settings();
+
+		if (private)
+			settings.hugepages[sz2ord(size)].enabled = THP_ALWAYS;
+		else
+			settings.shmem_hugepages[sz2ord(size)].enabled = SHMEM_ALWAYS;
+
+		thp_push_settings(&settings);
+
+		mem = mmap_aligned(size, prot, flags);
+	} else {
+		if (hugetlb) {
+			flags |= MAP_HUGETLB;
+			flags |= __builtin_ctzll(size) << MAP_HUGE_SHIFT;
+		}
+
+		mem = mmap(NULL, size, prot, flags, -1, 0);
+	}
+
+	if (mem == MAP_FAILED) {
+		mem = NULL;
+		goto out;
+	}
+
+	assert(((uintptr_t)mem & (size - 1)) == 0);
+
+	/*
+	 * Populate the folio by writing the first byte and check that all pages
+	 * are populated. Finally set the whole thing to non-zero data to avoid
+	 * kernel from mapping it back to the zero page.
+	 */
+	mem[0] = 1;
+	for (addr = mem; addr < mem + size; addr += pagesize) {
+		if (!pagemap_is_populated(pagemap_fd, addr)) {
+			munmap(mem, size);
+			mem = NULL;
+			goto out;
+		}
+	}
+	memset(mem, 1, size);
+out:
+	if (thp)
+		thp_pop_settings();
+
+	return mem;
+}
+
+static bool check_uffd_wp_state(void *mem, size_t size, bool expect)
+{
+	uint64_t pte;
+	void *addr;
+
+	for (addr = mem; addr < mem + size; addr += pagesize) {
+		pte = pagemap_get_entry(pagemap_fd, addr);
+		if (!!(pte & PM_UFFD_WP) != expect) {
+			ksft_test_result_fail("uffd-wp not %s for pte %lu!\n",
+					      expect ? "set" : "clear",
+					      (addr - mem) / pagesize);
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static bool range_is_swapped(void *addr, size_t size)
+{
+	for (; size; addr += pagesize, size -= pagesize)
+		if (!pagemap_is_swapped(pagemap_fd, addr))
+			return false;
+	return true;
+}
+
+static void test_one_folio(size_t size, bool private, bool swapout, bool hugetlb)
+{
+	struct uffdio_writeprotect wp_prms;
+	uint64_t features = 0;
+	void *addr = NULL;
+	void *mem = NULL;
+
+	assert(!(hugetlb && swapout));
+
+	ksft_print_msg("[RUN] %s(size=%zu, private=%s, swapout=%s, hugetlb=%s)\n",
+				__func__,
+				size,
+				private ? "true" : "false",
+				swapout ? "true" : "false",
+				hugetlb ? "true" : "false");
+
+	/* Allocate a folio of required size and type. */
+	mem = alloc_one_folio(size, private, hugetlb);
+	if (!mem) {
+		ksft_test_result_fail("alloc_one_folio() failed\n");
+		goto out;
+	}
+
+	/* Register range for uffd-wp. */
+	if (userfaultfd_open(&features)) {
+		ksft_test_result_fail("userfaultfd_open() failed\n");
+		goto out;
+	}
+	if (uffd_register(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)) {
+		ksft_test_result_fail("ioctl(UFFDIO_WRITEPROTECT) failed\n");
+		goto out;
+	}
+
+	if (swapout) {
+		madvise(mem, size, MADV_PAGEOUT);
+		if (!range_is_swapped(mem, size)) {
+			ksft_test_result_skip("MADV_PAGEOUT did not work, is swap enabled?\n");
+			goto out;
+		}
+	}
+
+	/* Check that uffd-wp is set for all PTEs in range. */
+	if (!check_uffd_wp_state(mem, size, true))
+		goto out;
+
+	/*
+	 * Move the mapping to a new, aligned location. Since
+	 * UFFD_FEATURE_EVENT_REMAP is not set, we expect the uffd-wp bit for
+	 * each PTE to be cleared in the new mapping.
+	 */
+	addr = mmap_aligned(size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS);
+	if (addr == MAP_FAILED) {
+		ksft_test_result_fail("mmap_aligned() failed\n");
+		goto out;
+	}
+	if (mremap(mem, size, size, MREMAP_FIXED | MREMAP_MAYMOVE, addr) == MAP_FAILED) {
+		ksft_test_result_fail("mremap() failed\n");
+		munmap(addr, size);
+		goto out;
+	}
+	mem = addr;
+
+	/* Check that uffd-wp is cleared for all PTEs in range. */
+	if (!check_uffd_wp_state(mem, size, false))
+		goto out;
+
+	ksft_test_result_pass("%s(size=%zu, private=%s, swapout=%s, hugetlb=%s)\n",
+				__func__,
+				size,
+				private ? "true" : "false",
+				swapout ? "true" : "false",
+				hugetlb ? "true" : "false");
+out:
+	if (mem)
+		munmap(mem, size);
+	if (uffd >= 0) {
+		close(uffd);
+		uffd = -1;
+	}
+}
+
+struct testcase {
+	size_t *sizes;
+	int *nr_sizes;
+	bool private;
+	bool swapout;
+	bool hugetlb;
+};
+
+static const struct testcase testcases[] = {
+	/* base pages. */
+	{
+		.sizes = &pagesize,
+		.nr_sizes = &nr_pagesizes,
+		.private = false,
+		.swapout = false,
+		.hugetlb = false,
+	},
+	{
+		.sizes = &pagesize,
+		.nr_sizes = &nr_pagesizes,
+		.private = true,
+		.swapout = false,
+		.hugetlb = false,
+	},
+	{
+		.sizes = &pagesize,
+		.nr_sizes = &nr_pagesizes,
+		.private = false,
+		.swapout = true,
+		.hugetlb = false,
+	},
+	{
+		.sizes = &pagesize,
+		.nr_sizes = &nr_pagesizes,
+		.private = true,
+		.swapout = true,
+		.hugetlb = false,
+	},
+
+	/* thp. */
+	{
+		.sizes = thpsizes,
+		.nr_sizes = &nr_thpsizes,
+		.private = false,
+		.swapout = false,
+		.hugetlb = false,
+	},
+	{
+		.sizes = thpsizes,
+		.nr_sizes = &nr_thpsizes,
+		.private = true,
+		.swapout = false,
+		.hugetlb = false,
+	},
+	{
+		.sizes = thpsizes,
+		.nr_sizes = &nr_thpsizes,
+		.private = false,
+		.swapout = true,
+		.hugetlb = false,
+	},
+	{
+		.sizes = thpsizes,
+		.nr_sizes = &nr_thpsizes,
+		.private = true,
+		.swapout = true,
+		.hugetlb = false,
+	},
+
+	/* hugetlb. */
+	{
+		.sizes = hugetlbsizes,
+		.nr_sizes = &nr_hugetlbsizes,
+		.private = false,
+		.swapout = false,
+		.hugetlb = true,
+	},
+	{
+		.sizes = hugetlbsizes,
+		.nr_sizes = &nr_hugetlbsizes,
+		.private = true,
+		.swapout = false,
+		.hugetlb = true,
+	},
+};
+
+int main(int argc, char **argv)
+{
+	struct thp_settings settings;
+	int i, j, plan = 0;
+
+	pagesize = getpagesize();
+	nr_thpsizes = detect_thp_sizes(thpsizes, ARRAY_SIZE(thpsizes));
+	nr_hugetlbsizes = detect_hugetlb_page_sizes(hugetlbsizes,
+						    ARRAY_SIZE(hugetlbsizes));
+
+	/* If THP is supported, save THP settings and initially disable THP. */
+	if (nr_thpsizes) {
+		thp_save_settings();
+		thp_read_settings(&settings);
+		for (i = 0; i < NR_ORDERS; i++) {
+			settings.hugepages[i].enabled = THP_NEVER;
+			settings.shmem_hugepages[i].enabled = SHMEM_NEVER;
+		}
+		thp_push_settings(&settings);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(testcases); i++)
+		plan += *testcases[i].nr_sizes;
+	ksft_set_plan(plan);
+
+	pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
+	if (pagemap_fd < 0)
+		ksft_exit_fail_msg("opening pagemap failed\n");
+
+	for (i = 0; i < ARRAY_SIZE(testcases); i++) {
+		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);
+	}
+
+	/* If THP is supported, restore original THP settings. */
+	if (nr_thpsizes)
+		thp_restore_settings();
+
+	i = ksft_get_fail_cnt();
+	if (i)
+		ksft_exit_fail_msg("%d out of %d tests failed\n",
+				   i, ksft_test_num());
+	ksft_exit_pass();
+}