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-rw-r--r--tools/testing/selftests/mm/mremap_test.c548
1 files changed, 548 insertions, 0 deletions
diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c
new file mode 100644
index 000000000000..5c3773de9f0f
--- /dev/null
+++ b/tools/testing/selftests/mm/mremap_test.c
@@ -0,0 +1,548 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2020 Google LLC
+ */
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <time.h>
+#include <stdbool.h>
+
+#include "../kselftest.h"
+
+#define EXPECT_SUCCESS 0
+#define EXPECT_FAILURE 1
+#define NON_OVERLAPPING 0
+#define OVERLAPPING 1
+#define NS_PER_SEC 1000000000ULL
+#define VALIDATION_DEFAULT_THRESHOLD 4 /* 4MB */
+#define VALIDATION_NO_THRESHOLD 0 /* Verify the entire region */
+
+#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
+
+struct config {
+ unsigned long long src_alignment;
+ unsigned long long dest_alignment;
+ unsigned long long region_size;
+ int overlapping;
+};
+
+struct test {
+ const char *name;
+ struct config config;
+ int expect_failure;
+};
+
+enum {
+ _1KB = 1ULL << 10, /* 1KB -> not page aligned */
+ _4KB = 4ULL << 10,
+ _8KB = 8ULL << 10,
+ _1MB = 1ULL << 20,
+ _2MB = 2ULL << 20,
+ _4MB = 4ULL << 20,
+ _1GB = 1ULL << 30,
+ _2GB = 2ULL << 30,
+ PMD = _2MB,
+ PUD = _1GB,
+};
+
+#define PTE page_size
+
+#define MAKE_TEST(source_align, destination_align, size, \
+ overlaps, should_fail, test_name) \
+(struct test){ \
+ .name = test_name, \
+ .config = { \
+ .src_alignment = source_align, \
+ .dest_alignment = destination_align, \
+ .region_size = size, \
+ .overlapping = overlaps, \
+ }, \
+ .expect_failure = should_fail \
+}
+
+/*
+ * Returns false if the requested remap region overlaps with an
+ * existing mapping (e.g text, stack) else returns true.
+ */
+static bool is_remap_region_valid(void *addr, unsigned long long size)
+{
+ void *remap_addr = NULL;
+ bool ret = true;
+
+ /* Use MAP_FIXED_NOREPLACE flag to ensure region is not mapped */
+ remap_addr = mmap(addr, size, PROT_READ | PROT_WRITE,
+ MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED,
+ -1, 0);
+
+ if (remap_addr == MAP_FAILED) {
+ if (errno == EEXIST)
+ ret = false;
+ } else {
+ munmap(remap_addr, size);
+ }
+
+ return ret;
+}
+
+/* Returns mmap_min_addr sysctl tunable from procfs */
+static unsigned long long get_mmap_min_addr(void)
+{
+ FILE *fp;
+ int n_matched;
+ static unsigned long long addr;
+
+ if (addr)
+ return addr;
+
+ fp = fopen("/proc/sys/vm/mmap_min_addr", "r");
+ if (fp == NULL) {
+ ksft_print_msg("Failed to open /proc/sys/vm/mmap_min_addr: %s\n",
+ strerror(errno));
+ exit(KSFT_SKIP);
+ }
+
+ n_matched = fscanf(fp, "%llu", &addr);
+ if (n_matched != 1) {
+ ksft_print_msg("Failed to read /proc/sys/vm/mmap_min_addr: %s\n",
+ strerror(errno));
+ fclose(fp);
+ exit(KSFT_SKIP);
+ }
+
+ fclose(fp);
+ return addr;
+}
+
+/*
+ * Using /proc/self/maps, assert that the specified address range is contained
+ * within a single mapping.
+ */
+static bool is_range_mapped(FILE *maps_fp, void *start, void *end)
+{
+ char *line = NULL;
+ size_t len = 0;
+ bool success = false;
+
+ rewind(maps_fp);
+
+ while (getline(&line, &len, maps_fp) != -1) {
+ char *first = strtok(line, "- ");
+ void *first_val = (void *)strtol(first, NULL, 16);
+ char *second = strtok(NULL, "- ");
+ void *second_val = (void *) strtol(second, NULL, 16);
+
+ if (first_val <= start && second_val >= end) {
+ success = true;
+ break;
+ }
+ }
+
+ return success;
+}
+
+/*
+ * This test validates that merge is called when expanding a mapping.
+ * Mapping containing three pages is created, middle page is unmapped
+ * and then the mapping containing the first page is expanded so that
+ * it fills the created hole. The two parts should merge creating
+ * single mapping with three pages.
+ */
+static void mremap_expand_merge(FILE *maps_fp, unsigned long page_size)
+{
+ char *test_name = "mremap expand merge";
+ bool success = false;
+ char *remap, *start;
+
+ start = mmap(NULL, 3 * page_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+ if (start == MAP_FAILED) {
+ ksft_print_msg("mmap failed: %s\n", strerror(errno));
+ goto out;
+ }
+
+ munmap(start + page_size, page_size);
+ remap = mremap(start, page_size, 2 * page_size, 0);
+ if (remap == MAP_FAILED) {
+ ksft_print_msg("mremap failed: %s\n", strerror(errno));
+ munmap(start, page_size);
+ munmap(start + 2 * page_size, page_size);
+ goto out;
+ }
+
+ success = is_range_mapped(maps_fp, start, start + 3 * page_size);
+ munmap(start, 3 * page_size);
+
+out:
+ if (success)
+ ksft_test_result_pass("%s\n", test_name);
+ else
+ ksft_test_result_fail("%s\n", test_name);
+}
+
+/*
+ * Similar to mremap_expand_merge() except instead of removing the middle page,
+ * we remove the last then attempt to remap offset from the second page. This
+ * should result in the mapping being restored to its former state.
+ */
+static void mremap_expand_merge_offset(FILE *maps_fp, unsigned long page_size)
+{
+
+ char *test_name = "mremap expand merge offset";
+ bool success = false;
+ char *remap, *start;
+
+ start = mmap(NULL, 3 * page_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+ if (start == MAP_FAILED) {
+ ksft_print_msg("mmap failed: %s\n", strerror(errno));
+ goto out;
+ }
+
+ /* Unmap final page to ensure we have space to expand. */
+ munmap(start + 2 * page_size, page_size);
+ remap = mremap(start + page_size, page_size, 2 * page_size, 0);
+ if (remap == MAP_FAILED) {
+ ksft_print_msg("mremap failed: %s\n", strerror(errno));
+ munmap(start, 2 * page_size);
+ goto out;
+ }
+
+ success = is_range_mapped(maps_fp, start, start + 3 * page_size);
+ munmap(start, 3 * page_size);
+
+out:
+ if (success)
+ ksft_test_result_pass("%s\n", test_name);
+ else
+ ksft_test_result_fail("%s\n", test_name);
+}
+
+/*
+ * Returns the start address of the mapping on success, else returns
+ * NULL on failure.
+ */
+static void *get_source_mapping(struct config c)
+{
+ unsigned long long addr = 0ULL;
+ void *src_addr = NULL;
+ unsigned long long mmap_min_addr;
+
+ mmap_min_addr = get_mmap_min_addr();
+
+retry:
+ addr += c.src_alignment;
+ if (addr < mmap_min_addr)
+ goto retry;
+
+ src_addr = mmap((void *) addr, c.region_size, PROT_READ | PROT_WRITE,
+ MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED,
+ -1, 0);
+ if (src_addr == MAP_FAILED) {
+ if (errno == EPERM || errno == EEXIST)
+ goto retry;
+ goto error;
+ }
+ /*
+ * Check that the address is aligned to the specified alignment.
+ * Addresses which have alignments that are multiples of that
+ * specified are not considered valid. For instance, 1GB address is
+ * 2MB-aligned, however it will not be considered valid for a
+ * requested alignment of 2MB. This is done to reduce coincidental
+ * alignment in the tests.
+ */
+ if (((unsigned long long) src_addr & (c.src_alignment - 1)) ||
+ !((unsigned long long) src_addr & c.src_alignment)) {
+ munmap(src_addr, c.region_size);
+ goto retry;
+ }
+
+ if (!src_addr)
+ goto error;
+
+ return src_addr;
+error:
+ ksft_print_msg("Failed to map source region: %s\n",
+ strerror(errno));
+ return NULL;
+}
+
+/* Returns the time taken for the remap on success else returns -1. */
+static long long remap_region(struct config c, unsigned int threshold_mb,
+ char pattern_seed)
+{
+ void *addr, *src_addr, *dest_addr;
+ unsigned long long i;
+ struct timespec t_start = {0, 0}, t_end = {0, 0};
+ long long start_ns, end_ns, align_mask, ret, offset;
+ unsigned long long threshold;
+
+ if (threshold_mb == VALIDATION_NO_THRESHOLD)
+ threshold = c.region_size;
+ else
+ threshold = MIN(threshold_mb * _1MB, c.region_size);
+
+ src_addr = get_source_mapping(c);
+ if (!src_addr) {
+ ret = -1;
+ goto out;
+ }
+
+ /* Set byte pattern */
+ srand(pattern_seed);
+ for (i = 0; i < threshold; i++)
+ memset((char *) src_addr + i, (char) rand(), 1);
+
+ /* Mask to zero out lower bits of address for alignment */
+ align_mask = ~(c.dest_alignment - 1);
+ /* Offset of destination address from the end of the source region */
+ offset = (c.overlapping) ? -c.dest_alignment : c.dest_alignment;
+ addr = (void *) (((unsigned long long) src_addr + c.region_size
+ + offset) & align_mask);
+
+ /* See comment in get_source_mapping() */
+ if (!((unsigned long long) addr & c.dest_alignment))
+ addr = (void *) ((unsigned long long) addr | c.dest_alignment);
+
+ /* Don't destroy existing mappings unless expected to overlap */
+ while (!is_remap_region_valid(addr, c.region_size) && !c.overlapping) {
+ /* Check for unsigned overflow */
+ if (addr + c.dest_alignment < addr) {
+ ksft_print_msg("Couldn't find a valid region to remap to\n");
+ ret = -1;
+ goto out;
+ }
+ addr += c.dest_alignment;
+ }
+
+ clock_gettime(CLOCK_MONOTONIC, &t_start);
+ dest_addr = mremap(src_addr, c.region_size, c.region_size,
+ MREMAP_MAYMOVE|MREMAP_FIXED, (char *) addr);
+ clock_gettime(CLOCK_MONOTONIC, &t_end);
+
+ if (dest_addr == MAP_FAILED) {
+ ksft_print_msg("mremap failed: %s\n", strerror(errno));
+ ret = -1;
+ goto clean_up_src;
+ }
+
+ /* Verify byte pattern after remapping */
+ srand(pattern_seed);
+ for (i = 0; i < threshold; i++) {
+ char c = (char) rand();
+
+ if (((char *) dest_addr)[i] != c) {
+ ksft_print_msg("Data after remap doesn't match at offset %d\n",
+ i);
+ ksft_print_msg("Expected: %#x\t Got: %#x\n", c & 0xff,
+ ((char *) dest_addr)[i] & 0xff);
+ ret = -1;
+ goto clean_up_dest;
+ }
+ }
+
+ start_ns = t_start.tv_sec * NS_PER_SEC + t_start.tv_nsec;
+ end_ns = t_end.tv_sec * NS_PER_SEC + t_end.tv_nsec;
+ ret = end_ns - start_ns;
+
+/*
+ * Since the destination address is specified using MREMAP_FIXED, subsequent
+ * mremap will unmap any previous mapping at the address range specified by
+ * dest_addr and region_size. This significantly affects the remap time of
+ * subsequent tests. So we clean up mappings after each test.
+ */
+clean_up_dest:
+ munmap(dest_addr, c.region_size);
+clean_up_src:
+ munmap(src_addr, c.region_size);
+out:
+ return ret;
+}
+
+static void run_mremap_test_case(struct test test_case, int *failures,
+ unsigned int threshold_mb,
+ unsigned int pattern_seed)
+{
+ long long remap_time = remap_region(test_case.config, threshold_mb,
+ pattern_seed);
+
+ if (remap_time < 0) {
+ if (test_case.expect_failure)
+ ksft_test_result_xfail("%s\n\tExpected mremap failure\n",
+ test_case.name);
+ else {
+ ksft_test_result_fail("%s\n", test_case.name);
+ *failures += 1;
+ }
+ } else {
+ /*
+ * Comparing mremap time is only applicable if entire region
+ * was faulted in.
+ */
+ if (threshold_mb == VALIDATION_NO_THRESHOLD ||
+ test_case.config.region_size <= threshold_mb * _1MB)
+ ksft_test_result_pass("%s\n\tmremap time: %12lldns\n",
+ test_case.name, remap_time);
+ else
+ ksft_test_result_pass("%s\n", test_case.name);
+ }
+}
+
+static void usage(const char *cmd)
+{
+ fprintf(stderr,
+ "Usage: %s [[-t <threshold_mb>] [-p <pattern_seed>]]\n"
+ "-t\t only validate threshold_mb of the remapped region\n"
+ " \t if 0 is supplied no threshold is used; all tests\n"
+ " \t are run and remapped regions validated fully.\n"
+ " \t The default threshold used is 4MB.\n"
+ "-p\t provide a seed to generate the random pattern for\n"
+ " \t validating the remapped region.\n", cmd);
+}
+
+static int parse_args(int argc, char **argv, unsigned int *threshold_mb,
+ unsigned int *pattern_seed)
+{
+ const char *optstr = "t:p:";
+ int opt;
+
+ while ((opt = getopt(argc, argv, optstr)) != -1) {
+ switch (opt) {
+ case 't':
+ *threshold_mb = atoi(optarg);
+ break;
+ case 'p':
+ *pattern_seed = atoi(optarg);
+ break;
+ default:
+ usage(argv[0]);
+ return -1;
+ }
+ }
+
+ if (optind < argc) {
+ usage(argv[0]);
+ return -1;
+ }
+
+ return 0;
+}
+
+#define MAX_TEST 13
+#define MAX_PERF_TEST 3
+int main(int argc, char **argv)
+{
+ int failures = 0;
+ int i, run_perf_tests;
+ unsigned int threshold_mb = VALIDATION_DEFAULT_THRESHOLD;
+ unsigned int pattern_seed;
+ int num_expand_tests = 2;
+ struct test test_cases[MAX_TEST];
+ struct test perf_test_cases[MAX_PERF_TEST];
+ int page_size;
+ time_t t;
+ FILE *maps_fp;
+
+ pattern_seed = (unsigned int) time(&t);
+
+ if (parse_args(argc, argv, &threshold_mb, &pattern_seed) < 0)
+ exit(EXIT_FAILURE);
+
+ ksft_print_msg("Test configs:\n\tthreshold_mb=%u\n\tpattern_seed=%u\n\n",
+ threshold_mb, pattern_seed);
+
+ page_size = sysconf(_SC_PAGESIZE);
+
+ /* Expected mremap failures */
+ test_cases[0] = MAKE_TEST(page_size, page_size, page_size,
+ OVERLAPPING, EXPECT_FAILURE,
+ "mremap - Source and Destination Regions Overlapping");
+
+ test_cases[1] = MAKE_TEST(page_size, page_size/4, page_size,
+ NON_OVERLAPPING, EXPECT_FAILURE,
+ "mremap - Destination Address Misaligned (1KB-aligned)");
+ test_cases[2] = MAKE_TEST(page_size/4, page_size, page_size,
+ NON_OVERLAPPING, EXPECT_FAILURE,
+ "mremap - Source Address Misaligned (1KB-aligned)");
+
+ /* Src addr PTE aligned */
+ test_cases[3] = MAKE_TEST(PTE, PTE, PTE * 2,
+ NON_OVERLAPPING, EXPECT_SUCCESS,
+ "8KB mremap - Source PTE-aligned, Destination PTE-aligned");
+
+ /* Src addr 1MB aligned */
+ test_cases[4] = MAKE_TEST(_1MB, PTE, _2MB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "2MB mremap - Source 1MB-aligned, Destination PTE-aligned");
+ test_cases[5] = MAKE_TEST(_1MB, _1MB, _2MB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "2MB mremap - Source 1MB-aligned, Destination 1MB-aligned");
+
+ /* Src addr PMD aligned */
+ test_cases[6] = MAKE_TEST(PMD, PTE, _4MB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "4MB mremap - Source PMD-aligned, Destination PTE-aligned");
+ test_cases[7] = MAKE_TEST(PMD, _1MB, _4MB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "4MB mremap - Source PMD-aligned, Destination 1MB-aligned");
+ test_cases[8] = MAKE_TEST(PMD, PMD, _4MB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "4MB mremap - Source PMD-aligned, Destination PMD-aligned");
+
+ /* Src addr PUD aligned */
+ test_cases[9] = MAKE_TEST(PUD, PTE, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "2GB mremap - Source PUD-aligned, Destination PTE-aligned");
+ test_cases[10] = MAKE_TEST(PUD, _1MB, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "2GB mremap - Source PUD-aligned, Destination 1MB-aligned");
+ test_cases[11] = MAKE_TEST(PUD, PMD, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "2GB mremap - Source PUD-aligned, Destination PMD-aligned");
+ test_cases[12] = MAKE_TEST(PUD, PUD, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "2GB mremap - Source PUD-aligned, Destination PUD-aligned");
+
+ perf_test_cases[0] = MAKE_TEST(page_size, page_size, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "1GB mremap - Source PTE-aligned, Destination PTE-aligned");
+ /*
+ * mremap 1GB region - Page table level aligned time
+ * comparison.
+ */
+ perf_test_cases[1] = MAKE_TEST(PMD, PMD, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "1GB mremap - Source PMD-aligned, Destination PMD-aligned");
+ perf_test_cases[2] = MAKE_TEST(PUD, PUD, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "1GB mremap - Source PUD-aligned, Destination PUD-aligned");
+
+ run_perf_tests = (threshold_mb == VALIDATION_NO_THRESHOLD) ||
+ (threshold_mb * _1MB >= _1GB);
+
+ ksft_set_plan(ARRAY_SIZE(test_cases) + (run_perf_tests ?
+ ARRAY_SIZE(perf_test_cases) : 0) + num_expand_tests);
+
+ for (i = 0; i < ARRAY_SIZE(test_cases); i++)
+ run_mremap_test_case(test_cases[i], &failures, threshold_mb,
+ pattern_seed);
+
+ maps_fp = fopen("/proc/self/maps", "r");
+
+ if (maps_fp == NULL) {
+ ksft_print_msg("Failed to read /proc/self/maps: %s\n", strerror(errno));
+ exit(KSFT_FAIL);
+ }
+
+ mremap_expand_merge(maps_fp, page_size);
+ mremap_expand_merge_offset(maps_fp, page_size);
+
+ fclose(maps_fp);
+
+ if (run_perf_tests) {
+ ksft_print_msg("\n%s\n",
+ "mremap HAVE_MOVE_PMD/PUD optimization time comparison for 1GB region:");
+ for (i = 0; i < ARRAY_SIZE(perf_test_cases); i++)
+ run_mremap_test_case(perf_test_cases[i], &failures,
+ threshold_mb, pattern_seed);
+ }
+
+ if (failures > 0)
+ ksft_exit_fail();
+ else
+ ksft_exit_pass();
+}
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