1 // SPDX-License-Identifier: GPL-2.0 2 #include <stdio.h> 3 #include <string.h> 4 #include <stdbool.h> 5 #include <fcntl.h> 6 #include <stdint.h> 7 #include <malloc.h> 8 #include <sys/mman.h> 9 #include "../kselftest.h" 10 #include "vm_util.h" 11 12 #define PAGEMAP_FILE_PATH "/proc/self/pagemap" 13 #define TEST_ITERATIONS 10000 14 15 static void test_simple(int pagemap_fd, int pagesize) 16 { 17 int i; 18 char *map; 19 20 map = aligned_alloc(pagesize, pagesize); 21 if (!map) 22 ksft_exit_fail_msg("mmap failed\n"); 23 24 clear_softdirty(); 25 26 for (i = 0 ; i < TEST_ITERATIONS; i++) { 27 if (pagemap_is_softdirty(pagemap_fd, map) == 1) { 28 ksft_print_msg("dirty bit was 1, but should be 0 (i=%d)\n", i); 29 break; 30 } 31 32 clear_softdirty(); 33 // Write something to the page to get the dirty bit enabled on the page 34 map[0]++; 35 36 if (pagemap_is_softdirty(pagemap_fd, map) == 0) { 37 ksft_print_msg("dirty bit was 0, but should be 1 (i=%d)\n", i); 38 break; 39 } 40 41 clear_softdirty(); 42 } 43 free(map); 44 45 ksft_test_result(i == TEST_ITERATIONS, "Test %s\n", __func__); 46 } 47 48 static void test_vma_reuse(int pagemap_fd, int pagesize) 49 { 50 char *map, *map2; 51 52 map = mmap(NULL, pagesize, (PROT_READ | PROT_WRITE), (MAP_PRIVATE | MAP_ANON), -1, 0); 53 if (map == MAP_FAILED) 54 ksft_exit_fail_msg("mmap failed"); 55 56 // The kernel always marks new regions as soft dirty 57 ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, 58 "Test %s dirty bit of allocated page\n", __func__); 59 60 clear_softdirty(); 61 munmap(map, pagesize); 62 63 map2 = mmap(NULL, pagesize, (PROT_READ | PROT_WRITE), (MAP_PRIVATE | MAP_ANON), -1, 0); 64 if (map2 == MAP_FAILED) 65 ksft_exit_fail_msg("mmap failed"); 66 67 // Dirty bit is set for new regions even if they are reused 68 if (map == map2) 69 ksft_test_result(pagemap_is_softdirty(pagemap_fd, map2) == 1, 70 "Test %s dirty bit of reused address page\n", __func__); 71 else 72 ksft_test_result_skip("Test %s dirty bit of reused address page\n", __func__); 73 74 munmap(map2, pagesize); 75 } 76 77 static void test_hugepage(int pagemap_fd, int pagesize) 78 { 79 char *map; 80 int i, ret; 81 size_t hpage_len = read_pmd_pagesize(); 82 83 map = memalign(hpage_len, hpage_len); 84 if (!map) 85 ksft_exit_fail_msg("memalign failed\n"); 86 87 ret = madvise(map, hpage_len, MADV_HUGEPAGE); 88 if (ret) 89 ksft_exit_fail_msg("madvise failed %d\n", ret); 90 91 for (i = 0; i < hpage_len; i++) 92 map[i] = (char)i; 93 94 if (check_huge_anon(map, 1, hpage_len)) { 95 ksft_test_result_pass("Test %s huge page allocation\n", __func__); 96 97 clear_softdirty(); 98 for (i = 0 ; i < TEST_ITERATIONS ; i++) { 99 if (pagemap_is_softdirty(pagemap_fd, map) == 1) { 100 ksft_print_msg("dirty bit was 1, but should be 0 (i=%d)\n", i); 101 break; 102 } 103 104 clear_softdirty(); 105 // Write something to the page to get the dirty bit enabled on the page 106 map[0]++; 107 108 if (pagemap_is_softdirty(pagemap_fd, map) == 0) { 109 ksft_print_msg("dirty bit was 0, but should be 1 (i=%d)\n", i); 110 break; 111 } 112 clear_softdirty(); 113 } 114 115 ksft_test_result(i == TEST_ITERATIONS, "Test %s huge page dirty bit\n", __func__); 116 } else { 117 // hugepage allocation failed. skip these tests 118 ksft_test_result_skip("Test %s huge page allocation\n", __func__); 119 ksft_test_result_skip("Test %s huge page dirty bit\n", __func__); 120 } 121 free(map); 122 } 123 124 static void test_mprotect(int pagemap_fd, int pagesize, bool anon) 125 { 126 const char *type[] = {"file", "anon"}; 127 const char *fname = "./soft-dirty-test-file"; 128 int test_fd; 129 char *map; 130 131 if (anon) { 132 map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE, 133 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); 134 if (!map) 135 ksft_exit_fail_msg("anon mmap failed\n"); 136 } else { 137 test_fd = open(fname, O_RDWR | O_CREAT); 138 if (test_fd < 0) { 139 ksft_test_result_skip("Test %s open() file failed\n", __func__); 140 return; 141 } 142 unlink(fname); 143 ftruncate(test_fd, pagesize); 144 map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE, 145 MAP_SHARED, test_fd, 0); 146 if (!map) 147 ksft_exit_fail_msg("file mmap failed\n"); 148 } 149 150 *map = 1; 151 ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, 152 "Test %s-%s dirty bit of new written page\n", 153 __func__, type[anon]); 154 clear_softdirty(); 155 ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0, 156 "Test %s-%s soft-dirty clear after clear_refs\n", 157 __func__, type[anon]); 158 mprotect(map, pagesize, PROT_READ); 159 ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0, 160 "Test %s-%s soft-dirty clear after marking RO\n", 161 __func__, type[anon]); 162 mprotect(map, pagesize, PROT_READ|PROT_WRITE); 163 ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0, 164 "Test %s-%s soft-dirty clear after marking RW\n", 165 __func__, type[anon]); 166 *map = 2; 167 ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, 168 "Test %s-%s soft-dirty after rewritten\n", 169 __func__, type[anon]); 170 171 munmap(map, pagesize); 172 173 if (!anon) 174 close(test_fd); 175 } 176 177 static void test_mprotect_anon(int pagemap_fd, int pagesize) 178 { 179 test_mprotect(pagemap_fd, pagesize, true); 180 } 181 182 static void test_mprotect_file(int pagemap_fd, int pagesize) 183 { 184 test_mprotect(pagemap_fd, pagesize, false); 185 } 186 187 int main(int argc, char **argv) 188 { 189 int pagemap_fd; 190 int pagesize; 191 192 ksft_print_header(); 193 ksft_set_plan(15); 194 195 pagemap_fd = open(PAGEMAP_FILE_PATH, O_RDONLY); 196 if (pagemap_fd < 0) 197 ksft_exit_fail_msg("Failed to open %s\n", PAGEMAP_FILE_PATH); 198 199 pagesize = getpagesize(); 200 201 test_simple(pagemap_fd, pagesize); 202 test_vma_reuse(pagemap_fd, pagesize); 203 test_hugepage(pagemap_fd, pagesize); 204 test_mprotect_anon(pagemap_fd, pagesize); 205 test_mprotect_file(pagemap_fd, pagesize); 206 207 close(pagemap_fd); 208 209 return ksft_exit_pass(); 210 } 211