memcmp.c 3.7 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. #include <malloc.h>
  3. #include <stdlib.h>
  4. #include <string.h>
  5. #include <sys/mman.h>
  6. #include <time.h>
  7. #include "utils.h"
  8. #define SIZE 256
  9. #define ITERATIONS 10000
  10. #define LARGE_SIZE (5 * 1024)
  11. #define LARGE_ITERATIONS 1000
  12. #define LARGE_MAX_OFFSET 32
  13. #define LARGE_SIZE_START 4096
  14. /* This is big enough to fit LARGE_SIZE and works on 4K & 64K kernels */
  15. #define MAP_SIZE (64 * 1024)
  16. #define MAX_OFFSET_DIFF_S1_S2 48
  17. int vmx_count;
  18. int enter_vmx_ops(void)
  19. {
  20. vmx_count++;
  21. return 1;
  22. }
  23. void exit_vmx_ops(void)
  24. {
  25. vmx_count--;
  26. }
  27. int test_memcmp(const void *s1, const void *s2, size_t n);
  28. /* test all offsets and lengths */
  29. static void test_one(char *s1, char *s2, unsigned long max_offset,
  30. unsigned long size_start, unsigned long max_size)
  31. {
  32. unsigned long offset, size;
  33. for (offset = 0; offset < max_offset; offset++) {
  34. for (size = size_start; size < (max_size - offset); size++) {
  35. int x, y;
  36. unsigned long i;
  37. y = memcmp(s1+offset, s2+offset, size);
  38. x = test_memcmp(s1+offset, s2+offset, size);
  39. if (((x ^ y) < 0) && /* Trick to compare sign */
  40. ((x | y) != 0)) { /* check for zero */
  41. printf("memcmp returned %d, should have returned %d (offset %ld size %ld)\n", x, y, offset, size);
  42. for (i = offset; i < offset+size; i++)
  43. printf("%02x ", s1[i]);
  44. printf("\n");
  45. for (i = offset; i < offset+size; i++)
  46. printf("%02x ", s2[i]);
  47. printf("\n");
  48. abort();
  49. }
  50. if (vmx_count != 0) {
  51. printf("vmx enter/exit not paired.(offset:%ld size:%ld s1:%p s2:%p vc:%d\n",
  52. offset, size, s1, s2, vmx_count);
  53. printf("\n");
  54. abort();
  55. }
  56. }
  57. }
  58. }
  59. static int testcase(bool islarge)
  60. {
  61. unsigned long i, comp_size, alloc_size;
  62. char *p, *s1, *s2;
  63. int iterations;
  64. comp_size = (islarge ? LARGE_SIZE : SIZE);
  65. alloc_size = comp_size + MAX_OFFSET_DIFF_S1_S2;
  66. iterations = islarge ? LARGE_ITERATIONS : ITERATIONS;
  67. p = mmap(NULL, 4 * MAP_SIZE, PROT_READ | PROT_WRITE,
  68. MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
  69. FAIL_IF(p == MAP_FAILED);
  70. /* Put s1/s2 at the end of a page */
  71. s1 = p + MAP_SIZE - alloc_size;
  72. s2 = p + 3 * MAP_SIZE - alloc_size;
  73. /* And unmap the subsequent page to force a fault if we overread */
  74. munmap(p + MAP_SIZE, MAP_SIZE);
  75. munmap(p + 3 * MAP_SIZE, MAP_SIZE);
  76. srandom(time(0));
  77. for (i = 0; i < iterations; i++) {
  78. unsigned long j;
  79. unsigned long change;
  80. char *rand_s1 = s1;
  81. char *rand_s2 = s2;
  82. for (j = 0; j < alloc_size; j++)
  83. s1[j] = random();
  84. rand_s1 += random() % MAX_OFFSET_DIFF_S1_S2;
  85. rand_s2 += random() % MAX_OFFSET_DIFF_S1_S2;
  86. memcpy(rand_s2, rand_s1, comp_size);
  87. /* change one byte */
  88. change = random() % comp_size;
  89. rand_s2[change] = random() & 0xff;
  90. if (islarge)
  91. test_one(rand_s1, rand_s2, LARGE_MAX_OFFSET,
  92. LARGE_SIZE_START, comp_size);
  93. else
  94. test_one(rand_s1, rand_s2, SIZE, 0, comp_size);
  95. }
  96. srandom(time(0));
  97. for (i = 0; i < iterations; i++) {
  98. unsigned long j;
  99. unsigned long change;
  100. char *rand_s1 = s1;
  101. char *rand_s2 = s2;
  102. for (j = 0; j < alloc_size; j++)
  103. s1[j] = random();
  104. rand_s1 += random() % MAX_OFFSET_DIFF_S1_S2;
  105. rand_s2 += random() % MAX_OFFSET_DIFF_S1_S2;
  106. memcpy(rand_s2, rand_s1, comp_size);
  107. /* change multiple bytes, 1/8 of total */
  108. for (j = 0; j < comp_size / 8; j++) {
  109. change = random() % comp_size;
  110. s2[change] = random() & 0xff;
  111. }
  112. if (islarge)
  113. test_one(rand_s1, rand_s2, LARGE_MAX_OFFSET,
  114. LARGE_SIZE_START, comp_size);
  115. else
  116. test_one(rand_s1, rand_s2, SIZE, 0, comp_size);
  117. }
  118. return 0;
  119. }
  120. static int testcases(void)
  121. {
  122. #ifdef __powerpc64__
  123. // vcmpequd used in memcmp_64.S is v2.07
  124. SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_2_07));
  125. #endif
  126. testcase(0);
  127. testcase(1);
  128. return 0;
  129. }
  130. int main(void)
  131. {
  132. test_harness_set_timeout(300);
  133. return test_harness(testcases, "memcmp");
  134. }