8 typedef unsigned long long u64;
10 #define PME_PRESENT (1ULL << 63)
11 #define PME_SOFT_DIRTY (1Ull << 55)
13 #define PAGES_TO_TEST 3
15 #define PAGE_SIZE 4096
18 static void get_pagemap2(char *mem, u64 *map)
22 fd = open("/proc/self/pagemap2", O_RDONLY);
24 perror("Can't open pagemap2");
28 lseek(fd, (unsigned long)mem / PAGE_SIZE * sizeof(u64), SEEK_SET);
29 read(fd, map, sizeof(u64) * PAGES_TO_TEST);
33 static inline char map_p(u64 map)
35 return map & PME_PRESENT ? 'p' : '-';
38 static inline char map_sd(u64 map)
40 return map & PME_SOFT_DIRTY ? 'd' : '-';
43 static int check_pte(int step, int page, u64 *map, u64 want)
45 if ((map[page] & want) != want) {
46 printf("Step %d Page %d has %c%c, want %c%c\n",
48 map_p(map[page]), map_sd(map[page]),
49 map_p(want), map_sd(want));
56 static void clear_refs(void)
61 fd = open("/proc/self/clear_refs", O_WRONLY);
62 if (write(fd, v, 3) < 3) {
63 perror("Can't clear soft-dirty bit");
72 u64 map[PAGES_TO_TEST];
74 mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE,
75 PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, 0, 0);
78 mem[2 * PAGE_SIZE] = 'c';
79 get_pagemap2(mem, map);
81 if (check_pte(1, 0, map, PME_PRESENT))
83 if (check_pte(1, 1, map, 0))
85 if (check_pte(1, 2, map, PME_PRESENT | PME_SOFT_DIRTY))
89 get_pagemap2(mem, map);
91 if (check_pte(2, 0, map, PME_PRESENT))
93 if (check_pte(2, 1, map, 0))
95 if (check_pte(2, 2, map, PME_PRESENT))
100 x = mem[2 * PAGE_SIZE];
101 get_pagemap2(mem, map);
103 if (check_pte(3, 0, map, PME_PRESENT | PME_SOFT_DIRTY))
105 if (check_pte(3, 1, map, PME_PRESENT | PME_SOFT_DIRTY))
107 if (check_pte(3, 2, map, PME_PRESENT))
110 (void)x; /* gcc warn */