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#include <stdlib.h>
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
typedef unsigned long long u64;
#define PME_PRESENT (1ULL << 63)
#define PME_SOFT_DIRTY (1Ull << 55)
#define PAGES_TO_TEST 3
#ifndef PAGE_SIZE
#define PAGE_SIZE 4096
#endif
static void get_pagemap2(char *mem, u64 *map)
{
int fd;
fd = open("/proc/self/pagemap2", O_RDONLY);
if (fd < 0) {
perror("Can't open pagemap2");
exit(1);
}
lseek(fd, (unsigned long)mem / PAGE_SIZE * sizeof(u64), SEEK_SET);
read(fd, map, sizeof(u64) * PAGES_TO_TEST);
close(fd);
}
static inline char map_p(u64 map)
{
return map & PME_PRESENT ? 'p' : '-';
}
static inline char map_sd(u64 map)
{
return map & PME_SOFT_DIRTY ? 'd' : '-';
}
static int check_pte(int step, int page, u64 *map, u64 want)
{
if ((map[page] & want) != want) {
printf("Step %d Page %d has %c%c, want %c%c\n",
step, page,
map_p(map[page]), map_sd(map[page]),
map_p(want), map_sd(want));
return 1;
}
return 0;
}
static void clear_refs(void)
{
int fd;
char *v = "4";
fd = open("/proc/self/clear_refs", O_WRONLY);
if (write(fd, v, 3) < 3) {
perror("Can't clear soft-dirty bit");
exit(1);
}
close(fd);
}
int main(void)
{
char *mem, x;
u64 map[PAGES_TO_TEST];
mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE,
PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, 0, 0);
x = mem[0];
mem[2 * PAGE_SIZE] = 'c';
get_pagemap2(mem, map);
if (check_pte(1, 0, map, PME_PRESENT))
return 1;
if (check_pte(1, 1, map, 0))
return 1;
if (check_pte(1, 2, map, PME_PRESENT | PME_SOFT_DIRTY))
return 1;
clear_refs();
get_pagemap2(mem, map);
if (check_pte(2, 0, map, PME_PRESENT))
return 1;
if (check_pte(2, 1, map, 0))
return 1;
if (check_pte(2, 2, map, PME_PRESENT))
return 1;
mem[0] = 'a';
mem[PAGE_SIZE] = 'b';
x = mem[2 * PAGE_SIZE];
get_pagemap2(mem, map);
if (check_pte(3, 0, map, PME_PRESENT | PME_SOFT_DIRTY))
return 1;
if (check_pte(3, 1, map, PME_PRESENT | PME_SOFT_DIRTY))
return 1;
if (check_pte(3, 2, map, PME_PRESENT))
return 1;
(void)x; /* gcc warn */
printf("PASS\n");
return 0;
}
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