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// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <fcntl.h>
#include <stdint.h>
#include <malloc.h>
#include <sys/mman.h>
#include "../kselftest.h"
#include "vm_util.h"
#define PAGEMAP_FILE_PATH "/proc/self/pagemap"
#define TEST_ITERATIONS 10000
static void test_simple(int pagemap_fd, int pagesize)
{
int i;
char *map;
map = aligned_alloc(pagesize, pagesize);
if (!map)
ksft_exit_fail_msg("mmap failed\n");
clear_softdirty();
for (i = 0 ; i < TEST_ITERATIONS; i++) {
if (pagemap_is_softdirty(pagemap_fd, map) == 1) {
ksft_print_msg("dirty bit was 1, but should be 0 (i=%d)\n", i);
break;
}
clear_softdirty();
// Write something to the page to get the dirty bit enabled on the page
map[0]++;
if (pagemap_is_softdirty(pagemap_fd, map) == 0) {
ksft_print_msg("dirty bit was 0, but should be 1 (i=%d)\n", i);
break;
}
clear_softdirty();
}
free(map);
ksft_test_result(i == TEST_ITERATIONS, "Test %s\n", __func__);
}
static void test_vma_reuse(int pagemap_fd, int pagesize)
{
char *map, *map2;
map = mmap(NULL, pagesize, (PROT_READ | PROT_WRITE), (MAP_PRIVATE | MAP_ANON), -1, 0);
if (map == MAP_FAILED)
ksft_exit_fail_msg("mmap failed");
// The kernel always marks new regions as soft dirty
ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1,
"Test %s dirty bit of allocated page\n", __func__);
clear_softdirty();
munmap(map, pagesize);
map2 = mmap(NULL, pagesize, (PROT_READ | PROT_WRITE), (MAP_PRIVATE | MAP_ANON), -1, 0);
if (map2 == MAP_FAILED)
ksft_exit_fail_msg("mmap failed");
// Dirty bit is set for new regions even if they are reused
if (map == map2)
ksft_test_result(pagemap_is_softdirty(pagemap_fd, map2) == 1,
"Test %s dirty bit of reused address page\n", __func__);
else
ksft_test_result_skip("Test %s dirty bit of reused address page\n", __func__);
munmap(map2, pagesize);
}
static void test_hugepage(int pagemap_fd, int pagesize)
{
char *map;
int i, ret;
size_t hpage_len = read_pmd_pagesize();
if (!hpage_len)
ksft_exit_fail_msg("Reading PMD pagesize failed");
map = memalign(hpage_len, hpage_len);
if (!map)
ksft_exit_fail_msg("memalign failed\n");
ret = madvise(map, hpage_len, MADV_HUGEPAGE);
if (ret)
ksft_exit_fail_msg("madvise failed %d\n", ret);
for (i = 0; i < hpage_len; i++)
map[i] = (char)i;
if (check_huge_anon(map, 1, hpage_len)) {
ksft_test_result_pass("Test %s huge page allocation\n", __func__);
clear_softdirty();
for (i = 0 ; i < TEST_ITERATIONS ; i++) {
if (pagemap_is_softdirty(pagemap_fd, map) == 1) {
ksft_print_msg("dirty bit was 1, but should be 0 (i=%d)\n", i);
break;
}
clear_softdirty();
// Write something to the page to get the dirty bit enabled on the page
map[0]++;
if (pagemap_is_softdirty(pagemap_fd, map) == 0) {
ksft_print_msg("dirty bit was 0, but should be 1 (i=%d)\n", i);
break;
}
clear_softdirty();
}
ksft_test_result(i == TEST_ITERATIONS, "Test %s huge page dirty bit\n", __func__);
} else {
// hugepage allocation failed. skip these tests
ksft_test_result_skip("Test %s huge page allocation\n", __func__);
ksft_test_result_skip("Test %s huge page dirty bit\n", __func__);
}
free(map);
}
static void test_mprotect(int pagemap_fd, int pagesize, bool anon)
{
const char *type[] = {"file", "anon"};
const char *fname = "./soft-dirty-test-file";
int test_fd;
char *map;
if (anon) {
map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
if (!map)
ksft_exit_fail_msg("anon mmap failed\n");
} else {
test_fd = open(fname, O_RDWR | O_CREAT, 0664);
if (test_fd < 0) {
ksft_test_result_skip("Test %s open() file failed\n", __func__);
return;
}
unlink(fname);
ftruncate(test_fd, pagesize);
map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE,
MAP_SHARED, test_fd, 0);
if (!map)
ksft_exit_fail_msg("file mmap failed\n");
}
*map = 1;
ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1,
"Test %s-%s dirty bit of new written page\n",
__func__, type[anon]);
clear_softdirty();
ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0,
"Test %s-%s soft-dirty clear after clear_refs\n",
__func__, type[anon]);
mprotect(map, pagesize, PROT_READ);
ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0,
"Test %s-%s soft-dirty clear after marking RO\n",
__func__, type[anon]);
mprotect(map, pagesize, PROT_READ|PROT_WRITE);
ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0,
"Test %s-%s soft-dirty clear after marking RW\n",
__func__, type[anon]);
*map = 2;
ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1,
"Test %s-%s soft-dirty after rewritten\n",
__func__, type[anon]);
munmap(map, pagesize);
if (!anon)
close(test_fd);
}
static void test_mprotect_anon(int pagemap_fd, int pagesize)
{
test_mprotect(pagemap_fd, pagesize, true);
}
static void test_mprotect_file(int pagemap_fd, int pagesize)
{
test_mprotect(pagemap_fd, pagesize, false);
}
int main(int argc, char **argv)
{
int pagemap_fd;
int pagesize;
ksft_print_header();
ksft_set_plan(15);
pagemap_fd = open(PAGEMAP_FILE_PATH, O_RDONLY);
if (pagemap_fd < 0)
ksft_exit_fail_msg("Failed to open %s\n", PAGEMAP_FILE_PATH);
pagesize = getpagesize();
test_simple(pagemap_fd, pagesize);
test_vma_reuse(pagemap_fd, pagesize);
test_hugepage(pagemap_fd, pagesize);
test_mprotect_anon(pagemap_fd, pagesize);
test_mprotect_file(pagemap_fd, pagesize);
close(pagemap_fd);
ksft_exit_pass();
}
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