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// SPDX-License-Identifier: GPL-2.0
#include <string.h>
#include <fcntl.h>
#include "../kselftest.h"
#include "vm_util.h"
#define PMD_SIZE_FILE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
#define SMAP_FILE_PATH "/proc/self/smaps"
#define MAX_LINE_LENGTH 500
uint64_t pagemap_get_entry(int fd, char *start)
{
const unsigned long pfn = (unsigned long)start / getpagesize();
uint64_t entry;
int ret;
ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry));
if (ret != sizeof(entry))
ksft_exit_fail_msg("reading pagemap failed\n");
return entry;
}
bool pagemap_is_softdirty(int fd, char *start)
{
uint64_t entry = pagemap_get_entry(fd, start);
// Check if dirty bit (55th bit) is set
return entry & 0x0080000000000000ull;
}
void clear_softdirty(void)
{
int ret;
const char *ctrl = "4";
int fd = open("/proc/self/clear_refs", O_WRONLY);
if (fd < 0)
ksft_exit_fail_msg("opening clear_refs failed\n");
ret = write(fd, ctrl, strlen(ctrl));
close(fd);
if (ret != strlen(ctrl))
ksft_exit_fail_msg("writing clear_refs failed\n");
}
bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len)
{
while (fgets(buf, len, fp)) {
if (!strncmp(buf, pattern, strlen(pattern)))
return true;
}
return false;
}
uint64_t read_pmd_pagesize(void)
{
int fd;
char buf[20];
ssize_t num_read;
fd = open(PMD_SIZE_FILE_PATH, O_RDONLY);
if (fd == -1)
ksft_exit_fail_msg("Open hpage_pmd_size failed\n");
num_read = read(fd, buf, 19);
if (num_read < 1) {
close(fd);
ksft_exit_fail_msg("Read hpage_pmd_size failed\n");
}
buf[num_read] = '\0';
close(fd);
return strtoul(buf, NULL, 10);
}
char *__get_smap_entry(void *addr, const char *pattern, char *buf, size_t len)
{
int ret;
FILE *fp;
char *entry = NULL;
char addr_pattern[MAX_LINE_LENGTH];
ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
(unsigned long)addr);
if (ret >= MAX_LINE_LENGTH)
ksft_exit_fail_msg("%s: Pattern is too long\n", __func__);
fp = fopen(SMAP_FILE_PATH, "r");
if (!fp)
ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__,
SMAP_FILE_PATH);
if (!check_for_pattern(fp, addr_pattern, buf, len))
goto err_out;
/* Fetch the pattern in the same block */
if (!check_for_pattern(fp, pattern, buf, len))
goto err_out;
/* Trim trailing newline */
entry = strchr(buf, '\n');
if (entry)
*entry = '\0';
entry = buf + strlen(pattern);
err_out:
fclose(fp);
return entry;
}
bool __check_huge(void *addr, char *pattern, int nr_hpages,
uint64_t hpage_size)
{
uint64_t thp = -1;
int ret;
FILE *fp;
char buffer[MAX_LINE_LENGTH];
char addr_pattern[MAX_LINE_LENGTH];
ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
(unsigned long) addr);
if (ret >= MAX_LINE_LENGTH)
ksft_exit_fail_msg("%s: Pattern is too long\n", __func__);
fp = fopen(SMAP_FILE_PATH, "r");
if (!fp)
ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, SMAP_FILE_PATH);
if (!check_for_pattern(fp, addr_pattern, buffer, sizeof(buffer)))
goto err_out;
/*
* Fetch the pattern in the same block and check the number of
* hugepages.
*/
if (!check_for_pattern(fp, pattern, buffer, sizeof(buffer)))
goto err_out;
snprintf(addr_pattern, MAX_LINE_LENGTH, "%s%%9ld kB", pattern);
if (sscanf(buffer, addr_pattern, &thp) != 1)
ksft_exit_fail_msg("Reading smap error\n");
err_out:
fclose(fp);
return thp == (nr_hpages * (hpage_size >> 10));
}
bool check_huge_anon(void *addr, int nr_hpages, uint64_t hpage_size)
{
return __check_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size);
}
bool check_huge_file(void *addr, int nr_hpages, uint64_t hpage_size)
{
return __check_huge(addr, "FilePmdMapped:", nr_hpages, hpage_size);
}
bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size)
{
return __check_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size);
}
static bool check_vmflag(void *addr, const char *flag)
{
char buffer[MAX_LINE_LENGTH];
const char *flags;
size_t flaglen;
flags = __get_smap_entry(addr, "VmFlags:", buffer, sizeof(buffer));
if (!flags)
ksft_exit_fail_msg("%s: No VmFlags for %p\n", __func__, addr);
while (true) {
flags += strspn(flags, " ");
flaglen = strcspn(flags, " ");
if (!flaglen)
return false;
if (flaglen == strlen(flag) && !memcmp(flags, flag, flaglen))
return true;
flags += flaglen;
}
}
bool softdirty_supported(void)
{
char *addr;
bool supported = false;
const size_t pagesize = getpagesize();
/* New mappings are expected to be marked with VM_SOFTDIRTY (sd). */
addr = mmap(0, pagesize, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (!addr)
ksft_exit_fail_msg("mmap failed\n");
supported = check_vmflag(addr, "sd");
munmap(addr, pagesize);
return supported;
}
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