1 files changed, 151 insertions, 0 deletions
diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
new file mode 100644
index 000000000000..40e795624ff3
--- /dev/null
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -0,0 +1,151 @@
+// 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;
+}
+
+bool pagemap_is_swapped(int fd, char *start)
+{
+	uint64_t entry = pagemap_get_entry(fd, start);
+
+	return entry & 0x4000000000000000ull;
+}
+
+bool pagemap_is_populated(int fd, char *start)
+{
+	uint64_t entry = pagemap_get_entry(fd, start);
+
+	/* Present or swapped. */
+	return entry & 0xc000000000000000ull;
+}
+
+unsigned long pagemap_get_pfn(int fd, char *start)
+{
+	uint64_t entry = pagemap_get_entry(fd, start);
+
+	/* If present (63th bit), PFN is at bit 0 -- 54. */
+	if (entry & 0x8000000000000000ull)
+		return entry & 0x007fffffffffffffull;
+	return -1ul;
+}
+
+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);
+}
+
+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);
+}