path: root/tools/testing/selftests/resctrl/resctrlfs.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Basic resctrl file system operations
 *
 * Copyright (C) 2018 Intel Corporation
 *
 * Authors:
 *    Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
 *    Fenghua Yu <fenghua.yu@intel.com>
 */
#include <fcntl.h>
#include <limits.h>

#include "resctrl.h"

static int find_resctrl_mount(char *buffer)
{
	FILE *mounts;
	char line[256], *fs, *mntpoint;

	mounts = fopen("/proc/mounts", "r");
	if (!mounts) {
		ksft_perror("/proc/mounts");
		return -ENXIO;
	}
	while (!feof(mounts)) {
		if (!fgets(line, 256, mounts))
			break;
		fs = strtok(line, " \t");
		if (!fs)
			continue;
		mntpoint = strtok(NULL, " \t");
		if (!mntpoint)
			continue;
		fs = strtok(NULL, " \t");
		if (!fs)
			continue;
		if (strcmp(fs, "resctrl"))
			continue;

		fclose(mounts);
		if (buffer)
			strncpy(buffer, mntpoint, 256);

		return 0;
	}

	fclose(mounts);

	return -ENOENT;
}

/*
 * mount_resctrlfs - Mount resctrl FS at /sys/fs/resctrl
 *
 * Mounts resctrl FS. Fails if resctrl FS is already mounted to avoid
 * pre-existing settings interfering with the test results.
 *
 * Return: 0 on success, < 0 on error.
 */
int mount_resctrlfs(void)
{
	int ret;

	ret = find_resctrl_mount(NULL);
	if (ret != -ENOENT)
		return -1;

	ksft_print_msg("Mounting resctrl to \"%s\"\n", RESCTRL_PATH);
	ret = mount("resctrl", RESCTRL_PATH, "resctrl", 0, NULL);
	if (ret)
		ksft_perror("mount");

	return ret;
}

int umount_resctrlfs(void)
{
	char mountpoint[256];
	int ret;

	ret = find_resctrl_mount(mountpoint);
	if (ret == -ENOENT)
		return 0;
	if (ret)
		return ret;

	if (umount(mountpoint)) {
		ksft_perror("Unable to umount resctrl");

		return -1;
	}

	return 0;
}

/*
 * get_cache_level - Convert cache level from string to integer
 * @cache_type:		Cache level as string
 *
 * Return: cache level as integer or -1 if @cache_type is invalid.
 */
static int get_cache_level(const char *cache_type)
{
	if (!strcmp(cache_type, "L3"))
		return 3;
	if (!strcmp(cache_type, "L2"))
		return 2;

	ksft_print_msg("Invalid cache level\n");
	return -1;
}

static int get_resource_cache_level(const char *resource)
{
	/* "MB" use L3 (LLC) as resource */
	if (!strcmp(resource, "MB"))
		return 3;
	return get_cache_level(resource);
}

/*
 * get_domain_id - Get resctrl domain ID for a specified CPU
 * @resource:	resource name
 * @cpu_no:	CPU number
 * @domain_id:	domain ID (cache ID; for MB, L3 cache ID)
 *
 * Return: >= 0 on success, < 0 on failure.
 */
int get_domain_id(const char *resource, int cpu_no, int *domain_id)
{
	char phys_pkg_path[1024];
	int cache_num;
	FILE *fp;

	cache_num = get_resource_cache_level(resource);
	if (cache_num < 0)
		return cache_num;

	sprintf(phys_pkg_path, "%s%d/cache/index%d/id", PHYS_ID_PATH, cpu_no, cache_num);

	fp = fopen(phys_pkg_path, "r");
	if (!fp) {
		ksft_perror("Failed to open cache id file");

		return -1;
	}
	if (fscanf(fp, "%d", domain_id) <= 0) {
		ksft_perror("Could not get domain ID");
		fclose(fp);

		return -1;
	}
	fclose(fp);

	return 0;
}

/*
 * get_cache_size - Get cache size for a specified CPU
 * @cpu_no:	CPU number
 * @cache_type:	Cache level L2/L3
 * @cache_size:	pointer to cache_size
 *
 * Return: = 0 on success, < 0 on failure.
 */
int get_cache_size(int cpu_no, const char *cache_type, unsigned long *cache_size)
{
	char cache_path[1024], cache_str[64];
	int length, i, cache_num;
	FILE *fp;

	cache_num = get_cache_level(cache_type);
	if (cache_num < 0)
		return cache_num;

	sprintf(cache_path, "/sys/bus/cpu/devices/cpu%d/cache/index%d/size",
		cpu_no, cache_num);
	fp = fopen(cache_path, "r");
	if (!fp) {
		ksft_perror("Failed to open cache size");

		return -1;
	}
	if (fscanf(fp, "%s", cache_str) <= 0) {
		ksft_perror("Could not get cache_size");
		fclose(fp);

		return -1;
	}
	fclose(fp);

	length = (int)strlen(cache_str);

	*cache_size = 0;

	for (i = 0; i < length; i++) {
		if ((cache_str[i] >= '0') &&