1/*-
2 *   BSD LICENSE
3 *
4 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
5 *   All rights reserved.
6 *
7 *   Redistribution and use in source and binary forms, with or without
8 *   modification, are permitted provided that the following conditions
9 *   are met:
10 *
11 *     * Redistributions of source code must retain the above copyright
12 *       notice, this list of conditions and the following disclaimer.
13 *     * Redistributions in binary form must reproduce the above copyright
14 *       notice, this list of conditions and the following disclaimer in
15 *       the documentation and/or other materials provided with the
16 *       distribution.
17 *     * Neither the name of Intel Corporation nor the names of its
18 *       contributors may be used to endorse or promote products derived
19 *       from this software without specific prior written permission.
20 *
21 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <unistd.h>
35#include <limits.h>
36#include <string.h>
37#include <dirent.h>
38
39#include <rte_log.h>
40#include <rte_eal.h>
41#include <rte_lcore.h>
42#include <rte_common.h>
43#include <rte_string_fns.h>
44#include <rte_debug.h>
45
46#include "eal_private.h"
47#include "eal_filesystem.h"
48#include "eal_thread.h"
49
50#define SYS_CPU_DIR "/sys/devices/system/cpu/cpu%u"
51#define CORE_ID_FILE "topology/core_id"
52#define NUMA_NODE_PATH "/sys/devices/system/node"
53
54/* Check if a cpu is present by the presence of the cpu information for it */
55int
56eal_cpu_detected(unsigned lcore_id)
57{
58	char path[PATH_MAX];
59	int len = snprintf(path, sizeof(path), SYS_CPU_DIR
60		"/"CORE_ID_FILE, lcore_id);
61	if (len <= 0 || (unsigned)len >= sizeof(path))
62		return 0;
63	if (access(path, F_OK) != 0)
64		return 0;
65
66	return 1;
67}
68
69/*
70 * Get CPU socket id (NUMA node) for a logical core.
71 *
72 * This searches each nodeX directories in /sys for the symlink for the given
73 * lcore_id and returns the numa node where the lcore is found. If lcore is not
74 * found on any numa node, returns zero.
75 */
76unsigned
77eal_cpu_socket_id(unsigned lcore_id)
78{
79	unsigned socket;
80
81	for (socket = 0; socket < RTE_MAX_NUMA_NODES; socket++) {
82		char path[PATH_MAX];
83
84		snprintf(path, sizeof(path), "%s/node%u/cpu%u", NUMA_NODE_PATH,
85				socket, lcore_id);
86		if (access(path, F_OK) == 0)
87			return socket;
88	}
89	return 0;
90}
91
92/* Get the cpu core id value from the /sys/.../cpuX core_id value */
93unsigned
94eal_cpu_core_id(unsigned lcore_id)
95{
96	char path[PATH_MAX];
97	unsigned long id;
98
99	int len = snprintf(path, sizeof(path), SYS_CPU_DIR "/%s", lcore_id, CORE_ID_FILE);
100	if (len <= 0 || (unsigned)len >= sizeof(path))
101		goto err;
102	if (eal_parse_sysfs_value(path, &id) != 0)
103		goto err;
104	return (unsigned)id;
105
106err:
107	RTE_LOG(ERR, EAL, "Error reading core id value from %s "
108			"for lcore %u - assuming core 0\n", SYS_CPU_DIR, lcore_id);
109	return 0;
110}
111