1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * (C) 2004-2009 Dominik Brodowski <linux@dominikbrodowski.de> |
4 | */ |
5 | |
6 | #include <sys/types.h> |
7 | #include <sys/stat.h> |
8 | #include <fcntl.h> |
9 | #include <unistd.h> |
10 | #include <stdio.h> |
11 | #include <errno.h> |
12 | #include <stdlib.h> |
13 | |
14 | #include "cpupower.h" |
15 | #include "cpupower_intern.h" |
16 | |
17 | int is_valid_path(const char *path) |
18 | { |
19 | if (access(path, F_OK) == -1) |
20 | return 0; |
21 | return 1; |
22 | } |
23 | |
24 | unsigned int cpupower_read_sysfs(const char *path, char *buf, size_t buflen) |
25 | { |
26 | ssize_t numread; |
27 | int fd; |
28 | |
29 | fd = open(path, O_RDONLY); |
30 | if (fd == -1) |
31 | return 0; |
32 | |
33 | numread = read(fd, buf, buflen - 1); |
34 | if (numread < 1) { |
35 | close(fd); |
36 | return 0; |
37 | } |
38 | |
39 | buf[numread] = '\0'; |
40 | close(fd); |
41 | |
42 | return (unsigned int) numread; |
43 | } |
44 | |
45 | unsigned int cpupower_write_sysfs(const char *path, char *buf, size_t buflen) |
46 | { |
47 | ssize_t numwritten; |
48 | int fd; |
49 | |
50 | fd = open(path, O_WRONLY); |
51 | if (fd == -1) |
52 | return 0; |
53 | |
54 | numwritten = write(fd, buf, buflen - 1); |
55 | if (numwritten < 1) { |
56 | perror(path); |
57 | close(fd); |
58 | return -1; |
59 | } |
60 | |
61 | close(fd); |
62 | |
63 | return (unsigned int) numwritten; |
64 | } |
65 | |
66 | /* |
67 | * Detect whether a CPU is online |
68 | * |
69 | * Returns: |
70 | * 1 -> if CPU is online |
71 | * 0 -> if CPU is offline |
72 | * negative errno values in error case |
73 | */ |
74 | int cpupower_is_cpu_online(unsigned int cpu) |
75 | { |
76 | char path[SYSFS_PATH_MAX]; |
77 | int fd; |
78 | ssize_t numread; |
79 | unsigned long long value; |
80 | char linebuf[MAX_LINE_LEN]; |
81 | char *endp; |
82 | struct stat statbuf; |
83 | |
84 | snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u" , cpu); |
85 | |
86 | if (stat(path, &statbuf) != 0) |
87 | return 0; |
88 | |
89 | /* |
90 | * kernel without CONFIG_HOTPLUG_CPU |
91 | * -> cpuX directory exists, but not cpuX/online file |
92 | */ |
93 | snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/online" , cpu); |
94 | if (stat(path, &statbuf) != 0) |
95 | return 1; |
96 | |
97 | fd = open(path, O_RDONLY); |
98 | if (fd == -1) |
99 | return -errno; |
100 | |
101 | numread = read(fd, linebuf, MAX_LINE_LEN - 1); |
102 | if (numread < 1) { |
103 | close(fd); |
104 | return -EIO; |
105 | } |
106 | linebuf[numread] = '\0'; |
107 | close(fd); |
108 | |
109 | value = strtoull(linebuf, &endp, 0); |
110 | if (value > 1) |
111 | return -EINVAL; |
112 | |
113 | return value; |
114 | } |
115 | |
116 | /* returns -1 on failure, 0 on success */ |
117 | static int sysfs_topology_read_file(unsigned int cpu, const char *fname, int *result) |
118 | { |
119 | char linebuf[MAX_LINE_LEN]; |
120 | char *endp; |
121 | char path[SYSFS_PATH_MAX]; |
122 | |
123 | snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/topology/%s" , |
124 | cpu, fname); |
125 | if (cpupower_read_sysfs(path, linebuf, MAX_LINE_LEN) == 0) |
126 | return -1; |
127 | *result = strtol(linebuf, &endp, 0); |
128 | if (endp == linebuf || errno == ERANGE) |
129 | return -1; |
130 | return 0; |
131 | } |
132 | |
133 | static int __compare(const void *t1, const void *t2) |
134 | { |
135 | struct cpuid_core_info *top1 = (struct cpuid_core_info *)t1; |
136 | struct cpuid_core_info *top2 = (struct cpuid_core_info *)t2; |
137 | if (top1->pkg < top2->pkg) |
138 | return -1; |
139 | else if (top1->pkg > top2->pkg) |
140 | return 1; |
141 | else if (top1->core < top2->core) |
142 | return -1; |
143 | else if (top1->core > top2->core) |
144 | return 1; |
145 | else if (top1->cpu < top2->cpu) |
146 | return -1; |
147 | else if (top1->cpu > top2->cpu) |
148 | return 1; |
149 | else |
150 | return 0; |
151 | } |
152 | |
153 | /* |
154 | * Returns amount of cpus, negative on error, cpu_top must be |
155 | * passed to cpu_topology_release to free resources |
156 | * |
157 | * Array is sorted after ->pkg, ->core, then ->cpu |
158 | */ |
159 | int get_cpu_topology(struct cpupower_topology *cpu_top) |
160 | { |
161 | int cpu, last_pkg, cpus = sysconf(_SC_NPROCESSORS_CONF); |
162 | |
163 | cpu_top->core_info = malloc(sizeof(struct cpuid_core_info) * cpus); |
164 | if (cpu_top->core_info == NULL) |
165 | return -ENOMEM; |
166 | cpu_top->pkgs = cpu_top->cores = 0; |
167 | for (cpu = 0; cpu < cpus; cpu++) { |
168 | cpu_top->core_info[cpu].cpu = cpu; |
169 | cpu_top->core_info[cpu].is_online = cpupower_is_cpu_online(cpu); |
170 | if(sysfs_topology_read_file( |
171 | cpu, |
172 | fname: "physical_package_id" , |
173 | result: &(cpu_top->core_info[cpu].pkg)) < 0) { |
174 | cpu_top->core_info[cpu].pkg = -1; |
175 | cpu_top->core_info[cpu].core = -1; |
176 | continue; |
177 | } |
178 | if(sysfs_topology_read_file( |
179 | cpu, |
180 | fname: "core_id" , |
181 | result: &(cpu_top->core_info[cpu].core)) < 0) { |
182 | cpu_top->core_info[cpu].pkg = -1; |
183 | cpu_top->core_info[cpu].core = -1; |
184 | continue; |
185 | } |
186 | } |
187 | |
188 | qsort(cpu_top->core_info, cpus, sizeof(struct cpuid_core_info), |
189 | __compare); |
190 | |
191 | /* Count the number of distinct pkgs values. This works |
192 | because the primary sort of the core_info struct was just |
193 | done by pkg value. */ |
194 | last_pkg = cpu_top->core_info[0].pkg; |
195 | for(cpu = 1; cpu < cpus; cpu++) { |
196 | if (cpu_top->core_info[cpu].pkg != last_pkg && |
197 | cpu_top->core_info[cpu].pkg != -1) { |
198 | |
199 | last_pkg = cpu_top->core_info[cpu].pkg; |
200 | cpu_top->pkgs++; |
201 | } |
202 | } |
203 | if (!(cpu_top->core_info[0].pkg == -1)) |
204 | cpu_top->pkgs++; |
205 | |
206 | /* Intel's cores count is not consecutively numbered, there may |
207 | * be a core_id of 3, but none of 2. Assume there always is 0 |
208 | * Get amount of cores by counting duplicates in a package |
209 | for (cpu = 0; cpu_top->core_info[cpu].pkg = 0 && cpu < cpus; cpu++) { |
210 | if (cpu_top->core_info[cpu].core == 0) |
211 | cpu_top->cores++; |
212 | */ |
213 | return cpus; |
214 | } |
215 | |
216 | void cpu_topology_release(struct cpupower_topology cpu_top) |
217 | { |
218 | free(cpu_top.core_info); |
219 | } |
220 | |