1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2013-2015, Michael Ellerman, IBM Corp.
4 */
5
6 #define _GNU_SOURCE /* For CPU_ZERO etc. */
7
8 #include <elf.h>
9 #include <errno.h>
10 #include <fcntl.h>
11 #include <link.h>
12 #include <sched.h>
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <string.h>
16 #include <sys/ioctl.h>
17 #include <sys/stat.h>
18 #include <sys/sysinfo.h>
19 #include <sys/types.h>
20 #include <sys/utsname.h>
21 #include <unistd.h>
22 #include <asm/unistd.h>
23 #include <linux/limits.h>
24
25 #include "utils.h"
26
27 static char auxv[4096];
28
read_auxv(char * buf,ssize_t buf_size)29 int read_auxv(char *buf, ssize_t buf_size)
30 {
31 ssize_t num;
32 int rc, fd;
33
34 fd = open("/proc/self/auxv", O_RDONLY);
35 if (fd == -1) {
36 perror("open");
37 return -errno;
38 }
39
40 num = read(fd, buf, buf_size);
41 if (num < 0) {
42 perror("read");
43 rc = -EIO;
44 goto out;
45 }
46
47 if (num > buf_size) {
48 printf("overflowed auxv buffer\n");
49 rc = -EOVERFLOW;
50 goto out;
51 }
52
53 rc = 0;
54 out:
55 close(fd);
56 return rc;
57 }
58
find_auxv_entry(int type,char * auxv)59 void *find_auxv_entry(int type, char *auxv)
60 {
61 ElfW(auxv_t) *p;
62
63 p = (ElfW(auxv_t) *)auxv;
64
65 while (p->a_type != AT_NULL) {
66 if (p->a_type == type)
67 return p;
68
69 p++;
70 }
71
72 return NULL;
73 }
74
get_auxv_entry(int type)75 void *get_auxv_entry(int type)
76 {
77 ElfW(auxv_t) *p;
78
79 if (read_auxv(auxv, sizeof(auxv)))
80 return NULL;
81
82 p = find_auxv_entry(type, auxv);
83 if (p)
84 return (void *)p->a_un.a_val;
85
86 return NULL;
87 }
88
pick_online_cpu(void)89 int pick_online_cpu(void)
90 {
91 int ncpus, cpu = -1;
92 cpu_set_t *mask;
93 size_t size;
94
95 ncpus = get_nprocs_conf();
96 size = CPU_ALLOC_SIZE(ncpus);
97 mask = CPU_ALLOC(ncpus);
98 if (!mask) {
99 perror("malloc");
100 return -1;
101 }
102
103 CPU_ZERO_S(size, mask);
104
105 if (sched_getaffinity(0, size, mask)) {
106 perror("sched_getaffinity");
107 goto done;
108 }
109
110 /* We prefer a primary thread, but skip 0 */
111 for (cpu = 8; cpu < ncpus; cpu += 8)
112 if (CPU_ISSET_S(cpu, size, mask))
113 goto done;
114
115 /* Search for anything, but in reverse */
116 for (cpu = ncpus - 1; cpu >= 0; cpu--)
117 if (CPU_ISSET_S(cpu, size, mask))
118 goto done;
119
120 printf("No cpus in affinity mask?!\n");
121
122 done:
123 CPU_FREE(mask);
124 return cpu;
125 }
126
is_ppc64le(void)127 bool is_ppc64le(void)
128 {
129 struct utsname uts;
130 int rc;
131
132 errno = 0;
133 rc = uname(&uts);
134 if (rc) {
135 perror("uname");
136 return false;
137 }
138
139 return strcmp(uts.machine, "ppc64le") == 0;
140 }
141
read_sysfs_file(char * fpath,char * result,size_t result_size)142 int read_sysfs_file(char *fpath, char *result, size_t result_size)
143 {
144 char path[PATH_MAX] = "/sys/";
145 int rc = -1, fd;
146
147 strncat(path, fpath, PATH_MAX - strlen(path) - 1);
148
149 if ((fd = open(path, O_RDONLY)) < 0)
150 return rc;
151
152 rc = read(fd, result, result_size);
153
154 close(fd);
155
156 if (rc < 0)
157 return rc;
158
159 return 0;
160 }
161
read_debugfs_file(char * debugfs_file,int * result)162 int read_debugfs_file(char *debugfs_file, int *result)
163 {
164 int rc = -1, fd;
165 char path[PATH_MAX];
166 char value[16];
167
168 strcpy(path, "/sys/kernel/debug/");
169 strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
170
171 if ((fd = open(path, O_RDONLY)) < 0)
172 return rc;
173
174 if ((rc = read(fd, value, sizeof(value))) < 0)
175 return rc;
176
177 value[15] = 0;
178 *result = atoi(value);
179 close(fd);
180
181 return 0;
182 }
183
write_debugfs_file(char * debugfs_file,int result)184 int write_debugfs_file(char *debugfs_file, int result)
185 {
186 int rc = -1, fd;
187 char path[PATH_MAX];
188 char value[16];
189
190 strcpy(path, "/sys/kernel/debug/");
191 strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
192
193 if ((fd = open(path, O_WRONLY)) < 0)
194 return rc;
195
196 snprintf(value, 16, "%d", result);
197
198 if ((rc = write(fd, value, strlen(value))) < 0)
199 return rc;
200
201 close(fd);
202
203 return 0;
204 }
205
perf_event_open(struct perf_event_attr * hw_event,pid_t pid,int cpu,int group_fd,unsigned long flags)206 static long perf_event_open(struct perf_event_attr *hw_event, pid_t pid,
207 int cpu, int group_fd, unsigned long flags)
208 {
209 return syscall(__NR_perf_event_open, hw_event, pid, cpu,
210 group_fd, flags);
211 }
212
perf_event_attr_init(struct perf_event_attr * event_attr,unsigned int type,unsigned long config)213 static void perf_event_attr_init(struct perf_event_attr *event_attr,
214 unsigned int type,
215 unsigned long config)
216 {
217 memset(event_attr, 0, sizeof(*event_attr));
218
219 event_attr->type = type;
220 event_attr->size = sizeof(struct perf_event_attr);
221 event_attr->config = config;
222 event_attr->read_format = PERF_FORMAT_GROUP;
223 event_attr->disabled = 1;
224 event_attr->exclude_kernel = 1;
225 event_attr->exclude_hv = 1;
226 event_attr->exclude_guest = 1;
227 }
228
perf_event_open_counter(unsigned int type,unsigned long config,int group_fd)229 int perf_event_open_counter(unsigned int type,
230 unsigned long config, int group_fd)
231 {
232 int fd;
233 struct perf_event_attr event_attr;
234
235 perf_event_attr_init(&event_attr, type, config);
236
237 fd = perf_event_open(&event_attr, 0, -1, group_fd, 0);
238
239 if (fd < 0)
240 perror("perf_event_open() failed");
241
242 return fd;
243 }
244
perf_event_enable(int fd)245 int perf_event_enable(int fd)
246 {
247 if (ioctl(fd, PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1) {
248 perror("error while enabling perf events");
249 return -1;
250 }
251
252 return 0;
253 }
254
perf_event_disable(int fd)255 int perf_event_disable(int fd)
256 {
257 if (ioctl(fd, PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1) {
258 perror("error disabling perf events");
259 return -1;
260 }
261
262 return 0;
263 }
264
perf_event_reset(int fd)265 int perf_event_reset(int fd)
266 {
267 if (ioctl(fd, PERF_EVENT_IOC_RESET, PERF_IOC_FLAG_GROUP) == -1) {
268 perror("error resetting perf events");
269 return -1;
270 }
271
272 return 0;
273 }
274
using_hash_mmu(bool * using_hash)275 int using_hash_mmu(bool *using_hash)
276 {
277 char line[128];
278 FILE *f;
279 int rc;
280
281 f = fopen("/proc/cpuinfo", "r");
282 FAIL_IF(!f);
283
284 rc = 0;
285 while (fgets(line, sizeof(line), f) != NULL) {
286 if (!strcmp(line, "MMU : Hash\n") ||
287 !strcmp(line, "platform : Cell\n") ||
288 !strcmp(line, "platform : PowerMac\n")) {
289 *using_hash = true;
290 goto out;
291 }
292
293 if (strcmp(line, "MMU : Radix\n") == 0) {
294 *using_hash = false;
295 goto out;
296 }
297 }
298
299 rc = -1;
300 out:
301 fclose(f);
302 return rc;
303 }
304