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 <signal.h>
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <string.h>
17 #include <sys/ioctl.h>
18 #include <sys/stat.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 cpu_set_t mask;
92 int cpu;
93
94 CPU_ZERO(&mask);
95
96 if (sched_getaffinity(0, sizeof(mask), &mask)) {
97 perror("sched_getaffinity");
98 return -1;
99 }
100
101 /* We prefer a primary thread, but skip 0 */
102 for (cpu = 8; cpu < CPU_SETSIZE; cpu += 8)
103 if (CPU_ISSET(cpu, &mask))
104 return cpu;
105
106 /* Search for anything, but in reverse */
107 for (cpu = CPU_SETSIZE - 1; cpu >= 0; cpu--)
108 if (CPU_ISSET(cpu, &mask))
109 return cpu;
110
111 printf("No cpus in affinity mask?!\n");
112 return -1;
113 }
114
is_ppc64le(void)115 bool is_ppc64le(void)
116 {
117 struct utsname uts;
118 int rc;
119
120 errno = 0;
121 rc = uname(&uts);
122 if (rc) {
123 perror("uname");
124 return false;
125 }
126
127 return strcmp(uts.machine, "ppc64le") == 0;
128 }
129
read_debugfs_file(char * debugfs_file,int * result)130 int read_debugfs_file(char *debugfs_file, int *result)
131 {
132 int rc = -1, fd;
133 char path[PATH_MAX];
134 char value[16];
135
136 strcpy(path, "/sys/kernel/debug/");
137 strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
138
139 if ((fd = open(path, O_RDONLY)) < 0)
140 return rc;
141
142 if ((rc = read(fd, value, sizeof(value))) < 0)
143 return rc;
144
145 value[15] = 0;
146 *result = atoi(value);
147 close(fd);
148
149 return 0;
150 }
151
write_debugfs_file(char * debugfs_file,int result)152 int write_debugfs_file(char *debugfs_file, int result)
153 {
154 int rc = -1, fd;
155 char path[PATH_MAX];
156 char value[16];
157
158 strcpy(path, "/sys/kernel/debug/");
159 strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
160
161 if ((fd = open(path, O_WRONLY)) < 0)
162 return rc;
163
164 snprintf(value, 16, "%d", result);
165
166 if ((rc = write(fd, value, strlen(value))) < 0)
167 return rc;
168
169 close(fd);
170
171 return 0;
172 }
173
perf_event_open(struct perf_event_attr * hw_event,pid_t pid,int cpu,int group_fd,unsigned long flags)174 static long perf_event_open(struct perf_event_attr *hw_event, pid_t pid,
175 int cpu, int group_fd, unsigned long flags)
176 {
177 return syscall(__NR_perf_event_open, hw_event, pid, cpu,
178 group_fd, flags);
179 }
180
perf_event_attr_init(struct perf_event_attr * event_attr,unsigned int type,unsigned long config)181 static void perf_event_attr_init(struct perf_event_attr *event_attr,
182 unsigned int type,
183 unsigned long config)
184 {
185 memset(event_attr, 0, sizeof(*event_attr));
186
187 event_attr->type = type;
188 event_attr->size = sizeof(struct perf_event_attr);
189 event_attr->config = config;
190 event_attr->read_format = PERF_FORMAT_GROUP;
191 event_attr->disabled = 1;
192 event_attr->exclude_kernel = 1;
193 event_attr->exclude_hv = 1;
194 event_attr->exclude_guest = 1;
195 }
196
perf_event_open_counter(unsigned int type,unsigned long config,int group_fd)197 int perf_event_open_counter(unsigned int type,
198 unsigned long config, int group_fd)
199 {
200 int fd;
201 struct perf_event_attr event_attr;
202
203 perf_event_attr_init(&event_attr, type, config);
204
205 fd = perf_event_open(&event_attr, 0, -1, group_fd, 0);
206
207 if (fd < 0)
208 perror("perf_event_open() failed");
209
210 return fd;
211 }
212
perf_event_enable(int fd)213 int perf_event_enable(int fd)
214 {
215 if (ioctl(fd, PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1) {
216 perror("error while enabling perf events");
217 return -1;
218 }
219
220 return 0;
221 }
222
perf_event_disable(int fd)223 int perf_event_disable(int fd)
224 {
225 if (ioctl(fd, PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1) {
226 perror("error disabling perf events");
227 return -1;
228 }
229
230 return 0;
231 }
232
perf_event_reset(int fd)233 int perf_event_reset(int fd)
234 {
235 if (ioctl(fd, PERF_EVENT_IOC_RESET, PERF_IOC_FLAG_GROUP) == -1) {
236 perror("error resetting perf events");
237 return -1;
238 }
239
240 return 0;
241 }
242
sigill_handler(int signr,siginfo_t * info,void * unused)243 static void sigill_handler(int signr, siginfo_t *info, void *unused)
244 {
245 static int warned = 0;
246 ucontext_t *ctx = (ucontext_t *)unused;
247 unsigned long *pc = &UCONTEXT_NIA(ctx);
248
249 /* mtspr 3,RS to check for move to DSCR below */
250 if ((*((unsigned int *)*pc) & 0xfc1fffff) == 0x7c0303a6) {
251 if (!warned++)
252 printf("WARNING: Skipping over dscr setup. Consider running 'ppc64_cpu --dscr=1' manually.\n");
253 *pc += 4;
254 } else {
255 printf("SIGILL at %p\n", pc);
256 abort();
257 }
258 }
259
set_dscr(unsigned long val)260 void set_dscr(unsigned long val)
261 {
262 static int init = 0;
263 struct sigaction sa;
264
265 if (!init) {
266 memset(&sa, 0, sizeof(sa));
267 sa.sa_sigaction = sigill_handler;
268 sa.sa_flags = SA_SIGINFO;
269 if (sigaction(SIGILL, &sa, NULL))
270 perror("sigill_handler");
271 init = 1;
272 }
273
274 asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));
275 }
276
