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
 27static char auxv[4096];
 28
 29int 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;
 54out:
 55	close(fd);
 56	return rc;
 57}
 58
 59void *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
 75void *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
 89int 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
122done:
123	CPU_FREE(mask);
124	return cpu;
125}
126
127bool 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
142int 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
162int 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
184int 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
206static 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
213static 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
229int 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
245int 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
255int 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
265int 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
275int 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;
300out:
301	fclose(f);
302	return rc;
303}