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/sysinfo.h>
 20#include <sys/types.h>
 21#include <sys/utsname.h>
 22#include <unistd.h>
 23#include <asm/unistd.h>
 24#include <linux/limits.h>
 25
 26#include "utils.h"
 27
 28static char auxv[4096];
 29
 30int read_auxv(char *buf, ssize_t buf_size)
 31{
 32	ssize_t num;
 33	int rc, fd;
 34
 35	fd = open("/proc/self/auxv", O_RDONLY);
 36	if (fd == -1) {
 37		perror("open");
 38		return -errno;
 39	}
 40
 41	num = read(fd, buf, buf_size);
 42	if (num < 0) {
 43		perror("read");
 44		rc = -EIO;
 45		goto out;
 46	}
 47
 48	if (num > buf_size) {
 49		printf("overflowed auxv buffer\n");
 50		rc = -EOVERFLOW;
 51		goto out;
 52	}
 53
 54	rc = 0;
 55out:
 56	close(fd);
 57	return rc;
 58}
 59
 60void *find_auxv_entry(int type, char *auxv)
 61{
 62	ElfW(auxv_t) *p;
 63
 64	p = (ElfW(auxv_t) *)auxv;
 65
 66	while (p->a_type != AT_NULL) {
 67		if (p->a_type == type)
 68			return p;
 69
 70		p++;
 71	}
 72
 73	return NULL;
 74}
 75
 76void *get_auxv_entry(int type)
 77{
 78	ElfW(auxv_t) *p;
 79
 80	if (read_auxv(auxv, sizeof(auxv)))
 81		return NULL;
 82
 83	p = find_auxv_entry(type, auxv);
 84	if (p)
 85		return (void *)p->a_un.a_val;
 86
 87	return NULL;
 88}
 89
 90int pick_online_cpu(void)
 91{
 92	int ncpus, cpu = -1;
 93	cpu_set_t *mask;
 94	size_t size;
 95
 96	ncpus = get_nprocs_conf();
 97	size = CPU_ALLOC_SIZE(ncpus);
 98	mask = CPU_ALLOC(ncpus);
 99	if (!mask) {
100		perror("malloc");
101		return -1;
102	}
103
104	CPU_ZERO_S(size, mask);
105
106	if (sched_getaffinity(0, size, mask)) {
107		perror("sched_getaffinity");
108		goto done;
109	}
110
111	/* We prefer a primary thread, but skip 0 */
112	for (cpu = 8; cpu < ncpus; cpu += 8)
113		if (CPU_ISSET_S(cpu, size, mask))
114			goto done;
115
116	/* Search for anything, but in reverse */
117	for (cpu = ncpus - 1; cpu >= 0; cpu--)
118		if (CPU_ISSET_S(cpu, size, mask))
119			goto done;
120
121	printf("No cpus in affinity mask?!\n");
122
123done:
124	CPU_FREE(mask);
125	return cpu;
126}
127
128bool is_ppc64le(void)
129{
130	struct utsname uts;
131	int rc;
132
133	errno = 0;
134	rc = uname(&uts);
135	if (rc) {
136		perror("uname");
137		return false;
138	}
139
140	return strcmp(uts.machine, "ppc64le") == 0;
141}
142
143int read_sysfs_file(char *fpath, char *result, size_t result_size)
144{
145	char path[PATH_MAX] = "/sys/";
146	int rc = -1, fd;
147
148	strncat(path, fpath, PATH_MAX - strlen(path) - 1);
149
150	if ((fd = open(path, O_RDONLY)) < 0)
151		return rc;
152
153	rc = read(fd, result, result_size);
154
155	close(fd);
156
157	if (rc < 0)
158		return rc;
159
160	return 0;
161}
162
163int read_debugfs_file(char *debugfs_file, int *result)
164{
165	int rc = -1, fd;
166	char path[PATH_MAX];
167	char value[16];
168
169	strcpy(path, "/sys/kernel/debug/");
170	strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
171
172	if ((fd = open(path, O_RDONLY)) < 0)
173		return rc;
174
175	if ((rc = read(fd, value, sizeof(value))) < 0)
176		return rc;
177
178	value[15] = 0;
179	*result = atoi(value);
180	close(fd);
181
182	return 0;
183}
184
185int write_debugfs_file(char *debugfs_file, int result)
186{
187	int rc = -1, fd;
188	char path[PATH_MAX];
189	char value[16];
190
191	strcpy(path, "/sys/kernel/debug/");
192	strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
193
194	if ((fd = open(path, O_WRONLY)) < 0)
195		return rc;
196
197	snprintf(value, 16, "%d", result);
198
199	if ((rc = write(fd, value, strlen(value))) < 0)
200		return rc;
201
202	close(fd);
203
204	return 0;
205}
206
207static long perf_event_open(struct perf_event_attr *hw_event, pid_t pid,
208		int cpu, int group_fd, unsigned long flags)
209{
210	return syscall(__NR_perf_event_open, hw_event, pid, cpu,
211		      group_fd, flags);
212}
213
214static void perf_event_attr_init(struct perf_event_attr *event_attr,
215					unsigned int type,
216					unsigned long config)
217{
218	memset(event_attr, 0, sizeof(*event_attr));
219
220	event_attr->type = type;
221	event_attr->size = sizeof(struct perf_event_attr);
222	event_attr->config = config;
223	event_attr->read_format = PERF_FORMAT_GROUP;
224	event_attr->disabled = 1;
225	event_attr->exclude_kernel = 1;
226	event_attr->exclude_hv = 1;
227	event_attr->exclude_guest = 1;
228}
229
230int perf_event_open_counter(unsigned int type,
231			    unsigned long config, int group_fd)
232{
233	int fd;
234	struct perf_event_attr event_attr;
235
236	perf_event_attr_init(&event_attr, type, config);
237
238	fd = perf_event_open(&event_attr, 0, -1, group_fd, 0);
239
240	if (fd < 0)
241		perror("perf_event_open() failed");
242
243	return fd;
244}
245
246int perf_event_enable(int fd)
247{
248	if (ioctl(fd, PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1) {
249		perror("error while enabling perf events");
250		return -1;
251	}
252
253	return 0;
254}
255
256int perf_event_disable(int fd)
257{
258	if (ioctl(fd, PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1) {
259		perror("error disabling perf events");
260		return -1;
261	}
262
263	return 0;
264}
265
266int perf_event_reset(int fd)
267{
268	if (ioctl(fd, PERF_EVENT_IOC_RESET, PERF_IOC_FLAG_GROUP) == -1) {
269		perror("error resetting perf events");
270		return -1;
271	}
272
273	return 0;
274}
275
276static void sigill_handler(int signr, siginfo_t *info, void *unused)
277{
278	static int warned = 0;
279	ucontext_t *ctx = (ucontext_t *)unused;
280	unsigned long *pc = &UCONTEXT_NIA(ctx);
281
282	/* mtspr 3,RS to check for move to DSCR below */
283	if ((*((unsigned int *)*pc) & 0xfc1fffff) == 0x7c0303a6) {
284		if (!warned++)
285			printf("WARNING: Skipping over dscr setup. Consider running 'ppc64_cpu --dscr=1' manually.\n");
286		*pc += 4;
287	} else {
288		printf("SIGILL at %p\n", pc);
289		abort();
290	}
291}
292
293void set_dscr(unsigned long val)
294{
295	static int init = 0;
296	struct sigaction sa;
297
298	if (!init) {
299		memset(&sa, 0, sizeof(sa));
300		sa.sa_sigaction = sigill_handler;
301		sa.sa_flags = SA_SIGINFO;
302		if (sigaction(SIGILL, &sa, NULL))
303			perror("sigill_handler");
304		init = 1;
305	}
306
307	asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));
308}
309
310int using_hash_mmu(bool *using_hash)
311{
312	char line[128];
313	FILE *f;
314	int rc;
315
316	f = fopen("/proc/cpuinfo", "r");
317	FAIL_IF(!f);
318
319	rc = 0;
320	while (fgets(line, sizeof(line), f) != NULL) {
321		if (strcmp(line, "MMU		: Hash\n") == 0) {
322			*using_hash = true;
323			goto out;
324		}
325
326		if (strcmp(line, "MMU		: Radix\n") == 0) {
327			*using_hash = false;
328			goto out;
329		}
330	}
331
332	rc = -1;
333out:
334	fclose(f);
335	return rc;
336}