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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2013-2015, Michael Ellerman, IBM Corp.
*/
#define _GNU_SOURCE /* For CPU_ZERO etc. */
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <link.h>
#include <sched.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <unistd.h>
#include <asm/unistd.h>
#include <linux/limits.h>
#include "utils.h"
static char auxv[4096];
int read_auxv(char *buf, ssize_t buf_size)
{
ssize_t num;
int rc, fd;
fd = open("/proc/self/auxv", O_RDONLY);
if (fd == -1) {
perror("open");
return -errno;
}
num = read(fd, buf, buf_size);
if (num < 0) {
perror("read");
rc = -EIO;
goto out;
}
if (num > buf_size) {
printf("overflowed auxv buffer\n");
rc = -EOVERFLOW;
goto out;
}
rc = 0;
out:
close(fd);
return rc;
}
void *find_auxv_entry(int type, char *auxv)
{
ElfW(auxv_t) *p;
p = (ElfW(auxv_t) *)auxv;
while (p->a_type != AT_NULL) {
if (p->a_type == type)
return p;
p++;
}
return NULL;
}
void *get_auxv_entry(int type)
{
ElfW(auxv_t) *p;
if (read_auxv(auxv, sizeof(auxv)))
return NULL;
p = find_auxv_entry(type, auxv);
if (p)
return (void *)p->a_un.a_val;
return NULL;
}
int pick_online_cpu(void)
{
cpu_set_t mask;
int cpu;
CPU_ZERO(&mask);
if (sched_getaffinity(0, sizeof(mask), &mask)) {
perror("sched_getaffinity");
return -1;
}
/* We prefer a primary thread, but skip 0 */
for (cpu = 8; cpu < CPU_SETSIZE; cpu += 8)
if (CPU_ISSET(cpu, &mask))
return cpu;
/* Search for anything, but in reverse */
for (cpu = CPU_SETSIZE - 1; cpu >= 0; cpu--)
if (CPU_ISSET(cpu, &mask))
return cpu;
printf("No cpus in affinity mask?!\n");
return -1;
}
bool is_ppc64le(void)
{
struct utsname uts;
int rc;
errno = 0;
rc = uname(&uts);
if (rc) {
perror("uname");
return false;
}
return strcmp(uts.machine, "ppc64le") == 0;
}
int read_debugfs_file(char *debugfs_file, int *result)
{
int rc = -1, fd;
char path[PATH_MAX];
char value[16];
strcpy(path, "/sys/kernel/debug/");
strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
if ((fd = open(path, O_RDONLY)) < 0)
return rc;
if ((rc = read(fd, value, sizeof(value))) < 0)
return rc;
value[15] = 0;
*result = atoi(value);
close(fd);
return 0;
}
int write_debugfs_file(char *debugfs_file, int result)
{
int rc = -1, fd;
char path[PATH_MAX];
char value[16];
strcpy(path, "/sys/kernel/debug/");
strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
if ((fd = open(path, O_WRONLY)) < 0)
return rc;
snprintf(value, 16, "%d", result);
if ((rc = write(fd, value, strlen(value))) < 0)
return rc;
close(fd);
return 0;
}
static long perf_event_open(struct perf_event_attr *hw_event, pid_t pid,
int cpu, int group_fd, unsigned long flags)
{
return syscall(__NR_perf_event_open, hw_event, pid, cpu,
group_fd, flags);
}
static void perf_event_attr_init(struct perf_event_attr *event_attr,
unsigned int type,
unsigned long config)
{
memset(event_attr, 0, sizeof(*event_attr));
event_attr->type = type;
event_attr->size = sizeof(struct perf_event_attr);
event_attr->config = config;
event_attr->read_format = PERF_FORMAT_GROUP;
event_attr->disabled = 1;
event_attr->exclude_kernel = 1;
event_attr->exclude_hv = 1;
event_attr->exclude_guest = 1;
}
int perf_event_open_counter(unsigned int type,
unsigned long config, int group_fd)
{
int fd;
struct perf_event_attr event_attr;
perf_event_attr_init(&event_attr, type, config);
fd = perf_event_open(&event_attr, 0, -1, group_fd, 0);
if (fd < 0)
perror("perf_event_open() failed");
return fd;
}
int perf_event_enable(int fd)
{
if (ioctl(fd, PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1) {
perror("error while enabling perf events");
return -1;
}
return 0;
}
int perf_event_disable(int fd)
{
if (ioctl(fd, PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1) {
perror("error disabling perf events");
return -1;
}
return 0;
}
int perf_event_reset(int fd)
{
if (ioctl(fd, PERF_EVENT_IOC_RESET, PERF_IOC_FLAG_GROUP) == -1) {
perror("error resetting perf events");
return -1;
}
return 0;
}
static void sigill_handler(int signr, siginfo_t *info, void *unused)
{
static int warned = 0;
ucontext_t *ctx = (ucontext_t *)unused;
unsigned long *pc = &UCONTEXT_NIA(ctx);
/* mtspr 3,RS to check for move to DSCR below */
if ((*((unsigned int *)*pc) & 0xfc1fffff) == 0x7c0303a6) {
if (!warned++)
printf("WARNING: Skipping over dscr setup. Consider running 'ppc64_cpu --dscr=1' manually.\n");
*pc += 4;
} else {
printf("SIGILL at %p\n", pc);
abort();
}
}
void set_dscr(unsigned long val)
{
static int init = 0;
struct sigaction sa;
if (!init) {
memset(&sa, 0, sizeof(sa));
sa.sa_sigaction = sigill_handler;
sa.sa_flags = SA_SIGINFO;
if (sigaction(SIGILL, &sa, NULL))
perror("sigill_handler");
init = 1;
}
asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));
}
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