diff options
Diffstat (limited to 'tools/testing/selftests/powerpc/utils.c')
-rw-r--r-- | tools/testing/selftests/powerpc/utils.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/utils.c b/tools/testing/selftests/powerpc/utils.c new file mode 100644 index 000000000000..dcf74184bfd0 --- /dev/null +++ b/tools/testing/selftests/powerpc/utils.c @@ -0,0 +1,87 @@ +/* + * Copyright 2013-2015, Michael Ellerman, IBM Corp. + * Licensed under GPLv2. + */ + +#define _GNU_SOURCE /* For CPU_ZERO etc. */ + +#include <elf.h> +#include <errno.h> +#include <fcntl.h> +#include <link.h> +#include <sched.h> +#include <stdio.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> + +#include "utils.h" + +static char auxv[4096]; + +void *get_auxv_entry(int type) +{ + ElfW(auxv_t) *p; + void *result; + ssize_t num; + int fd; + + fd = open("/proc/self/auxv", O_RDONLY); + if (fd == -1) { + perror("open"); + return NULL; + } + + result = NULL; + + num = read(fd, auxv, sizeof(auxv)); + if (num < 0) { + perror("read"); + goto out; + } + + if (num > sizeof(auxv)) { + printf("Overflowed auxv buffer\n"); + goto out; + } + + p = (ElfW(auxv_t) *)auxv; + + while (p->a_type != AT_NULL) { + if (p->a_type == type) { + result = (void *)p->a_un.a_val; + break; + } + + p++; + } +out: + close(fd); + return result; +} + +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; +} |