Linux 3.8-rc7
[cris-mirror.git] / arch / x86 / um / os-Linux / tls.c
blob9d94b3b76c746ac6ca5f5e5eb39f0caf48096693
1 #include <errno.h>
2 #include <linux/unistd.h>
4 #include <sys/ptrace.h>
5 #include <sys/syscall.h>
6 #include <unistd.h>
8 #include <sysdep/tls.h>
10 #ifndef PTRACE_GET_THREAD_AREA
11 #define PTRACE_GET_THREAD_AREA 25
12 #endif
14 #ifndef PTRACE_SET_THREAD_AREA
15 #define PTRACE_SET_THREAD_AREA 26
16 #endif
18 /* Checks whether host supports TLS, and sets *tls_min according to the value
19 * valid on the host.
20 * i386 host have it == 6; x86_64 host have it == 12, for i386 emulation. */
21 void check_host_supports_tls(int *supports_tls, int *tls_min)
23 /* Values for x86 and x86_64.*/
24 int val[] = {GDT_ENTRY_TLS_MIN_I386, GDT_ENTRY_TLS_MIN_X86_64};
25 int i;
27 for (i = 0; i < ARRAY_SIZE(val); i++) {
28 user_desc_t info;
29 info.entry_number = val[i];
31 if (syscall(__NR_get_thread_area, &info) == 0) {
32 *tls_min = val[i];
33 *supports_tls = 1;
34 return;
35 } else {
36 if (errno == EINVAL)
37 continue;
38 else if (errno == ENOSYS)
39 *supports_tls = 0;
40 return;
44 *supports_tls = 0;
47 int os_set_thread_area(user_desc_t *info, int pid)
49 int ret;
51 ret = ptrace(PTRACE_SET_THREAD_AREA, pid, info->entry_number,
52 (unsigned long) info);
53 if (ret < 0)
54 ret = -errno;
55 return ret;
58 int os_get_thread_area(user_desc_t *info, int pid)
60 int ret;
62 ret = ptrace(PTRACE_GET_THREAD_AREA, pid, info->entry_number,
63 (unsigned long) info);
64 if (ret < 0)
65 ret = -errno;
66 return ret;