SAFE public projects git trees. - safe/jmp/linux-2.6/blob - arch/um/os-Linux/sys-i386/tls.c

   1 #include <errno.h>
   2 #include <linux/unistd.h>
   3
   4 #include <sys/syscall.h>
   5 #include <unistd.h>
   6
   7 #include "sysdep/tls.h"
   8 #include "user.h"
   9 #include "user_util.h"
  10
  11 /* Checks whether host supports TLS, and sets *tls_min according to the value
  12  * valid on the host.
  13  * i386 host have it == 6; x86_64 host have it == 12, for i386 emulation. */
  14 void check_host_supports_tls(int *supports_tls, int *tls_min) {
  15         /* Values for x86 and x86_64.*/
  16         int val[] = {GDT_ENTRY_TLS_MIN_I386, GDT_ENTRY_TLS_MIN_X86_64};
  17         int i;
  18
  19         for (i = 0; i < ARRAY_SIZE(val); i++) {
  20                 user_desc_t info;
  21                 info.entry_number = val[i];
  22
  23                 if (syscall(__NR_get_thread_area, &info) == 0) {
  24                         *tls_min = val[i];
  25                         *supports_tls = 1;
  26                         return;
  27                 } else {
  28                         if (errno == EINVAL)
  29                                 continue;
  30                         else if (errno == ENOSYS)
  31                                 *supports_tls = 0;
  32                                 return;
  33                 }
  34         }
  35
  36         *supports_tls = 0;
  37 }