#include <errno.h> | |
#include <linux/unistd.h> | |
#include <sys/syscall.h> | |
#include <unistd.h> | |
#include "sysdep/tls.h" | |
#include "user.h" | |
/* Checks whether host supports TLS, and sets *tls_min according to the value | |
* valid on the host. | |
* i386 host have it == 6; x86_64 host have it == 12, for i386 emulation. */ | |
void check_host_supports_tls(int *supports_tls, int *tls_min) { | |
/* Values for x86 and x86_64.*/ | |
int val[] = {GDT_ENTRY_TLS_MIN_I386, GDT_ENTRY_TLS_MIN_X86_64}; | |
int i; | |
for (i = 0; i < ARRAY_SIZE(val); i++) { | |
user_desc_t info; | |
info.entry_number = val[i]; | |
if (syscall(__NR_get_thread_area, &info) == 0) { | |
*tls_min = val[i]; | |
*supports_tls = 1; | |
return; | |
} else { | |
if (errno == EINVAL) | |
continue; | |
else if (errno == ENOSYS) | |
*supports_tls = 0; | |
return; | |
} | |
} | |
*supports_tls = 0; | |
} |