diff options
Diffstat (limited to 'arch/x86/um/os-Linux/tls.c')
-rw-r--r-- | arch/x86/um/os-Linux/tls.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/x86/um/os-Linux/tls.c b/arch/x86/um/os-Linux/tls.c new file mode 100644 index 00000000000..281e83ecce3 --- /dev/null +++ b/arch/x86/um/os-Linux/tls.c @@ -0,0 +1,35 @@ +#include <errno.h> +#include <linux/unistd.h> + +#include <sys/syscall.h> +#include <unistd.h> + +#include "sysdep/tls.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; +} |