Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / x86 / um / os-Linux / tls.c

diff --git a/kernel/arch/x86/um/os-Linux/tls.c b/kernel/arch/x86/um/os-Linux/tls.c
new file mode 100644 (file)
index 0000000..9d94b3b
--- /dev/null
+++ b/kernel/arch/x86/um/os-Linux/tls.c
@@ -0,0 +1,67 @@
+#include <errno.h>
+#include <linux/unistd.h>
+
+#include <sys/ptrace.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include <sysdep/tls.h>
+
+#ifndef PTRACE_GET_THREAD_AREA
+#define PTRACE_GET_THREAD_AREA 25
+#endif
+
+#ifndef PTRACE_SET_THREAD_AREA
+#define PTRACE_SET_THREAD_AREA 26
+#endif
+
+/* 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;
+}
+
+int os_set_thread_area(user_desc_t *info, int pid)
+{
+       int ret;
+
+       ret = ptrace(PTRACE_SET_THREAD_AREA, pid, info->entry_number,
+                    (unsigned long) info);
+       if (ret < 0)
+               ret = -errno;
+       return ret;
+}
+
+int os_get_thread_area(user_desc_t *info, int pid)
+{
+       int ret;
+
+       ret = ptrace(PTRACE_GET_THREAD_AREA, pid, info->entry_number,
+                    (unsigned long) info);
+       if (ret < 0)
+               ret = -errno;
+       return ret;
+}