um: merge os-Linux/tls.c into arch/x86/um/os-Linux/tls.c

it's i386-specific; moreover, analogs on other targets have
incompatible interface - PTRACE_GET_THREAD_AREA does exist
elsewhere, but struct user_desc does *not*

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

2 files changed, 36 insertions, 1 deletions

diff --git a/arch/x86/um/os-Linux/tls.c b/arch/x86/um/os-Linux/tls.c
index 281e83ecce3d..82276b6071af 100644
--- a/arch/x86/um/os-Linux/tls.c
+++ b/arch/x86/um/os-Linux/tls.c
@@ -1,15 +1,25 @@
 #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) {
+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;
@@ -33,3 +43,25 @@ void check_host_supports_tls(int *supports_tls, int *tls_min) {
 
         *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;
+}
diff --git a/arch/x86/um/shared/sysdep/tls.h b/arch/x86/um/shared/sysdep/tls.h
index db2ae9c12e23..f2f30bd67b9b 100644
--- a/arch/x86/um/shared/sysdep/tls.h
+++ b/arch/x86/um/shared/sysdep/tls.h
@@ -29,6 +29,9 @@ typedef struct user_desc user_desc_t;
 
 # endif /* __KERNEL__ */
 
+extern int os_set_thread_area(user_desc_t *info, int pid);
+extern int os_get_thread_area(user_desc_t *info, int pid);
+
 #ifdef __i386__
 #define GDT_ENTRY_TLS_MIN_I386 6
 #define GDT_ENTRY_TLS_MIN_X86_64 12