x86/tls: Don't validate lm in set_thread_area() after all

[pandora-kernel.git] / arch / x86 / include / asm / ldt.h

diff --git a/arch/x86/include/asm/ldt.h b/arch/x86/include/asm/ldt.h
index 46727eb..6e1aaf7 100644 (file)
--- a/arch/x86/include/asm/ldt.h
+++ b/arch/x86/include/asm/ldt.h
@@ -28,6 +28,13 @@ struct user_desc {
        unsigned int  seg_not_present:1;
        unsigned int  useable:1;
 #ifdef __x86_64__
+       /*
+        * Because this bit is not present in 32-bit user code, user
+        * programs can pass uninitialized values here.  Therefore, in
+        * any context in which a user_desc comes from a 32-bit program,
+        * the kernel must act as though lm == 0, regardless of the
+        * actual value.
+        */
        unsigned int  lm:1;
 #endif
 };