[PATCH] uml: maintain own LDT entries

Patch imlements full LDT handling in SKAS:
 * UML holds it's own LDT table, used to deliver data on
   modify_ldt(READ)
 * UML disables the default_ldt, inherited from the host (SKAS3)
   or resets LDT entries, set by host's clib and inherited in
   SKAS0
 * A new global variable skas_needs_stub is inserted, that
   can be used to decide, whether stub-pages must be supported
   or not.
 * Uses the syscall-stub to replace missing PTRACE_LDT (therefore,
   write_ldt_entry needs to be modified)

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index 42f2da6..599d679 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -381,9 +381,9 @@
 }
 
 /*
- * This is used only, if proc_mm is available, while PTRACE_FAULTINFO
- * isn't. Opening /proc/mm creates a new mm_context, which lacks the stub-pages
- * Thus, we map them using /proc/mm-fd
+ * This is used only, if stub pages are needed, while proc_mm is
+ * availabl. Opening /proc/mm creates a new mm_context, which lacks
+ * the stub-pages. Thus, we map them using /proc/mm-fd
  */
 void map_stub_pages(int fd, unsigned long code,
 		    unsigned long data, unsigned long stack)