[ARM] nommu: uaccess tweaks

MMUless systems have only one address space for all threads, so
both the usual access_ok() checks, and the exception handling do
not make much sense.

Hence, discard the fixup and exception tables at link time, use
memcpy/memset for the user copy/clearing functions, and define
the permission check macros to be constants.

Some of this patch was derived from the equivalent patch by
Hyok S. Choi.

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/vmlinux.lds.S

@@ -80,6 +80,10 @@ SECTIONS
 		*(.exit.text)
 		*(.exit.data)
 		*(.exitcall.exit)
+#ifndef CONFIG_MMU
+		*(.fixup)
+		*(__ex_table)
+#endif
 	}
 
 	.text : {			/* Real text segment		*/
@@ -87,7 +91,9 @@ SECTIONS
 			*(.text)
 			SCHED_TEXT
 			LOCK_TEXT
+#ifdef CONFIG_MMU
 			*(.fixup)
+#endif
 			*(.gnu.warning)
 			*(.rodata)
 			*(.rodata.*)
@@ -142,7 +148,9 @@ SECTIONS
 		 */
 		. = ALIGN(32);
 		__start___ex_table = .;
+#ifdef CONFIG_MMU
 		*(__ex_table)
+#endif
 		__stop___ex_table = .;
 
 		/*