add patch_process_vm(). (in progress)

This function patches specified range of specified user space even if
the range is not writable.

refs #401

arch/x86/kernel/include/registers.h

@@ -219,6 +219,7 @@ enum x86_pf_error_code {
 	PF_RSVD		=		1 << 3,
 	PF_INSTR	=		1 << 4,
 
+	PF_PATCH	=		1 << 29,
 	PF_POPULATE	=		1 << 30,
 };