vm: add MAP_FIXED

include/sys/mman.h

@@ -56,6 +56,8 @@ typedef	__off_t		off_t;		/* file offset */
 #define	MAP_ALIGNMENT_64KB	MAP_ALIGN64K
 #define	MAP_IPC_SHARED	0x0100	/* share changes */
 
+#define MAP_FIXED      0x0200  /* require mapping to happen at hint */
+
 /*
  * Error indicator returned by mmap(2)
  */

servers/vm/mmap.c

@@ -88,6 +88,8 @@ int do_mmap(message *m)
 			addr = arch_vir2map(vmp, m->VMM_ADDR);
 			vr = map_page_region(vmp, addr, 0, len, MAP_NONE,
 				vrflags, mfflags);
+			if(!vr && (m->VMM_FLAGS & MAP_FIXED))
+				return ENOMEM;
 		}
 		if (!vr) {
 			/* No address given or address already in use. */