Index: uspace/app/tester/mm/common.c
===================================================================
--- uspace/app/tester/mm/common.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/app/tester/mm/common.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -342,7 +342,7 @@
 	link_initialize(&area->link);
 	
-	area->addr = as_area_create((void *) -1, size,
+	area->addr = as_area_create(AS_AREA_ANY, size,
 	    AS_AREA_WRITE | AS_AREA_READ);
-	if (area->addr == (void *) -1) {
+	if (area->addr == AS_MAP_FAILED) {
 		free(area);
 		check_consistency("map_area (a)");
Index: uspace/app/tester/mm/mapping1.c
===================================================================
--- uspace/app/tester/mm/mapping1.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/app/tester/mm/mapping1.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -42,7 +42,7 @@
 	TPRINTF("Creating AS area...\n");
 	
-	void *result = as_area_create((void *) -1, size,
+	void *result = as_area_create(AS_AREA_ANY, size,
 	    AS_AREA_READ | AS_AREA_WRITE);
-	if (result == (void *) -1)
+	if (result == AS_MAP_FAILED)
 		return NULL;
 	
Index: uspace/drv/bus/usb/uhci/utils/malloc32.h
===================================================================
--- uspace/drv/bus/usb/uhci/utils/malloc32.h	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/drv/bus/usb/uhci/utils/malloc32.h	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -99,7 +99,7 @@
 static inline void * get_page(void)
 {
-	void *address = as_area_create((void *) -1, UHCI_REQUIRED_PAGE_SIZE,
+	void *address = as_area_create(AS_AREA_ANY, UHCI_REQUIRED_PAGE_SIZE,
 	    AS_AREA_READ | AS_AREA_WRITE);
-	if (address == (void *) -1)
+	if (address == AS_MAP_FAILED)
 		return NULL;
 	
Index: uspace/drv/bus/usb/usbmast/main.c
===================================================================
--- uspace/drv/bus/usb/usbmast/main.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/drv/bus/usb/usbmast/main.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -302,5 +302,5 @@
 	
 	(void) async_share_out_finalize(callid, &comm_buf);
-	if (comm_buf == (void *) -1) {
+	if (comm_buf == AS_MAP_FAILED) {
 		async_answer_0(callid, EHANGUP);
 		return;
Index: uspace/lib/c/generic/as.c
===================================================================
--- uspace/lib/c/generic/as.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/lib/c/generic/as.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -46,11 +46,11 @@
  *
  * @param base  Starting virtual address of the area.
- *              If set to (void *) -1, the kernel finds
- *              a mappable area.
+ *              If set to AS_AREA_ANY ((void *) -1),
+ *              the kernel finds a mappable area.
  * @param size  Size of the area.
  * @param flags Flags describing type of the area.
  *
  * @return Starting virtual address of the created area on success.
- * @return (void *) -1 otherwise.
+ * @return AS_MAP_FAILED ((void *) -1) otherwise.
  *
  */
Index: uspace/lib/c/generic/elf/elf_load.c
===================================================================
--- uspace/lib/c/generic/elf/elf_load.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/lib/c/generic/elf/elf_load.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -366,5 +366,5 @@
 	a = as_area_create((uint8_t *) base + bias, mem_sz,
 	    AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE);
-	if (a == (void *) -1) {
+	if (a == AS_MAP_FAILED) {
 		DPRINTF("memory mapping failed (0x%x, %d)\n",
 		    base + bias, mem_sz);
Index: uspace/lib/c/generic/malloc.c
===================================================================
--- uspace/lib/c/generic/malloc.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/lib/c/generic/malloc.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -285,7 +285,7 @@
 	/* Align the heap area size on page boundary */
 	size_t asize = ALIGN_UP(size, PAGE_SIZE);
-	void *astart = as_area_create((void *) -1, asize,
+	void *astart = as_area_create(AS_AREA_ANY, asize,
 	    AS_AREA_WRITE | AS_AREA_READ);
-	if (astart == (void *) -1)
+	if (astart == AS_MAP_FAILED)
 		return false;
 	
Index: uspace/lib/c/generic/mman.c
===================================================================
--- uspace/lib/c/generic/mman.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/lib/c/generic/mman.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -42,5 +42,5 @@
 {
 	if (!start)
-		start = (void *) -1;
+		start = AS_AREA_ANY;
 	
 //	if (!((flags & MAP_SHARED) ^ (flags & MAP_PRIVATE)))
Index: uspace/lib/c/include/as.h
===================================================================
--- uspace/lib/c/include/as.h	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/lib/c/include/as.h	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -41,4 +41,7 @@
 #include <libarch/config.h>
 
+#define AS_AREA_ANY    ((void *) -1)
+#define AS_MAP_FAILED  ((void *) -1)
+
 static inline size_t SIZE2PAGES(size_t size)
 {
Index: uspace/lib/c/include/sys/mman.h
===================================================================
--- uspace/lib/c/include/sys/mman.h	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/lib/c/include/sys/mman.h	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -39,5 +39,5 @@
 #include <sys/types.h>
 
-#define MAP_FAILED  ((void *) -1)
+#define MAP_FAILED  AS_MAP_FAILED
 
 #define MAP_SHARED     (1 << 0)
Index: uspace/lib/fb/imgmap.c
===================================================================
--- uspace/lib/fb/imgmap.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/lib/fb/imgmap.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -420,7 +420,7 @@
 	
 	if ((flags & IMGMAP_FLAG_SHARED) == IMGMAP_FLAG_SHARED) {
-		imgmap = (imgmap_t *) as_area_create((void *) -1, size,
+		imgmap = (imgmap_t *) as_area_create(AS_AREA_ANY, size,
 		    AS_AREA_READ | AS_AREA_WRITE);
-		if (imgmap == (void *) -1)
+		if (imgmap == AS_MAP_FAILED)
 			return NULL;
 	} else {
Index: uspace/lib/fb/screenbuffer.c
===================================================================
--- uspace/lib/fb/screenbuffer.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/lib/fb/screenbuffer.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -79,7 +79,7 @@
 	
 	if ((flags & SCREENBUFFER_FLAG_SHARED) == SCREENBUFFER_FLAG_SHARED) {
-		scrbuf = (screenbuffer_t *) as_area_create((void *) -1, size,
+		scrbuf = (screenbuffer_t *) as_area_create(AS_AREA_ANY, size,
 		    AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE);
-		if (scrbuf == (void *) -1)
+		if (scrbuf == AS_MAP_FAILED)
 			return NULL;
 	} else {
Index: uspace/lib/fs/libfs.c
===================================================================
--- uspace/lib/fs/libfs.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/lib/fs/libfs.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -339,5 +339,5 @@
 	 */
 	rc = async_share_in_start_0_0(exch, PLB_SIZE, (void *) &reg.plb_ro);
-	if (reg.plb_ro == (void *) -1) {
+	if (reg.plb_ro == AS_MAP_FAILED) {
 		async_exchange_end(exch);
 		async_forget(req);
Index: uspace/srv/bd/ata_bd/ata_bd.c
===================================================================
--- uspace/srv/bd/ata_bd/ata_bd.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/srv/bd/ata_bd/ata_bd.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -308,5 +308,5 @@
 
 	(void) async_share_out_finalize(callid, &fs_va);
-	if (fs_va == (void *) -1) {
+	if (fs_va == AS_MAP_FAILED) {
 		async_answer_0(callid, EHANGUP);
 		return;
Index: uspace/srv/bd/file_bd/file_bd.c
===================================================================
--- uspace/srv/bd/file_bd/file_bd.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/srv/bd/file_bd/file_bd.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -189,5 +189,5 @@
 
 	(void) async_share_out_finalize(callid, &fs_va);
-	if (fs_va == (void *) -1) {
+	if (fs_va == AS_MAP_FAILED) {
 		async_answer_0(callid, EHANGUP);
 		return;
Index: uspace/srv/bd/gxe_bd/gxe_bd.c
===================================================================
--- uspace/srv/bd/gxe_bd/gxe_bd.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/srv/bd/gxe_bd/gxe_bd.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -196,5 +196,5 @@
 
 	(void) async_share_out_finalize(callid, &fs_va);
-	if (fs_va == (void *) -1) {
+	if (fs_va == AS_MAP_FAILED) {
 		async_answer_0(callid, EHANGUP);
 		return;
Index: uspace/srv/bd/part/guid_part/guid_part.c
===================================================================
--- uspace/srv/bd/part/guid_part/guid_part.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/srv/bd/part/guid_part/guid_part.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -350,5 +350,5 @@
 
 	(void) async_share_out_finalize(callid, &fs_va);
-	if (fs_va == (void *) -1) {
+	if (fs_va == AS_MAP_FAILED) {
 		async_answer_0(callid, EHANGUP);
 		return;
Index: uspace/srv/bd/part/mbr_part/mbr_part.c
===================================================================
--- uspace/srv/bd/part/mbr_part/mbr_part.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/srv/bd/part/mbr_part/mbr_part.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -427,5 +427,5 @@
 
 	(void) async_share_out_finalize(callid, &fs_va);
-	if (fs_va == (void *) -1) {
+	if (fs_va == AS_MAP_FAILED) {
 		async_answer_0(callid, EHANGUP);
 		return;
Index: uspace/srv/bd/rd/rd.c
===================================================================
--- uspace/srv/bd/rd/rd.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/srv/bd/rd/rd.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -106,5 +106,5 @@
 	if (async_share_out_receive(&callid, &comm_size, &flags)) {
 		(void) async_share_out_finalize(callid, &fs_va);
-		if (fs_va == (void *) -1) {
+		if (fs_va == AS_MAP_FAILED) {
 			async_answer_0(callid, EHANGUP);
 			return;
Index: uspace/srv/hid/fb/fb.c
===================================================================
--- uspace/srv/hid/fb/fb.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/srv/hid/fb/fb.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -305,5 +305,5 @@
 	
 	int rc = async_share_out_finalize(callid, &frontbuf->data);
-	if ((rc != EOK) || (frontbuf->data == (void *) -1)) {
+	if ((rc != EOK) || (frontbuf->data == AS_MAP_FAILED)) {
 		free(frontbuf);
 		async_answer_0(iid, ENOMEM);
@@ -348,5 +348,5 @@
 	
 	int rc = async_share_out_finalize(callid, &imagemap->data);
-	if ((rc != EOK) || (imagemap->data == (void *) -1)) {
+	if ((rc != EOK) || (imagemap->data == AS_MAP_FAILED)) {
 		free(imagemap);
 		async_answer_0(iid, ENOMEM);
Index: uspace/srv/vfs/vfs.c
===================================================================
--- uspace/srv/vfs/vfs.c	(revision 32d19f757b014501ef88e20a2fa7d354e4bc0b39)
+++ uspace/srv/vfs/vfs.c	(revision faba83975da4ba5bb605f70d4e02e065f9513e84)
@@ -173,7 +173,7 @@
 	 * Allocate and initialize the Path Lookup Buffer.
 	 */
-	plb = as_area_create((void *) -1, PLB_SIZE,
+	plb = as_area_create(AS_AREA_ANY, PLB_SIZE,
 	    AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE);
-	if (plb == (void *) -1) {
+	if (plb == AS_MAP_FAILED) {
 		printf("%s: Cannot create address space area\n", NAME);
 		return ENOMEM;