diff --git a/conts/libl4/include/l4lib/arch-arm/utcb.h b/conts/libl4/include/l4lib/arch-arm/utcb.h
index 674ca7e..a6171eb 100644
--- a/conts/libl4/include/l4lib/arch-arm/utcb.h
+++ b/conts/libl4/include/l4lib/arch-arm/utcb.h
@@ -11,6 +11,7 @@
 #ifndef __ASSEMBLY__
 #include <l4lib/types.h>
 #include <l4/macros.h>
+#include <l4/lib/math.h>
 #include INC_GLUE(message.h)
 #include INC_GLUE(memory.h)
 #include <string.h>
@@ -41,10 +42,11 @@ extern struct utcb **kip_utcb_ref;
 static inline struct utcb *l4_get_utcb()
 {
  	/*
-	 * By double dereferencing, we get the private TLS (aka UTCB). First
-	 * reference is to the KIP's utcb offset, second is to the utcb itself,
-	 * to which the KIP's utcb reference had been updated during context
-	 * switch.
+	 * By double dereferencing, we get the private TLS
+	 * (aka UTCB). First reference is to the KIP's utcb
+	 * offset, second is to the utcb itself, to which
+	 * the KIP's utcb reference had been updated during
+	 * context switch.
 	 */
 	return *kip_utcb_ref;
 }
@@ -66,6 +68,36 @@ static inline void write_mr(unsigned int offset, unsigned int val)
 		l4_get_utcb()->mr_rest[offset - MR_TOTAL] = val;
 }
 
+
+static inline void *utcb_full_buffer()
+{
+	return &l4_get_utcb()->mr_rest[0];
+}
+
+static inline char *utcb_full_strcpy_from(const char *src)
+{
+	return strncpy((char *)&l4_get_utcb()->mr_rest[0], src,
+		       L4_UTCB_FULL_BUFFER_SIZE);
+}
+
+static inline void *utcb_full_memcpy_from(const char *src, int size)
+{
+	return memcpy(&l4_get_utcb()->mr_rest[0], src,
+		      min(size, L4_UTCB_FULL_BUFFER_SIZE));
+}
+
+static inline char *utcb_full_strcpy_to(char *dst)
+{
+	return strncpy(dst, (char *)&l4_get_utcb()->mr_rest[0],
+		       L4_UTCB_FULL_BUFFER_SIZE);
+}
+
+static inline void *utcb_full_memcpy_to(char *dst, int size)
+{
+	return memcpy(dst, &l4_get_utcb()->mr_rest[0],
+		      min(size, L4_UTCB_FULL_BUFFER_SIZE));
+}
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ARM_UTCB_H__ */
diff --git a/conts/posix/libposix/SConscript b/conts/posix/libposix/SConscript
index 0ad256e..cda7781 100644
--- a/conts/posix/libposix/SConscript
+++ b/conts/posix/libposix/SConscript
@@ -8,7 +8,7 @@ Import('env')
 
 e = env.Clone()
 e.Append(CPPPATH = ['include', 'include/posix'])
-e.Replace(CCFLAGS = ['-g', '-nostdlib', '-Wall', '-ffreestanding', '-std=gnu99'])
+e.Replace(CCFLAGS = ['-g', '-nostdlib', '-Wall', '-Werror', '-ffreestanding', '-std=gnu99'])
 
 objects = e.StaticObject(Glob('*.c'))
 libposix = e.StaticLibrary('posix', objects)
diff --git a/conts/posix/libposix/chdir.c b/conts/posix/libposix/chdir.c
index 5169745..77b8dad 100644
--- a/conts/posix/libposix/chdir.c
+++ b/conts/posix/libposix/chdir.c
@@ -22,12 +22,12 @@ static inline int l4_chdir(const char *pathname)
 {
 	int fd;
 
-	// write_mr(L4SYS_ARG0, (unsigned long)pathname);
-	copy_to_shpage((void *)pathname, 0, strlen(pathname) + 1);
-	write_mr(L4SYS_ARG0, (unsigned long)shared_page);
+	utcb_full_strcpy_from(pathname);
+
+	write_mr(L4SYS_ARG0, (unsigned long)utcb_full_buffer());
 
 	/* Call pager with shmget() request. Check ipc error. */
-	if ((fd = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_CHDIR)) < 0) {
+	if ((fd = l4_sendrecv_full(VFS_TID, VFS_TID, L4_IPC_TAG_CHDIR)) < 0) {
 		print_err("%s: L4 IPC Error: %d.\n", __FUNCTION__, fd);
 		return fd;
 	}
diff --git a/conts/posix/libposix/fork.c b/conts/posix/libposix/fork.c
index 4072bf8..ef1726a 100644
--- a/conts/posix/libposix/fork.c
+++ b/conts/posix/libposix/fork.c
@@ -42,13 +42,6 @@ int fork(void)
 		return -1;
 	}
 
-	/*
-	 * If we're a child, we need to initialise the default
-	 * shared page via libposix_init()
-	 */
-	if (ret == 0)
-		shared_page_init();
-
 	return ret;
 }
 
diff --git a/conts/posix/libposix/mkdir.c b/conts/posix/libposix/mkdir.c
index c25342b..856ca62 100644
--- a/conts/posix/libposix/mkdir.c
+++ b/conts/posix/libposix/mkdir.c
@@ -25,12 +25,12 @@ static inline int l4_mkdir(const char *pathname, mode_t mode)
 	int fd;
 
 	// write_mr(L4SYS_ARG0, (unsigned long)pathname);
-	copy_to_shpage((void *)pathname, 0, strlen(pathname) + 1);
-	write_mr(L4SYS_ARG0, (unsigned long)shared_page);
+	utcb_full_strcpy_from(pathname);
+	write_mr(L4SYS_ARG0, (unsigned long)utcb_full_buffer());
 	write_mr(L4SYS_ARG1, (u32)mode);
 
 	/* Call pager with shmget() request. Check ipc error. */
-	if ((fd = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_MKDIR)) < 0) {
+	if ((fd = l4_sendrecv_full(PAGER_TID, PAGER_TID, L4_IPC_TAG_MKDIR)) < 0) {
 		print_err("%s: L4 IPC Error: %d.\n", __FUNCTION__, fd);
 		return fd;
 	}
diff --git a/conts/posix/libposix/open.c b/conts/posix/libposix/open.c
index b12fb05..0231f26 100644
--- a/conts/posix/libposix/open.c
+++ b/conts/posix/libposix/open.c
@@ -25,13 +25,12 @@ static inline int l4_open(const char *pathname, int flags, mode_t mode)
 {
 	int fd;
 
-	copy_to_shpage((void *)pathname, 0, strlen(pathname) + 1);
-	write_mr(L4SYS_ARG0, (unsigned long)shared_page);
-	write_mr(L4SYS_ARG1, flags);
-	write_mr(L4SYS_ARG2, (u32)mode);
+	utcb_full_strcpy_from(pathname);
+	write_mr(L4SYS_ARG0, flags);
+	write_mr(L4SYS_ARG1, (u32)mode);
 
 	/* Call pager with open() request. Check ipc error. */
-	if ((fd = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_OPEN)) < 0) {
+	if ((fd = l4_sendrecv_full(PAGER_TID, PAGER_TID, L4_IPC_TAG_OPEN)) < 0) {
 		print_err("%s: L4 IPC Error: %d.\n", __FUNCTION__, fd);
 		return fd;
 	}
diff --git a/conts/posix/libposix/read.c b/conts/posix/libposix/read.c
index 5dd9c88..dfe37f1 100644
--- a/conts/posix/libposix/read.c
+++ b/conts/posix/libposix/read.c
@@ -18,16 +18,26 @@
 #include <shpage.h>
 #include <libposix.h>
 
+/*
+ * TODO:
+ *
+ * Do this as follows:
+ *
+ * A short ipc l4_send() to indicate request
+ * An extended l4_receive_extended() to get back extended buffer.
+ *
+ * Or do it just like read()
+ */
 static inline int l4_readdir(int fd, void *buf, size_t count)
 {
 	int cnt;
 
 	write_mr(L4SYS_ARG0, fd);
-	write_mr(L4SYS_ARG1, (unsigned long)shared_page);
+	write_mr(L4SYS_ARG1, (unsigned long)buf);
 	write_mr(L4SYS_ARG2, count);
 
 	/* Call pager with readdir() request. Check ipc error. */
-	if ((cnt = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_READDIR)) < 0) {
+	if ((cnt = l4_sendrecv(PAGER_TID, PAGER_TID, L4_IPC_TAG_READDIR)) < 0) {
 		print_err("%s: L4 IPC Error: %d.\n", __FUNCTION__, cnt);
 		return cnt;
 	}
@@ -38,7 +48,6 @@ static inline int l4_readdir(int fd, void *buf, size_t count)
 
 	}
 
-	copy_from_shpage(buf, 0, cnt);
 	return cnt;
 }
 
diff --git a/conts/posix/libposix/stat.c b/conts/posix/libposix/stat.c
index 1ba5c0e..ed27bee 100644
--- a/conts/posix/libposix/stat.c
+++ b/conts/posix/libposix/stat.c
@@ -30,7 +30,7 @@ static inline int l4_fstat(int fd, void *buffer)
 	write_mr(L4SYS_ARG1, (unsigned long)buffer);
 
 	/* Call pager with open() request. Check ipc error. */
-	if ((err = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_FSTAT)) < 0) {
+	if ((err = l4_sendrecv_full(PAGER_TID, PAGER_TID, L4_IPC_TAG_FSTAT)) < 0) {
 		print_err("%s: L4 IPC Error: %d.\n", __FUNCTION__, err);
 		return err;
 	}
@@ -66,16 +66,16 @@ static inline int l4_stat(const char *pathname, void *buffer)
 	int err;
 	struct kstat ks;
 
-	copy_to_shpage((void *)pathname, 0, strlen(pathname) + 1);
+	utcb_full_strcpy_from(pathname);
 
 	/* Pathname address on utcb page */
-	write_mr(L4SYS_ARG0, (unsigned long)shared_page);
+	write_mr(L4SYS_ARG0, (unsigned long)utcb_full_buffer());
 
 	/* Pass on buffer that should receive stat */
 	write_mr(L4SYS_ARG1, (unsigned long)&ks);
 
 	/* Call vfs with stat() request. Check ipc error. */
-	if ((err = l4_sendrecv(VFS_TID, VFS_TID, L4_IPC_TAG_STAT)) < 0) {
+	if ((err = l4_sendrecv_full(PAGER_TID, PAGER_TID, L4_IPC_TAG_STAT)) < 0) {
 		print_err("%s: L4 IPC Error: %d.\n", __FUNCTION__, err);
 		return err;
 	}
diff --git a/conts/posix/mm0/main.c b/conts/posix/mm0/main.c
index 9b11b5d..0939f89 100644
--- a/conts/posix/mm0/main.c
+++ b/conts/posix/mm0/main.c
@@ -156,7 +156,7 @@ void handle_requests(void)
 	/* FIXME: Fix all these syscalls to read any buffer data from the caller task's utcb. */
 	/* FS0 System calls */
 	case L4_IPC_TAG_OPEN:
-		ret = sys_open(sender, (void *)mr[0], (int)mr[1], (unsigned int)mr[2]);
+		ret = sys_open(sender, utcb_full_buffer(), (int)mr[0], (unsigned int)mr[1]);
 		break;
 	case L4_IPC_TAG_MKDIR:
 		ret = sys_mkdir(sender, (const char *)mr[0], (unsigned int)mr[1]);
diff --git a/include/l4/glue/arm/message.h b/include/l4/glue/arm/message.h
index e49238e..24210f6 100644
--- a/include/l4/glue/arm/message.h
+++ b/include/l4/glue/arm/message.h
@@ -84,6 +84,9 @@
 
 #define L4_IPC_EXTENDED_MAX_SIZE	(SZ_1K*2)
 
+/* Primaries aren't used for memcopy. Those ops use this as a parameter */
+#define L4_UTCB_FULL_BUFFER_SIZE	(MR_REST * sizeof(int)) 
+
 #include INC_GLUE(memlayout.h)
 
 #if defined (__KERNEL__)
diff --git a/include/l4/lib/math.h b/include/l4/lib/math.h
index d5ce96e..2752f6d 100644
--- a/include/l4/lib/math.h
+++ b/include/l4/lib/math.h
@@ -1,8 +1,8 @@
 #ifndef __LIB_MATH_H__
 #define __LIB_MATH_H__
 
-#define min(x, y)		(((x) < (y)) ? x : y)
-#define max(x, y)		(((x) > (y)) ? x : y)
+#define min(x, y)		(((x) < (y)) ? (x) : (y))
+#define max(x, y)		(((x) > (y)) ? (x) : (y))
 
 /* Tests if ranges a-b intersect with range c-d */
 static inline int set_intersection(unsigned long a, unsigned long b,