Index: kernel/Makefile
===================================================================
--- kernel/Makefile	(revision 3529fbf0dcb9c1b1a37194a16e000ee253b245a3)
+++ kernel/Makefile	(revision 62ca560dd1468a2f5b122d9ee3473a376d048bae)
@@ -213,4 +213,5 @@
 	generic/src/lib/gsort.c \
 	generic/src/lib/str.c \
+	generic/src/lib/str_error.c \
 	generic/src/lib/elf.c \
 	generic/src/lib/ra.c \
Index: kernel/generic/include/str.h
===================================================================
--- kernel/generic/include/str.h	(revision 3529fbf0dcb9c1b1a37194a16e000ee253b245a3)
+++ kernel/generic/include/str.h	(revision 62ca560dd1468a2f5b122d9ee3473a376d048bae)
@@ -39,4 +39,5 @@
 #include <stddef.h>
 #include <stdint.h>
+#include <errno.h>
 
 /**< Common Unicode characters */
@@ -104,4 +105,7 @@
 extern void bin_order_suffix(const uint64_t, uint64_t *, const char **, bool);
 
+extern const char *str_error(errno_t err);
+extern const char *str_error_name(errno_t err);
+
 #endif
 
Index: kernel/generic/src/lib/str_error.c
===================================================================
--- kernel/generic/src/lib/str_error.c	(revision 62ca560dd1468a2f5b122d9ee3473a376d048bae)
+++ kernel/generic/src/lib/str_error.c	(revision 62ca560dd1468a2f5b122d9ee3473a376d048bae)
@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2010 Martin Decky
+ * Copyright (c) 2017 CZ.NIC, z.s.p.o.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <errno.h>
+#include <str.h>
+
+/* The arrays below are automatically generated from the same file that
+ * errno.h constants are generated from. Triple-include of the same list
+ * with redefinitions of __errno() macro are used to ensure that the
+ * information cannot get out of synch. This is inpired by musl libc.
+ */
+
+#undef __errno_entry
+#define __errno_entry(name, num, desc) num,
+
+static const int err_num[] = {
+#include <abi/errno.in>
+};
+
+#undef __errno_entry
+#define __errno_entry(name, num, desc) #name,
+
+static const char* err_name[] = {
+#include <abi/errno.in>
+};
+
+#undef __errno_entry
+#define __errno_entry(name, num, desc) "[" #name "]" desc,
+
+static const char* err_desc[] = {
+#include <abi/errno.in>
+};
+
+/* Returns index corresponding to the given errno, or -1 if not found. */
+static int find_errno(errno_t e)
+{
+	/* Just a dumb linear search.
+	 * There too few entries to warrant anything smarter.
+	 */
+
+	int len = sizeof(err_num) / sizeof(errno_t);
+
+	for (int i = 0; i < len; i++) {
+		if (err_num[i] == e) {
+			return i;
+		}
+	}
+
+	return -1;
+}
+
+const char *str_error_name(errno_t e)
+{
+	int i = find_errno(e);
+
+	if (i >= 0) {
+		return err_name[i];
+	}
+
+	return "(unknown)";
+}
+
+const char *str_error(errno_t e)
+{
+	int i = find_errno(e);
+
+	if (i >= 0) {
+		return err_desc[i];
+	}
+
+	return "Unknown error code";
+}
+
Index: kernel/generic/src/main/kinit.c
===================================================================
--- kernel/generic/src/main/kinit.c	(revision 3529fbf0dcb9c1b1a37194a16e000ee253b245a3)
+++ kernel/generic/src/main/kinit.c	(revision 62ca560dd1468a2f5b122d9ee3473a376d048bae)
@@ -290,6 +290,6 @@
 			log(LF_OTHER, LVL_ERROR,
 			    "init[%zu]: Init binary load failed "
-			    "(error %d, loader status %u)", i, rc,
-			    programs[i].loader_status);
+			    "(error %s, loader status %u)", i,
+			    str_error_name(rc), programs[i].loader_status);
 	}
 	
Index: kernel/generic/src/mm/backend_user.c
===================================================================
--- kernel/generic/src/mm/backend_user.c	(revision 3529fbf0dcb9c1b1a37194a16e000ee253b245a3)
+++ kernel/generic/src/mm/backend_user.c	(revision 62ca560dd1468a2f5b122d9ee3473a376d048bae)
@@ -49,4 +49,5 @@
 #include <errno.h>
 #include <log.h>
+#include <str.h>
 
 static bool user_create(as_area_t *);
@@ -130,6 +131,6 @@
 		log(LF_USPACE, LVL_FATAL,
 		    "Page-in request for page %#" PRIxPTR
-		    " at pager %d failed with error %d.",
-		    upage, pager_info->pager, rc);
+		    " at pager %d failed with error %s.",
+		    upage, pager_info->pager, str_error_name(rc));
 		return AS_PF_FAULT;
 	}