diff --git a/.travis-ci.sh b/.travis-ci.sh
index 5062492..98eae70 100755
--- a/.travis-ci.sh
+++ b/.travis-ci.sh
@@ -55,12 +55,10 @@ fi
 
 export OPAMYES=1
 export OPAMVERBOSE=1
-export CI_CFLAGS=-Werror
+#export CI_CFLAGS=-Werror
 
 eval `opam config env`
 
-opam remote add dev https://github.com/mirage/mirage-dev.git
-
 opam pin add -n mirage-xen-posix .
 opam pin add -n mirage-xen-ocaml .
 opam pin add -n mirage-xen .
diff --git a/.travis.yml b/.travis.yml
index 03a4685..1c091e9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,4 @@ language: c
 script: bash -ex .travis-ci.sh
 sudo: required
 env:
-  - OCAML_VERSION=4.02
-  - OCAML_VERSION=4.03
   - OCAML_VERSION=4.04
diff --git a/CHANGES.md b/CHANGES.md
index 698fb0f..d30159c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,9 @@
+## 3.0.4
+
+* remove support for versions of OCaml older than 4.04.2, and add support
+  for OCaml 4.04.2 and OCaml 4.05.0.  For older revisions of OCaml, use
+  an older revision of mirage-xen-ocaml.
+
 ## 3.0.3 (2017-06-16)
 * xen: we need io-page-xen because
   - mirage-xen depends on xen-gnt (for suspend/resume callbacks)
diff --git a/mirage-xen-ocaml.opam b/mirage-xen-ocaml.opam
index 44a331b..f795ba1 100644
--- a/mirage-xen-ocaml.opam
+++ b/mirage-xen-ocaml.opam
@@ -15,4 +15,4 @@ depends: [
   "ocaml-src"
   "ocamlbuild" {build}
 ]
-available: [ocaml-version >= "4.01.0" & os = "linux"]
+available: [ocaml-version >= "4.04.2" & ocaml-version <= "4.05.0" & os = "linux"]
diff --git a/xen-ocaml/build.sh b/xen-ocaml/build.sh
index a98b376..9c35e70 100755
--- a/xen-ocaml/build.sh
+++ b/xen-ocaml/build.sh
@@ -32,39 +32,38 @@ fi
 CC=${CC:-cc}
 PWD=`pwd`
 CFLAGS="-Wall -Wno-attributes ${ARCH_CFLAGS} ${EXTRA_CFLAGS} ${CI_CFLAGS} -DSYS_xen -USYS_linux \
-  -fno-builtin-fprintf -DHAS_UNISTD -Werror=format \
+  -fno-builtin-fprintf -Werror=format \
   $(pkg-config --cflags $PKG_CONFIG_DEPS) \
   "
 
 rm -rf ocaml-src
-cp -r `ocamlfind query ocaml-src` ocaml-src
+cp -r `opam config exec -- ocamlfind query ocaml-src` ocaml-src
 chmod -R u+w ocaml-src
 
 echo Detected OCaml version `ocamlopt -version`
 case `ocamlopt -version` in
-4.01.* | 4.02.[01])
-  echo Applying GC trace patch
-  patch < trace-gc.patch -p 0
-  ;;
-4.03.*)
-  echo Applying OCaml 4.03 config
-  cp config/version-403.h ocaml-src/byterun/caml/version.h
-  patch < clambda-warnings.patch -p 0
-  ;;
-4.04.*)
+4.04.2)
   echo Applying OCaml 4.04 config
   cp config/version-404.h ocaml-src/byterun/caml/version.h
-  patch < clambda-warnings.patch -p 0
-  patch < os-type-xen.patch -p 0
+  BIGARRAY_OBJ="mmap_unix.o"
+  ;;
+4.05.*)
+  echo Applying OCaml 4.05 config
+  cp config/version-405.h ocaml-src/byterun/caml/version.h
+  BIGARRAY_OBJ=""
+  CFLAGS="-D__ANDROID__"
+  ;;
+*)
+  echo unsupported OCaml version `ocamlopt -version`
+  exit 1
+  ;;
 esac
 
+cd ocaml-src && ./configure && cd ..
 cp config/s.h ocaml-src/config/
-cp config/m.${m_file}.h ocaml-src/config/m.h
-cp config/Makefile.${m_file} ocaml-src/config/Makefile
-touch ocaml-src/config/Makefile
 cd ocaml-src
 # cd byterun && make BYTECCCOMPOPTS="${CFLAGS}" BYTECCCOMPOPTS="${CFLAGS}" libcamlrun.a && cd ..
 cd asmrun && make -j${NJOBS} UNIX_OR_WIN32=unix NATIVECCCOMPOPTS="-DNATIVE_CODE ${CFLAGS}" NATIVECCPROFOPTS="-DNATIVE_CODE ${CFLAGS}" libasmrun.a && cd ..
 CFLAGS="$CFLAGS -I../../byterun"
-cd otherlibs/bigarray && make CFLAGS="${CFLAGS}" bigarray_stubs.o mmap_unix.o && cd ../..
-ar rcs libxenotherlibs.a otherlibs/bigarray/bigarray_stubs.o otherlibs/bigarray/mmap_unix.o
+cd otherlibs/bigarray && make CFLAGS="${CFLAGS}" bigarray_stubs.o ${BIGARRAY_OBJ}
+ar rcs ../../libxenotherlibs.a bigarray_stubs.o ${BIGARRAY_OBJ}
diff --git a/xen-ocaml/clambda-warnings.patch b/xen-ocaml/clambda-warnings.patch
deleted file mode 100644
index b2bf53d..0000000
--- a/xen-ocaml/clambda-warnings.patch
+++ /dev/null
@@ -1,32 +0,0 @@
-This undoes commit d8e802431b1cfe769956140dd127d488c24f38fb in ocaml/ocaml
-which causes format warnings as lld is not the same as the actual type in
-the ARCH defines
---- ocaml-src/asmrun/clambda_checks.c.orig	2016-05-03 00:16:07.721188693 +0100
-+++ ocaml-src/asmrun/clambda_checks.c	2016-05-03 00:16:51.401188693 +0100
-@@ -59,13 +59,13 @@
-   value orig_v = v;
-   if (v == (value) 0) {
-     fprintf(stderr, "Access to field %lld of NULL: %s\n",
--      (ARCH_UINT64_TYPE) Long_val(pos), descr);
-+      (long long int) Long_val(pos), descr);
-     abort();
-   }
-   if (!Is_block(v)) {
-     fprintf(stderr,
-       "Access to field %lld of non-boxed value %p is illegal: %s\n",
--      (ARCH_UINT64_TYPE) Long_val(pos), (void*) v, descr);
-+      (long long int) Long_val(pos), (void*) v, descr);
-     abort();
-   }
-   if (Tag_val(v) == Infix_tag) {
-@@ -77,8 +77,8 @@
-   if (Long_val(pos) >= Wosize_val(v)) {
-     fprintf(stderr,
-       "Access to field %lld of value %p of size %lld is illegal: %s\n",
--      (ARCH_UINT64_TYPE) Long_val(pos), (void*) v,
--      (ARCH_UINT64_TYPE) Wosize_val(v),
-+      (long long int) Long_val(pos), (void*) v,
-+      (long long int) Wosize_val(v),
-       descr);
-     abort();
-   }
diff --git a/xen-ocaml/config/Makefile.arm b/xen-ocaml/config/Makefile.arm
deleted file mode 100644
index 0e3bf08..0000000
--- a/xen-ocaml/config/Makefile.arm
+++ /dev/null
@@ -1,77 +0,0 @@
-# generated by ./configure 
-PREFIX=/usr/local
-BINDIR=$(PREFIX)/bin
-LIBDIR=$(PREFIX)/lib/ocaml
-STUBLIBDIR=$(LIBDIR)/stublibs
-MANDIR=$(PREFIX)/man
-MANEXT=1
-RANLIB=ranlib
-RANLIBCMD=ranlib
-ARCMD=ar
-SHARPBANGSCRIPTS=true
-BNG_ARCH=generic
-BNG_ASM_LEVEL=0
-PTHREAD_LINK=-cclib -lpthread
-X11_INCLUDES= 
-X11_LINK=-lX11  
-TK_DEFS=
-TK_LINK=
-LIBBFD_LINK=
-BYTECC=gcc
-BYTECCCOMPOPTS=-fno-defer-pop -Wall -D_FILE_OFFSET_BITS=64 -D_REENTRANT
-BYTECCLINKOPTS= -Wl,-E
-BYTECCLIBS= -lm  -ldl -lcurses -lpthread
-BYTECCRPATH=-Wl,-rpath,
-EXE=
-SUPPORTS_SHARED_LIBRARIES=true
-SHAREDCCCOMPOPTS=-fPIC
-MKSHAREDLIBRPATH=-Wl,-rpath,
-NATDYNLINKOPTS=-Wl,-E
-SYSLIB=-l$(1)
-#ml let syslib x = "-l"^x;;
-
-### How to build a static library
-MKLIB=ar rc $(1) $(2); ranlib $(1)
-#ml let mklib out files opts = Printf.sprintf "ar rc %s %s %s; ranlib %s" out opts files out;;
-ARCH=arm
-MODEL=default
-SYSTEM=linux_eabihf
-NATIVECC=gcc
-NATIVECCCOMPOPTS=-Wall -D_FILE_OFFSET_BITS=64 -D_REENTRANT
-NATIVECCPROFOPTS=-Wall -D_FILE_OFFSET_BITS=64 -D_REENTRANT
-NATIVECCLINKOPTS=
-NATIVECCRPATH=-Wl,-rpath,
-NATIVECCLIBS= -lm  -ldl
-ASM=as
-ASPP=gcc -c
-ASPPPROFFLAGS=-DPROFILING
-PROFILING=prof
-DYNLINKOPTS= -ldl
-OTHERLIBRARIES=unix str num dynlink bigarray systhreads threads graph
-DEBUGGER=ocamldebugger
-CC_PROFILE=-pg
-SYSTHREAD_SUPPORT=true
-PARTIALLD=ld -r
-PACKLD=$(PARTIALLD) $(NATIVECCLINKOPTS) -o\ 
-DLLCCCOMPOPTS=
-IFLEXDIR=
-O=o
-A=a
-SO=so
-EXT_OBJ=.o
-EXT_ASM=.s
-EXT_LIB=.a
-EXT_DLL=.so
-EXTRALIBS=
-CCOMPTYPE=cc
-TOOLCHAIN=cc
-NATDYNLINK=true
-CMXS=cmxs
-MKEXE=$(BYTECC)
-MKEXEDEBUGFLAG=-g
-MKDLL=gcc -shared
-MKMAINDLL=gcc -shared
-RUNTIMED=noruntimed
-CAMLP4=camlp4
-ASM_CFI_SUPPORTED=true
-WITH_FRAME_POINTERS=false
diff --git a/xen-ocaml/config/Makefile.x86_64 b/xen-ocaml/config/Makefile.x86_64
deleted file mode 100644
index 72923c0..0000000
--- a/xen-ocaml/config/Makefile.x86_64
+++ /dev/null
@@ -1,77 +0,0 @@
-# generated by ./configure 
-PREFIX=/usr/local
-BINDIR=$(PREFIX)/bin
-LIBDIR=$(PREFIX)/lib/ocaml
-STUBLIBDIR=$(LIBDIR)/stublibs
-MANDIR=$(PREFIX)/man
-MANEXT=1
-RANLIB=ranlib
-RANLIBCMD=ranlib
-ARCMD=ar
-SHARPBANGSCRIPTS=true
-BNG_ARCH=amd64
-BNG_ASM_LEVEL=1
-PTHREAD_LINK=-cclib -lpthread
-X11_INCLUDES=
-X11_LINK=-lX11 
-TK_DEFS=-I/usr/include/tcl8.5 -I/usr/include/tk8.5 $(X11_INCLUDES)
-TK_LINK= -ltk8.5 -ltcl8.5  -ldl $(X11_LINK)
-LIBBFD_LINK=
-BYTECC=gcc
-BYTECCCOMPOPTS=-fno-defer-pop -Wall -D_FILE_OFFSET_BITS=64 -D_REENTRANT
-BYTECCLINKOPTS= -Wl,-E
-BYTECCLIBS= -lm  -ldl -lcurses -lpthread
-BYTECCRPATH=-Wl,-rpath,
-EXE=
-SUPPORTS_SHARED_LIBRARIES=true
-SHAREDCCCOMPOPTS=-fPIC
-MKSHAREDLIBRPATH=-Wl,-rpath,
-NATDYNLINKOPTS=-Wl,-E
-SYSLIB=-l$(1)
-#ml let syslib x = "-l"^x;;
-
-### How to build a static library
-MKLIB=ar rc $(1) $(2); ranlib $(1)
-#ml let mklib out files opts = Printf.sprintf "ar rc %s %s %s; ranlib %s" out opts files out;;
-ARCH=amd64
-MODEL=default
-SYSTEM=linux
-NATIVECC=gcc
-NATIVECCCOMPOPTS=-Wall -D_FILE_OFFSET_BITS=64 -D_REENTRANT
-NATIVECCPROFOPTS=-Wall -D_FILE_OFFSET_BITS=64 -D_REENTRANT
-NATIVECCLINKOPTS=
-NATIVECCRPATH=-Wl,-rpath,
-NATIVECCLIBS= -lm  -ldl
-ASM=as
-ASPP=gcc -c
-ASPPPROFFLAGS=-DPROFILING
-PROFILING=prof
-DYNLINKOPTS= -ldl
-OTHERLIBRARIES=unix str num dynlink bigarray systhreads threads graph labltk
-DEBUGGER=ocamldebugger
-CC_PROFILE=-pg
-SYSTHREAD_SUPPORT=true
-PARTIALLD=ld -r
-PACKLD=$(PARTIALLD) $(NATIVECCLINKOPTS) -o\ 
-DLLCCCOMPOPTS=
-IFLEXDIR=
-O=o
-A=a
-SO=so
-EXT_OBJ=.o
-EXT_ASM=.s
-EXT_LIB=.a
-EXT_DLL=.so
-EXTRALIBS=
-CCOMPTYPE=cc
-TOOLCHAIN=cc
-NATDYNLINK=true
-CMXS=cmxs
-MKEXE=$(BYTECC)
-MKEXEDEBUGFLAG=-g
-MKDLL=gcc -shared
-MKMAINDLL=gcc -shared
-RUNTIMED=noruntimed
-CAMLP4=camlp4
-ASM_CFI_SUPPORTED=true
-WITH_FRAME_POINTERS=false
diff --git a/xen-ocaml/config/m.arm.h b/xen-ocaml/config/m.arm.h
deleted file mode 100644
index d1c854f..0000000
--- a/xen-ocaml/config/m.arm.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#define ARCH_ALIGN_DOUBLE
-#define SIZEOF_INT 4
-#define SIZEOF_LONG 4
-#define SIZEOF_PTR 4
-#define SIZEOF_SHORT 2
-#define ARCH_INT64_TYPE long long
-#define ARCH_UINT64_TYPE unsigned long long
-#define ARCH_INT64_PRINTF_FORMAT "ll"
-#define ARCH_ALIGN_INT64
-#define PROFINFO_WIDTH 26
diff --git a/xen-ocaml/config/m.x86_64.h b/xen-ocaml/config/m.x86_64.h
deleted file mode 100644
index 6dbfb67..0000000
--- a/xen-ocaml/config/m.x86_64.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#define ARCH_SIXTYFOUR
-#define SIZEOF_INT 4
-#define SIZEOF_LONG 8
-#define SIZEOF_PTR 8
-#define SIZEOF_SHORT 2
-#define ARCH_INT64_TYPE long
-#define ARCH_UINT64_TYPE unsigned long
-#define ARCH_INT64_PRINTF_FORMAT "l"
-#undef ARCH_BIG_ENDIAN
-#undef ARCH_ALIGN_DOUBLE
-#undef ARCH_ALIGN_INT64
-#undef NONSTANDARD_DIV_MOD
diff --git a/xen-ocaml/config/s.h b/xen-ocaml/config/s.h
index 5e0d154..ea254d7 100644
--- a/xen-ocaml/config/s.h
+++ b/xen-ocaml/config/s.h
@@ -1,44 +1,57 @@
-#define OCAML_OS_TYPE "Unix"
+#define OCAML_OS_TYPE "xen"
 #define OCAML_STDLIB_DIR "/usr/local/lib/ocaml"
-#define POSIX_SIGNALS
-//#define HAS_GETRUSAGE
+#define  POSIX_SIGNALS
+#define HAS_C99_FLOAT_OPS
+#define HAS_GETRUSAGE
 #define HAS_TIMES
-//#define HAS_SOCKETS
-//#define HAS_SOCKLEN_T
-//#define HAS_INET_ATON
-//#define HAS_IPV6
-//#define HAS_UNISTD
-//#define HAS_OFF_T
+#undef HAS_ISSETUGID
+#undef HAS_TERMCAP
+#undef HAS_SOCKETS
+#undef HAS_SOCKLEN_T
+#define HAS_INET_ATON
+#define HAS_IPV6
+#define HAS_STDINT_H
+#define HAS_UNISTD
+#define HAS_OFF_T
 #define HAS_DIRENT
-//#define HAS_REWINDDIR
-//#define HAS_LOCKF
-//#define HAS_MKFIFO
+#define HAS_REWINDDIR
+#define HAS_LOCKF
+#define HAS_MKFIFO
 #define HAS_GETCWD
-#define HAS_EXPM1_LOG1P
-//#define HAS_GETWD
-//#define HAS_GETPRIORITY
-//#define HAS_UTIME
-//#define HAS_UTIMES
-//#define HAS_DUP2
-//#define HAS_FCHMOD
-//#define HAS_TRUNCATE
-//#define HAS_SYS_SELECT_H
-//#define HAS_SELECT
-//#define HAS_SYMLINK
-//#define HAS_WAITPID
-//#define HAS_WAIT4
-//#define HAS_GETGROUPS
-//#define HAS_TERMIOS
-//#define HAS_SETITIMER
-//#define HAS_GETHOSTNAME
-//#define HAS_UNAME
+#define HAS_GETPRIORITY
+#define HAS_UTIME
+#define HAS_UTIMES
+#define HAS_DUP2
+#define HAS_FCHMOD
+#define HAS_TRUNCATE
+#define HAS_SYS_SELECT_H
+#define HAS_SELECT
+#define HAS_NANOSLEEP
+#define HAS_SYMLINK
+#define HAS_WAITPID
+#define HAS_WAIT4
+#define HAS_GETGROUPS
+#define HAS_SETGROUPS
+#define HAS_INITGROUPS
+#define HAS_TERMIOS
+#define HAS_ASYNC_IO
+#define HAS_SETITIMER
+#define HAS_GETHOSTNAME
+#define HAS_UNAME
 #define HAS_GETTIMEOFDAY
-//#define HAS_MKTIME
-//#define HAS_SETSID
-//#define HAS_PUTENV
-//#define HAS_LOCALE
-//#define HAS_MMAP
-//#define HAS_GETHOSTBYNAME_R 6
-//#define HAS_GETHOSTBYADDR_R 8
-//#define HAS_STACK_OVERFLOW_DETECTION
-#define PROFINFO_WIDTH 26
+#define HAS_MKTIME
+#define HAS_SETSID
+#define HAS_PUTENV
+#undef HAS_LOCALE
+#undef SUPPORT_DYNAMIC_LINKING
+#undef HAS_MMAP
+#undef HAS_PWRITE
+#define HAS_NANOSECOND_STAT 1
+#define HAS_GETHOSTBYNAME_R 6
+#define HAS_GETHOSTBYADDR_R 8
+#define HAS_MKSTEMP
+#define HAS_NICE
+#undef HAS_STACK_OVERFLOW_DETECTION
+#undef HAS_SIGWAIT
+#undef HAS_HUGE_PAGES
+//#define HUGE_PAGE_SIZE (4 * 1024 * 1024)
diff --git a/xen-ocaml/config/version-404.h b/xen-ocaml/config/version-404.h
index d16ff01..8ee0fbb 100644
--- a/xen-ocaml/config/version-404.h
+++ b/xen-ocaml/config/version-404.h
@@ -1,6 +1,6 @@
 #define OCAML_VERSION_MAJOR 4
 #define OCAML_VERSION_MINOR 4
-#define OCAML_VERSION_PATCHLEVEL 0
+#define OCAML_VERSION_PATCHLEVEL 2
 #undef OCAML_VERSION_ADDITIONAL
-#define OCAML_VERSION 40400
-#define OCAML_VERSION_STRING "4.04.0"
+#define OCAML_VERSION 40402
+#define OCAML_VERSION_STRING "4.04.2"
diff --git a/xen-ocaml/config/version-403.h b/xen-ocaml/config/version-405.h
similarity index 50%
rename from xen-ocaml/config/version-403.h
rename to xen-ocaml/config/version-405.h
index 1e5da2d..8602203 100644
--- a/xen-ocaml/config/version-403.h
+++ b/xen-ocaml/config/version-405.h
@@ -1,6 +1,6 @@
 #define OCAML_VERSION_MAJOR 4
-#define OCAML_VERSION_MINOR 3
+#define OCAML_VERSION_MINOR 5
 #define OCAML_VERSION_PATCHLEVEL 0
 #undef OCAML_VERSION_ADDITIONAL
-#define OCAML_VERSION 40300
-#define OCAML_VERSION_STRING "4.03.0"
+#define OCAML_VERSION 40500
+#define OCAML_VERSION_STRING "4.05.0"
diff --git a/xen-ocaml/install.sh b/xen-ocaml/install.sh
index d263192..1a52765 100755
--- a/xen-ocaml/install.sh
+++ b/xen-ocaml/install.sh
@@ -28,8 +28,14 @@ fi
 
 PUBLIC_INCLUDES="alloc.h callback.h config.h custom.h fail.h hash.h intext.h \
   memory.h misc.h mlvalues.h printexc.h signals.h compatibility.h"
-for i in ${PUBLIC_INCLUDES}; do
-  sed -f ../tools/cleanup-header $HEADERS_SRC/$i > $idir/caml/$i
-done
-cd ../otherlibs/bigarray
-sed -f ../../tools/cleanup-header bigarray.h > $idir/caml/bigarray.h
+if [ -e ../tools/cleanup-header ]; then
+  for i in ${PUBLIC_INCLUDES}; do
+    sed -f ../tools/cleanup-header $HEADERS_SRC/$i > $idir/caml/$i
+  done
+  cd ../otherlibs/bigarray
+  sed -f ../../tools/cleanup-header bigarray.h > $idir/caml/bigarray.h
+else
+  for i in ${PUBLIC_INCLUDES} bigarray.h; do
+    cp ${HEADERS_SRC}/$i $idir/caml/$i
+  done
+fi
diff --git a/xen-ocaml/os-type-xen.patch b/xen-ocaml/os-type-xen.patch
deleted file mode 100644
index 122f164..0000000
--- a/xen-ocaml/os-type-xen.patch
+++ /dev/null
@@ -1,10 +0,0 @@
-define OCAML_OS_TYPE as "xen".  Only a good idea for compiler versions >= 4.04.0.
-See https://github.com/mirage/mirage-platform/pull/78/ .
---- config/s.h
-+++ config/s.h
-@@ -1,4 +1,4 @@
--#define OCAML_OS_TYPE "Unix"
-+#define OCAML_OS_TYPE "xen"
- #define OCAML_STDLIB_DIR "/usr/local/lib/ocaml"
- #define POSIX_SIGNALS
- //#define HAS_GETRUSAGE
diff --git a/xen-ocaml/trace-gc.patch b/xen-ocaml/trace-gc.patch
deleted file mode 100644
index 3014372..0000000
--- a/xen-ocaml/trace-gc.patch
+++ /dev/null
@@ -1,43 +0,0 @@
-diff -ur ocaml-src/byterun/minor_gc.c ocaml-src.new/byterun/minor_gc.c
---- ocaml-src/byterun/minor_gc.c	2015-02-03 15:10:46.743321379 +0000
-+++ ocaml-src.new/byterun/minor_gc.c	2015-02-03 15:11:27.756654339 +0000
-@@ -25,6 +25,11 @@
- #include "roots.h"
- #include "signals.h"
- #include "weak.h"
-+#include "callback.h"
-+#include "mlvalues.h"
-+#include "alloc.h"
-+#include <time.h>
-+#include <mini-os/console.h>
- 
- asize_t caml_minor_heap_size;
- static void *caml_young_base = NULL;
-@@ -271,6 +276,13 @@
- */
- CAMLexport void caml_minor_collection (void)
- {
-+  value *note_gc;
-+  uint64_t start_time;
-+
-+  note_gc = caml_named_value("MProf.Trace.note_gc");
-+  if (note_gc)
-+    start_time = NOW();
-+
-   intnat prev_alloc_words = caml_allocated_words;
- 
-   caml_empty_minor_heap ();
-@@ -282,6 +294,13 @@
- 
-   caml_final_do_calls ();
- 
-+  if (note_gc){
-+    double duration_ns = (double) (NOW () - start_time);
-+    value result = caml_callback_exn(*note_gc, caml_copy_double(duration_ns / 1000000000));
-+    if (Is_exception_result(result))
-+      printk("warning: note_gc threw an exception!\n");
-+  }
-+
-   caml_empty_minor_heap ();
- }
- 
diff --git a/xen-posix/src/mini_libc.c b/xen-posix/src/mini_libc.c
index bfe9971..72c8871 100644
--- a/xen-posix/src/mini_libc.c
+++ b/xen-posix/src/mini_libc.c
@@ -192,6 +192,11 @@ clock_t times(struct tms *buf)
     return now;
 }
 
+uid_t geteuid() { return 0; }
+uid_t getuid() { return 0; }
+uid_t getgid() { return 0; }
+uid_t getegid() { return 0; }
+
 /* Not supported by FS yet.  */
 unsupported_function_crash(link);
 unsupported_function(int, readlink, -1);