diff --git a/Makefile.in b/Makefile.in
index 448f0387..9962af91 100755
--- a/Makefile.in
+++ b/Makefile.in
@@ -16,7 +16,7 @@ glibc_url := $(GNU_MIRROR)/glibc/glibc-$(glibc_version).tar.gz
 newlib_url := ftp://sourceware.org/pub/newlib/newlib-$(newlib_version).tar.gz
 
 XLEN ?= @XLEN@
-SYSROOT := $(INSTALL_DIR)/sysroot$(XLEN)
+SYSROOT := $(INSTALL_DIR)/sysroot
 
 SHELL := /bin/sh
 AWK := @GAWK@
@@ -24,11 +24,32 @@ SED := @GSED@
 PATH := $(INSTALL_DIR)/bin:$(builddir)/scripts/wrapper:$(PATH)
 export PATH AWK SED
 
+MULTILIB_FLAGS := @multilib_flags@
+ATOMIC_CFLAGS := @atomic_cflags@
+FLOAT_CFLAGS := @float_cflags@
+FLOAT_ASFLAGS := @float_asflags@
+GLIBC_CONFIGURE_FLAGS := @glibc_configure_flags@
+
+CFLAGS_FOR_TARGET := $(CFLAGS_FOR_TARGET_EXTRA) $(ATOMIC_CFLAGS) $(FLOAT_CFLAGS)
+ASFLAGS_FOR_TARGET := $(ASFLAGS_FOR_TARGET_EXTRA) $(FLOAT_ASFLAGS)
+
 all: @default_target@
 
 newlib: stamps/build-gcc-newlib
 
+ifneq ($(findstring --disable-multilib,$(MULTILIB_FLAGS)),)
 linux: stamps/build-gcc-linux-stage2
+else
+linux:
+	$(MAKE) stamps/build-gcc-linux-stage1 XLEN=
+	$(MAKE) stamps/build-glibc-linux XLEN=
+	$(MAKE) stamps/build-glibc-linux32 XLEN=32 \
+		CC="riscv-unknown-linux-gnu-gcc -m32" \
+		READELF=riscv-unknown-linux-gnu-readelf \
+		CFLAGS_FOR_TARGET_EXTRA="-m32" \
+		ASFLAGS_FOR_TARGET_EXTRA="-m32"
+	$(MAKE) stamps/build-gcc-linux-stage2 XLEN=
+endif
 
 $(addprefix src/original-,$(PACKAGES)):
 	mkdir -p src
@@ -58,7 +79,7 @@ stamps/build-binutils-linux: src/binutils
 		--target=riscv$(XLEN)-unknown-linux-gnu \
 		--prefix=$(INSTALL_DIR) \
 		--with-sysroot=$(SYSROOT) \
-		--disable-multilib \
+		$(MULTILIB_FLAGS) \
 		--disable-nls
 	$(MAKE) -C $(notdir $@)
 	$(MAKE) -C $(notdir $@) install
@@ -73,7 +94,7 @@ stamps/build-glibc-linux-headers: src/glibc
 	rm -rf $@ $(notdir $@)
 	mkdir $(notdir $@)
 	mkdir -p $(SYSROOT)/usr/lib $(SYSROOT)/lib
-	cd $(notdir $@) && CC= $(CURDIR)/$</configure \
+	cd $(notdir $@) && $(CURDIR)/$</configure \
 		--host=riscv$(XLEN)-unknown-linux-gnu \
 		--prefix=/usr \
 		libc_cv_forced_unwind=yes \
@@ -85,19 +106,22 @@ stamps/build-glibc-linux-headers: src/glibc
 	$(MAKE) -C $(notdir $@) install-headers install_root=$(SYSROOT)
 	mkdir -p $(dir $@) && touch $@
 
-stamps/build-glibc-linux: src/glibc stamps/build-gcc-linux-stage1
+stamps/build-glibc-linux$(XLEN): src/glibc stamps/build-gcc-linux-stage1
 	rm -rf $@ $(notdir $@)
 	mkdir $(notdir $@)
 	mkdir -p $(SYSROOT)/usr/lib $(SYSROOT)/lib
-	cd $(notdir $@) && CC= $(CURDIR)/$</configure \
+	cd $(notdir $@) && CFLAGS="$(CFLAGS_FOR_TARGET) -g -O2" \
+		ASFLAGS="$(ASFLAGS_FOR_TARGET)" \
+		$(CURDIR)/$</configure \
 		--host=riscv$(XLEN)-unknown-linux-gnu \
 		--prefix=/usr \
 		libc_cv_forced_unwind=yes \
 		libc_cv_c_cleanup=yes \
 		--enable-shared \
 		--enable-__thread \
-		--disable-multilib \
-		--enable-kernel=2.6.32
+		$(MULTILIB_FLAGS) \
+		--enable-kernel=2.6.32 \
+		$(GLIBC_CONFIGURE_FLAGS)
 	$(MAKE) -C $(notdir $@)
 	$(MAKE) -C $(notdir $@) install install_root=$(SYSROOT)
 	mkdir -p $(dir $@) && touch $@
@@ -123,7 +147,7 @@ stamps/build-gcc-linux-stage1: src/gcc stamps/build-binutils-linux \
 		--disable-libquadmath \
 		--disable-libgomp \
 		--disable-nls \
-		--disable-multilib \
+		$(MULTILIB_FLAGS) \
 		--disable-bootstrap
 	$(MAKE) -C $(notdir $@) inhibit-libc=true all-gcc
 	$(MAKE) -C $(notdir $@) inhibit-libc=true install-gcc
@@ -131,7 +155,7 @@ stamps/build-gcc-linux-stage1: src/gcc stamps/build-binutils-linux \
 	$(MAKE) -C $(notdir $@) inhibit-libc=true install-target-libgcc
 	mkdir -p $(dir $@) && touch $@
 
-stamps/build-gcc-linux-stage2: src/gcc stamps/build-glibc-linux
+stamps/build-gcc-linux-stage2: src/gcc stamps/build-glibc-linux$(XLEN)
 	rm -rf $@ $(notdir $@)
 	mkdir $(notdir $@)
 	cd $(notdir $@) && $(CURDIR)/$</configure \
@@ -145,7 +169,7 @@ stamps/build-gcc-linux-stage2: src/gcc stamps/build-glibc-linux
 		--disable-libssp \
 		--disable-libquadmath \
 		--disable-nls \
-		--disable-multilib \
+		$(MULTILIB_FLAGS) \
 		--disable-bootstrap
 	$(MAKE) -C $(notdir $@)
 	$(MAKE) -C $(notdir $@) install
diff --git a/README.md b/README.md
index 7b1f668e..0529e84d 100644
--- a/README.md
+++ b/README.md
@@ -51,3 +51,18 @@ run the following command:
     ./configure --prefix=/opt/riscv
     make linux
 
+### Installation (Linux multilib)
+
+To build the Linux cross-compiler with support for both 32-bit and
+64-bit, run the following commands:
+
+    ./configure --prefix=/opt/riscv --enable-multilib
+    make linux
+
+The multilib compiler will have the prefix riscv-unknown-linux-gnu-,
+rather than the usual prefix (riscv32-... or riscv64-...).
+
+### Advanced Options
+
+There are a number of additional options that may be passed to
+configure.  See './configure --help' for more details.
diff --git a/configure b/configure
index a38d4e62..ac9f41cd 100755
--- a/configure
+++ b/configure
@@ -584,6 +584,11 @@ PACKAGE_URL=''
 
 ac_subst_vars='LTLIBOBJS
 LIBOBJS
+multilib_flags
+glibc_configure_flags
+float_asflags
+float_cflags
+atomic_cflags
 XLEN
 default_target
 FETCHER
@@ -645,6 +650,9 @@ ac_user_opts='
 enable_option_checking
 enable_linux
 with_xlen
+enable_atomic
+enable_float
+enable_multilib
 '
       ac_precious_vars='build_alias
 host_alias
@@ -1265,6 +1273,12 @@ Optional Features:
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
   --enable-linux          set linux as the default make target
                           [--disable-linux]
+  --disable-atomic        disable use of atomic memory instructions in glibc
+                          [--enable-atomic]
+  --disable-float         use software floating point in glibc
+                          [--enable-float]
+  --enable-multilib       build multilib glibc (32 and 64 bit)
+                          [--disable-multilib]
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -3126,6 +3140,56 @@ else
 fi
 
 
+# Check whether --enable-atomic was given.
+if test "${enable_atomic+set}" = set; then :
+  enableval=$enable_atomic;
+else
+  enable_atomic=yes
+
+fi
+
+
+if test "x$enable_atomic" != xno; then :
+
+else
+  atomic_cflags=-mno-atomic
+
+fi
+
+# Check whether --enable-float was given.
+if test "${enable_float+set}" = set; then :
+  enableval=$enable_float;
+else
+  enable_float=yes
+
+fi
+
+
+if test "x$enable_float" != xno; then :
+
+else
+  float_cflags=-msoft-float
+float_asflags=-msoft-float
+glibc_configure_flags=--without-fp
+
+fi
+
+# Check whether --enable-multilib was given.
+if test "${enable_multilib+set}" = set; then :
+  enableval=$enable_multilib;
+else
+  enable_multilib=no
+
+fi
+
+
+if test "x$enable_multilib" != xno; then :
+
+else
+  multilib_flags=--disable-multilib
+
+fi
+
 ac_config_files="$ac_config_files Makefile"
 
 ac_config_files="$ac_config_files scripts/wrapper/awk"
diff --git a/configure.ac b/configure.ac
index 185239fe..2f2254c5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -54,6 +54,41 @@ AC_ARG_WITH(xlen,
 	AC_SUBST(XLEN, 64)
 	)
 
+AC_ARG_ENABLE(atomic,
+	[AS_HELP_STRING([--disable-atomic],
+		[disable use of atomic memory instructions in glibc @<:@--enable-atomic@:>@])],
+	[],
+	[enable_atomic=yes]
+	)
+
+AS_IF([test "x$enable_atomic" != xno],
+        [],
+	[AC_SUBST(atomic_cflags,-mno-atomic)])
+
+AC_ARG_ENABLE(float,
+	[AS_HELP_STRING([--disable-float],
+		[use software floating point in glibc @<:@--enable-float@:>@])],
+	[],
+	[enable_float=yes]
+	)
+
+AS_IF([test "x$enable_float" != xno],
+	    [],
+	    [AC_SUBST(float_cflags,-msoft-float)dnl
+AC_SUBST(float_asflags,-msoft-float)dnl
+AC_SUBST(glibc_configure_flags,--without-fp)])
+
+AC_ARG_ENABLE(multilib,
+	[AS_HELP_STRING([--enable-multilib],
+		[build multilib glibc (32 and 64 bit) @<:@--disable-multilib@:>@])],
+	[],
+	[enable_multilib=no]
+	)
+
+AS_IF([test "x$enable_multilib" != xno],
+        [AC_SUBST(multilib_flags,)],
+	[AC_SUBST(multilib_flags,--disable-multilib)])
+
 AC_CONFIG_FILES([Makefile])
 AC_CONFIG_FILES([scripts/wrapper/awk], [chmod +x scripts/wrapper/awk])
 AC_CONFIG_FILES([scripts/wrapper/sed], [chmod +x scripts/wrapper/sed])