Preliminary EFI support. Based, in part, on patches from Andy Turner.

Add support for being able to boot off both UEFI and BIOS firmware,
ala the memstick trick.

Add support for writing to GPT volumes.

Move away from using bsd labels at all for these embedded stuff.

Minor tweaks to README.

tools/tools/nanobsd/embedded/README

@@ -10,8 +10,6 @@ and DHCPd.
 This is a work in progress. Generally, to build this you should
      cd tools/tools/nanobsd/embedded
      sudo sh ../nanobsd.sh -c foo.cfg
-but do be careful if things are interrupted. There may still be
-bugs lurking that cause your entire FreeBSD tree to disappear.
 
 Some features:
 

tools/tools/nanobsd/embedded/common

@@ -76,6 +76,8 @@ fi
 NANO_SLICE_FAT_SIZE=32m
 NANO_SLICE_CFG_SIZE=32m
 
+NANO_BOOT2CFG="-D -h -S115200 comconsole_port=0x3e8"
+
 NANO_RAM_ETCSIZE=8192
 NANO_RAM_TMPVARSIZE=8192
 NANO_IMAGES=2
@@ -292,7 +294,7 @@ create_diskimage_mbr ( ) (
 	bootbsd=${NANO_BOOT_BSD:+-b ${NANO_BOOT_BSD}}
 	skiparg=${NANO_MBR_FIRST_SKIP:+-S ${NANO_MBR_FIRST_SKIP}}
 
-	for i in s1 s2 s3 s4 empty; do
+	for i in s1 s2 s3 s4 p1 p2 p3 p4 p5 empty; do
 		rm -fr ${NANO_OBJ}/_.${i}*
 	done
 
@@ -317,10 +319,10 @@ create_diskimage_mbr ( ) (
 	# bsd label
 	[ -z ${NANO_NOPRIV_BUILD} ] || extra="-F ${NANO_METALOG}"
 	sz=${NANO_SLICE_ROOT_SIZE:+-s ${NANO_SLICE_ROOT_SIZE}}
-	eval "${NANO_MAKEFS_UFS}" ${extra} $sz "${NANO_OBJ}/_.${NANO_SLICE_ROOT}a" \
+	eval "${NANO_MAKEFS_UFS}" ${extra} $sz "${NANO_OBJ}/_.${NANO_SLICE_ROOT}" \
 		"${NANO_WORLDDIR}"
-	mkimg -s bsd ${bootbsd} -p freebsd-ufs:=${NANO_OBJ}/_.${NANO_SLICE_ROOT}a \
-		-o ${NANO_OBJ}/_.${NANO_SLICE_ROOT}
+#	mkimg -s bsd ${bootbsd} -p freebsd-ufs:=${NANO_OBJ}/_.${NANO_SLICE_ROOT} \
+#		-o ${NANO_OBJ}/_.${NANO_SLICE_ROOT}
 
 	# Populate the /cfg partition, empty if none given
 	if [ -z "${NANO_CFGDIR}" ]; then
@@ -339,8 +341,18 @@ create_diskimage_mbr ( ) (
 	if [ -n "$NANO_SLICE_FAT" ]; then
 		eval $NANO_SLICE_FAT=fat16b
 	fi
-	eval $NANO_SLICE_CFG=freebsd
-	eval $NANO_SLICE_ROOT=freebsd
+	case ${NANO_SLICE_CFG} in
+	s*)
+	echo slice
+		eval $NANO_SLICE_CFG=freebsd
+		eval $NANO_SLICE_ROOT=freebsd
+		;;
+	p*)
+	echo part
+		eval $NANO_SLICE_CFG=freebsd-ufs
+		eval $NANO_SLICE_ROOT=freebsd-ufs
+		;;
+	esac
 	# below depends on https://reviews.freebsd.org/D4403 not yet in the tree
 	# but there's problems: it marks all partitions as active, so you have to
 	# boot off parittion 3 or 2 by hand if you're playing around with this WIP
@@ -358,6 +370,25 @@ create_diskimage_mbr ( ) (
 			-p ${s2}:=${NANO_OBJ}/_.s2 \
 			-o ${NANO_OBJ}/_.disk.image.${NANO_NAME}${fmt}
 		;;
+	std-uefi)
+		# s1 is boot, s2 is cfg, s3 is /, not sure how to make that
+		# boot (marked as active) with mkimg yet
+		mkimg -a 2 ${fmtarg} ${bootmbr} -s mbr \
+			-p efi:=${NANO_WORLDDIR}/boot/boot1.efifat \
+			-p ${s2}:=${NANO_OBJ}/_.s2 \
+			-p ${s3}:=${NANO_OBJ}/_.s3 \
+			-o ${NANO_OBJ}/_.disk.image.${NANO_NAME}${fmt}
+		;;
+	std-uefi-bios)
+		# p1 is boot for uefi, p2 is boot for gpt, p3 is cfg, p4 is /
+		# and p5 is alt-root (after resize)
+		mkimg -a 2 ${fmtarg} ${bootmbr} -s gpt \
+			-p efi:=${NANO_WORLDDIR}/boot/boot1.efifat \
+			-p freebsd-boot:=${NAANO_WORLDDIR}/boot/gptboot \
+			-p ${p3}:=${NANO_OBJ}/_.p3 \
+			-p ${p4}:=${NANO_OBJ}/_.p4 \
+			-o ${NANO_OBJ}/_.disk.image.${NANO_NAME}${fmt}
+		;;
 	powerpc64-ibm)
 		# A lie to make the boot loader work, it boots the first BSD partition
 		# it finds, regardless of the active flag.
@@ -658,6 +689,19 @@ powerpc64-apple)
 	echo Not yet
 	exit 1
 	;;
+std-uefi)
+	NANO_SLICE_UEFI=s1
+	NANO_SLICE_CFG=s2
+	NANO_SLICE_ROOT=s3
+	NANO_SLICE_ALTROOT=s4
+	;;
+std-uefi-bios)
+	NANO_SLICE_UEFI=p1
+	NANO_SLICE_BOOT=p2
+	NANO_SLICE_CFG=p3
+	NANO_SLICE_ROOT=p4
+	NANO_SLICE_ALTROOT=p5
+	;;
 *)
 	echo Unknown Layout ${NANO_LAYOUT}
 	exit 1