x86/boot: Modernize genimage script; hdimage+EFI support

The image generation scripts in arch/x86/boot are pretty out of date,
except for the isoimage target. Update and clean up the
genimage.sh script, and make it support an arbitrary number of
initramfs files in the image.

Add a "hdimage" target, which can be booted by either BIOS or
EFI (if the kernel is compiled with the EFI stub.) For EFI to be able
to pass the command line to the kernel, we need the EFI shell, but the
firmware builtin EFI shell, if it even exists, is pretty much always
the last resort boot option, so search for OVMF or EDK2 and explicitly
include a copy of the EFI shell.

To make this all work, use bash features in the script.  Furthermore,
this version of the script makes use of some mtools features,
especially mpartition, that might not exist in very old version of
mtools, but given all the other dependencies on this script this
doesn't seem such a big deal.

Finally, put a volume label ("LINUX_BOOT") on all generated images.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210510082840.628372-1-hpa@zytor.com

1 files changed, 222 insertions, 81 deletions

diff --git a/arch/x86/boot/genimage.sh b/arch/x86/boot/genimage.sh
index 6a10d52a4145..0673fdfc1a11 100644
--- a/arch/x86/boot/genimage.sh
+++ b/arch/x86/boot/genimage.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 # This file is subject to the terms and conditions of the GNU General Public
 # License.  See the file "COPYING" in the main directory of this archive
@@ -8,15 +8,24 @@
 #
 # Adapted from code in arch/x86/boot/Makefile by H. Peter Anvin and others
 #
-# "make fdimage/fdimage144/fdimage288/isoimage" script for x86 architecture
+# "make fdimage/fdimage144/fdimage288/hdimage/isoimage"
+# script for x86 architecture
 #
 # Arguments:
-#   $1 - fdimage format
-#   $2 - target image file
-#   $3 - kernel bzImage file
-#   $4 - mtool configuration file
-#   $5 - kernel cmdline
-#   $6 - inird image file
+#   $1  - fdimage format
+#   $2  - target image file
+#   $3  - kernel bzImage file
+#   $4  - mtools configuration file
+#   $5  - kernel cmdline
+#   $6+ - initrd image file(s)
+#
+# This script requires:
+#   bash
+#   syslinux
+#   mtools (for fdimage* and hdimage)
+#   edk2/OVMF (for hdimage)
+#
+# Otherwise try to stick to POSIX shell commands...
 #
 
 # Use "make V=1" to debug this script
@@ -26,105 +35,237 @@ case "${KBUILD_VERBOSE}" in
         ;;
 esac
 
-verify () {
-	if [ ! -f "$1" ]; then
-		echo ""                                                   1>&2
-		echo " *** Missing file: $1"                              1>&2
-		echo ""                                                   1>&2
-		exit 1
+# Exit the top-level shell with an error
+topshell=$$
+trap 'exit 1' USR1
+die() {
+	echo ""        1>&2
+	echo " *** $*" 1>&2
+	echo ""        1>&2
+	kill -USR1 $topshell
+}
+
+# Verify the existence and readability of a file
+verify() {
+	if [ ! -f "$1" -o ! -r "$1" ]; then
+		die "Missing file: $1"
 	fi
 }
 
+diskfmt="$1"
+FIMAGE="$2"
+FBZIMAGE="$3"
+MTOOLSRC="$4"
+KCMDLINE="$5"
+shift 5				# Remaining arguments = initrd files
+
+export MTOOLSRC
 
-export MTOOLSRC=$4
-FIMAGE=$2
-FBZIMAGE=$3
-KCMDLINE=$5
-FDINITRD=$6
+# common options for dd
+dd='dd iflag=fullblock'
 
 # Make sure the files actually exist
 verify "$FBZIMAGE"
 
-genbzdisk() {
-	verify "$MTOOLSRC"
-	mformat a:
-	syslinux $FIMAGE
-	echo "$KCMDLINE" | mcopy - a:syslinux.cfg
-	if [ -f "$FDINITRD" ] ; then
-		mcopy "$FDINITRD" a:initrd.img
+declare -a FDINITRDS
+irdpfx=' initrd='
+initrdopts_syslinux=''
+initrdopts_efi=''
+for f in "$@"; do
+	if [ -f "$f" -a -r "$f" ]; then
+	    FDINITRDS=("${FDINITRDS[@]}" "$f")
+	    fname="$(basename "$f")"
+	    initrdopts_syslinux="${initrdopts_syslinux}${irdpfx}${fname}"
+	    irdpfx=,
+	    initrdopts_efi="${initrdopts_efi} initrd=${fname}"
 	fi
-	mcopy $FBZIMAGE a:linux
+done
+
+# Read a $3-byte littleendian unsigned value at offset $2 from file $1
+le() {
+	local n=0
+	local m=1
+	for b in $(od -A n -v -j $2 -N $3 -t u1 "$1"); do
+		n=$((n + b*m))
+		m=$((m * 256))
+	done
+	echo $n
 }
 
-genfdimage144() {
-	verify "$MTOOLSRC"
-	dd if=/dev/zero of=$FIMAGE bs=1024 count=1440 2> /dev/null
-	mformat v:
-	syslinux $FIMAGE
-	echo "$KCMDLINE" | mcopy - v:syslinux.cfg
-	if [ -f "$FDINITRD" ] ; then
-		mcopy "$FDINITRD" v:initrd.img
-	fi
-	mcopy $FBZIMAGE v:linux
+# Get the EFI architecture name such that boot{name}.efi is the default
+# boot file name. Returns false with no output if the file is not an
+# EFI image or otherwise unknown.
+efiarch() {
+	[ -f "$1" ] || return
+	[ $(le "$1" 0 2) -eq 23117 ] || return		# MZ magic
+	peoffs=$(le "$1" 60 4)				# PE header offset
+	[ $peoffs -ge 64 ] || return
+	[ $(le "$1" $peoffs 4) -eq 17744 ] || return	# PE magic
+	case $(le "$1" $((peoffs+4+20)) 2) in		# PE type
+		267)	;;				# PE32
+		523)	;;				# PE32+
+		*) return 1 ;;				# Invalid
+	esac
+	[ $(le "$1" $((peoffs+4+20+68)) 2) -eq 10 ] || return # EFI app
+	case $(le "$1" $((peoffs+4)) 2) in		# Machine type
+		 332)	echo i386	;;
+		 450)	echo arm	;;
+		 512)	echo ia64	;;
+		20530)	echo riscv32	;;
+		20580)	echo riscv64	;;
+		20776)	echo riscv128	;;
+		34404)	echo x64	;;
+		43620)	echo aa64	;;
+	esac
 }
 
-genfdimage288() {
-	verify "$MTOOLSRC"
-	dd if=/dev/zero of=$FIMAGE bs=1024 count=2880 2> /dev/null
-	mformat w:
-	syslinux $FIMAGE
-	echo "$KCMDLINE" | mcopy - W:syslinux.cfg
-	if [ -f "$FDINITRD" ] ; then
-		mcopy "$FDINITRD" w:initrd.img
-	fi
-	mcopy $FBZIMAGE w:linux
+# Get the combined sizes in bytes of the files given, counting sparse
+# files as full length, and padding each file to a 4K block size
+filesizes() {
+	local t=0
+	local s
+	for s in $(ls -lnL "$@" 2>/dev/null | awk '/^-/{ print $5; }'); do
+		t=$((t + ((s+4095)/4096)*4096))
+	done
+	echo $t
 }
 
-geniso() {
-	tmp_dir=`dirname $FIMAGE`/isoimage
-	rm -rf $tmp_dir
-	mkdir $tmp_dir
-	for i in lib lib64 share ; do
-		for j in syslinux ISOLINUX ; do
-			if [ -f /usr/$i/$j/isolinux.bin ] ; then
-				isolinux=/usr/$i/$j/isolinux.bin
-			fi
+# Expand directory names which should be in /usr/share into a list
+# of possible alternatives
+sharedirs() {
+	local dir file
+	for dir in /usr/share /usr/lib64 /usr/lib; do
+		for file; do
+			echo "$dir/$file"
+			echo "$dir/${file^^}"
 		done
-		for j in syslinux syslinux/modules/bios ; do
-			if [ -f /usr/$i/$j/ldlinux.c32 ]; then
-				ldlinux=/usr/$i/$j/ldlinux.c32
-			fi
+	done
+}
+efidirs() {
+	local dir file
+	for dir in /usr/share /boot /usr/lib64 /usr/lib; do
+		for file; do
+			echo "$dir/$file"
+			echo "$dir/${file^^}"
 		done
-		if [ -n "$isolinux" -a -n "$ldlinux" ] ; then
-			break
+	done
+}
+
+findsyslinux() {
+	local f="$(find -L $(sharedirs syslinux isolinux) \
+		    -name "$1" -readable -type f -print -quit 2>/dev/null)"
+	if [ ! -f "$f" ]; then
+		die "Need a $1 file, please install syslinux/isolinux."
+	fi
+	echo "$f"
+	return 0
+}
+
+findovmf() {
+	local arch="$1"
+	shift
+	local -a names=(-false)
+	local name f
+	for name; do
+		names=("${names[@]}" -or -iname "$name")
+	done
+	for f in $(find -L $(efidirs edk2 ovmf) \
+			\( "${names[@]}" \) -readable -type f \
+			-print 2>/dev/null); do
+		if [ "$(efiarch "$f")" = "$arch" ]; then
+			echo "$f"
+			return 0
 		fi
 	done
-	if [ -z "$isolinux" ] ; then
-		echo 'Need an isolinux.bin file, please install syslinux/isolinux.'
-		exit 1
+	die "Need a $1 file for $arch, please install EDK2/OVMF."
+}
+
+do_mcopy() {
+	if [ ${#FDINITRDS[@]} -gt 0 ]; then
+		mcopy "${FDINITRDS[@]}" "$1"
+	fi
+	if [ -n "$efishell" ]; then
+		mmd "$1"EFI "$1"EFI/Boot
+		mcopy "$efishell" "$1"EFI/Boot/boot${kefiarch}.efi
 	fi
-	if [ -z "$ldlinux" ] ; then
-		echo 'Need an ldlinux.c32 file, please install syslinux/isolinux.'
-		exit 1
+	if [ -n "$kefiarch" ]; then
+		echo linux "$KCMDLINE$initrdopts_efi" | \
+			mcopy - "$1"startup.nsh
 	fi
-	cp $isolinux $tmp_dir
-	cp $ldlinux $tmp_dir
-	cp $FBZIMAGE $tmp_dir/linux
-	echo "$KCMDLINE" > $tmp_dir/isolinux.cfg
-	if [ -f "$FDINITRD" ] ; then
-		cp "$FDINITRD" $tmp_dir/initrd.img
+	echo default linux "$KCMDLINE$initrdopts_syslinux" | \
+		mcopy - "$1"syslinux.cfg
+	mcopy "$FBZIMAGE" "$1"linux
+}
+
+genbzdisk() {
+	verify "$MTOOLSRC"
+	mformat -v 'LINUX_BOOT' a:
+	syslinux "$FIMAGE"
+	do_mcopy a:
+}
+
+genfdimage144() {
+	verify "$MTOOLSRC"
+	$dd if=/dev/zero of="$FIMAGE" bs=1024 count=1440 2>/dev/null
+	mformat -v 'LINUX_BOOT' v:
+	syslinux "$FIMAGE"
+	do_mcopy v:
+}
+
+genfdimage288() {
+	verify "$MTOOLSRC"
+	$dd if=/dev/zero of="$FIMAGE" bs=1024 count=2880 2>/dev/null
+	mformat -v 'LINUX_BOOT' w:
+	syslinux "$FIMAGE"
+	do_mcopy w:
+}
+
+genhdimage() {
+	verify "$MTOOLSRC"
+	mbr="$(findsyslinux mbr.bin)"
+	kefiarch="$(efiarch "$FBZIMAGE")"
+	if [ -n "$kefiarch" ]; then
+		# The efishell provides command line handling
+		efishell="$(findovmf $kefiarch shell.efi shell${kefiarch}.efi)"
+		ptype='-T 0xef'	# EFI system partition, no GPT
 	fi
-	genisoimage -J -r -input-charset=utf-8 -quiet -o $FIMAGE \
-		-b isolinux.bin -c boot.cat -no-emul-boot -boot-load-size 4 \
-		-boot-info-table $tmp_dir
-	isohybrid $FIMAGE 2>/dev/null || true
-	rm -rf $tmp_dir
+	sizes=$(filesizes "$FBZIMAGE" "${FDINITRDS[@]}" "$efishell")
+	# Allow 1% + 1 MiB for filesystem and partition table overhead,
+	# syslinux, and config files
+	megs=$(((sizes + sizes/100 + 2*1024*1024 - 1)/(1024*1024)))
+	$dd if=/dev/zero of="$FIMAGE" bs=$((1024*1024)) count=$megs 2>/dev/null
+	mpartition -I -c -s 32 -h 64 -t $megs $ptype -b 512 -a h:
+	$dd if="$mbr" of="$FIMAGE" bs=440 count=1 conv=notrunc 2>/dev/null
+	mformat -v 'LINUX_BOOT' -s 32 -h 64 -t $megs h:
+	syslinux --offset $((512*512)) "$FIMAGE"
+	do_mcopy h:
+}
+
+geniso() {
+	tmp_dir="$(dirname "$FIMAGE")/isoimage"
+	rm -rf "$tmp_dir"
+	mkdir "$tmp_dir"
+	isolinux=$(findsyslinux isolinux.bin)
+	ldlinux=$(findsyslinux  ldlinux.c32)
+	cp "$isolinux" "$ldlinux" "$tmp_dir"
+	cp "$FBZIMAGE" "$tmp_dir"/linux
+	echo default linux "$KCMDLINE" > "$tmp_dir"/isolinux.cfg
+	cp "${FDINITRDS[@]}" "$tmp_dir"/
+	genisoimage -J -r -appid 'LINUX_BOOT' -input-charset=utf-8 \
+		    -quiet -o "$FIMAGE" -b isolinux.bin \
+		    -c boot.cat -no-emul-boot -boot-load-size 4 \
+		    -boot-info-table "$tmp_dir"
+	isohybrid "$FIMAGE" 2>/dev/null || true
+	rm -rf "$tmp_dir"
 }
 
-case $1 in
+rm -f "$FIMAGE"
+
+case "$diskfmt" in
 	bzdisk)     genbzdisk;;
 	fdimage144) genfdimage144;;
 	fdimage288) genfdimage288;;
+	hdimage)    genhdimage;;
 	isoimage)   geniso;;
-	*)          echo 'Unknown image format'; exit 1;
+	*)          die "Unknown image format: $diskfmt";;
 esac