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The image generation scripts in arch/x86/boot are pretty out of date,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

Author: H. Peter Anvin (Intel)

arch/x86/Makefile

@@ -256,7 +256,7 @@ drivers-$(CONFIG_FB) += arch/x86/video/
 
 boot := arch/x86/boot
 
-BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
+BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
 
 PHONY += bzImage $(BOOT_TARGETS)
 
@@ -314,8 +314,9 @@ define archhelp
   echo  '  fdimage		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
   echo  '  fdimage144		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
   echo  '  fdimage288		- Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
+  echo  '  hdimage		- Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
   echo  '  isoimage		- Create a boot CD-ROM image (arch/x86/boot/image.iso)'
-  echo  '			  bzdisk/fdimage*/isoimage also accept:'
+  echo  '			  bzdisk/fdimage*/hdimage/isoimage also accept:'
   echo  '			  FDARGS="..."  arguments for the booted kernel'
   echo  '                  	  FDINITRD=file initrd for the booted kernel'
   echo  ''

arch/x86/boot/.gitignore

@@ -11,3 +11,4 @@ setup.elf
 fdimage
 mtools.conf
 image.iso
+hdimage

arch/x86/boot/Makefile

@@ -29,7 +29,7 @@ KCOV_INSTRUMENT		:= n
 SVGA_MODE	:= -DSVGA_MODE=NORMAL_VGA
 
 targets		:= vmlinux.bin setup.bin setup.elf bzImage
-targets		+= fdimage fdimage144 fdimage288 image.iso mtools.conf
+targets		+= fdimage fdimage144 fdimage288 image.iso hdimage
 subdir-		:= compressed
 
 setup-y		+= a20.o bioscall.o cmdline.o copy.o cpu.o cpuflags.o cpucheck.o
@@ -115,47 +115,49 @@ $(obj)/compressed/vmlinux: FORCE
 	$(Q)$(MAKE) $(build)=$(obj)/compressed $@
 
 # Set this if you want to pass append arguments to the
-# bzdisk/fdimage/isoimage kernel
+# bzdisk/fdimage/hdimage/isoimage kernel
 FDARGS =
-# Set this if you want an initrd included with the
-# bzdisk/fdimage/isoimage kernel
+# Set this if you want one or more initrds included in the image
 FDINITRD =
 
-image_cmdline = default linux $(FDARGS) $(if $(FDINITRD),initrd=initrd.img,)
+imgdeps = $(obj)/bzImage $(obj)/mtools.conf $(src)/genimage.sh
 
 $(obj)/mtools.conf: $(src)/mtools.conf.in
 	sed -e 's|@OBJ@|$(obj)|g' < $< > $@
 
+targets += mtools.conf
+
+# genimage.sh requires bash, but it also has a bunch of other
+# external dependencies.
 quiet_cmd_genimage = GENIMAGE $3
-cmd_genimage = sh $(srctree)/$(src)/genimage.sh $2 $3 $(obj)/bzImage \
-			$(obj)/mtools.conf '$(image_cmdline)' $(FDINITRD)
+cmd_genimage = $(BASH) $(srctree)/$(src)/genimage.sh $2 $3 $(obj)/bzImage \
+		$(obj)/mtools.conf '$(FDARGS)' $(FDINITRD)
 
-PHONY += bzdisk fdimage fdimage144 fdimage288 isoimage bzlilo install
+PHONY += bzdisk fdimage fdimage144 fdimage288 hdimage isoimage install
 
 # This requires write access to /dev/fd0
-bzdisk: $(obj)/bzImage $(obj)/mtools.conf
+# All images require syslinux to be installed; hdimage also requires
+# EDK2/OVMF if the kernel is compiled with the EFI stub.
+bzdisk: $(imgdeps)
 	$(call cmd,genimage,bzdisk,/dev/fd0)
 
-# These require being root or having syslinux 2.02 or higher installed
-fdimage fdimage144: $(obj)/bzImage $(obj)/mtools.conf
+fdimage fdimage144: $(imgdeps)
 	$(call cmd,genimage,fdimage144,$(obj)/fdimage)
 	@$(kecho) 'Kernel: $(obj)/fdimage is ready'
 
-fdimage288: $(obj)/bzImage $(obj)/mtools.conf
+fdimage288: $(imgdeps)
 	$(call cmd,genimage,fdimage288,$(obj)/fdimage)
 	@$(kecho) 'Kernel: $(obj)/fdimage is ready'
 
-isoimage: $(obj)/bzImage
+hdimage: $(imgdeps)
+	$(call cmd,genimage,hdimage,$(obj)/hdimage)
+	@$(kecho) 'Kernel: $(obj)/hdimage is ready'
+
+isoimage: $(imgdeps)
 	$(call cmd,genimage,isoimage,$(obj)/image.iso)
 	@$(kecho) 'Kernel: $(obj)/image.iso is ready'
 
-bzlilo:
-	if [ -f $(INSTALL_PATH)/vmlinuz ]; then mv $(INSTALL_PATH)/vmlinuz $(INSTALL_PATH)/vmlinuz.old; fi
-	if [ -f $(INSTALL_PATH)/System.map ]; then mv $(INSTALL_PATH)/System.map $(INSTALL_PATH)/System.old; fi
-	cat $(obj)/bzImage > $(INSTALL_PATH)/vmlinuz
-	cp System.map $(INSTALL_PATH)/
-	if [ -x /sbin/lilo ]; then /sbin/lilo; else /etc/lilo/install; fi
-
 install:
-	sh $(srctree)/$(src)/install.sh $(KERNELRELEASE) $(obj)/bzImage \
+	$(CONFIG_SHELL) $(srctree)/$(src)/install.sh \
+		$(KERNELRELEASE) $(obj)/bzImage \
 		System.map "$(INSTALL_PATH)"