Merge tag 'x86-build-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 build updates from Ingo Molnar:

 - Drop CRC-32 checksum and the build tool that generates it (Ard
   Biesheuvel)

 - Fix broken copy command in genimage.sh when making isoimage (Nir
   Lichtman)

* tag 'x86-build-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Add back some padding for the CRC-32 checksum
  x86/boot: Drop CRC-32 checksum and the build tool that generates it
  x86/build: Fix broken copy command in genimage.sh when making isoimage

Author: torvalds

Documentation/arch/x86/boot.rst

@@ -1038,16 +1038,6 @@ Offset/size:	0x000c/4
   This field contains maximal allowed type for setup_data and setup_indirect structs.
 
 
-The Image Checksum
-==================
-
-From boot protocol version 2.08 onwards the CRC-32 is calculated over
-the entire file using the characteristic polynomial 0x04C11DB7 and an
-initial remainder of 0xffffffff.  The checksum is appended to the
-file; therefore the CRC of the file up to the limit specified in the
-syssize field of the header is always 0.
-
-
 The Kernel Command Line
 =======================
 

arch/x86/boot/Makefile

@@ -35,7 +35,6 @@ setup-y		+= video-vesa.o
 setup-y		+= video-bios.o
 
 targets		+= $(setup-y)
-hostprogs	:= tools/build
 hostprogs	+= mkcpustr
 
 HOST_EXTRACFLAGS += -I$(srctree)/tools/include \
@@ -61,11 +60,9 @@ KBUILD_CFLAGS	+= $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
 $(obj)/bzImage: asflags-y  := $(SVGA_MODE)
 
 quiet_cmd_image = BUILD   $@
-silent_redirect_image = >/dev/null
-cmd_image = $(obj)/tools/build $(obj)/setup.bin $(obj)/vmlinux.bin \
-			       $(obj)/zoffset.h $@ $($(quiet)redirect_image)
+      cmd_image = cp $< $@; truncate -s %4K $@; cat $(obj)/vmlinux.bin >>$@
 
-$(obj)/bzImage: $(obj)/setup.bin $(obj)/vmlinux.bin $(obj)/tools/build FORCE
+$(obj)/bzImage: $(obj)/setup.bin $(obj)/vmlinux.bin FORCE
 	$(call if_changed,image)
 	@$(kecho) 'Kernel: $@ is ready' ' (#'$(or $(KBUILD_BUILD_VERSION),`cat .version`)')'
 

arch/x86/boot/compressed/vmlinux.lds.S

@@ -48,7 +48,7 @@ SECTIONS
 		*(.data)
 		*(.data.*)
 
-		/* Add 4 bytes of extra space for a CRC-32 checksum */
+		/* Add 4 bytes of extra space for the obsolete CRC-32 checksum */
 		. = ALIGN(. + 4, 0x200);
 		_edata = . ;
 	}

arch/x86/boot/genimage.sh

@@ -22,6 +22,7 @@
 # This script requires:
 #   bash
 #   syslinux
+#   genisoimage
 #   mtools (for fdimage* and hdimage)
 #   edk2/OVMF (for hdimage)
 #
@@ -251,7 +252,9 @@ geniso() {
 	cp "$isolinux" "$ldlinux" "$tmp_dir"
 	cp "$FBZIMAGE" "$tmp_dir"/linux
 	echo default linux "$KCMDLINE" > "$tmp_dir"/isolinux.cfg
-	cp "${FDINITRDS[@]}" "$tmp_dir"/
+	if [ ${#FDINITRDS[@]} -gt 0 ]; then
+		cp "${FDINITRDS[@]}" "$tmp_dir"/
+	fi
 	genisoimage -J -r -appid 'LINUX_BOOT' -input-charset=utf-8 \
 		    -quiet -o "$FIMAGE" -b isolinux.bin \
 		    -c boot.cat -no-emul-boot -boot-load-size 4 \

arch/x86/boot/setup.ld

@@ -45,6 +45,8 @@ SECTIONS
 
 		setup_size = ALIGN(ABSOLUTE(.), 4096);
 		setup_sects = ABSOLUTE(setup_size / 512);
+		ASSERT(setup_sects >= 5, "The setup must be at least 5 sectors in size");
+		ASSERT(setup_sects <= 64, "The setup must be at most 64 sectors in size");
 	}
 
 	. = ALIGN(16);