Re: bootloader support for DTB on x86

@@ -161,6 +161,9 @@ endif
 	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
 	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
 
+bzImage.%: vmlinux
+	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+
 $(BOOT_TARGETS): vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) $@
 

@@ -177,6 +180,9 @@ archclean:
 	$(Q)rm -rf $(objtree)/arch/x86_64
 	$(Q)$(MAKE) $(clean)=$(boot)
 
+%.dtb:
+	$(Q)$(MAKE) $(build)=$(boot) $@
+
 define archhelp
   echo  '* bzImage      - Compressed kernel image (arch/x86/boot/bzImage)'
   echo  '  install      - Install kernel using'

@@ -72,20 +72,30 @@ KBUILD_CFLAGS	+= $(call cc-option, -m32)
 KBUILD_AFLAGS	:= $(KBUILD_CFLAGS) -D__ASSEMBLY__
 GCOV_PROFILE := n
 
-$(obj)/bzImage: asflags-y  := $(SVGA_MODE)
+$(obj)/bzImage $(obj)/bzImage.%: asflags-y  := $(SVGA_MODE)
 
 quiet_cmd_image = BUILD   $@
-cmd_image = $(obj)/tools/build $(obj)/setup.bin $(obj)/vmlinux.bin \
+cmd_image = $(obj)/tools/build $(obj)/setup.bin $2 \
 	$(ROOT_DEV) > $@
 
 $(obj)/bzImage: $(obj)/setup.bin $(obj)/vmlinux.bin $(obj)/tools/build FORCE
-	$(call if_changed,image)
+	$(call if_changed,image, $(obj)/vmlinux.bin)
+	@echo 'Kernel: $@ is ready' ' (#'`cat .version`')'
+
+$(obj)/bzImage.%: $(obj)/setup.bin $(obj)/vmlinux.bin.% $(obj)/tools/build FORCE
+	$(call if_changed,image,$(obj)/vmlinux.bin.$*)
 	@echo 'Kernel: $@ is ready' ' (#'`cat .version`')'
 
 OBJCOPYFLAGS_vmlinux.bin := -O binary -R .note -R .comment -S
 $(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE
 	$(call if_changed,objcopy)
 
+quiet_cmd_objcopybin = OBJCOPY $@
+      cmd_objcopybin = $(OBJCOPY) $(OBJCOPYFLAGS) -O binary -R .note -R .comment -S $< $@
+
+$(obj)/vmlinux.bin.%: $(obj)/compressed/vmlinux.dtb.% FORCE
+	$(call if_changed,objcopybin)
+
 SETUP_OBJS = $(addprefix $(obj)/,$(setup-y))
 
 sed-voffset := -e 's/^\([0-9a-fA-F]*\) . \(_text\|_end\)$$/\#define VO_\2 0x\1/p'

@@ -121,6 +131,19 @@ $(obj)/setup.bin: $(obj)/setup.elf FORCE
 $(obj)/compressed/vmlinux: FORCE
 	$(Q)$(MAKE) $(build)=$(obj)/compressed $@
 
+$(obj)/compressed/vmlinux.dtb.%: FORCE
+	$(Q)$(MAKE) $(build)=$(obj)/compressed $@
+
+dtstree		:= $(srctree)/$(src)/dts
+DTC = $(objtree)/scripts/dtc/dtc
+
+quiet_cmd_dtc = DTC	$@
+	cmd_dtc = $(DTC) -O dtb -o $(obj)/$*.dtb -b 0 -p 1024 $(dtstree)/$*.dts
+
+# Rule to build device tree blobs
+$(obj)/%.dtb: $(dtstree)/%.dts FORCE
+	$(call if_changed,dtc)
+
 # Set this if you want to pass append arguments to the
 # bzdisk/fdimage/isoimage kernel
 FDARGS =

@@ -18,15 +18,34 @@ KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector)
 KBUILD_AFLAGS  := $(KBUILD_CFLAGS) -D__ASSEMBLY__
 GCOV_PROFILE := n
 
-LDFLAGS := -m elf_$(UTS_MACHINE)
-LDFLAGS_vmlinux := -T
+LDFLAGS := -m elf_$(UTS_MACHINE) -T
 
 hostprogs-y	:= mkpiggy
 
-$(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o $(obj)/string.o $(obj)/cmdline.o $(obj)/early_serial_console.o $(obj)/piggy.o FORCE
+VMLINUX_DEP	:= $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o $(obj)/string.o $(obj)/cmdline.o $(obj)/early_serial_console.o $(obj)/piggy.o
+
+$(obj)/vmlinux: $(VMLINUX_DEP) FORCE
+	$(call if_changed,ld)
+	@:
+
+dtstree		:= $(srctree)/arch/x86/boot/dts
+DTC = $(objtree)/scripts/dtc/dtc
+
+quiet_cmd_dtc = DTC	$@
+      cmd_dtc = $(DTC) -O dtb -o $(obj)/$*.dtb -b 0 -p 1024 $(dtstree)/$*.dts
+
+$(obj)/%.dtb: $(dtstree)/%.dts
+	$(call if_changed,dtc)
+
+$(obj)/%.dtb.S: $(obj)/%.dtb
+	@echo '.section .data..dtb,"a"' > $@
+	@echo '.incbin "$<" ' >> $@
+
+$(obj)/vmlinux.dtb.%: $(VMLINUX_DEP) $(obj)/%.dtb.o FORCE
 	$(call if_changed,ld)
 	@:
 
+targets += vmlinux.dtb.%
 OBJCOPYFLAGS_vmlinux.bin :=  -R .comment -S
 $(obj)/vmlinux.bin: vmlinux FORCE
 	$(call if_changed,objcopy)

@@ -101,7 +101,8 @@
 #undef memcpy
 #define memzero(s, n)	memset((s), 0, (n))
 
-
+extern char _dtb_end[];
+extern char _dtb_start[];
 static void error(char *m);
 
 /*

@@ -302,6 +303,40 @@ static void parse_elf(void *output)
 	}
 }
 
+static u64 attach_initdata(u64 old_sd, void *dest, void *data, unsigned int len,
+		unsigned int type)
+{
+	struct setup_data *sd = dest;
+
+	sd->next = old_sd;
+	sd->type = type;
+	sd->len = len;
+	memcpy(&sd->data[0], data, len);
+	return (u64) (u32) sd;
+}
+
+static u64 attach_dtb(u64 old_sd, void *dest, void *data, unsigned int len)
+{
+	return attach_initdata(old_sd, dest, data, len, SETUP_DTB);
+}
+
+static int dtb_passed(u64 setup_data)
+{
+	int ret = 0;
+
+	while (setup_data) {
+		struct setup_data *sdata;
+
+		sdata = (void *)(u32)setup_data;
+		if (sdata->type == SETUP_DTB) {
+			ret = 1;
+			break;
+		}
+		setup_data = sdata->next;
+	}
+	return ret;
+}
+
 asmlinkage void decompress_kernel(void *rmode, memptr heap,
 				  unsigned char *input_data,
 				  unsigned long input_len,

@@ -350,6 +385,29 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
 		putstr("\nDecompressing Linux... ");
 	decompress(input_data, input_len, NULL, NULL, output, NULL, error);
 	parse_elf(output);
+	if (_dtb_end > _dtb_start && !dtb_passed(real_mode->hdr.setup_data)) {
+		u32 k_dtb;
+
+		if (real_mode->hdr.ramdisk_image)
+			k_dtb = real_mode->hdr.ramdisk_image;
+		else {
+			k_dtb = real_mode->alt_mem_k;
+			k_dtb++;
+			k_dtb *= 1024;
+		}
+		if (k_dtb > 128 * 1024 * 1024)
+			k_dtb = 128 * 1024 * 1024;
+		k_dtb -= (_dtb_end -  _dtb_start);
+		if (!IS_ALIGNED(k_dtb, 4096)) {
+			/* align down */
+			k_dtb = ALIGN(k_dtb, 4096);
+			k_dtb -= 4096;
+		}
+		real_mode->hdr.setup_data =
+			attach_dtb(real_mode->hdr.setup_data, (void *)k_dtb,
+					_dtb_start, _dtb_end - _dtb_start);
+	}
+
 	if (!quiet)
 		putstr("done.\nBooting the kernel.\n");
 	return;

@@ -41,6 +41,13 @@ SECTIONS
 		*(.rodata.*)
 		_erodata = . ;
 	}
+
+	_dtb_start = .;
+	.data..dtb : {
+		*(.data..dtb)
+	}
+	_dtb_end = . ;
+
 	.got : {
 		_got = .;
 		KEEP(*(.got.plt))