[build] Do not use "objcopy -O binary" for objects with relocation re…

…cords The mbr.bin and usbdisk.bin standalone blobs are currently generated using "objcopy -O binary", which does not process relocation records. For the i386 build, this does not matter since the section start address is zero and so the ".rel" relocation records are effectively no-ops anyway. For the x86_64 build, the ".rela" relocation records are not no-ops, since the addend is included as part of the relocation record (rather than inline). Using "objcopy -O binary" will silently discard the relocation records, with the result that all symbols are effectively given a value of zero. Fix by using "ld --oformat binary" instead of "objcopy -O binary" to generate mbr.bin and usbdisk.bin. Signed-off-by: Michael Brown <mcb30@ipxe.org>
ipxe · Mar 21, 2016 · 1afcccd · 1afcccd
1 parent 173c0c2
commit 1afcccd
Showing 1 changed file with 8 additions and 4 deletions.
diff --git a/src/arch/x86/Makefile.pcbios b/src/arch/x86/Makefile.pcbios
@@ -12,6 +12,10 @@ LDSCRIPT	= arch/x86/scripts/pcbios.lds
 #
 LDFLAGS		+= -N --no-check-sections
 
+# Prefix always starts at address zero
+#
+LDFLAGS		+= --section-start=.prefix=0
+
 # Media types.
 #
 MEDIA		+= rom
@@ -103,13 +107,13 @@ NON_AUTO_MEDIA	+= fd0
 
 # Special target for building Master Boot Record binary
 $(BIN)/mbr.bin : $(BIN)/mbr.o
-	$(QM)$(ECHO) "  [OBJCOPY] $@"
-	$(Q)$(OBJCOPY) -O binary $< $@
+	$(QM)$(ECHO) "  [LD] $@"
+	$(Q)$(LD) $(LDFLAGS) -o $@ --oformat binary -e 0 $<
 
 # rule to make a USB disk image
 $(BIN)/usbdisk.bin : $(BIN)/usbdisk.o
-	$(QM)$(ECHO) "  [OBJCOPY] $@"
-	$(Q)$(OBJCOPY) -O binary $< $@
+	$(QM)$(ECHO) "  [LD] $@"
+	$(Q)$(LD) $(LDFLAGS) -o $@ --oformat binary -e 0 $<
 
 NON_AUTO_MEDIA	+= usb
 %usb: $(BIN)/usbdisk.bin %hd