linux-kernel - [PATCH 2/2] FRV: Remove the .gnu.build-id note when producing the loadable image

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Date:	Thu, 15 Dec 2011 11:11:48 +0000
From:	David Howells <dhowells@...hat.com>
To:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org
Cc:	linux-kernel@...r.kernel.org, David Howells <dhowells@...hat.com>
Subject: [PATCH 2/2] FRV: Remove the .gnu.build-id note when producing the
 loadable image

Remove the .gnu.build-id note when producing the loadable image as this is
marked Allocatable in the ELF section table and is marked as being loaded at
address 0 if the linker is recent enough to generate it:

  [ 1] .note.gnu.build-i NOTE            00000000 004000 000024 00   A  0   0  4

This is a problem for objcopying the vmlinux file to the loadable image file as
the objcopy -O binary starts writing the file from the base address of the
lowest entry in the ELF program headers table:

  LOAD           0x004000 0x00000000 0x00000000 0x00024  0x00024  R   0x4000
  LOAD           0x008000 0xc0000000 0xc0000000 0x2a6138 0x2c9e8c RWE 0x4000
  NOTE           0x004000 0x00000000 0x00000000 0x00024  0x00024  R   0x4

The kernel actually resides at 0xc0000000 and so objcopy pads the output file
between the note (at 0) and the kernel, resulting in a 3.3GB file - which
confuses things like TFTP and RedBoot (when loading raw binary data).

The old linker - which doesn't produce this note - shows this:

  LOAD           0x001000 0xc0000000 0xc0000000 0x2aa260 0x2aaa54 RWE 0x1000
  LOAD           0x2ab000 0xc02ac000 0xc02ac000 0x00000  0x21d8c  RW  0x1000

Signed-off-by: David Howells <dhowells@...hat.com>
---

 arch/frv/boot/Makefile |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)


diff --git a/arch/frv/boot/Makefile b/arch/frv/boot/Makefile
index 6ae3254..6359c49 100644
--- a/arch/frv/boot/Makefile
+++ b/arch/frv/boot/Makefile
@@ -31,19 +31,21 @@ Image: $(obj)/Image
 
 targets: $(obj)/Image
 
+REMOVE_SECTIONS	:= -R .note -R .comment -R .note.gnu.build-id
+
 $(obj)/Image: vmlinux FORCE
-	$(OBJCOPY) -O binary -R .note -R .comment -S vmlinux $@
+	$(OBJCOPY) -O binary $(REMOVE_SECTIONS) -S vmlinux $@
 
 #$(obj)/Image:	$(CONFIGURE) $(SYSTEM)
-#	$(OBJCOPY) -O binary -R .note -R .comment -g -S $(SYSTEM) $@
+#	$(OBJCOPY) -O binary $(REMOVE_SECTIONS) -g -S $(SYSTEM) $@
 
 bzImage: zImage
 
 zImage:	$(CONFIGURE) compressed/$(LINUX)
-	$(OBJCOPY) -O binary -R .note -R .comment -S compressed/$(LINUX) $@
+	$(OBJCOPY) -O binary $(REMOVE_SECTIONS) -S compressed/$(LINUX) $@
 
 bootpImage: bootp/bootp
-	$(OBJCOPY) -O binary -R .note -R .comment -S bootp/bootp $@
+	$(OBJCOPY) -O binary $(REMOVE_SECTIONS) -S bootp/bootp $@
 
 compressed/$(LINUX): $(LINUX) dep
 	@$(MAKE) -C compressed $(LINUX)

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