Change our ELF binary branding to something more acceptable to the Binutils

maintainers.

After we established our branding method of writing upto 8 characters of
the OS name into the ELF header in the padding; the Binutils maintainers
and/or SCO (as USL) decided that instead the ELF header should grow two new
fields -- EI_OSABI and EI_ABIVERSION.  Each of these are an 8-bit unsigned
integer.  SCO has assigned official values for the EI_OSABI field.  In
addition to this, the Binutils maintainers and NetBSD decided that a better
ELF branding method was to include ABI information in a ".note" ELF
section.

With this set of changes, we will now create ELF binaries branded using
both "official" methods.  Due to the complexity of adding a section to a
binary, binaries branded with ``brandelf'' will only brand using the
EI_OSABI method.  Also due to the complexity of pulling a section out of an
ELF file vs. poking around in the ELF header, our image activator only
looks at the EI_OSABI header field.

Note that a new kernel can still properly load old binaries except for
Linux static binaries branded in our old method.

  *
  * For a short period of time, ``ld'' will also brand ELF binaries
  * using our old method.  This is so people can still use kernel.old
  * with a new world.  This support will be removed before 5.0-RELEASE,
  * and may not last anywhere upto the actual release.  My expiration
  * time for this is about 6mo.
  *

2 files changed, 28 insertions, 0 deletions

diff --git a/lib/csu/amd64/crti.S b/lib/csu/amd64/crti.S
index 0038497..a4df32e 100644
--- a/lib/csu/amd64/crti.S
+++ b/lib/csu/amd64/crti.S
@@ -25,6 +25,20 @@
  * $FreeBSD$
  */
 
+	/* See http://www.netbsd.org/Documentation/kernel/elf-notes.html for
+	   details on the ELF .note section as we are using it. */
+	.section .note.ABI-tag, "a"
+	.align	4
+	.long	1f - 0f		# name length
+	.long	3f - 2f		# data length
+	.long	1		# note type
+0: 	.asciz	"FreeBSD"	# vendor name
+1:	.align	4
+2:	.long	500000		# data - ABI tag
+				#   (from __FreeBSD_version (param.h))
+3:	.align	4		# pad out section
+
+
 	.section .init,"ax",@progbits
 	.align	4
 	.globl	_init
diff --git a/lib/csu/i386-elf/crti.S b/lib/csu/i386-elf/crti.S
index 0038497..a4df32e 100644
--- a/lib/csu/i386-elf/crti.S
+++ b/lib/csu/i386-elf/crti.S
@@ -25,6 +25,20 @@
  * $FreeBSD$
  */
 
+	/* See http://www.netbsd.org/Documentation/kernel/elf-notes.html for
+	   details on the ELF .note section as we are using it. */
+	.section .note.ABI-tag, "a"
+	.align	4
+	.long	1f - 0f		# name length
+	.long	3f - 2f		# data length
+	.long	1		# note type
+0: 	.asciz	"FreeBSD"	# vendor name
+1:	.align	4
+2:	.long	500000		# data - ABI tag
+				#   (from __FreeBSD_version (param.h))
+3:	.align	4		# pad out section
+
+
 	.section .init,"ax",@progbits
 	.align	4
 	.globl	_init