From 9696fcae9251610f5935a3823be40d1365649720 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Thu, 19 Jun 2014 22:44:32 +0100 Subject: [PATCH] ARM: 8079/1: zImage: identify kernel endianness With patch #8067/1 ("zImage: ensure header in LE format for BE8 kernels") applied, it is no longer possible to determine the endianness of a compiled kernel image. This normally shouldn't matter to the boot environment, except for those cases where the selection of a ramdisk or root filesystem with a matching endianness has to be automated. Let's add a flag to the zImage header indicating the actual endianness. Four bytes from offset 0x30 can be interpreted as follows: 04 03 02 01 big endian kernel 01 02 03 04 little endian kernel Anything else should be interpreted as "unknown", in which case it is most likely that patch #8067/1 was not applied either and the zImage magic number at offset 0x24 could be used instead to determine endianness. No zImage before this patch ever produced 0x01020304 nor 0x04030201 at offset 0x30 so there is no confusion possible. Signed-off-by: Nicolas Pitre Acked-by: Kevin Hilman Signed-off-by: Russell King --- arch/arm/boot/compressed/head.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index c95feab6ce7f..413fd94b5301 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -128,6 +128,7 @@ start: .word _magic_sig @ Magic numbers to help the loader .word _magic_start @ absolute load/run zImage address .word _magic_end @ zImage end address + .word 0x04030201 @ endianness flag THUMB( .thumb ) 1: -- 2.20.1