From: Nicolas Pitre <nicolas.pitre@xxxxxxxxxx>
commit 9696fcae9251610f5935a3823be40d1365649720 upstream
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 <nico@xxxxxxxxxx>
Acked-by: Kevin Hilman <khilman@xxxxxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
---
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 ac7ff2a..d087554 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -133,6 +133,7 @@ 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:
--
1.8.3.4
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html