ARM: 7743/1: compressed/head.S: work around new binutils warning

In August 2012, Matthew Gretton-Dann checked a change into binutils
labelled "Error on obsolete & warn on deprecated registers", apparently as
part of ARMv8 support. Apparently, this was supposed to emit the message
"Warning: This coprocessor register access is deprecated in ARMv8" when
using certain mcr/mrc instructions and building for ARMv8. Unfortunately,
the message that is actually emitted appears to be '(null)', which is
less helpful in comparison.

Even more unfortunately, this is biting us on every single kernel
build with a new gas, because arch/arm/boot/compressed/head.S and some
other files in that directory are built with -march=all since kernel
commit 80cec14a8 "[ARM] Add -march=all to assembly file build in
arch/arm/boot/compressed" back in v2.6.28.

This patch reverts Russell's nice solution and instead marks the head.S
file to be built for armv7-a, which fortunately lets us build all
instructions in that file without warnings even on the broken binutils.

Without this patch, building anything results in:

arch/arm/boot/compressed/head.S: Assembler messages:
arch/arm/boot/compressed/head.S:565: Warning: (null)
arch/arm/boot/compressed/head.S:676: Warning: (null)
arch/arm/boot/compressed/head.S:698: Warning: (null)
arch/arm/boot/compressed/head.S:722: Warning: (null)
arch/arm/boot/compressed/head.S:726: Warning: (null)
arch/arm/boot/compressed/head.S:957: Warning: (null)
arch/arm/boot/compressed/head.S:996: Warning: (null)
arch/arm/boot/compressed/head.S:997: Warning: (null)
arch/arm/boot/compressed/head.S:1027: Warning: (null)
arch/arm/boot/compressed/head.S:1035: Warning: (null)
arch/arm/boot/compressed/head.S:1046: Warning: (null)
arch/arm/boot/compressed/head.S:1060: Warning: (null)
arch/arm/boot/compressed/head.S:1092: Warning: (null)
arch/arm/boot/compressed/head.S:1094: Warning: (null)
arch/arm/boot/compressed/head.S:1095: Warning: (null)
arch/arm/boot/compressed/head.S:1102: Warning: (null)
arch/arm/boot/compressed/head.S:1134: Warning: (null)

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org
Cc: Matthew Gretton-Dann <matthew.gretton-dann@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Arnd Bergmann 2013-05-31 22:50:47 +01:00 committed by Russell King
parent 92bdd3f5eb
commit da94a82930
4 changed files with 4 additions and 1 deletions

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@ -124,7 +124,7 @@ KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS))
endif
ccflags-y := -fpic -mno-single-pic-base -fno-builtin -I$(obj)
asflags-y := -Wa,-march=all -DZIMAGE
asflags-y := -DZIMAGE
# Supply kernel BSS size to the decompressor via a linker symbol.
KBSS_SZ = $(shell $(CROSS_COMPILE)size $(obj)/../../../../vmlinux | \

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@ -11,6 +11,7 @@
#include <asm/mach-types.h>
.section ".start", "ax"
.arch armv4
__SA1100_start:

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@ -18,6 +18,7 @@
.section ".start", "ax"
.arch armv4
b __beginning
__ofw_data: .long 0 @ the number of memory blocks

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@ -11,6 +11,7 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
.arch armv7-a
/*
* Debugging stuff
*