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>

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 3580d57ea21841285bc687d928f39268a325edc1..79e9bdbfc491a29521939aa2747862fc491c6d6d 100644 (file)
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -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 | \

diff --git a/arch/arm/boot/compressed/head-sa1100.S b/arch/arm/boot/compressed/head-sa1100.S
index 6179d94dd5c665a634e5e2913a916c96c9652c84..3115e313d9f65a31ad746b7d8d282741a5b1f765 100644 (file)
--- a/arch/arm/boot/compressed/head-sa1100.S
+++ b/arch/arm/boot/compressed/head-sa1100.S
@@ -11,6 +11,7 @@
 #include <asm/mach-types.h>
 
                .section        ".start", "ax"
+               .arch   armv4
 
 __SA1100_start:
 

diff --git a/arch/arm/boot/compressed/head-shark.S b/arch/arm/boot/compressed/head-shark.S
index 089c560e07f13947ed68ab446edcc9de40c30604..92b56897ed64014037b48eb0e677bb633d646be1 100644 (file)
--- a/arch/arm/boot/compressed/head-shark.S
+++ b/arch/arm/boot/compressed/head-shark.S
@@ -18,6 +18,7 @@
        
                .section        ".start", "ax"
 
+               .arch armv4
                b       __beginning
        
 __ofw_data:    .long   0                               @ the number of memory blocks

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index fe4d9c3ad761c8dfaadce6e214d709417947f396..693855995407b3a302227cb079f6373064759ee6 100644 (file)
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -11,6 +11,7 @@
 #include <linux/linkage.h>
 #include <asm/assembler.h>
 
+       .arch   armv7-a
 /*
  * Debugging stuff
  *