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

commit da94a829305f1c217cfdf6771cb1faca0917e3b9 upstream.

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: Matthew Gretton-Dann <matthew.gretton-dann@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[bwh: Backported to 3.2:
 - Adjust context
 - Remove definition of asflags-y as it is now empty]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 21f56ff32797eaef80af79c49db60ce2c89912fa..5954a1a39348baf128a6f9d0e5f3a63dba2ba281 100644 (file)
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -123,7 +123,6 @@ KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS))
 endif
 
 ccflags-y := -fpic -fno-builtin -I$(obj)
-asflags-y := -Wa,-march=all
 
 # Supply kernel BSS size to the decompressor via a linker symbol.
 KBSS_SZ = $(shell size $(obj)/../../../../vmlinux | awk 'END{print $$3}')

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 d63632f353d76c18cd58eee210a38c771e3e56ab..8c5735960b6f7f74c00387c686afdf3845ef12f6 100644 (file)
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -10,6 +10,7 @@
  */
 #include <linux/linkage.h>
 
+       .arch   armv7-a
 /*
  * Debugging stuff
  *