linux-kernel - [60/83] ARM: 7743/1: compressed/head.S: work around new binutils warning

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <lsq.1371420098.934754348@decadent.org.uk>
Date:	Sun, 16 Jun 2013 23:01:38 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "Arnd Bergmann" <arnd@...db.de>,
	"Russell King" <rmk+kernel@....linux.org.uk>,
	"Matthew Gretton-Dann" <matthew.gretton-dann@....com>
Subject: [60/83] ARM: 7743/1: compressed/head.S: work around new binutils
 warning

3.2.47-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@...db.de>

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@...db.de>
Cc: Matthew Gretton-Dann <matthew.gretton-dann@....com>
Signed-off-by: Russell King <rmk+kernel@....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@...adent.org.uk>
---
 arch/arm/boot/compressed/Makefile      |    2 +-
 arch/arm/boot/compressed/head-sa1100.S |    1 +
 arch/arm/boot/compressed/head-shark.S  |    1 +
 arch/arm/boot/compressed/head.S        |    1 +
 4 files changed, 4 insertions(+), 1 deletion(-)

--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -123,7 +123,6 @@ KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CF
 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}')
--- 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:
 
--- 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
--- 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
  *

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/