Commit 67b0141b authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Russell King
Browse files

ARM: 8995/1: drop Thumb-2 workaround for ancient binutils 



The CONFIG_THUMB2_AVOID_R_ARM_THM_JUMP11 workaround addresses an issue
which was fixed before the oldest supported binutils (2.23 at this time)
were released. So we can remove it now.

Acked-by: default avatarDave Martin <Dave.Martin@arm.com>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent 4d44a399

arch/arm/Kconfig

+0 −31
Original line number Diff line number Diff line
@@ -1422,37 +1422,6 @@ config THUMB2_KERNEL 


	  If unsure, say N.



config THUMB2_AVOID_R_ARM_THM_JUMP11

	bool "Work around buggy Thumb-2 short branch relocations in gas"

	depends on THUMB2_KERNEL && MODULES

	default y

	help

	  Various binutils versions can resolve Thumb-2 branches to

	  locally-defined, preemptible global symbols as short-range "b.n"

	  branch instructions.



	  This is a problem, because there's no guarantee the final

	  destination of the symbol, or any candidate locations for a

	  trampoline, are within range of the branch.  For this reason, the

	  kernel does not support fixing up the R_ARM_THM_JUMP11 (102)

	  relocation in modules at all, and it makes little sense to add

	  support.



	  The symptom is that the kernel fails with an "unsupported

	  relocation" error when loading some modules.



	  Until fixed tools are available, passing

	  -fno-optimize-sibling-calls to gcc should prevent gcc generating

	  code which hits this problem, at the cost of a bit of extra runtime

	  stack usage in some cases.



	  The problem is described in more detail at:

	      https://bugs.launchpad.net/binutils-linaro/+bug/725126



	  Only Thumb-2 kernels are affected.



	  Unless you are sure your tools don't have this problem, say Y.



config ARM_PATCH_IDIV

	bool "Runtime patch udiv/sdiv instructions into __aeabi_{u}idiv()"

	depends on CPU_32v7 && !XIP_KERNEL

arch/arm/Makefile

+0 −4
Original line number Diff line number Diff line
@@ -123,10 +123,6 @@ AFLAGS_NOWARN :=$(call as-option,-Wa$(comma)-mno-warn-deprecated,-Wa$(comma)-W) 
ifeq ($(CONFIG_THUMB2_KERNEL),y)

CFLAGS_ISA	:=-mthumb -Wa,-mimplicit-it=always $(AFLAGS_NOWARN)

AFLAGS_ISA	:=$(CFLAGS_ISA) -Wa$(comma)-mthumb

# Work around buggy relocation from gas if requested:

ifeq ($(CONFIG_THUMB2_AVOID_R_ARM_THM_JUMP11),y)

KBUILD_CFLAGS_MODULE	+=-fno-optimize-sibling-calls

endif

else

CFLAGS_ISA	:=$(call cc-option,-marm,) $(AFLAGS_NOWARN)

AFLAGS_ISA	:=$(CFLAGS_ISA)

CRA Git | Maintained and supported by SUSTech CRA and CCSE