From 67b0141bd12d3a609d47ebbb53a4df67e3fdf4c4 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@kernel.org>
Date: Tue, 21 Jul 2020 09:21:08 +0100
Subject: [PATCH] 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: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
arch/arm/Kconfig | 31 -------------------------------
arch/arm/Makefile | 4 ----
2 files changed, 35 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 910e89f9023c34..1b65ff94ad1cd3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -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
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 2731c20dee5851..f0ef23865df7fc 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -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)
--
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