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From 4850e9e3c6a34f7e30a6d073629d98c826698033 Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Wed, 8 Sep 2021 19:25:59 +0100
Subject: [PATCH] ARM: 9122/1: select HAVE_FUTEX_CMPXCHG
Git-commit: 9d417cbe36eee7afdd85c2e871685f8dab7c2dba
Patch-mainline: v5.15-rc7
References: stable-5.14.15

commit 9d417cbe36eee7afdd85c2e871685f8dab7c2dba upstream.

tglx notes:
  This function [futex_detect_cmpxchg] is only needed when an
  architecture has to runtime discover whether the CPU supports it or
  not.  ARM has unconditional support for this, so the obvious thing to
  do is the below.

Fixes linkage failure from Clang randconfigs:
kernel/futex.o:(.text.fixup+0x5c): relocation truncated to fit: R_ARM_JUMP24 against `.init.text'
and boot failures for CONFIG_THUMB2_KERNEL.

Link: https://github.com/ClangBuiltLinux/linux/issues/325

Comments from Nick Desaulniers:

 See-also: 03b8c7b623c8 ("futex: Allow architectures to skip
 futex_atomic_cmpxchg_inatomic() test")

Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: stable@vger.kernel.org # v3.14+
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 arch/arm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2fb7012c3246..110b305af27f 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -93,6 +93,7 @@ config ARM
 	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
 	select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG
 	select HAVE_FUNCTION_TRACER if !XIP_KERNEL
+	select HAVE_FUTEX_CMPXCHG if FUTEX
 	select HAVE_GCC_PLUGINS
 	select HAVE_HW_BREAKPOINT if PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7)
 	select HAVE_IRQ_TIME_ACCOUNTING
-- 
2.26.2