ARM: 9122/1: select HAVE_FUTEX_CMPXCHG

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>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 89f7d0c2824066313f9e64a64a5d203eceb476f1..86ed77d75e4bb2fc932136714277795be33def45 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -65,6 +65,7 @@ config ARM
        select HAVE_FTRACE_MCOUNT_RECORD if (!XIP_KERNEL)
        select HAVE_FUNCTION_GRAPH_TRACER if (!THUMB2_KERNEL)
        select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
+       select HAVE_FUTEX_CMPXCHG if FUTEX
        select HAVE_GCC_PLUGINS
        select HAVE_GENERIC_DMA_COHERENT
        select HAVE_HW_BREAKPOINT if (PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7))