From: Nick Desaulniers ndesaulniers@google.com
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 --- arch/arm/Kconfig | 1 + 1 file changed, 1 insertion(+)
--- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -70,6 +70,7 @@ 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))