ARM: 5889/1: Add atomic64 routines for ARMv6k and above.

In preparation for perf-events support, ARM needs to support atomic64_t
operations. v6k and above support the ldrexd and strexd instructions to
do just that.

This patch adds atomic64 support to the ARM architecture. v6k and above
make use of new instructions whilst older cores fall back on the generic
solution using spinlocks. If and when v7-M cores are supported by Linux,
they will need to fall back on the spinlock implementation too.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b224216c11db..762ae536f909 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -12,6 +12,7 @@ config ARM
         select HAVE_IDE
         select RTC_LIB
         select SYS_SUPPORTS_APM_EMULATION
+        select GENERIC_ATOMIC64 if (!CPU_32v6K)
         select HAVE_OPROFILE
         select HAVE_ARCH_KGDB
         select HAVE_KPROBES if (!XIP_KERNEL)