[ARM SMP] Add configuration option for ARMv6K processors

The 'K' extension adds several new instructions to the ARMv6 ISA
which are primerily useful for SMP.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Makefile

@@ -38,6 +38,7 @@ comma = ,
 # macro, but instead defines a whole series of macros which makes
 # testing for a specific architecture or later rather impossible.
 arch-$(CONFIG_CPU_32v6)		:=-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6,-march=armv5t -Wa$(comma)-march=armv6)
+arch-$(CONFIG_CPU_32v6K)	:=-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6k,-march=armv5t -Wa$(comma)-march=armv6k)
 arch-$(CONFIG_CPU_32v5)		:=-D__LINUX_ARM_ARCH__=5 $(call cc-option,-march=armv5te,-march=armv4)
 arch-$(CONFIG_CPU_32v4)		:=-D__LINUX_ARM_ARCH__=4 -march=armv4
 arch-$(CONFIG_CPU_32v3)		:=-D__LINUX_ARM_ARCH__=3 -march=armv3

arch/arm/lib/bitops.h

@@ -1,6 +1,6 @@
 #include <linux/config.h>
 
-#if __LINUX_ARM_ARCH__ >= 6 && defined(CONFIG_CPU_MPCORE)
+#if __LINUX_ARM_ARCH__ >= 6 && defined(CONFIG_CPU_32v6K)
 	.macro	bitop, instr
 	mov	r2, #1
 	and	r3, r0, #7		@ Get bit offset

arch/arm/mm/Kconfig

@@ -250,6 +250,18 @@ config CPU_V6
 	select CPU_COPY_V6
 	select CPU_TLB_V6
 
+# ARMv6k
+config CPU_32v6K
+	bool "Support ARM V6K processor extensions" if !SMP
+	depends on CPU_V6
+	default y if SMP
+	help
+	  Say Y here if your ARMv6 processor supports the 'K' extension.
+	  This enables the kernel to use some instructions not present
+	  on previous processors, and as such a kernel build with this
+	  enabled will not boot on processors with do not support these
+	  instructions.
+
 # Figure out what processor architecture version we should be using.
 # This defines the compiler instruction set which depends on the machine type.
 config CPU_32v3