ARM: ARMv7-M: Allow the building of new kernel port

This patch modifies the required Kconfig and Makefile files to allow the
building of kernel for Cortex-M3.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Jonathan Austin <jonathan.austin@arm.com>
Tested-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

arch/arm/Kconfig

@@ -9,7 +9,7 @@ config ARM
 	select BUILDTIME_EXTABLE_SORT if MMU
 	select CPU_PM if (SUSPEND || CPU_IDLE)
 	select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN && MMU
-	select GENERIC_ATOMIC64 if (CPU_V6 || !CPU_32v6K || !AEABI)
+	select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI)
 	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
@@ -1685,7 +1685,7 @@ config SCHED_HRTICK
 
 config THUMB2_KERNEL
 	bool "Compile the kernel in Thumb-2 mode" if !CPU_THUMBONLY
-	depends on CPU_V7 && !CPU_V6 && !CPU_V6K
+	depends on (CPU_V7 || CPU_V7M) && !CPU_V6 && !CPU_V6K
 	default y if CPU_THUMBONLY
 	select AEABI
 	select ARM_ASM_UNIFIED

arch/arm/Kconfig-nommu

@@ -28,7 +28,7 @@ config FLASH_SIZE
 config PROCESSOR_ID
 	hex 'Hard wire the processor ID'
 	default 0x00007700
-	depends on !CPU_CP15
+	depends on !(CPU_CP15 || CPU_V7M)
 	help
 	  If processor has no CP15 register, this processor ID is
 	  used instead of the auto-probing which utilizes the register.

arch/arm/Makefile

@@ -59,6 +59,7 @@ comma = ,
 # Note that GCC does not numerically define an architecture version
 # macro, but instead defines a whole series of macros which makes
 # testing for a specific architecture or later rather impossible.
+arch-$(CONFIG_CPU_32v7M)	:=-D__LINUX_ARM_ARCH__=7 -march=armv7-m -Wa,-march=armv7-m
 arch-$(CONFIG_CPU_32v7)		:=-D__LINUX_ARM_ARCH__=7 $(call cc-option,-march=armv7-a,-march=armv5t -Wa$(comma)-march=armv7-a)
 arch-$(CONFIG_CPU_32v6)		:=-D__LINUX_ARM_ARCH__=6 $(call cc-option,-march=armv6,-march=armv5t -Wa$(comma)-march=armv6)
 # Only override the compiler option if ARMv6. The ARMv6K extensions are

arch/arm/kernel/Makefile

@@ -15,7 +15,7 @@ CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
 
-obj-y		:= elf.o entry-armv.o entry-common.o irq.o opcodes.o \
+obj-y		:= elf.o entry-common.o irq.o opcodes.o \
 		   process.o ptrace.o return_address.o sched_clock.o \
 		   setup.o signal.o stacktrace.o sys_arm.o time.o traps.o
 
@@ -23,6 +23,12 @@ obj-$(CONFIG_ATAGS)		+= atags_parse.o
 obj-$(CONFIG_ATAGS_PROC)	+= atags_proc.o
 obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
 
+ifeq ($(CONFIG_CPU_V7M),y)
+obj-y		+= entry-v7m.o
+else
+obj-y		+= entry-armv.o
+endif
+
 obj-$(CONFIG_OC_ETM)		+= etm.o
 obj-$(CONFIG_CPU_IDLE)		+= cpuidle.o
 obj-$(CONFIG_ISA_DMA_API)	+= dma.o

arch/arm/mm/Kconfig

@@ -397,6 +397,15 @@ config CPU_V7
 	select CPU_PABRT_V7
 	select CPU_TLB_V7 if MMU
 
+# ARMv7M
+config CPU_V7M
+	bool
+	select CPU_32v7M
+	select CPU_ABRT_NOMMU
+	select CPU_CACHE_NOP
+	select CPU_PABRT_LEGACY
+	select CPU_THUMBONLY
+
 config CPU_THUMBONLY
 	bool
 	# There are no CPUs available with MMU that don't implement an ARM ISA:
@@ -441,6 +450,9 @@ config CPU_32v6K
 config CPU_32v7
 	bool
 
+config CPU_32v7M
+	bool
+
 # The abort model
 config CPU_ABRT_NOMMU
 	bool
@@ -494,6 +506,9 @@ config CPU_CACHE_V6
 config CPU_CACHE_V7
 	bool
 
+config CPU_CACHE_NOP
+	bool
+
 config CPU_CACHE_VIVT
 	bool
 
@@ -616,7 +631,11 @@ config ARCH_DMA_ADDR_T_64BIT
 
 config ARM_THUMB
 	bool "Support Thumb user binaries" if !CPU_THUMBONLY
-	depends on CPU_ARM720T || CPU_ARM740T || CPU_ARM920T || CPU_ARM922T || CPU_ARM925T || CPU_ARM926T || CPU_ARM940T || CPU_ARM946E || CPU_ARM1020 || CPU_ARM1020E || CPU_ARM1022 || CPU_ARM1026 || CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_V6 || CPU_V6K || CPU_V7 || CPU_FEROCEON
+	depends on CPU_ARM720T || CPU_ARM740T || CPU_ARM920T || CPU_ARM922T || \
+		CPU_ARM925T || CPU_ARM926T || CPU_ARM940T || CPU_ARM946E || \
+		CPU_ARM1020 || CPU_ARM1020E || CPU_ARM1022 || CPU_ARM1026 || \
+		CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_V6 || CPU_V6K || \
+		CPU_V7 || CPU_FEROCEON || CPU_V7M
 	default y
 	help
 	  Say Y if you want to include kernel support for running user space

arch/arm/mm/Makefile

@@ -40,6 +40,7 @@ obj-$(CONFIG_CPU_CACHE_V4WB)	+= cache-v4wb.o
 obj-$(CONFIG_CPU_CACHE_V6)	+= cache-v6.o
 obj-$(CONFIG_CPU_CACHE_V7)	+= cache-v7.o
 obj-$(CONFIG_CPU_CACHE_FA)	+= cache-fa.o
+obj-$(CONFIG_CPU_CACHE_NOP)	+= cache-nop.o
 
 AFLAGS_cache-v6.o	:=-Wa,-march=armv6
 AFLAGS_cache-v7.o	:=-Wa,-march=armv7-a
@@ -88,6 +89,7 @@ obj-$(CONFIG_CPU_FEROCEON)	+= proc-feroceon.o
 obj-$(CONFIG_CPU_V6)		+= proc-v6.o
 obj-$(CONFIG_CPU_V6K)		+= proc-v6.o
 obj-$(CONFIG_CPU_V7)		+= proc-v7.o
+obj-$(CONFIG_CPU_V7M)		+= proc-v7m.o
 
 AFLAGS_proc-v6.o	:=-Wa,-march=armv6
 AFLAGS_proc-v7.o	:=-Wa,-march=armv7-a