binfmt_flat: add a ARCH_HAS_BINFMT_FLAT option

Allow architectures to opt into ARCH_HAS_BINFMT_FLAT support instead of
assuming that all nommu ports support the format.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>

arch/arm/Kconfig

@@ -4,6 +4,7 @@ config ARM
 	default y
 	select ARCH_32BIT_OFF_T
 	select ARCH_CLOCKSOURCE_DATA
+	select ARCH_HAS_BINFMT_FLAT
 	select ARCH_HAS_DEBUG_VIRTUAL if MMU
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ELF_RANDOMIZE

arch/c6x/Kconfig

@@ -7,6 +7,7 @@
 config C6X
 	def_bool y
 	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_BINFMT_FLAT
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select CLKDEV_LOOKUP

arch/h8300/Kconfig

@@ -2,6 +2,7 @@
 config H8300
         def_bool y
 	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_BINFMT_FLAT
 	select BINFMT_FLAT_ARGVP_ENVP_ON_STACK
 	select BINFMT_FLAT_OLD_ALWAYS_RAM
 	select GENERIC_ATOMIC64

arch/m68k/Kconfig

@@ -3,6 +3,7 @@ config M68K
 	bool
 	default y
 	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_BINFMT_FLAT
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if HAS_DMA
 	select ARCH_MIGHT_HAVE_PC_PARPORT if ISA
 	select ARCH_NO_COHERENT_DMA_MMAP if !MMU

arch/microblaze/Kconfig

@@ -3,6 +3,7 @@ config MICROBLAZE
 	def_bool y
 	select ARCH_32BIT_OFF_T
 	select ARCH_NO_SWAP
+	select ARCH_HAS_BINFMT_FLAT if !MMU
 	select ARCH_HAS_DMA_COHERENT_TO_PFN if MMU
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_SYNC_DMA_FOR_CPU

arch/sh/Kconfig

 # SPDX-License-Identifier: GPL-2.0
 config SUPERH
 	def_bool y
+	select ARCH_HAS_BINFMT_FLAT if !MMU
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_MIGHT_HAVE_PC_PARPORT

arch/xtensa/Kconfig

@@ -2,6 +2,7 @@
 config XTENSA
 	def_bool y
 	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_BINFMT_FLAT if !MMU
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_NO_COHERENT_DMA_MMAP if !MMU

fs/Kconfig.binfmt

@@ -91,9 +91,12 @@ config BINFMT_SCRIPT
 
 	  Most systems will not boot if you say M or N here.  If unsure, say Y.
 
+config ARCH_HAS_BINFMT_FLAT
+	bool
+
 config BINFMT_FLAT
 	bool "Kernel support for flat binaries"
-	depends on !MMU || ARM || M68K
+	depends on ARCH_HAS_BINFMT_FLAT
 	help
 	  Support uClinux FLAT format binaries.