Introduce CONFIG_CHECK_SIGNATURE

Introduce CONFIG_CHECK_SIGNATURE to control inclusion of check_signature()
and avoid problems on platforms that don't have readb().

Let the few legacy (ISA || PCI || X86) drivers that need check_signature()
select CONFIG_CHECK_SIGNATURE.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 5 insertions, 1 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index e5c2c514174a..ba3d104994d9 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -138,4 +138,7 @@ config HAS_DMA
         depends on !NO_DMA
         default y
 
+config CHECK_SIGNATURE
+        bool
+
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index d9e5f1cd0bfb..6b0ba8cf4e5f 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -21,7 +21,8 @@ CFLAGS_kobject_uevent.o += -DDEBUG
 endif
 
 obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
-obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o check_signature.o
+obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
+obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
 obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o