kmemcheck: make kconfig accessible for other architectures

The Kconfig options of kmemcheck are hidden under arch/x86 which makes porting
to other architectures harder. To fix that, move the Kconfig bits to
lib/Kconfig.kmemcheck and introduce a CONFIG_HAVE_ARCH_KMEMCHECK config option
that architectures can define.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

arch/x86/Kconfig

@@ -46,6 +46,7 @@ config X86
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_BZIP2
 	select HAVE_KERNEL_LZMA
+	select HAVE_ARCH_KMEMCHECK
 
 config OUTPUT_FORMAT
 	string

arch/x86/Kconfig.debug

@@ -260,94 +260,6 @@ config DEFAULT_IO_DELAY_TYPE
 	default IO_DELAY_TYPE_NONE
 endif
 
-menuconfig KMEMCHECK
-	bool "kmemcheck: trap use of uninitialized memory"
-	depends on DEBUG_KERNEL
-	depends on !X86_USE_3DNOW
-	depends on SLUB || SLAB
-	depends on !CC_OPTIMIZE_FOR_SIZE
-	depends on !FUNCTION_TRACER
-	select FRAME_POINTER
-	select STACKTRACE
-	default n
-	help
-	  This option enables tracing of dynamically allocated kernel memory
-	  to see if memory is used before it has been given an initial value.
-	  Be aware that this requires half of your memory for bookkeeping and
-	  will insert extra code at *every* read and write to tracked memory
-	  thus slow down the kernel code (but user code is unaffected).
-
-	  The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable
-	  or enable kmemcheck at boot-time. If the kernel is started with
-	  kmemcheck=0, the large memory and CPU overhead is not incurred.
-
-choice
-	prompt "kmemcheck: default mode at boot"
-	depends on KMEMCHECK
-	default KMEMCHECK_ONESHOT_BY_DEFAULT
-	help
-	  This option controls the default behaviour of kmemcheck when the
-	  kernel boots and no kmemcheck= parameter is given.
-
-config KMEMCHECK_DISABLED_BY_DEFAULT
-	bool "disabled"
-	depends on KMEMCHECK
-
-config KMEMCHECK_ENABLED_BY_DEFAULT
-	bool "enabled"
-	depends on KMEMCHECK
-
-config KMEMCHECK_ONESHOT_BY_DEFAULT
-	bool "one-shot"
-	depends on KMEMCHECK
-	help
-	  In one-shot mode, only the first error detected is reported before
-	  kmemcheck is disabled.
-
-endchoice
-
-config KMEMCHECK_QUEUE_SIZE
-	int "kmemcheck: error queue size"
-	depends on KMEMCHECK
-	default 64
-	help
-	  Select the maximum number of errors to store in the queue. Since
-	  errors can occur virtually anywhere and in any context, we need a
-	  temporary storage area which is guarantueed not to generate any
-	  other faults. The queue will be emptied as soon as a tasklet may
-	  be scheduled. If the queue is full, new error reports will be
-	  lost.
-
-config KMEMCHECK_SHADOW_COPY_SHIFT
-	int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)"
-	depends on KMEMCHECK
-	range 2 8
-	default 5
-	help
-	  Select the number of shadow bytes to save along with each entry of
-	  the queue. These bytes indicate what parts of an allocation are
-	  initialized, uninitialized, etc. and will be displayed when an
-	  error is detected to help the debugging of a particular problem.
-
-config KMEMCHECK_PARTIAL_OK
-	bool "kmemcheck: allow partially uninitialized memory"
-	depends on KMEMCHECK
-	default y
-	help
-	  This option works around certain GCC optimizations that produce
-	  32-bit reads from 16-bit variables where the upper 16 bits are
-	  thrown away afterwards. This may of course also hide some real
-	  bugs.
-
-config KMEMCHECK_BITOPS_OK
-	bool "kmemcheck: allow bit-field manipulation"
-	depends on KMEMCHECK
-	default n
-	help
-	  This option silences warnings that would be generated for bit-field
-	  accesses where not all the bits are initialized at the same time.
-	  This may also hide some real bugs.
-
 config DEBUG_BOOT_PARAMS
 	bool "Debug boot parameters"
 	depends on DEBUG_KERNEL

lib/Kconfig.debug

@@ -996,3 +996,5 @@ config DMA_API_DEBUG
 source "samples/Kconfig"
 
 source "lib/Kconfig.kgdb"
+
+source "lib/Kconfig.kmemcheck"

lib/Kconfig.kmemcheck

@@ -0,0 +1,91 @@
+config HAVE_ARCH_KMEMCHECK
+	bool
+
+menuconfig KMEMCHECK
+	bool "kmemcheck: trap use of uninitialized memory"
+	depends on DEBUG_KERNEL
+	depends on !X86_USE_3DNOW
+	depends on SLUB || SLAB
+	depends on !CC_OPTIMIZE_FOR_SIZE
+	depends on !FUNCTION_TRACER
+	select FRAME_POINTER
+	select STACKTRACE
+	default n
+	help
+	  This option enables tracing of dynamically allocated kernel memory
+	  to see if memory is used before it has been given an initial value.
+	  Be aware that this requires half of your memory for bookkeeping and
+	  will insert extra code at *every* read and write to tracked memory
+	  thus slow down the kernel code (but user code is unaffected).
+
+	  The kernel may be started with kmemcheck=0 or kmemcheck=1 to disable
+	  or enable kmemcheck at boot-time. If the kernel is started with
+	  kmemcheck=0, the large memory and CPU overhead is not incurred.
+
+choice
+	prompt "kmemcheck: default mode at boot"
+	depends on KMEMCHECK
+	default KMEMCHECK_ONESHOT_BY_DEFAULT
+	help
+	  This option controls the default behaviour of kmemcheck when the
+	  kernel boots and no kmemcheck= parameter is given.
+
+config KMEMCHECK_DISABLED_BY_DEFAULT
+	bool "disabled"
+	depends on KMEMCHECK
+
+config KMEMCHECK_ENABLED_BY_DEFAULT
+	bool "enabled"
+	depends on KMEMCHECK
+
+config KMEMCHECK_ONESHOT_BY_DEFAULT
+	bool "one-shot"
+	depends on KMEMCHECK
+	help
+	  In one-shot mode, only the first error detected is reported before
+	  kmemcheck is disabled.
+
+endchoice
+
+config KMEMCHECK_QUEUE_SIZE
+	int "kmemcheck: error queue size"
+	depends on KMEMCHECK
+	default 64
+	help
+	  Select the maximum number of errors to store in the queue. Since
+	  errors can occur virtually anywhere and in any context, we need a
+	  temporary storage area which is guarantueed not to generate any
+	  other faults. The queue will be emptied as soon as a tasklet may
+	  be scheduled. If the queue is full, new error reports will be
+	  lost.
+
+config KMEMCHECK_SHADOW_COPY_SHIFT
+	int "kmemcheck: shadow copy size (5 => 32 bytes, 6 => 64 bytes)"
+	depends on KMEMCHECK
+	range 2 8
+	default 5
+	help
+	  Select the number of shadow bytes to save along with each entry of
+	  the queue. These bytes indicate what parts of an allocation are
+	  initialized, uninitialized, etc. and will be displayed when an
+	  error is detected to help the debugging of a particular problem.
+
+config KMEMCHECK_PARTIAL_OK
+	bool "kmemcheck: allow partially uninitialized memory"
+	depends on KMEMCHECK
+	default y
+	help
+	  This option works around certain GCC optimizations that produce
+	  32-bit reads from 16-bit variables where the upper 16 bits are
+	  thrown away afterwards. This may of course also hide some real
+	  bugs.
+
+config KMEMCHECK_BITOPS_OK
+	bool "kmemcheck: allow bit-field manipulation"
+	depends on KMEMCHECK
+	default n
+	help
+	  This option silences warnings that would be generated for bit-field
+	  accesses where not all the bits are initialized at the same time.
+	  This may also hide some real bugs.
+