[PATCH] mm/memtest: Add ARCH_USE_MEMTEST

[Anshuman Khandual <anshuman.khandual@arm.com>]

early_memtest() does not get called from all architectures. Hence enabling
CONFIG_MEMTEST and providing a valid memtest=[1..N] kernel command line
option might not trigger the memory pattern tests as would be expected in
normal circumstances. This situation is misleading.

The change here prevents the above mentioned problem after introducing a
new config option ARCH_USE_MEMTEST that should be subscribed on platforms
that call early_memtest(), in order to enable the config CONFIG_MEMTEST.
Conversely CONFIG_MEMTEST cannot be enabled on platforms where it would
not be tested anyway.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-xtensa@linux-xtensa.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This patch applies on v5.11-rc6 and has been tested on arm64 platform. But
it has been just build tested on all other platforms.

 arch/arm/Kconfig     | 1 +
 arch/arm64/Kconfig   | 1 +
 arch/mips/Kconfig    | 1 +
 arch/powerpc/Kconfig | 1 +
 arch/x86/Kconfig     | 1 +
 arch/xtensa/Kconfig  | 1 +
 lib/Kconfig.debug    | 9 ++++++++-
 7 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 138248999df7..a63b53c568df 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -32,6 +32,7 @@ config ARM
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_USE_MEMTEST
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select ARCH_WANT_LD_ORPHAN_WARN
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c4acf8230f20..dfee5831d876 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -70,6 +70,7 @@ config ARM64
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select ARCH_USE_SYM_ANNOTATIONS
+	select ARCH_USE_MEMTEST
 	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
 	select ARCH_SUPPORTS_MEMORY_FAILURE
 	select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 0a17bedf4f0d..1b21d8e53e6b 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -16,6 +16,7 @@ config MIPS
 	select ARCH_USE_CMPXCHG_LOCKREF if 64BIT
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
+	select ARCH_USE_MEMTEST
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_TABLE_SORT
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 107bb4319e0e..9935343a8750 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -151,6 +151,7 @@ config PPC
 	select ARCH_USE_CMPXCHG_LOCKREF		if PPC64
 	select ARCH_USE_QUEUED_RWLOCKS		if PPC_QUEUED_SPINLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS	if PPC_QUEUED_SPINLOCKS
+	select ARCH_USE_MEMTEST
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
 	select ARCH_WANT_LD_ORPHAN_WARN
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 21f851179ff0..90545348db1b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -100,6 +100,7 @@ config X86
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select ARCH_USE_SYM_ANNOTATIONS
+	select ARCH_USE_MEMTEST
 	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
 	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
 	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 37ce1489364e..8eb61fcdfc7f 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -9,6 +9,7 @@ config XTENSA
 	select ARCH_HAS_DMA_SET_UNCACHED if MMU
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
+	select ARCH_USE_MEMTEST
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_TABLE_SORT
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 7937265ef879..6dd25b755a82 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2469,11 +2469,18 @@ config TEST_FPU
 
 endif # RUNTIME_TESTING_MENU
 
+config ARCH_USE_MEMTEST
+	bool
+	help
+	  An architecture should select this when it uses early_memtest()
+	  during boot process.
+
 config MEMTEST
 	bool "Memtest"
+	depends on ARCH_USE_MEMTEST
 	help
 	  This option adds a kernel parameter 'memtest', which allows memtest
-	  to be set.
+	  to be set and executed.
 	        memtest=0, mean disabled; -- default
 	        memtest=1, mean do 1 test pattern;
 	        ...
-- 
2.20.1