mm: move memtest under mm

Memtest is a simple feature which fills the memory with a given set of
patterns and validates memory contents, if bad memory regions is detected
it reserves them via memblock API.  Since memblock API is widely used by
other architectures this feature can be enabled outside of x86 world.

This patch set promotes memtest to live under generic mm umbrella and
enables memtest feature for arm/arm64.

It was reported that this patch set was useful for tracking down an issue
with some errant DMA on an arm64 platform.

This patch (of 6):

There is nothing platform dependent in the core memtest code, so other
platforms might benefit from this feature too.

[linux@roeck-us.net: MEMTEST depends on MEMBLOCK]
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/Kconfig

@@ -721,17 +721,6 @@ endif #HYPERVISOR_GUEST
 config NO_BOOTMEM
 	def_bool y
 
-config MEMTEST
-	bool "Memtest"
-	---help---
-	  This option adds a kernel parameter 'memtest', which allows memtest
-	  to be set.
-	        memtest=0, mean disabled; -- default
-	        memtest=1, mean do 1 test pattern;
-	        ...
-	        memtest=4, mean do 4 test patterns.
-	  If you are unsure how to answer this question, answer N.
-
 source "arch/x86/Kconfig.cpu"
 
 config HPET_TIMER

arch/x86/include/asm/e820.h

@@ -40,14 +40,6 @@ static inline void e820_mark_nosave_regions(unsigned long limit_pfn)
 }
 #endif
 
-#ifdef CONFIG_MEMTEST
-extern void early_memtest(unsigned long start, unsigned long end);
-#else
-static inline void early_memtest(unsigned long start, unsigned long end)
-{
-}
-#endif
-
 extern unsigned long e820_end_of_ram_pfn(void);
 extern unsigned long e820_end_of_low_ram_pfn(void);
 extern u64 early_reserve_e820(u64 sizet, u64 align);

arch/x86/mm/Makefile

@@ -32,6 +32,4 @@ obj-$(CONFIG_AMD_NUMA)		+= amdtopology.o
 obj-$(CONFIG_ACPI_NUMA)		+= srat.o
 obj-$(CONFIG_NUMA_EMU)		+= numa_emulation.o
 
-obj-$(CONFIG_MEMTEST)		+= memtest.o
-
 obj-$(CONFIG_X86_INTEL_MPX)	+= mpx.o

include/linux/memblock.h

@@ -365,6 +365,14 @@ static inline unsigned long memblock_region_reserved_end_pfn(const struct memblo
 #define __initdata_memblock
 #endif
 
+#ifdef CONFIG_MEMTEST
+extern void early_memtest(unsigned long start, unsigned long end);
+#else
+static inline void early_memtest(unsigned long start, unsigned long end)
+{
+}
+#endif
+
 #else
 static inline phys_addr_t memblock_alloc(phys_addr_t size, phys_addr_t align)
 {

lib/Kconfig.debug

@@ -1745,6 +1745,18 @@ config TEST_UDELAY
 
 	  If unsure, say N.
 
+config MEMTEST
+	bool "Memtest"
+	depends on HAVE_MEMBLOCK
+	---help---
+	  This option adds a kernel parameter 'memtest', which allows memtest
+	  to be set.
+	        memtest=0, mean disabled; -- default
+	        memtest=1, mean do 1 test pattern;
+	        ...
+	        memtest=4, mean do 4 test patterns.
+	  If you are unsure how to answer this question, answer N.
+
 source "samples/Kconfig"
 
 source "lib/Kconfig.kgdb"

mm/Makefile

@@ -55,6 +55,7 @@ obj-$(CONFIG_KMEMCHECK) += kmemcheck.o
 obj-$(CONFIG_KASAN)	+= kasan/
 obj-$(CONFIG_FAILSLAB) += failslab.o
 obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
+obj-$(CONFIG_MEMTEST)		+= memtest.o
 obj-$(CONFIG_MIGRATION) += migrate.o
 obj-$(CONFIG_QUICKLIST) += quicklist.o
 obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o