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>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index e8cc453..6724cb0 100644
--- a/include/linux/memblock.h
+++ b/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)
 {