From 4f5b0c1789963477cc9a4d45b4b62d694665cceb Mon Sep 17 00:00:00 2001
From: Mike Rapoport <rppt@linux.ibm.com>
Date: Mon, 14 Dec 2020 19:09:59 -0800
Subject: arm, arm64: move free_unused_memmap() to generic mm

ARM and ARM64 free unused parts of the memory map just before the
initialization of the page allocator. To allow holes in the memory map both
architectures overload pfn_valid() and define HAVE_ARCH_PFN_VALID.

Allowing holes in the memory map for FLATMEM may be useful for small
machines, such as ARC and m68k and will enable those architectures to cease
using DISCONTIGMEM and still support more than one memory bank.

Move the functions that free unused memory map to generic mm and enable
them in case HAVE_ARCH_PFN_VALID=y.

Link: https://lkml.kernel.org/r/20201101170454.9567-10-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 arch/Kconfig | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'arch/Kconfig')

diff --git a/arch/Kconfig b/arch/Kconfig
index 54a240b61f56..8d5efff59cd8 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1044,6 +1044,9 @@ config ARCH_WANT_LD_ORPHAN_WARN
 	  by the linker, since the locations of such sections can change between linker
 	  versions.
 
+config HAVE_ARCH_PFN_VALID
+	bool
+
 source "kernel/gcov/Kconfig"
 
 source "scripts/gcc-plugins/Kconfig"
-- 
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