Commit 909ba297 authored Jan 20, 2015 by Masahiro Yamada Committed by Russell King Jan 21, 2015

ARM: 8292/1: mm: fix size rounding-down of arm_add_memory() function



The current rounding of "size" is wrong:

 - If "start" is sufficiently near the next page boundary, "size"
   is decremented by more than enough and the last page is lost.

 - If "size" is sufficiently small, it is wrapped around and gets
   a bogus value.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent 2d9ed740

arch/arm/kernel/setup.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -657,10 +657,13 @@ int __init arm_add_memory(u64 start, u64 size)

		/*
		* Ensure that start/size are aligned to a page boundary.
		* Size is appropriately rounded down, start is rounded up.
		* Size is rounded down, start is rounded up.
		*/
		size -= start & ~PAGE_MASK;
		aligned_start = PAGE_ALIGN(start);
		if (aligned_start > start + size)
		size = 0;
		else
		size -= aligned_start - start;

		#ifndef CONFIG_ARCH_PHYS_ADDR_T_64BIT
		if (aligned_start > ULONG_MAX) {