Commit 195320fd authored Oct 01, 2017 by Nicolas Pitre Committed by Russell King Oct 12, 2017

ARM: 8700/1: nommu: always reserve address 0 away



Some nommu systems have RAM at address 0. When vectors are not located
there, the very beginning of memory remains available for dynamic
allocations. The memblock allocator explicitly skips the first page
but the standard page allocator does not, and while it correctly returns
a non-null struct page pointer for that page, page_address() gives 0
which gets confused with NULL (out of memory) by callers despite having
plenty of free memory left.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

parent 2bd6bf03

arch/arm/mm/nommu.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -344,6 +344,11 @@ void __init arm_mm_memblock_reserve(void)
		* reserved here.
		*/
		#endif
		/*
		* In any case, always ensure address 0 is never used as many things
		* get very confused if 0 is returned as a legitimate address.
		*/
		memblock_reserve(0, 1);
		}

		void __init adjust_lowmem_bounds(void)

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