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Commit 9e25ebfe authored by Doug Berger's avatar Doug Berger Committed by Russell King
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ARM: 8685/1: ensure memblock-limit is pmd-aligned 



The pmd containing memblock_limit is cleared by prepare_page_table()
which creates the opportunity for early_alloc() to allocate unmapped
memory if memblock_limit is not pmd aligned causing a boot-time hang.

Commit 965278dc ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM")
attempted to resolve this problem, but there is a path through the
adjust_lowmem_bounds() routine where if all memory regions start and
end on pmd-aligned addresses the memblock_limit will be set to
arm_lowmem_limit.

Since arm_lowmem_limit can be affected by the vmalloc early parameter,
the value of arm_lowmem_limit may not be pmd-aligned. This commit
corrects this oversight such that memblock_limit is always rounded
down to pmd-alignment.

Fixes: 965278dc ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM")
Signed-off-by: default avatarDoug Berger <opendmb@gmail.com>
Suggested-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent d360a687

arch/arm/mm/mmu.c

+4 −4
Original line number Diff line number Diff line
@@ -1218,15 +1218,15 @@ void __init adjust_lowmem_bounds(void) 


	high_memory = __va(arm_lowmem_limit - 1) + 1;



	if (!memblock_limit)

		memblock_limit = arm_lowmem_limit;



	/*

	 * Round the memblock limit down to a pmd size.  This

	 * helps to ensure that we will allocate memory from the

	 * last full pmd, which should be mapped.

	 */

	if (memblock_limit)

	memblock_limit = round_down(memblock_limit, PMD_SIZE);

	if (!memblock_limit)

		memblock_limit = arm_lowmem_limit;



	if (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) {

		if (memblock_end_of_DRAM() > arm_lowmem_limit) {