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ARM: 8685/1: ensure memblock-limit is pmd-aligned

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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 965278dcb8 ("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: 965278dcb8 ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Doug Berger 2017-06-29 18:41:36 +01:00 committed by Russell King
parent d360a687d9
commit 9e25ebfe56
1 changed files with 4 additions and 4 deletions
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8
arch/arm/mm/mmu.c
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@ -1218,15 +1218,15 @@ void __init adjust_lowmem_bounds(void)
high_memory = __va(arm_lowmem_limit - 1) + 1; 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 * Round the memblock limit down to a pmd size. This
* helps to ensure that we will allocate memory from the * helps to ensure that we will allocate memory from the
* last full pmd, which should be mapped. * last full pmd, which should be mapped.
*/ */
if (memblock_limit) memblock_limit = round_down(memblock_limit, PMD_SIZE);
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 (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) {
if (memblock_end_of_DRAM() > arm_lowmem_limit) { if (memblock_end_of_DRAM() > arm_lowmem_limit) {