Messages in this thread Patch in this message | | | From | Doug Berger <> | Subject | [PATCH v2] ARM: memblock limit must be pmd-aligned | Date | Tue, 27 Jun 2017 10:33:29 -0700 |
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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 965278dcb8ab ("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: 965278dcb8ab ("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> --- Changes for v2: - Cleaner equivalent implementation suggested by Mark Rutland - Revised description to better capture the history
arch/arm/mm/mmu.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 31af3cb59a60..e46a6a446cdd 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -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; + memblock_limit = round_down(memblock_limit, PMD_SIZE); if (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) { if (memblock_end_of_DRAM() > arm_lowmem_limit) { -- 2.13.0
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