[PATCH] ARM: memblock limit must be pmd-aligned

From	Doug Berger <opendmb@gmail.com>
Newsgroups	linux.kernel
Subject	[PATCH] ARM: memblock limit must be pmd-aligned
Date	2017-06-26 19:30 +0200
Message-ID	<tWFZL-5dU-19@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

Show all headers | View raw

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.

However, 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.

The pmd containing arm_lowmem_limit is cleared by prepare_page_table()
and without this commit it is possible for early_alloc() to allocate
unmapped memory in that range when mapping the lowmem.

Signed-off-by: Doug Berger <opendmb@gmail.com>
---
 arch/arm/mm/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 31af3cb59a60..2ae4f9c9d757 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1226,7 +1226,7 @@ void __init adjust_lowmem_bounds(void)
 	if (memblock_limit)
 		memblock_limit = round_down(memblock_limit, PMD_SIZE);
 	if (!memblock_limit)
-		memblock_limit = arm_lowmem_limit;
+		memblock_limit = round_down(arm_lowmem_limit, PMD_SIZE);
 
 	if (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) {
 		if (memblock_end_of_DRAM() > arm_lowmem_limit) {
-- 
2.13.0

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

[PATCH] ARM: memblock limit must be pmd-aligned Doug Berger <opendmb@gmail.com> - 2017-06-26 19:30 +0200
  Re: [PATCH] ARM: memblock limit must be pmd-aligned Laura Abbott <labbott@redhat.com> - 2017-06-27 01:50 +0200
    Re: [PATCH] ARM: memblock limit must be pmd-aligned Doug Berger <opendmb@gmail.com> - 2017-06-27 03:00 +0200
      Re: [PATCH] ARM: memblock limit must be pmd-aligned Mark Rutland <mark.rutland@arm.com> - 2017-06-27 13:10 +0200
        Re: [PATCH] ARM: memblock limit must be pmd-aligned Doug Berger <opendmb@gmail.com> - 2017-06-27 19:00 +0200
          Re: [PATCH] ARM: memblock limit must be pmd-aligned Russell King - ARM Linux <linux@armlinux.org.uk> - 2017-06-27 19:10 +0200
          Re: [PATCH] ARM: memblock limit must be pmd-aligned Mark Rutland <mark.rutland@arm.com> - 2017-06-27 19:20 +0200

csiph-web