From 965278dcb8ab0b1f666cc47937933c4be4aea48d Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 13 May 2015 15:07:54 +0100 Subject: [PATCH] ARM: 8356/1: mm: handle non-pmd-aligned end of RAM At boot time we round the memblock limit down to section size in an attempt to ensure that we will have mapped this RAM with section mappings prior to allocating from it. When mapping RAM we iterate over PMD-sized chunks, creating these section mappings. Section mappings are only created when the end of a chunk is aligned to section size. Unfortunately, with classic page tables (where PMD_SIZE is 2 * SECTION_SIZE) this means that if a chunk is between 1M and 2M in size the first 1M will not be mapped despite having been accounted for in the memblock limit. This has been observed to result in page tables being allocated from unmapped memory, causing boot-time hangs. This patch modifies the memblock limit rounding to always round down to PMD_SIZE instead of SECTION_SIZE. For classic MMU this means that we will round the memblock limit down to a 2M boundary, matching the limits on section mappings, and preventing allocations from unmapped memory. For LPAE there should be no change as PMD_SIZE == SECTION_SIZE. Signed-off-by: Mark Rutland Reported-by: Stefan Agner Tested-by: Stefan Agner Acked-by: Laura Abbott Tested-by: Hans de Goede Cc: Catalin Marinas Cc: Steve Capper Cc: stable@vger.kernel.org Signed-off-by: Russell King --- Reading git-format-patch failed