ARM: 7113/1: mm: Align bank start to MAX_ORDER_NR_PAGES

The VM subsystem assumes that there are valid memmap entries from
the bank start aligned to MAX_ORDER_NR_PAGES.

On the Ux500 we have a lot of mem=N arguments on the commandline
triggering this bug several times over and causing kernel
oops messages.

Cc: stable@kernel.org
Cc: Michael Bohan <mbohan@codeaurora.org>
Cc: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Johan Palsson <johan.palsson@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index cc7e2d8be9aa..f8037ba338ac 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -496,6 +496,13 @@ static void __init free_unused_memmap(struct meminfo *mi)
                  */
                 bank_start = min(bank_start,
                                  ALIGN(prev_bank_end, PAGES_PER_SECTION));
+#else
+                /*
+                 * Align down here since the VM subsystem insists that the
+                 * memmap entries are valid from the bank start aligned to
+                 * MAX_ORDER_NR_PAGES.
+                 */
+                bank_start = round_down(bank_start, MAX_ORDER_NR_PAGES);
 #endif
                 /*
                  * If we had a previous bank, and there is a space