powerpc: Enforce sane MAX_ORDER

powerpc uses CONFIG_FORCE_MAX_ZONEORDER, and some things depend on it
being at least 10 when 64k pages are not configured (notably the dart
iommu code with CONFIG_PM). The defaults are fine, but when going from a
64K pages config to one without 64K pages, MAX_ORDER stays at 9 which is
too low for 4K pages.

This patch makes the Kconfig enforce at least the defaults.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 17c988b678d1..c171f5bcf258 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -415,8 +415,11 @@ config PPC_64K_PAGES
 
 config FORCE_MAX_ZONEORDER
         int "Maximum zone order"
+        range 9 64 if PPC_64K_PAGES
         default "9" if PPC_64K_PAGES
+        range 13 64 if PPC64 && !PPC_64K_PAGES
         default "13" if PPC64 && !PPC_64K_PAGES
+        range 11 64
         default "11"
         help
           The kernel memory allocator divides physically contiguous memory