From 3079abe555511031e2ba5d1e21ddc52edc9af349 Mon Sep 17 00:00:00 2001 From: Oliver O'Halloran Date: Wed, 11 May 2016 19:22:18 +1000 Subject: [PATCH] powerpc/mm: Ensure "special" zones are empty The mm zone mechanism was traditionally used by arch specific code to partition memory into allocation zones. However there are several zones that are managed by the mm subsystem rather than the architecture. Most architectures set the max PFN of these special zones to zero, however on powerpc we set them to ~0ul. This, in conjunction with a bug in free_area_init_nodes() results in all of system memory being placed in ZONE_DEVICE when enabled. Device memory cannot be used for regular kernel memory allocations so this will cause a kernel panic at boot. Given the planned addition of more mm managed zones (ZONE_CMA) we should aim to be consistent with every other architecture and set the max PFN for these zones to zero. Signed-off-by: Oliver O'Halloran Reviewed-by: Balbir Singh Signed-off-by: Michael Ellerman --- arch/powerpc/mm/mem.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 2fd57fa48429..9eac9d46f54b 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -239,8 +239,14 @@ static int __init mark_nonram_nosave(void) static bool zone_limits_final; +/* + * The memory zones past TOP_ZONE are managed by generic mm code. + * These should be set to zero since that's what every other + * architecture does. + */ static unsigned long max_zone_pfns[MAX_NR_ZONES] = { - [0 ... MAX_NR_ZONES - 1] = ~0UL + [0 ... TOP_ZONE ] = ~0UL, + [TOP_ZONE + 1 ... MAX_NR_ZONES - 1] = 0 }; /* -- 2.30.2