From 03800e0526ee25ed7c843ca1e57b69ac2a5af642 Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Tue, 25 Jun 2019 10:17:27 -0400 Subject: powerpc: fix off by one in max_zone_pfn initialization for ZONE_DMA 25078dc1f74be16b858e914f52cc8f4d03c2271a first introduced an off by one error in the ZONE_DMA initialization of PPC_BOOK3E_64=y and since 9739ab7eda459f0669ec9807e0d9be5020bab88c the off by one applies to PPC32=y too. This simply corrects the off by one and should resolve crashes like below: [ 65.179101] page 0x7fff outside node 0 zone DMA [ 0x0 - 0x7fff ] Unfortunately in various MM places "max" means a non inclusive end of range. free_area_init_nodes max_zone_pfn parameter is one case and MAX_ORDER is another one (unrelated) that comes by memory. Reported-by: Zorro Lang Fixes: 25078dc1f74b ("powerpc: use mm zones more sensibly") Fixes: 9739ab7eda45 ("powerpc: enable a 30-bit ZONE_DMA for 32-bit pmac") Signed-off-by: Andrea Arcangeli Reviewed-by: Christoph Hellwig Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190625141727.2883-1-aarcange@redhat.com --- arch/powerpc/mm/mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc') diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 6d5f0fc76666..b6beb86e5300 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -249,7 +249,7 @@ void __init paging_init(void) #ifdef CONFIG_ZONE_DMA max_zone_pfns[ZONE_DMA] = min(max_low_pfn, - ((1UL << ARCH_ZONE_DMA_BITS) - 1) >> PAGE_SHIFT); + 1UL << (ARCH_ZONE_DMA_BITS - PAGE_SHIFT)); #endif max_zone_pfns[ZONE_NORMAL] = max_low_pfn; #ifdef CONFIG_HIGHMEM -- cgit v1.2.3-55-g7522