From: Mike Rapoport Date: Wed, 4 Dec 2019 12:35:24 +0000 (+0200) Subject: powerpc: Ensure that swiotlb buffer is allocated from low memory X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=497e53c3482b2343e5e288a7cf916f87e9d21b19;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git powerpc: Ensure that swiotlb buffer is allocated from low memory [ Upstream commit 8fabc623238e68b3ac63c0dd1657bf86c1fa33af ] Some powerpc platforms (e.g. 85xx) limit DMA-able memory way below 4G. If a system has more physical memory than this limit, the swiotlb buffer is not addressable because it is allocated from memblock using top-down mode. Force memblock to bottom-up mode before calling swiotlb_init() to ensure that the swiotlb buffer is DMA-able. Reported-by: Christian Zigotzky Signed-off-by: Mike Rapoport Reviewed-by: Christoph Hellwig Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191204123524.22919-1-rppt@kernel.org Signed-off-by: Sasha Levin --- diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 1e93dbc88e80..34f70d36b16d 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -345,6 +345,14 @@ void __init mem_init(void) BUILD_BUG_ON(MMU_PAGE_COUNT > 16); #ifdef CONFIG_SWIOTLB + /* + * Some platforms (e.g. 85xx) limit DMA-able memory way below + * 4G. We force memblock to bottom-up mode to ensure that the + * memory allocated in swiotlb_init() is DMA-able. + * As it's the last memblock allocation, no need to reset it + * back to to-down. + */ + memblock_set_bottom_up(true); swiotlb_init(0); #endif