| From 5879917741ae241e3be4a27f7f45d261ea1efcb2 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 4 Dec 2019 14:35:24 +0200 |
| Subject: powerpc: Ensure that swiotlb buffer is allocated from low memory |
| |
| From: Mike Rapoport <rppt@linux.ibm.com> |
| |
| [ 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 <chzigotzky@xenosoft.de> |
| Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> |
| Reviewed-by: Christoph Hellwig <hch@lst.de> |
| Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
| Link: https://lore.kernel.org/r/20191204123524.22919-1-rppt@kernel.org |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/powerpc/mm/mem.c | 8 ++++++++ |
| 1 file changed, 8 insertions(+) |
| |
| diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c |
| index d30a2e6e68b4..9f5b32163bda 100644 |
| --- a/arch/powerpc/mm/mem.c |
| +++ b/arch/powerpc/mm/mem.c |
| @@ -282,6 +282,14 @@ 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 |
| |
| -- |
| 2.20.1 |
| |
