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| author |   Mike Rapoport <rppt@linux.ibm.com> | 2019-12-04 14:35:24 +0200 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2019-12-13 21:27:55 +1100 |
| commit | 8fabc623238e68b3ac63c0dd1657bf86c1fa33af (patch) | |
| tree | a818219c53fc6bf44e240eca0d537d10a88801ef /arch/powerpc/mm | |
| parent | powerpc/shared: Use static key to detect shared processor (diff) | |
| download | linux-dev-8fabc623238e68b3ac63c0dd1657bf86c1fa33af.tar.xz linux-dev-8fabc623238e68b3ac63c0dd1657bf86c1fa33af.zip | |
powerpc: Ensure that swiotlb buffer is allocated from low memory
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
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/mem.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 9488b63dfc87..617c2777926f 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -289,6 +289,14 @@ 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 |