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Revert "arm64: cache: Lower ARCH_DMA_MINALIGN to 64 (L1_CACHE_BYTES)"

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This reverts commit 65688d2a05.

Unfortunately, the original Qualcomm Kryo cores integrated into the
MSM8996 SoC feature an L2 cache with 128-byte lines which sits above
the Point of Coherency. Consequently, we must restore ARCH_DMA_MINALIGN
to its former ugly self so that non-coherent DMA can be performed safely
on devices built using this SoC.

Thanks to Jeffrey Hugo for confirming this with a hardware designer.

Link: https://lore.kernel.org/r/CAOCk7NqdpUZFMSXfGjw0_1NaSK5gyTLgpS9kSdZn1jmBy-QkfA@mail.gmail.com/
Reported-by: Yassine Oudjana <y.oudjana@protonmail.com>
Link: https://lore.kernel.org/r/uHgsRacR8hJ7nW-I-pIcehzg-lNIn7NJvaL7bP9tfAftFsBjsgaY2qTjG9zyBgxHkjNL1WPNrD7YVv2JVD2_Wy-a5VTbcq-1xEi8ZnwrXBo=@protonmail.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Will Deacon 2021-07-12 13:10:00 +01:00
parent e62e074814
commit c1132702c7
1 changed files with 1 additions and 1 deletions
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2
arch/arm64/include/asm/cache.h
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@ -47,7 +47,7 @@
* cache before the transfer is done, causing old data to be seen by
* the CPU.
*/
#define ARCH_DMA_MINALIGN L1_CACHE_BYTES
#define ARCH_DMA_MINALIGN (128)
#ifdef CONFIG_KASAN_SW_TAGS
#define ARCH_SLAB_MINALIGN (1ULL << KASAN_SHADOW_SCALE_SHIFT)