| Date | Wed, 19 Apr 2023 07:22:50 -0700 (PDT) | Subject | Re: [PATCH 08/21] riscv: dma-mapping: only invalidate after DMA, not flush | From | Palmer Dabbelt <> |
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On Mon, 27 Mar 2023 05:13:04 PDT (-0700), arnd@kernel.org wrote: > From: Arnd Bergmann <arnd@arndb.de> > > No other architecture intentionally writes back dirty cache lines into > a buffer that a device has just finished writing into. If the cache is > clean, this has no effect at all, but if a cacheline in the buffer has > actually been written by the CPU, there is a drive bug that is likely > made worse by overwriting that buffer. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > arch/riscv/mm/dma-noncoherent.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c > index d919efab6eba..640f4c496d26 100644 > --- a/arch/riscv/mm/dma-noncoherent.c > +++ b/arch/riscv/mm/dma-noncoherent.c > @@ -42,7 +42,7 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size, > break; > case DMA_FROM_DEVICE: > case DMA_BIDIRECTIONAL: > - ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size); > + ALT_CMO_OP(inval, vaddr, size, riscv_cbom_block_size); > break; > default: > break;
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
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