Messages in this thread | | | Subject | Re: [PATCH 0/2] riscv: implement Zicbom-based CMO instructions + the t-head variant | From | Samuel Holland <> | Date | Fri, 15 Apr 2022 21:19:23 -0500 |
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On 4/15/22 6:26 AM, Corentin Labbe wrote: > Le Mon, Mar 07, 2022 at 11:46:18PM +0100, Heiko Stuebner a écrit : >> This series is based on the alternatives changes done in my svpbmt series >> and thus also depends on Atish's isa-extension parsing series. >> >> It implements using the cache-management instructions from the Zicbom- >> extension to handle cache flush, etc actions on platforms needing them. >> >> SoCs using cpu cores from T-Head like the Allwinne D1 implement a >> different set of cache instructions. But while they are different, >> instructions they provide the same functionality, so a variant can >> easly hook into the existing alternatives mechanism on those. >> >> > > Hello > > I am testing https://github.com/smaeul/linux.git branch:origin/riscv/d1-wip which contain this serie. > > I am hitting a buffer corruption problem with DMA. > The sun8i-ce crypto driver fail self tests due to "device overran destination buffer". > In fact the buffer is not overran by device but by dma_map_single() operation. > > The following small code show the problem: > > dma_addr_t dma; > u8 *buf; > #define BSIZE 2048 > #define DMASIZE 16 > > buf = kmalloc(BSIZE, GFP_KERNEL | GFP_DMA); > for (i = 0; i < BSIZE; i++) > buf[i] = 0xFE; > print_hex_dump(KERN_INFO, "DMATEST1:", DUMP_PREFIX_NONE, 16, 4, buf, 256, false); > dma = dma_map_single(ce->dev, buf, DMASIZE, DMA_FROM_DEVICE);
This function (through dma_direct_map_page()) ends up calling arch_sync_dma_for_device(..., ..., DMA_FROM_DEVICE), which invalidates the CPU's cache. This is the same thing other architectures do (at least arm, arm64, openrisc, and powerpc). So this appears to be working as intended.
Regards, Samuel
> dma_unmap_single(ce->dev, dma, DMASIZE, DMA_FROM_DEVICE); > print_hex_dump(KERN_INFO, "DMATEST3:", DUMP_PREFIX_NONE, 16, 4, buf, 256, false); > > Will lead to: > [ 2.960040] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 2.965354] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 2.970709] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 2.976069] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 2.981440] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 2.986814] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 2.992188] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 2.997560] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 3.002934] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 3.008307] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 3.013680] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 3.019054] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 3.024427] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 3.029802] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 3.035175] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 3.040546] DMATEST1:fefefefe fefefefe fefefefe fefefefe > [ 3.401647] DMATEST3:a9c3a9c3 a9c3a9c3 a9c3a9c3 a9c3a9c3 > [ 3.406982] DMATEST3:a9c3a9c3 a9c3a9c3 a9c3a9c3 a9c3a9c3 > [ 3.412350] DMATEST3:a9c3a9c3 a9c3a9c3 a9c3a9c3 a9c3a9c3 > [ 3.417720] DMATEST3:a9c3a9c3 a9c3a9c3 a9c3a9c3 a9c3a9c3 > [ 3.423094] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.428468] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.433841] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.439213] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.444588] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.449962] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.455334] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.460707] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.466081] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.471454] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.476828] DMATEST3:fefefefe fefefefe fefefefe fefefefe > [ 3.482200] DMATEST3:fefefefe fefefefe fefefefe fefefefe > > Even with no DMA action, the buffer is corrupted. > > Regards >
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