Messages in this thread |  | | Date | Sat, 16 Apr 2022 09:35:13 +0200 | From | Corentin Labbe <> | Subject | Re: [PATCH 0/2] riscv: implement Zicbom-based CMO instructions + the t-head variant |
| |
Le Fri, Apr 15, 2022 at 09:19:23PM -0500, Samuel Holland a écrit : > 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 >
This behavour is not present at least on ARM and ARM64. The sample code I provided does not corrupt the buffer on them.
Regards
|  |