From 83fe7eb7539ec0739129c8b5a71c94f9790d419f Mon Sep 17 00:00:00 2001 From: Kory Maincent Date: Mon, 27 May 2024 21:03:34 +0800 Subject: [PATCH] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup mainline inclusion from mainline-v6.8-rc7 commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9Q8OH CVE: CVE-2024-27408 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bbcc1c83f343e580c3aa1f2a8593343bf7b55bba -------------------------------- The Linked list element and pointer are not stored in the same memory as the eDMA controller register. If the doorbell register is toggled before the full write of the linked list a race condition error will occur. In remote setup we can only use a readl to the memory to assure the full write has occurred. Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support") Reviewed-by: Serge Semin Reviewed-by: Manivannan Sadhasivam Signed-off-by: Kory Maincent Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-6-8e8c1acb7a46@bootlin.com Signed-off-by: Vinod Koul Conflicts: drivers/dma/dw-edma/dw-edma-v0-core.c [wangxiongfeng: Fix context conflicts] Signed-off-by: Xiongfeng Wang --- drivers/dma/dw-edma/dw-edma-v0-core.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c index 692de47b1670..cd739fdcbecc 100644 --- a/drivers/dma/dw-edma/dw-edma-v0-core.c +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c @@ -233,6 +233,20 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk) SET_LL(&llp->llp_high, upper_32_bits(chunk->ll_region.paddr)); } +static void dw_edma_v0_sync_ll_data(struct dw_edma_chunk *chunk) +{ + /* + * In case of remote eDMA engine setup, the DW PCIe RP/EP internal + * configuration registers and application memory are normally accessed + * over different buses. Ensure LL-data reaches the memory before the + * doorbell register is toggled by issuing the dummy-read from the remote + * LL memory in a hope that the MRd TLP will return only after the + * last MWr TLP is completed + */ + if (!(chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL)) + readl(chunk->ll_region.vaddr.io); +} + void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first) { struct dw_edma_chan *chan = chunk->chan; @@ -262,6 +276,9 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first) SET_CH(dw, chan->dir, chan->id, llp_high, upper_32_bits(chunk->ll_region.paddr)); } + + dw_edma_v0_sync_ll_data(chunk); + /* Doorbell */ SET_RW(dw, chan->dir, doorbell, FIELD_PREP(EDMA_V0_DOORBELL_CH_MASK, chan->id)); -- Gitee