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Subject[RESEND PATCH V6 5/6] dmaengine: pl330: Make sure microcode is privileged
Date
From: Mitchel Humpherys <mitchelh@codeaurora.org>

The PL330 performs privileged instruction fetches. This can result in
SMMU permission faults on SMMUs that implement the ARMv8 VMSA, which
specifies that mappings that are writeable at one execution level shall
not be executable at any higher-privileged level. Fix this by using the
DMA_ATTR_PRIVILEGED attribute, which will ensure that the microcode
IOMMU mapping is only accessible to the privileged level.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
---

[V6] No change

drivers/dma/pl330.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 030fe05..1a8bac2 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -1854,14 +1854,16 @@ static int dmac_alloc_resources(struct pl330_dmac *pl330)
{
int chans = pl330->pcfg.num_chan;
int ret;
+ unsigned long dma_attrs = DMA_ATTR_PRIVILEGED;

/*
* Alloc MicroCode buffer for 'chans' Channel threads.
* A channel's buffer offset is (Channel_Id * MCODE_BUFF_PERCHAN)
*/
- pl330->mcode_cpu = dma_alloc_coherent(pl330->ddma.dev,
+ pl330->mcode_cpu = dma_alloc_attrs(pl330->ddma.dev,
chans * pl330->mcbufsz,
- &pl330->mcode_bus, GFP_KERNEL);
+ &pl330->mcode_bus, GFP_KERNEL,
+ dma_attrs);
if (!pl330->mcode_cpu) {
dev_err(pl330->ddma.dev, "%s:%d Can't allocate memory!\n",
__func__, __LINE__);
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
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