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[PATCH v5 5/6] dmaengine: pl330: Make sure microcode is privileged

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  [PATCH v5 5/6] dmaengine: pl330: Make sure microcode is privileged Mitchel Humpherys <mitchelh@codeaurora.org> - 2016-07-28 01:50 +0200
    Re: [PATCH v5 5/6] dmaengine: pl330: Make sure microcode is  privileged Vinod Koul <vinod.koul@intel.com> - 2016-08-08 07:50 +0200

#1451582 — [PATCH v5 5/6] dmaengine: pl330: Make sure microcode is privileged

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>
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
---

Notes:
    v3..v4
    
      - Reworked against the new dma attrs format.

 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 4fc3ffbd5ca0..8cd624fc3760 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 Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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#1457535 — Re: [PATCH v5 5/6] dmaengine: pl330: Make sure microcode is privileged

On Wed, Jul 27, 2016 at 04:42:07PM -0700, Mitchel Humpherys wrote:
> The PL330 performs privileged instruction fetches.  This can result in
> SMMU permission faults on SMMUs that implement the ARMv8 VMSA, which

Lot of acronyms with no explanation whatsoever

> 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.

And I get satndalone patch with no context for the series!

> 
> 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>
> Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
> ---
> 
> Notes:
>     v3..v4
>     
>       - Reworked against the new dma attrs format.
> 
>  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 4fc3ffbd5ca0..8cd624fc3760 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 Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

-- 
~Vinod

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