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Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask

From Robin Murphy <robin.murphy@arm.com>
Newsgroups linux.kernel
Subject Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask
Date 2017-04-04 13:20 +0200
Message-ID <tsuFc-478-15@gated-at.bofh.it> (permalink)
References <tstSN-3z3-3@gated-at.bofh.it> <tstSN-3z3-5@gated-at.bofh.it> <tstSO-3z3-35@gated-at.bofh.it>
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On 04/04/17 11:18, Sricharan R wrote:
> Size of the dma-range is calculated as coherent_dma_mask + 1
> and passed to arch_setup_dma_ops further. It overflows when
> the coherent_dma_mask is set for full 64 bits 0xFFFFFFFFFFFFFFFF,
> resulting in size getting passed as 0 wrongly. Fix this by
> passsing in max(mask, mask + 1). Note that in this case
> when the mask is set to full 64bits, we will be passing the mask
> itself to arch_setup_dma_ops instead of the size. The real fix
> for this should be to make arch_setup_dma_ops receive the
> mask and handle it, to be done in the future.

Agreed; in the meantime, this fix is neat and robust enough.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>

> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> ---
>  drivers/of/device.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index c17c19d..c2ae6bb 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -107,7 +107,7 @@ void of_dma_configure(struct device *dev, struct device_node *np)
>  	ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
>  	if (ret < 0) {
>  		dma_addr = offset = 0;
> -		size = dev->coherent_dma_mask + 1;
> +		size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
>  	} else {
>  		offset = PFN_DOWN(paddr - dma_addr);
>  		dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
> 

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Thread

[PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Sricharan R <sricharan@codeaurora.org> - 2017-04-04 12:30 +0200
  Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Robin Murphy <robin.murphy@arm.com> - 2017-04-04 13:20 +0200
  Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Frank Rowand <frowand.list@gmail.com> - 2017-04-06 09:10 +0200
    Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Robin Murphy <robin.murphy@arm.com> - 2017-04-06 12:30 +0200
      Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Rob Herring <robh+dt@kernel.org> - 2017-04-06 16:00 +0200
        Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Robin Murphy <robin.murphy@arm.com> - 2017-04-06 16:50 +0200
      Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Frank Rowand <frowand.list@gmail.com> - 2017-04-06 21:30 +0200
    Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Sricharan R <sricharan@codeaurora.org> - 2017-04-06 13:10 +0200
      Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Frank Rowand <frowand.list@gmail.com> - 2017-04-06 21:40 +0200
        Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Sricharan R <sricharan@codeaurora.org> - 2017-04-07 06:20 +0200
        Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Robin Murphy <robin.murphy@arm.com> - 2017-04-07 16:50 +0200
          Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Frank Rowand <frowand.list@gmail.com> - 2017-04-08 01:20 +0200
            Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Robin Murphy <robin.murphy@arm.com> - 2017-04-10 15:30 +0200
    Re: [PATCH V10 06/12] of: device: Fix overflow of coherent_dma_mask Frank Rowand <frowand.list@gmail.com> - 2017-04-08 01:20 +0200

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