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