Messages in this thread | | | Date | Wed, 31 May 2023 01:08:29 +0100 | Subject | Re: [PATCH v2 2/3] soc: qcom: rmtfs: Support discarding guard pages | From | Caleb Connolly <> |
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On 31/05/2023 00:36, Bjorn Andersson wrote: > In some configurations, the exact placement of the rmtfs shared memory > region isn't so strict. The DeviceTree author can then choose to use the > "size" property and rely on the OS for placement (in combination with > "alloc-ranges", if desired). > > But on some platforms the rmtfs memory region may not be allocated > adjacent to regions allocated by other clients. Add support for > discarding the first and last 4k block in the region, if > qcom,use-guard-pages is specified in DeviceTree.
Oh nice! > > Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com> > --- > > Changes since v1: > - Drop the dma_alloc_coherent() based approach and just add support for > the guard pages. > > drivers/soc/qcom/rmtfs_mem.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/soc/qcom/rmtfs_mem.c b/drivers/soc/qcom/rmtfs_mem.c > index f83811f51175..28238974d913 100644 > --- a/drivers/soc/qcom/rmtfs_mem.c > +++ b/drivers/soc/qcom/rmtfs_mem.c > @@ -213,6 +213,16 @@ static int qcom_rmtfs_mem_probe(struct platform_device *pdev) > goto put_device; > } > > + /* > + * If requested, discard the first and last 4k block in order to ensure > + * that the rmtfs region isn't adjacent to other protected regions. > + */ > + if (of_property_present(node, "qcom,use-guard-pages")) { > + rmtfs_mem->addr += SZ_4K; > + rmtfs_mem->base += SZ_4K; > + rmtfs_mem->size -= 2 * SZ_4K; > + } > + > cdev_init(&rmtfs_mem->cdev, &qcom_rmtfs_mem_fops); > rmtfs_mem->cdev.owner = THIS_MODULE; >
-- // Caleb (they/them)
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