>At the end of this function we invoke kfree(metadata), which would be bad if that comes from dma_alloc_coherent().
+ if (mdata_phys) {
+ data = dma_alloc_coherent(dev, ehdr_size + hash_size, mdata_phys,
+ GFP_KERNEL);
+ } else {
+ data = kmalloc(ehdr_size + hash_size, GFP_KERNEL);
Adding dma_alloc_coherent without affecting the mss driver.
> As LKP points out, I don't seem to have this function.
Removing the qcom_get_scm_device() and calling dma_alloc_coherent from device context.
+ data = dma_alloc_coherent(dev, ehdr_size + hash_size, mdata_phys,
+ GFP_KERNEL);
>I am not thrilled about the idea of doing dma_alloc_coherent() in this file and dma_free_coherent() in the scm driver. Similarly, I consider these functions to operate in the context of the caller, so operating on the scm device's struct device isn't so nice.
>After trying various models I came to the conclusion that it was better to try to keep the MDT loader to just load MDT files, and move the SCM/PAS interaction out of that. Unfortunately we have a number of client drivers that would then need to (essentially) duplicate the content of qcom_mdt_pas_init() - so I left >that in there.
>I still believe that keeping the MDT loader focused on loading MDTs is a good idea, but I'm open to any suggestions for improvements in the interaction between these different components.
With this patch we moving all the dma_alloc_coherent() and dma_free_coherent() to the MDT loader.
So now the MDT loader has the functionality of loading and allocating memory
and the SCM driver packs the arguments and makes a call to the secure world.
-----Original Message-----
From: Bjorn Andersson <andersson@xxxxxxxxxx>
Sent: Tuesday, September 13, 2022 4:11 PM
To: Gokul krishna Krishnakumar (QUIC) <quic_gokukris@xxxxxxxxxxx>
Cc: Andy Gross <agross@xxxxxxxxxx>; Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxx>; Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>; linux-arm-msm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Trilok Soni (QUIC) <quic_tsoni@xxxxxxxxxxx>; Satya Durga Srinivasu Prabhala (QUIC) <quic_satyap@xxxxxxxxxxx>; Rajendra Nayak (QUIC) <quic_rjendra@xxxxxxxxxxx>; Elliot Berman (QUIC) <quic_eberman@xxxxxxxxxxx>; Guru Das Srinagesh (QUIC) <quic_gurus@xxxxxxxxxxx>
Subject: Re: [PATCH v1 2/2] soc: qcom: mdt_loader: Move the memory allocation into mdt loader
WARNING: This email originated from outside of Qualcomm. Please be wary of any links or attachments, and do not enable macros.
On Mon, Sep 12, 2022 at 11:41:32AM -0700, Gokul krishna Krishnakumar wrote:
> By moving the memory allocation to mdt loader we can simplify the scm
> call, by just packing arguments provided to it from the clients for
> making secuer world calls. We can also simplify the memory allocation
> for the qcom metadata, by just doing one memory allocation in the mdt
> loader.
>
> Signed-off-by: Gokul krishna Krishnakumar <quic_gokukris@xxxxxxxxxxx>
> ---
> drivers/remoteproc/qcom_q6v5_mss.c | 2 +-
> drivers/soc/qcom/mdt_loader.c | 41 ++++++++++++++++++++++++++++---------
> include/linux/soc/qcom/mdt_loader.h | 5 +++--
> 3 files changed, 35 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/remoteproc/qcom_q6v5_mss.c
> b/drivers/remoteproc/qcom_q6v5_mss.c
> index fddb63c..1919bfc 100644
> --- a/drivers/remoteproc/qcom_q6v5_mss.c
> +++ b/drivers/remoteproc/qcom_q6v5_mss.c
> @@ -947,7 +947,7 @@ static int q6v5_mpss_init_image(struct q6v5 *qproc, const struct firmware *fw,
> int ret;
> int i;
>
> - metadata = qcom_mdt_read_metadata(fw, &size, fw_name, qproc->dev);
> + metadata = qcom_mdt_read_metadata(fw, &size, fw_name,
> + qproc->dev, NULL);
At the end of this function we invoke kfree(metadata), which would be bad if that comes from dma_alloc_coherent().
> if (IS_ERR(metadata))
> return PTR_ERR(metadata);
>
> diff --git a/drivers/soc/qcom/mdt_loader.c
> b/drivers/soc/qcom/mdt_loader.c
[..]
> @@ -160,9 +164,18 @@ void *qcom_mdt_read_metadata(const struct firmware *fw, size_t *data_len,
> ehdr_size = phdrs[0].p_filesz;
> hash_size = phdrs[hash_segment].p_filesz;
>
> - data = kmalloc(ehdr_size + hash_size, GFP_KERNEL);
> - if (!data)
> - return ERR_PTR(-ENOMEM);
> + /*
> + * During the scm call memory protection will be enabled for the meta
> + * data blob, so make sure it's physically contiguous, 4K aligned and
> + * non-cachable to avoid XPU violations.
> + */
> + scm_dev = qcom_get_scm_device();
As LKP points out, I don't seem to have this function.
> + data = dma_alloc_coherent(scm_dev, ehdr_size + hash_size, mdata_phys,
> + GFP_KERNEL);
I am not thrilled about the idea of doing dma_alloc_coherent() in this file and dma_free_coherent() in the scm driver. Similarly, I consider these functions to operate in the context of the caller, so operating on the scm device's struct device isn't so nice.
After trying various models I came to the conclusion that it was better to try to keep the MDT loader to just load MDT files, and move the SCM/PAS interaction out of that. Unfortunately we have a number of client drivers that would then need to (essentially) duplicate the content of qcom_mdt_pas_init() - so I left that in there.
I still believe that keeping the MDT loader focused on loading MDTs is a good idea, but I'm open to any suggestions for improvements in the interaction between these different components.
Regards,
Bjorn
Attachment:
v2-0001-firmware-qcom_scm-Remove-memory-alloc-call-from-q.patch
Description: v2-0001-firmware-qcom_scm-Remove-memory-alloc-call-from-q.patch
Attachment:
v2-0002-soc-qcom-mdt_loader-Move-the-memory-allocation-in.patch
Description: v2-0002-soc-qcom-mdt_loader-Move-the-memory-allocation-in.patch
