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Date: Wed, 08 Apr 2020 17:50:14 +0530
From: Sibi Sankar <sibis@...eaurora.org>
To: Bjorn Andersson <bjorn.andersson@...aro.org>
Cc: agross@...nel.org, ohad@...ery.com, linux-arm-msm@...r.kernel.org,
linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
evgreen@...omium.org, linux-arm-msm-owner@...r.kernel.org
Subject: Re: [PATCH] remoteproc: qcom_q6v5_mss: map/unmap mpss region
before/after use
Hey Bjorn,
Thanks for review!
On 2020-04-08 07:40, Bjorn Andersson wrote:
> On Tue 17 Mar 12:19 PDT 2020, Sibi Sankar wrote:
>
>> The application processor accessing the mpss region when the Q6 modem
>> is running will lead to an XPU violation. Fix this by un-mapping the
>> mpss region post copy during processor out of reset sequence and
>> coredumps.
>>
>
> Does this problem not apply to the "mba" region?
For mba region, memcpy is expected
to be completed before bringing
the Q6 out of reset. Downstream they
seem to use a wmb() to accomplish
this. Since we havn't observed any
issues until now, we can defer adding
any fixes related to mba region.
>
>> Signed-off-by: Sibi Sankar <sibis@...eaurora.org>
>> ---
>> drivers/remoteproc/qcom_q6v5_mss.c | 53
>> ++++++++++++++++--------------
>> 1 file changed, 29 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/remoteproc/qcom_q6v5_mss.c
>> b/drivers/remoteproc/qcom_q6v5_mss.c
>> index ce49c3236ff7c..b1ad4de179019 100644
>> --- a/drivers/remoteproc/qcom_q6v5_mss.c
>> +++ b/drivers/remoteproc/qcom_q6v5_mss.c
>> @@ -196,7 +196,6 @@ struct q6v5 {
>>
>> phys_addr_t mpss_phys;
>> phys_addr_t mpss_reloc;
>> - void *mpss_region;
>> size_t mpss_size;
>>
>> struct qcom_rproc_glink glink_subdev;
>> @@ -1061,6 +1060,18 @@ static int q6v5_reload_mba(struct rproc *rproc)
>> return ret;
>> }
>>
>> +static void *q6v5_da_to_va(struct rproc *rproc, u64 da, size_t len)
>> +{
>> + struct q6v5 *qproc = rproc->priv;
>> + int offset;
>> +
>> + offset = da - qproc->mpss_reloc;
>> + if (offset < 0 || offset + len > qproc->mpss_size)
>> + return NULL;
>> +
>> + return devm_ioremap_wc(qproc->dev, qproc->mpss_phys + offset, len);
>
> This function isn't expected to have side effects.
unfortunately doing ioremap/iounmap
for the entire region isn't sufficient,
while testing I found per region remap
/unmap was required i.e after we moved to
away from the validating the entire blog
in a single pass.
Now with the mpss_region out of the picture
da_to_va really made no sense without having
ioremap function in it. Let me know what you
think.
>
> So I think you should add the ioremap/iounmap to the beginning/end of
> mpss_load and the dump_segment directly instead.
>
>> +}
>> +
>> static int q6v5_mpss_load(struct q6v5 *qproc)
>> {
>> const struct elf32_phdr *phdrs;
>> @@ -1156,7 +1167,11 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>> goto release_firmware;
>> }
>>
>> - ptr = qproc->mpss_region + offset;
>> + ptr = q6v5_da_to_va(qproc->rproc, phdr->p_paddr, phdr->p_memsz);
>
> rproc_da_to_va() here.
sure
>
>> + if (!ptr) {
>> + dev_err(qproc->dev, "failed to map memory\n");
>
> Now this will be able to fail, so you should add this error handling
> snippet, just with a slightly different message.
sure
>
>> + goto release_firmware;
>> + }
>>
>> if (phdr->p_filesz && phdr->p_offset < fw->size) {
>> /* Firmware is large enough to be non-split */
>> @@ -1165,6 +1180,7 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>> "failed to load segment %d from truncated file %s\n",
>> i, fw_name);
>> ret = -EINVAL;
>> + devm_iounmap(qproc->dev, ptr);
>> goto release_firmware;
>> }
>>
>> @@ -1175,6 +1191,7 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>> ret = request_firmware(&seg_fw, fw_name, qproc->dev);
>> if (ret) {
>> dev_err(qproc->dev, "failed to load %s\n", fw_name);
>> + devm_iounmap(qproc->dev, ptr);
>> goto release_firmware;
>> }
>>
>> @@ -1187,6 +1204,7 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
>> memset(ptr + phdr->p_filesz, 0,
>> phdr->p_memsz - phdr->p_filesz);
>> }
>> + devm_iounmap(qproc->dev, ptr);
>
> Move this to the end an unmap the entire thing.
>
> And generally, please avoid devm for things where you manually unmap.
will take care of ^^ in the next re-spin.
>
> Regards,
> Bjorn
>
>> size += phdr->p_memsz;
>>
>> code_length = readl(qproc->rmb_base + RMB_PMI_CODE_LENGTH_REG);
>> @@ -1236,7 +1254,7 @@ static void qcom_q6v5_dump_segment(struct rproc
>> *rproc,
>> int ret = 0;
>> struct q6v5 *qproc = rproc->priv;
>> unsigned long mask = BIT((unsigned long)segment->priv);
>> - void *ptr = rproc_da_to_va(rproc, segment->da, segment->size);
>> + void *ptr = NULL;
>>
>> /* Unlock mba before copying segments */
>> if (!qproc->dump_mba_loaded) {
>> @@ -1250,10 +1268,15 @@ static void qcom_q6v5_dump_segment(struct
>> rproc *rproc,
>> }
>> }
>>
>> - if (!ptr || ret)
>> - memset(dest, 0xff, segment->size);
>> - else
>> + if (!ret)
>> + ptr = rproc_da_to_va(rproc, segment->da, segment->size);
>> +
>> + if (ptr) {
>> memcpy(dest, ptr, segment->size);
>> + devm_iounmap(qproc->dev, ptr);
>> + } else {
>> + memset(dest, 0xff, segment->size);
>> + }
>>
>> qproc->dump_segment_mask |= mask;
>>
>> @@ -1327,18 +1350,6 @@ static int q6v5_stop(struct rproc *rproc)
>> return 0;
>> }
>>
>> -static void *q6v5_da_to_va(struct rproc *rproc, u64 da, size_t len)
>> -{
>> - struct q6v5 *qproc = rproc->priv;
>> - int offset;
>> -
>> - offset = da - qproc->mpss_reloc;
>> - if (offset < 0 || offset + len > qproc->mpss_size)
>> - return NULL;
>> -
>> - return qproc->mpss_region + offset;
>> -}
>> -
>> static int qcom_q6v5_register_dump_segments(struct rproc *rproc,
>> const struct firmware *mba_fw)
>> {
>> @@ -1595,12 +1606,6 @@ static int q6v5_alloc_memory_region(struct q6v5
>> *qproc)
>>
>> qproc->mpss_phys = qproc->mpss_reloc = r.start;
>> qproc->mpss_size = resource_size(&r);
>> - qproc->mpss_region = devm_ioremap_wc(qproc->dev, qproc->mpss_phys,
>> qproc->mpss_size);
>> - if (!qproc->mpss_region) {
>> - dev_err(qproc->dev, "unable to map memory region: %pa+%zx\n",
>> - &r.start, qproc->mpss_size);
>> - return -EBUSY;
>> - }
>>
>> return 0;
>> }
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>> Forum,
>> a Linux Foundation Collaborative Project
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.
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