linux-kernel - Re: [PATCH v2 11/11] firmware: qcom: scm: enable SHM bridge

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Date:   Thu, 5 Oct 2023 11:12:33 +0200
From:   Maximilian Luz <luzmaximilian@...il.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        kernel@...cinc.com,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH v2 11/11] firmware: qcom: scm: enable SHM bridge

Am 05/10/2023 um 09:12 schrieb Bartosz Golaszewski:
> On Thu, Oct 5, 2023 at 12:24 AM Maximilian Luz <luzmaximilian@...il.com> wrote:
>>
>> On 9/28/23 11:20, Bartosz Golaszewski wrote:
>>> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
>>>
>>> Extens the SCM memory allocator with using the SHM Bridge feature if
>>> available on the platform. This makes the trustzone only use dedicated
>>> buffers for SCM calls. We map the entire SCM genpool as a bridge.
>>>
>>> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
>>
>> This patch breaks something in early boot on my Surface Pro X (sc8180x).
>> Unfortunately I can't provide many details at the moment because the
>> only thing I can see are RCU stalls, and the traces from them are quite
>> useless.
>>
>> Without this patch, the rest of the series (with the fix you posted on
>> patch 6 applied) seems to work fine. Including both RFT qseecom patches.
>>
>> I plan to have a closer look at this once I have some more time though.
>>
> 
> Can it be the PAS image loading? This is something Andrew reported and
> I have it fixed for v3.

That is my current suspicion, but I haven't had the time to properly
check it yet.

Regards,
Max

> Bart
> 
>> Regards,
>> Max
>>
>>> ---
>>>    drivers/firmware/qcom/qcom_scm-mem.c | 42 ++++++++++++++++++++++++++--
>>>    1 file changed, 39 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/firmware/qcom/qcom_scm-mem.c b/drivers/firmware/qcom/qcom_scm-mem.c
>>> index eafecbe23770..12b12b15f46f 100644
>>> --- a/drivers/firmware/qcom/qcom_scm-mem.c
>>> +++ b/drivers/firmware/qcom/qcom_scm-mem.c
>>> @@ -16,6 +16,8 @@
>>>
>>>    #include "qcom_scm.h"
>>>
>>> +#define QCOM_SHM_BRIDGE_NUM_VM_SHIFT 9
>>> +
>>>    static size_t qcom_scm_mem_pool_size = SZ_2M;
>>>    module_param_named(qcom_scm_mem_pool_size, qcom_scm_mem_pool_size,
>>>                   ulong, 0400);
>>> @@ -108,8 +110,24 @@ phys_addr_t qcom_scm_mem_to_phys(void *vaddr)
>>>        return chunk->paddr;
>>>    }
>>>
>>> +static int qcom_scm_mem_shm_bridge_create(void)
>>> +{
>>> +     uint64_t pfn_and_ns_perm, ipfn_and_s_perm, size_and_flags, ns_perms;
>>> +
>>> +     ns_perms = (QCOM_SCM_PERM_WRITE | QCOM_SCM_PERM_READ);
>>> +     pfn_and_ns_perm = (u64)qcom_scm_mem.pbase | ns_perms;
>>> +     ipfn_and_s_perm = (u64)qcom_scm_mem.pbase | ns_perms;
>>> +     size_and_flags = qcom_scm_mem.size | (1 << QCOM_SHM_BRIDGE_NUM_VM_SHIFT);
>>> +
>>> +     return qcom_scm_create_shm_bridge(qcom_scm_mem.dev, pfn_and_ns_perm,
>>> +                                       ipfn_and_s_perm, size_and_flags,
>>> +                                       QCOM_SCM_VMID_HLOS);
>>> +}
>>> +
>>>    int qcom_scm_mem_enable(struct device *dev)
>>>    {
>>> +     int ret;
>>> +
>>>        INIT_RADIX_TREE(&qcom_scm_mem.chunks, GFP_ATOMIC);
>>>        spin_lock_init(&qcom_scm_mem.lock);
>>>        qcom_scm_mem.dev = dev;
>>> @@ -128,7 +146,25 @@ int qcom_scm_mem_enable(struct device *dev)
>>>
>>>        gen_pool_set_algo(qcom_scm_mem.pool, gen_pool_best_fit, NULL);
>>>
>>> -     return gen_pool_add_virt(qcom_scm_mem.pool,
>>> -                              (unsigned long)qcom_scm_mem.vbase,
>>> -                              qcom_scm_mem.pbase, qcom_scm_mem.size, -1);
>>> +     ret = gen_pool_add_virt(qcom_scm_mem.pool,
>>> +                             (unsigned long)qcom_scm_mem.vbase,
>>> +                             qcom_scm_mem.pbase, qcom_scm_mem.size, -1);
>>> +     if (ret)
>>> +             return ret;
>>> +
>>> +     ret = qcom_scm_enable_shm_bridge();
>>> +     if (ret) {
>>> +             if (ret == EOPNOTSUPP)
>>> +                     dev_info(dev, "SHM Bridge not supported\n");
>>> +             else
>>> +                     return ret;
>>> +     } else {
>>> +             ret = qcom_scm_mem_shm_bridge_create();
>>> +             if (ret)
>>> +                     return ret;
>>> +
>>> +             dev_info(dev, "SHM Bridge enabled\n");
>>> +     }
>>> +
>>> +     return 0;
>>>    }