Date:   Tue, 18 Apr 2023 20:22:16 +0530
From:   Mukesh Ojha <quic_mojha@...cinc.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        <agross@...nel.org>, <andersson@...nel.org>,
        <konrad.dybcio@...aro.org>, <corbet@....net>,
        <keescook@...omium.org>, <tony.luck@...el.com>,
        <gpiccoli@...lia.com>, <catalin.marinas@....com>, <will@...nel.org>
CC:     <linux-arm-msm@...r.kernel.org>,
        <linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-hardening@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-doc@...r.kernel.org>
Subject: Re: [PATCH v2 2/6] remoteproc: qcom: Move minidump specific data to
 qcom_minidump.h



On 4/18/2023 7:32 PM, Srinivas Kandagatla wrote:
> 
> 
> On 17/04/2023 14:22, Mukesh Ojha wrote:
>>
>>
>> On 4/14/2023 4:10 PM, Srinivas Kandagatla wrote:
>>>
>>>
>>> On 14/04/2023 08:05, Mukesh Ojha wrote:
>>>> Thanks again for coming back on this.
>>>>
>>>> On 4/14/2023 4:02 AM, Srinivas Kandagatla wrote:
>>>>>
>>>>>
>>>>> On 22/03/2023 13:30, Mukesh Ojha wrote:
>>>>>> Move minidump specific data types and macros to a separate internal
>>>>>> header(qcom_minidump.h) so that it can be shared among different
>>>>>
>>>>> minidump.h should be good as we are already in include/soc/qcom/
>>>>
>>>>
>>>> Initially, i wanted to protect the content of qcom_minidump.h 
>>>> between qcom_minidump.c and qcom_common.c
>>>>
>>>> Ideally, here qcom_minidump.h should be supplier/provider header and 
>>>> can 
>>>
>>> Am not sure if I understand the supplier concept correctly.
>>> AFAIU, we have a 2 sets of apis
>>>
>>> 1. get hold of minidump descriptor based on minidump_id fro gtoc 
>>> using qcom_minidump_subsystem_desc(). Am assuming which ever driver 
>>> uses this api will set there segments and regions in there respective 
>>> drivers.
>>>
>>> 2. setting regions/segments in APSS minidump descriptors which are 
>>> done via qcom_minidump_region_register(). TBH this should be renamed 
>>> to qcom_apss_minidump_region_register().
>>>
>>> mixing of thsee apis makes it bit confusing, specially we have these 
>>> two category of apis that deal with different things.
>>>
>>> Does it make sense to spit and abstract them properly by doing?
>>>
>>>
>>> 1. minidump driver to deal with handling gtoc and providing 
>>> descriptors to the consumers like remoteproc or apss, This can 
>>> probably live within smem driver as loc for this support is very 
>>> minimal and proabably rename the api accordingly.
>>>
>>
>>> 2. apss_minidump driver to allow other qcom drivers to 
>>> register/unregister regions within apss minidump descriptor.
>>>
>>> did I miss something?
>>
>> No, you are correct with your understanding.
>>
>> To your suggestion to split code and to keep 
>> qcom_minidump_subsystem_desc() live inside smem driver,
>>
>> And how about the header qcom_minidump.h, should we keep it separate 
>> than the apss minidump client header minidump.h ?
> 
> I tried to do what I suggested and it kinda looked okay w.r.t design but 
> started to look like a bit overdo.
> 
> other thing that I tried like what you have in patches but creating a 
> dedicated platform driver for minidump (along with apss minidump), just 
> like other smem devices like socinfo..
> 
> This should also get rid of qcom_minidump_ready().

This is exactly i have said below .

> 
>>
>> Since, you kind of understand the driver now, do you think it is worth
>> to create platform device for minidump from smem driver, and
>> have a probe inside apss minidump driver to solve chicken and egg 
>> problem for the clients who comes before minidump and try to register 
>> itself without doing ready check and apss_minidump can note this 
>> client entry and only register this region once minidump probe success 
>> and then it can register all the noted clients in one go.
> yes, it is doable.
> 
>>
>> The reason to do this would be apss_minidump driver has no meaning 
>> without smem, and for this reason checking qcom_minidump_ready() would 
>> not be ideal for at least qcom clients and for core kernel may be.
>>
> 
> how about something like this:

We are totally in sync, Thanks for your time spent on the snippet.

-Mukesh
> 
> -------------------->cut<-----------------------
> diff --git a/drivers/soc/qcom/minidump.c b/drivers/soc/qcom/minidump.c
> new file mode 100644
> index 000000000000..4171054b268d
> --- /dev/null
> +++ b/drivers/soc/qcom/minidump.c
> @@ -0,0 +1,100 @@
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/soc/qcom/smem.h>
> +#include <linux/soc/qcom/minidump.h>
> +
> +...
> +
> +struct minidump {
> +       struct minidump_global_toc      *md_gbl_toc;
> +       struct minidump_subsystem       *md_apss_toc;
> +       ...
> +};
> +
> +struct minidump *__md;
> +
> +struct minidump_subsystem *qcom_minidump_subsystem_desc(unsigned int 
> minidump_index)
> +{
> +       if (!__md)
> +               return PTR_ERR(-EPROBE_DEFER);
> +
> +       return &__mdgtoc->subsystems[minidump_index];
> +}
> +EXPORT_SYMBOL(qcom_minidump_subsystem_desc);
> +
> +
> +int qcom_minidump_apss_region_register(const struct 
> qcom_minidump_region *region)
> +{
> +       if (!__mdgtoc)
> +               return -EPROBE_DEFER;
> +       ...
> +}
> +EXPORT_SYMBOL_GPL(qcom_minidump_apss_region_register);
> +
> +static int qcom_minidump_init_apss_subsystem(struct minidumd *md)
> +{
> +       struct minidump_subsystem *apsstoc;
> +
> +       apsstoc = qcom_minidump_subsystem_desc(MINIDUMP_APSS_DESC);
> +       if (IS_ERR(apsstoc))
> +               return -EINVAL;
> +
> +       md->md_regions = kcalloc(MAX_NUM_ENTRIES,
> +                             sizeof(struct minidump_region), GFP_KERNEL);
> +       if (!md->md_regions)
> +               return -ENOMEM;
> +
> +       minidump.apss_toc = apsstoc;
> +
> +       ...
> +
> +       return 0;
> +}
> +static int qcom_minidump_probe(struct platform_device *pdev)
> +{
> +       struct minidump *md;
> +       struct minidump_global_toc *mdgtoc;
> +
> +       md = devm_kzalloc(&pdev->dev, sizeof(*md), GFP_KERNEL);
> +
> +       ...
> +       mdgtoc = qcom_smem_get(QCOM_SMEM_HOST_ANY, SBL_MINIDUMP_SMEM_ID, 
> &size);
> +       if (IS_ERR(mdgtoc)) {
> +               dev_err(&pdev->dev, "Couldn't find minidump\n");
> +               return ERR_PTR(mdgtoc);
> +       }
> +
> +       if (size < sizeof(*mdgtoc) || !mdgtoc->status) {
> +               dev_err(&pdev->dev, "Minidump table is not initialized\n");
> +               return ERR_PTR(-EINVAL);
> +       }
> +       ...
> +       qcom_minidump_init_apss_subsystem(md);
> +
> +       __md = md;
> +       ...
> +       return 0;
> +}
> +
> +static int qcom_minidump_remove(struct platform_device *pdev)
> +{
> +       struct qcom_minidump *qs = platform_get_drvdata(pdev);
> +
> +       ...
> +
> +       return 0;
> +}
> +
> +static struct platform_driver qcom_minidump_driver = {
> +       .probe = qcom_minidump_probe,
> +       .remove = qcom_minidump_remove,
> +       .driver  = {
> +               .name = "qcom-minidump",
> +       },
> +};
> +
> +module_platform_driver(qcom_minidump_driver);
> +
> +MODULE_DESCRIPTION("Qualcomm minidump driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:qcom-minidump");
> diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
> index 4f163d62942c..d54b07095ddd 100644
> --- a/drivers/soc/qcom/smem.c
> +++ b/drivers/soc/qcom/smem.c
> @@ -279,6 +279,7 @@ struct qcom_smem {
> 
>          u32 item_count;
>          struct platform_device *socinfo;
> +       struct platform_device *minidump;
>          struct smem_ptable *ptable;
>          struct smem_partition global_partition;
>          struct smem_partition partitions[SMEM_HOST_COUNT];
> @@ -1151,12 +1152,19 @@ static int qcom_smem_probe(struct 
> platform_device *pdev)
>          if (IS_ERR(smem->socinfo))
>                  dev_dbg(&pdev->dev, "failed to register socinfo 
> device\n");
> 
> +       smem->minidump = platform_device_register_data(&pdev->dev, 
> "qcom-minidump",
> + PLATFORM_DEVID_NONE, NULL,
> +                                                     0);
> +       if (IS_ERR(smem->minidump))
> +               dev_dbg(&pdev->dev, "failed to register minidump 
> device\n");
> +
>          return 0;
>   }
> 
>   static int qcom_smem_remove(struct platform_device *pdev)
>   {
>          platform_device_unregister(__smem->socinfo);
> +       platform_device_unregister(__smem->minidump);
> 
>          hwspin_lock_free(__smem->hwlock);
>          __smem = NULL;
> (END)
> -------------------->cut<-----------------------
> 
>> --Mukesh
>>>
>>> thanks,
>>> Srini
>>>
>>>> be shared among above qcom_minidump.c and qcom_common.c but since 
>>>> they are not in same directory, moved it inside include/soc/qcom/ as 
>>>> separate header than consumer header minidump.h . >
>>>> -Mukesh
>>>>>
>>>>> --srini
>>>>>
>>>>>> Qualcomm drivers.
>>>>>>
>>>>>> There is no change in functional behavior after this.
>>>>>>
>>>>>> Signed-off-by: Mukesh Ojha <quic_mojha@...cinc.com>
>>>>>> ---
>>>>>>   drivers/remoteproc/qcom_common.c | 56 
>>>>>> +---------------------------------
>>>>>>   include/soc/qcom/qcom_minidump.h | 66 
>>>>>> ++++++++++++++++++++++++++++++++++++++++
>>>>>>   2 files changed, 67 insertions(+), 55 deletions(-)
>>>>>>   create mode 100644 include/soc/qcom/qcom_minidump.h
>>>>>>
>>>>>> diff --git a/drivers/remoteproc/qcom_common.c 
>>>>>> b/drivers/remoteproc/qcom_common.c
>>>>>> index 805e525..88fc984 100644
>>>>>> --- a/drivers/remoteproc/qcom_common.c
>>>>>> +++ b/drivers/remoteproc/qcom_common.c
>>>>>> @@ -18,6 +18,7 @@
>>>>>>   #include <linux/slab.h>
>>>>>>   #include <linux/soc/qcom/mdt_loader.h>
>>>>>>   #include <linux/soc/qcom/smem.h>
>>>>>> +#include <soc/qcom/qcom_minidump.h>
>>>>>>   #include "remoteproc_internal.h"
>>>>>>   #include "qcom_common.h"
>>>>>> @@ -26,61 +27,6 @@
>>>>>>   #define to_smd_subdev(d) container_of(d, struct 
>>>>>> qcom_rproc_subdev, subdev)
>>>>>>   #define to_ssr_subdev(d) container_of(d, struct qcom_rproc_ssr, 
>>>>>> subdev)
>>>>>> -#define MAX_NUM_OF_SS           10
>>>>>> -#define MAX_REGION_NAME_LENGTH  16
>>>>>> -#define SBL_MINIDUMP_SMEM_ID    602
>>>>>> -#define MINIDUMP_REGION_VALID        ('V' << 24 | 'A' << 16 | 'L' 
>>>>>> << 8 | 'I' << 0)
>>>>>> -#define MINIDUMP_SS_ENCR_DONE        ('D' << 24 | 'O' << 16 | 'N' 
>>>>>> << 8 | 'E' << 0)
>>>>>> -#define MINIDUMP_SS_ENABLED        ('E' << 24 | 'N' << 16 | 'B' 
>>>>>> << 8 | 'L' << 0)
>>>>>> -
>>>>>> -/**
>>>>>> - * struct minidump_region - Minidump region
>>>>>> - * @name        : Name of the region to be dumped
>>>>>> - * @seq_num:        : Use to differentiate regions with same name.
>>>>>> - * @valid        : This entry to be dumped (if set to 1)
>>>>>> - * @address        : Physical address of region to be dumped
>>>>>> - * @size        : Size of the region
>>>>>> - */
>>>>>> -struct minidump_region {
>>>>>> -    char    name[MAX_REGION_NAME_LENGTH];
>>>>>> -    __le32    seq_num;
>>>>>> -    __le32    valid;
>>>>>> -    __le64    address;
>>>>>> -    __le64    size;
>>>>>> -};
>>>>>> -
>>>>>> -/**
>>>>>> - * struct minidump_subsystem - Subsystem's SMEM Table of content
>>>>>> - * @status : Subsystem toc init status
>>>>>> - * @enabled : if set to 1, this region would be copied during 
>>>>>> coredump
>>>>>> - * @encryption_status: Encryption status for this subsystem
>>>>>> - * @encryption_required : Decides to encrypt the subsystem 
>>>>>> regions or not
>>>>>> - * @region_count : Number of regions added in this subsystem toc
>>>>>> - * @regions_baseptr : regions base pointer of the subsystem
>>>>>> - */
>>>>>> -struct minidump_subsystem {
>>>>>> -    __le32    status;
>>>>>> -    __le32    enabled;
>>>>>> -    __le32    encryption_status;
>>>>>> -    __le32    encryption_required;
>>>>>> -    __le32    region_count;
>>>>>> -    __le64    regions_baseptr;
>>>>>> -};
>>>>>> -
>>>>>> -/**
>>>>>> - * struct minidump_global_toc - Global Table of Content
>>>>>> - * @status : Global Minidump init status
>>>>>> - * @md_revision : Minidump revision
>>>>>> - * @enabled : Minidump enable status
>>>>>> - * @subsystems : Array of subsystems toc
>>>>>> - */
>>>>>> -struct minidump_global_toc {
>>>>>> -    __le32                status;
>>>>>> -    __le32                md_revision;
>>>>>> -    __le32                enabled;
>>>>>> -    struct minidump_subsystem    subsystems[MAX_NUM_OF_SS];
>>>>>> -};
>>>>>> -
>>>>>>   struct qcom_ssr_subsystem {
>>>>>>       const char *name;
>>>>>>       struct srcu_notifier_head notifier_list;
>>>>>> diff --git a/include/soc/qcom/qcom_minidump.h 
>>>>>> b/include/soc/qcom/qcom_minidump.h
>>>>>> new file mode 100644
>>>>>> index 0000000..84c8605
>>>>>> --- /dev/null
>>>>>> +++ b/include/soc/qcom/qcom_minidump.h
>>>>>> @@ -0,0 +1,66 @@
>>>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>>>>> +/*
>>>>>> + * Qualcomm minidump shared data structures and macros
>>>>>> + *
>>>>>> + * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights 
>>>>>> reserved.
>>>>>> + */
>>>>>> +
>>>>>> +#ifndef _QCOM_MINIDUMP_H_
>>>>>> +#define _QCOM_MINIDUMP_H_
>>>>>> +
>>>>>> +#define MAX_NUM_OF_SS           10
>>>>>> +#define MAX_REGION_NAME_LENGTH  16
>>>>>> +#define SBL_MINIDUMP_SMEM_ID    602
>>>>>> +#define MINIDUMP_REGION_VALID        ('V' << 24 | 'A' << 16 | 'L' 
>>>>>> << 8 | 'I' << 0)
>>>>>> +#define MINIDUMP_SS_ENCR_DONE        ('D' << 24 | 'O' << 16 | 'N' 
>>>>>> << 8 | 'E' << 0)
>>>>>> +#define MINIDUMP_SS_ENABLED        ('E' << 24 | 'N' << 16 | 'B' 
>>>>>> << 8 | 'L' << 0)
>>>>>> +
>>>>>> +/**
>>>>>> + * struct minidump_region - Minidump region
>>>>>> + * @name        : Name of the region to be dumped
>>>>>> + * @seq_num:        : Use to differentiate regions with same name.
>>>>>> + * @valid        : This entry to be dumped (if set to 1)
>>>>>> + * @address        : Physical address of region to be dumped
>>>>>> + * @size        : Size of the region
>>>>>> + */
>>>>>> +struct minidump_region {
>>>>>> +    char    name[MAX_REGION_NAME_LENGTH];
>>>>>> +    __le32    seq_num;
>>>>>> +    __le32    valid;
>>>>>> +    __le64    address;
>>>>>> +    __le64    size;
>>>>>> +};
>>>>>> +
>>>>>> +/**
>>>>>> + * struct minidump_subsystem - Subsystem's SMEM Table of content
>>>>>> + * @status : Subsystem toc init status
>>>>>> + * @enabled : if set to 1, this region would be copied during 
>>>>>> coredump
>>>>>> + * @encryption_status: Encryption status for this subsystem
>>>>>> + * @encryption_required : Decides to encrypt the subsystem 
>>>>>> regions or not
>>>>>> + * @region_count : Number of regions added in this subsystem toc
>>>>>> + * @regions_baseptr : regions base pointer of the subsystem
>>>>>> + */
>>>>>> +struct minidump_subsystem {
>>>>>> +    __le32    status;
>>>>>> +    __le32    enabled;
>>>>>> +    __le32    encryption_status;
>>>>>> +    __le32    encryption_required;
>>>>>> +    __le32    region_count;
>>>>>> +    __le64    regions_baseptr;
>>>>>> +};
>>>>>> +
>>>>>> +/**
>>>>>> + * struct minidump_global_toc - Global Table of Content
>>>>>> + * @status : Global Minidump init status
>>>>>> + * @md_revision : Minidump revision
>>>>>> + * @enabled : Minidump enable status
>>>>>> + * @subsystems : Array of subsystems toc
>>>>>> + */
>>>>>> +struct minidump_global_toc {
>>>>>> +    __le32                status;
>>>>>> +    __le32                md_revision;
>>>>>> +    __le32                enabled;
>>>>>> +    struct minidump_subsystem    subsystems[MAX_NUM_OF_SS];
>>>>>> +};
>>>>>> +
>>>>>> +#endif  /* _QCOM_MINIDUMP_H_ */

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