2023-07-26 10:30:28

by Simon Horman

[permalink] [raw]
Subject: Re: [PATCH v2 05/11] firewall: introduce stm32_firewall framework

On Tue, Jul 25, 2023 at 06:40:58PM +0200, Gatien Chevallier wrote:
> Introduce a STM32 firewall framework that offers to firewall consumers
> different firewall services such as the ability to check their access
> rights against their firewall controller(s).
>
> The STM32 firewall framework offers a generic API for STM32 firewall
> controllers that is defined in their drivers to best fit the
> specificity of each firewall.
>
> There are various types of firewalls:
> -Peripheral firewalls that filter accesses to peripherals
> -Memory firewalls that filter accesses to memories or memory regions
> -No type for undefined type of firewall
>
> Signed-off-by: Gatien Chevallier <[email protected]>

...

> diff --git a/drivers/bus/stm32_firewall.c b/drivers/bus/stm32_firewall.c

...

> +int stm32_firewall_populate_bus(struct stm32_firewall_controller *firewall_controller)
> +{
> + struct stm32_firewall *firewalls;
> + struct device_node *child;
> + struct device *parent;
> + unsigned int i;
> + int len;
> + int err;
> +
> + parent = firewall_controller->dev;
> +
> + dev_dbg(parent, "Populating %s system bus\n", dev_name(firewall_controller->dev));
> +
> + for_each_available_child_of_node(dev_of_node(parent), child) {
> + /* The feature-domains property is mandatory for firewall bus devices */
> + len = of_count_phandle_with_args(child, "feature-domains", "#feature-domain-cells");
> + if (len <= 0)

Coccinelle says that, due to breaking out of a
for_each_available_child_of_node() loop, a call to of_node_put()
is needed here

> + return -EINVAL;
> +
> + firewalls = kcalloc(len, sizeof(*firewalls), GFP_KERNEL);
> + if (!firewalls)

And here.

> + return -ENOMEM;
> +
> + err = stm32_firewall_get_firewall(child, firewalls, (unsigned int)len);
> + if (err) {
> + kfree(firewalls);

And here.

> + return err;
> + }
> +
> + for (i = 0; i < len; i++) {
> + if (firewall_controller->grant_access(firewall_controller,
> + firewalls[i].firewall_id)) {
> + /*
> + * Peripheral access not allowed or not defined.
> + * Mark the node as populated so platform bus won't probe it
> + */
> + of_node_set_flag(child, OF_POPULATED);
> + dev_err(parent, "%s: Device driver will not be probed\n",
> + child->full_name);
> + }
> + }
> +
> + kfree(firewalls);
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(stm32_firewall_populate_bus);

> diff --git a/drivers/bus/stm32_firewall.h b/drivers/bus/stm32_firewall.h

...

> +/**
> + * struct stm32_firewall_controller - Information on firewall controller supplying services
> + *
> + * @name Name of the firewall controller

kernel-doc complains that name and the other fields of
struct stm32_firewall_controller are not documented.
I believe this is because a ':' is needed after the name of
the parameter (in this case 'name').

* @name: Name of the firewall controller

Likewise, elsewhere.

> + * @dev Device reference of the firewall controller
> + * @mmio Base address of the firewall controller
> + * @entry List entry of the firewall controller list
> + * @type Type of firewall
> + * @max_entries Number of entries covered by the firewall
> + * @grant_access Callback used to grant access for a device access against a
> + * firewall controller
> + * @release_access Callback used to release resources taken by a device when access was
> + * granted
> + * @grant_memory_range_access Callback used to grant access for a device to a given memory region
> + */
> +struct stm32_firewall_controller {
> + const char *name;
> + struct device *dev;
> + void __iomem *mmio;
> + struct list_head entry;
> + unsigned int type;
> + unsigned int max_entries;
> +
> + int (*grant_access)(struct stm32_firewall_controller *ctrl, u32 id);
> + void (*release_access)(struct stm32_firewall_controller *ctrl, u32 id);
> + int (*grant_memory_range_access)(struct stm32_firewall_controller *ctrl, phys_addr_t paddr,
> + size_t size);
> +};
> +
> +/**
> + * int stm32_firewall_controller_register - Register a firewall controller to the STM32 firewall

kernel-doc seems unhappy about the presence of 'int' on this line.

* stm32_firewall_controller_register - Register a firewall controller to the STM32 firewall

Likewise, elsewhere.

> + * framework
> + * @firewall_controller Firewall controller to register
> + *
> + * Returns 0 in case of success or -ENODEV if no controller was given.
> + */
> +int stm32_firewall_controller_register(struct stm32_firewall_controller *firewall_controller);

...

> diff --git a/include/linux/bus/stm32_firewall_device.h b/include/linux/bus/stm32_firewall_device.h
> new file mode 100644
> index 000000000000..9bdc4060154c
> --- /dev/null
> +++ b/include/linux/bus/stm32_firewall_device.h
> @@ -0,0 +1,140 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2023, STMicroelectronics - All Rights Reserved
> + */
> +
> +#ifndef STM32_FIREWALL_DEVICE_H
> +#define STM32_FIREWALL_DEVICE_H
> +
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/types.h>
> +
> +#define STM32_FIREWALL_MAX_EXTRA_ARGS 5
> +
> +/* Opaque reference to stm32_firewall_controller */
> +struct stm32_firewall_controller;
> +
> +/**
> + * stm32_firewall - Information on a device's firewall. Each device can have more than one firewall.

kernel-doc seems unhappy about the absence of struct on this line.

* struct stm32_firewall - Information on a device's firewall. Each device can have more than one firewall.

> + *
> + * @firewall_ctrl Pointer referencing a firewall controller of the device. It is
> + * opaque so a device cannot manipulate the controller's ops or access
> + * the controller's data
> + * @extra_args Extra arguments that are implementation dependent
> + * @entry Name of the firewall entry
> + * @extra_args_size Number of extra arguments
> + * @firewall_id Firewall ID associated the device for this firewall controller
> + */
> +struct stm32_firewall {
> + struct stm32_firewall_controller *firewall_ctrl;
> + u32 extra_args[STM32_FIREWALL_MAX_EXTRA_ARGS];
> + const char *entry;
> + size_t extra_args_size;
> + u32 firewall_id;
> +};

...

--
pw-bot: changes-requested


2023-07-26 10:41:23

by Gatien CHEVALLIER

[permalink] [raw]
Subject: Re: [PATCH v2 05/11] firewall: introduce stm32_firewall framework



On 7/26/23 12:19, Simon Horman wrote:
> On Tue, Jul 25, 2023 at 06:40:58PM +0200, Gatien Chevallier wrote:
>> Introduce a STM32 firewall framework that offers to firewall consumers
>> different firewall services such as the ability to check their access
>> rights against their firewall controller(s).
>>
>> The STM32 firewall framework offers a generic API for STM32 firewall
>> controllers that is defined in their drivers to best fit the
>> specificity of each firewall.
>>
>> There are various types of firewalls:
>> -Peripheral firewalls that filter accesses to peripherals
>> -Memory firewalls that filter accesses to memories or memory regions
>> -No type for undefined type of firewall
>>
>> Signed-off-by: Gatien Chevallier <[email protected]>
>
> ...
>
>> diff --git a/drivers/bus/stm32_firewall.c b/drivers/bus/stm32_firewall.c
>
> ...
>
>> +int stm32_firewall_populate_bus(struct stm32_firewall_controller *firewall_controller)
>> +{
>> + struct stm32_firewall *firewalls;
>> + struct device_node *child;
>> + struct device *parent;
>> + unsigned int i;
>> + int len;
>> + int err;
>> +
>> + parent = firewall_controller->dev;
>> +
>> + dev_dbg(parent, "Populating %s system bus\n", dev_name(firewall_controller->dev));
>> +
>> + for_each_available_child_of_node(dev_of_node(parent), child) {
>> + /* The feature-domains property is mandatory for firewall bus devices */
>> + len = of_count_phandle_with_args(child, "feature-domains", "#feature-domain-cells");
>> + if (len <= 0)
>
> Coccinelle says that, due to breaking out of a
> for_each_available_child_of_node() loop, a call to of_node_put()
> is needed here
>

Hi Simon,

Thank you, I already sent a V3 correcting the patch ordering issue. I
will implement this for V4.

>> + return -EINVAL;
>> +
>> + firewalls = kcalloc(len, sizeof(*firewalls), GFP_KERNEL);
>> + if (!firewalls)
>
> And here.
>

ditto

>> + return -ENOMEM;
>> +
>> + err = stm32_firewall_get_firewall(child, firewalls, (unsigned int)len);
>> + if (err) {
>> + kfree(firewalls);
>
> And here.
>

ditto

>> + return err;
>> + }
>> +
>> + for (i = 0; i < len; i++) {
>> + if (firewall_controller->grant_access(firewall_controller,
>> + firewalls[i].firewall_id)) {
>> + /*
>> + * Peripheral access not allowed or not defined.
>> + * Mark the node as populated so platform bus won't probe it
>> + */
>> + of_node_set_flag(child, OF_POPULATED);
>> + dev_err(parent, "%s: Device driver will not be probed\n",
>> + child->full_name);
>> + }
>> + }
>> +
>> + kfree(firewalls);
>> + }
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(stm32_firewall_populate_bus);
>
>> diff --git a/drivers/bus/stm32_firewall.h b/drivers/bus/stm32_firewall.h
>
> ...
>
>> +/**
>> + * struct stm32_firewall_controller - Information on firewall controller supplying services
>> + *
>> + * @name Name of the firewall controller
>
> kernel-doc complains that name and the other fields of
> struct stm32_firewall_controller are not documented.
> I believe this is because a ':' is needed after the name of
> the parameter (in this case 'name').
>
> * @name: Name of the firewall controller
>
> Likewise, elsewhere.
>

I will implement it in V4, thank you.

>> + * @dev Device reference of the firewall controller
>> + * @mmio Base address of the firewall controller
>> + * @entry List entry of the firewall controller list
>> + * @type Type of firewall
>> + * @max_entries Number of entries covered by the firewall
>> + * @grant_access Callback used to grant access for a device access against a
>> + * firewall controller
>> + * @release_access Callback used to release resources taken by a device when access was
>> + * granted
>> + * @grant_memory_range_access Callback used to grant access for a device to a given memory region
>> + */
>> +struct stm32_firewall_controller {
>> + const char *name;
>> + struct device *dev;
>> + void __iomem *mmio;
>> + struct list_head entry;
>> + unsigned int type;
>> + unsigned int max_entries;
>> +
>> + int (*grant_access)(struct stm32_firewall_controller *ctrl, u32 id);
>> + void (*release_access)(struct stm32_firewall_controller *ctrl, u32 id);
>> + int (*grant_memory_range_access)(struct stm32_firewall_controller *ctrl, phys_addr_t paddr,
>> + size_t size);
>> +};
>> +
>> +/**
>> + * int stm32_firewall_controller_register - Register a firewall controller to the STM32 firewall
>
> kernel-doc seems unhappy about the presence of 'int' on this line.
>
> * stm32_firewall_controller_register - Register a firewall controller to the STM32 firewall
>
> Likewise, elsewhere.
>

Yes, I will remove the type in V4.

>> + * framework
>> + * @firewall_controller Firewall controller to register
>> + *
>> + * Returns 0 in case of success or -ENODEV if no controller was given.
>> + */
>> +int stm32_firewall_controller_register(struct stm32_firewall_controller *firewall_controller);
>
> ...
>
>> diff --git a/include/linux/bus/stm32_firewall_device.h b/include/linux/bus/stm32_firewall_device.h
>> new file mode 100644
>> index 000000000000..9bdc4060154c
>> --- /dev/null
>> +++ b/include/linux/bus/stm32_firewall_device.h
>> @@ -0,0 +1,140 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * Copyright (C) 2023, STMicroelectronics - All Rights Reserved
>> + */
>> +
>> +#ifndef STM32_FIREWALL_DEVICE_H
>> +#define STM32_FIREWALL_DEVICE_H
>> +
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/types.h>
>> +
>> +#define STM32_FIREWALL_MAX_EXTRA_ARGS 5
>> +
>> +/* Opaque reference to stm32_firewall_controller */
>> +struct stm32_firewall_controller;
>> +
>> +/**
>> + * stm32_firewall - Information on a device's firewall. Each device can have more than one firewall.
>
> kernel-doc seems unhappy about the absence of struct on this line.
>
> * struct stm32_firewall - Information on a device's firewall. Each device can have more than one firewall.
>

Yes, I will add the struct in V4.

>> + *
>> + * @firewall_ctrl Pointer referencing a firewall controller of the device. It is
>> + * opaque so a device cannot manipulate the controller's ops or access
>> + * the controller's data
>> + * @extra_args Extra arguments that are implementation dependent
>> + * @entry Name of the firewall entry
>> + * @extra_args_size Number of extra arguments
>> + * @firewall_id Firewall ID associated the device for this firewall controller
>> + */
>> +struct stm32_firewall {
>> + struct stm32_firewall_controller *firewall_ctrl;
>> + u32 extra_args[STM32_FIREWALL_MAX_EXTRA_ARGS];
>> + const char *entry;
>> + size_t extra_args_size;
>> + u32 firewall_id;
>> +};
>
> ...
>
Best regards,
Gatien

2023-07-26 11:49:48

by Simon Horman

[permalink] [raw]
Subject: Re: [PATCH v2 05/11] firewall: introduce stm32_firewall framework

On Wed, Jul 26, 2023 at 12:38:00PM +0200, Gatien CHEVALLIER wrote:
>
>
> On 7/26/23 12:19, Simon Horman wrote:
> > On Tue, Jul 25, 2023 at 06:40:58PM +0200, Gatien Chevallier wrote:
> > > Introduce a STM32 firewall framework that offers to firewall consumers
> > > different firewall services such as the ability to check their access
> > > rights against their firewall controller(s).
> > >
> > > The STM32 firewall framework offers a generic API for STM32 firewall
> > > controllers that is defined in their drivers to best fit the
> > > specificity of each firewall.
> > >
> > > There are various types of firewalls:
> > > -Peripheral firewalls that filter accesses to peripherals
> > > -Memory firewalls that filter accesses to memories or memory regions
> > > -No type for undefined type of firewall
> > >
> > > Signed-off-by: Gatien Chevallier <[email protected]>
> >
> > ...
> >
> > > diff --git a/drivers/bus/stm32_firewall.c b/drivers/bus/stm32_firewall.c
> >
> > ...
> >
> > > +int stm32_firewall_populate_bus(struct stm32_firewall_controller *firewall_controller)
> > > +{
> > > + struct stm32_firewall *firewalls;
> > > + struct device_node *child;
> > > + struct device *parent;
> > > + unsigned int i;
> > > + int len;
> > > + int err;
> > > +
> > > + parent = firewall_controller->dev;
> > > +
> > > + dev_dbg(parent, "Populating %s system bus\n", dev_name(firewall_controller->dev));
> > > +
> > > + for_each_available_child_of_node(dev_of_node(parent), child) {
> > > + /* The feature-domains property is mandatory for firewall bus devices */
> > > + len = of_count_phandle_with_args(child, "feature-domains", "#feature-domain-cells");
> > > + if (len <= 0)
> >
> > Coccinelle says that, due to breaking out of a
> > for_each_available_child_of_node() loop, a call to of_node_put()
> > is needed here
> >
>
> Hi Simon,
>
> Thank you, I already sent a V3 correcting the patch ordering issue. I
> will implement this for V4.

Hi Gatien,

Thanks and sorry for not noticing v3 - I think it arrived while
I was in the middle of reviewing v2.