From: Benjamin GAIGNARD <benjamin.gaignard@st.com>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: "broonie@kernel.org" <broonie@kernel.org>,
"robh@kernel.org" <robh@kernel.org>,
"arnd@arndb.de" <arnd@arndb.de>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
"fabio.estevam@nxp.com" <fabio.estevam@nxp.com>,
"lkml@metux.net" <lkml@metux.net>,
Loic PALLARDY <loic.pallardy@st.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-imx@nxp.com" <linux-imx@nxp.com>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"system-dt@lists.openampproject.org"
<system-dt@lists.openampproject.org>,
"stefano.stabellini@xilinx.com" <stefano.stabellini@xilinx.com>
Subject: Re: [PATCH v2 0/7] Introduce bus firewall controller framework
Date: Tue, 28 Jan 2020 16:46:41 +0000 [thread overview]
Message-ID: <7f54ec36-8022-a57a-c634-45257f4c6984@st.com> (raw)
In-Reply-To: <20200128163628.GB30489@bogus>
On 1/28/20 5:36 PM, Sudeep Holla wrote:
> On Tue, Jan 28, 2020 at 04:37:59PM +0100, Benjamin Gaignard wrote:
>> Bus firewall framework aims to provide a kernel API to set the configuration
>> of the harware blocks in charge of busses access control.
>>
>> Framework architecture is inspirated by pinctrl framework:
>> - a default configuration could be applied before bind the driver.
>> If a configuration could not be applied the driver is not bind
>> to avoid doing accesses on prohibited regions.
>> - configurations could be apllied dynamically by drivers.
>> - device node provides the bus firewall configurations.
>>
>> An example of bus firewall controller is STM32 ETZPC hardware block
>> which got 3 possible configurations:
>> - trust: hardware blocks are only accessible by software running on trust
>> zone (i.e op-tee firmware).
>> - non-secure: hardware blocks are accessible by non-secure software (i.e.
>> linux kernel).
>> - coprocessor: hardware blocks are only accessible by the coprocessor.
>> Up to 94 hardware blocks of the soc could be managed by ETZPC.
>>
> /me confused. Is ETZPC accessible from the non-secure kernel space to
> begin with ? If so, is it allowed to configure hardware blocks as secure
> or trusted ? I am failing to understand the overall design of a system
> with ETZPC controller.
Non-secure kernel could read the values set in ETZPC, if it doesn't match
with what is required by the device node the driver won't be probed.
Benjamin
>
>> At least two other hardware blocks can take benefits of this:
>> - ARM TZC-400: http://infocenter.arm.com/help/topic/com.arm.doc.100325_0001_02_en/arm_corelink_tzc400_trustzone_address_space_controller_trm_100325_0001_02_en.pdf
>> which is able to manage up to 8 regions in address space.
> I strongly have to disagree with the above and NACK any patch trying
> to do so. AFAIK, no system designed has TZC with non-secure access.
> So we simply can't access this in the kernel and hence need no driver
> for the same. Please avoid adding above misleading information in future.
>
> --
> Regards,
> Sudeep
>
next prev parent reply other threads:[~2020-01-28 16:47 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 15:37 [PATCH v2 0/7] Introduce bus firewall controller framework Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 1/7] dt-bindings: bus: Add firewall bindings Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 2/7] bus: Introduce firewall controller framework Benjamin Gaignard
2020-01-28 15:52 ` Greg KH
2020-01-28 16:41 ` Benjamin GAIGNARD
2020-01-28 16:57 ` Greg KH
2020-01-28 20:29 ` Benjamin GAIGNARD
2020-01-29 5:49 ` Greg KH
2020-01-29 9:42 ` Linus Walleij
2020-01-29 9:52 ` Greg KH
2020-01-29 11:17 ` Mark Brown
2020-01-31 8:37 ` Benjamin GAIGNARD
2020-01-31 9:06 ` Greg KH
2020-02-14 16:05 ` Linus Walleij
2020-02-14 21:40 ` Greg KH
2020-02-15 12:41 ` Benjamin GAIGNARD
2020-02-16 7:21 ` Greg KH
2020-01-28 15:38 ` [PATCH v2 3/7] base: Add calls to firewall controller Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 4/7] dt-bindings: bus: Add STM32 ETZPC " Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 5/7] bus: firewall: Add driver for STM32 ETZPC controller Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 6/7] ARM: dts: stm32: Add firewall node for stm32mp157 SoC Benjamin Gaignard
2020-01-28 15:38 ` [PATCH v2 7/7] ARM: dts: stm32: enable firewall controller node on stm32mp157c-ed1 Benjamin Gaignard
2020-01-28 16:36 ` [PATCH v2 0/7] Introduce bus firewall controller framework Sudeep Holla
2020-01-28 16:46 ` Benjamin GAIGNARD [this message]
2020-01-28 17:17 ` Sudeep Holla
2020-01-28 20:06 ` Benjamin GAIGNARD
2020-01-28 22:06 ` Robin Murphy
2020-01-29 13:40 ` Benjamin GAIGNARD
2020-01-31 18:25 ` Robin Murphy
2020-02-03 13:16 ` Benjamin GAIGNARD
2020-01-31 20:51 ` Florian Fainelli
2020-02-03 13:41 ` Benjamin GAIGNARD
2020-01-31 20:48 ` Florian Fainelli
2020-02-02 12:23 ` Mark Brown
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