Re: [PATCH v8 1/5] ARM: add basic support for Trusted Foundations

[Alex Courbot <acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

On 10/15/2013 04:07 AM, Russell King - ARM Linux wrote:
> On Fri, Oct 11, 2013 at 02:45:34PM -0700, Alexandre Courbot wrote:
>> Trusted Foundations is a TrustZone-based secure monitor for ARM that
>> can be invoked using the same SMC-based API on all supported
>> platforms. This patch adds initial basic support for Trusted
>> Foundations using the ARM firmware API. Current features are limited
>> to the ability to boot secondary processors.
>>
>> Note: The API followed by Trusted Foundations does *not* follow the SMC
>> calling conventions. It has nothing to do with PSCI neither and is only
>> relevant to devices that use Trusted Foundations (like most Tegra-based
>> retail devices).
>>
>> Signed-off-by: Alexandre Courbot <acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
>> Reviewed-by: Tomasz Figa <t.figa-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
>> Reviewed-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
>> ---
>>   .../arm/firmware/tl,trusted-foundations.txt        | 20 ++++++
>>   .../devicetree/bindings/vendor-prefixes.txt        |  1 +
>>   arch/arm/Kconfig                                   |  2 +
>>   arch/arm/Makefile                                  |  1 +
>>   arch/arm/firmware/Kconfig                          | 28 ++++++++
>>   arch/arm/firmware/Makefile                         |  1 +
>>   arch/arm/firmware/trusted_foundations.c            | 79 ++++++++++++++++++++++
>>   arch/arm/include/asm/trusted_foundations.h         | 68 +++++++++++++++++++
>>   8 files changed, 200 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/arm/firmware/tl,trusted-foundations.txt
>>   create mode 100644 arch/arm/firmware/Kconfig
>>   create mode 100644 arch/arm/firmware/Makefile
>>   create mode 100644 arch/arm/firmware/trusted_foundations.c
>>   create mode 100644 arch/arm/include/asm/trusted_foundations.h
>
> Is having this under arch/arm appropriate?  What happens if the API
> gets re-used on ARM64 for example?  Would drivers/firmware be a better
> cross-arch location for this?

The reason why this has been put into arch/arm is that the firmware_ops 
feature this patch depends also resides there 
(arch/arm/include/asm/firmware.h).

On the other hand it might also make sense to move firmware_ops out of 
ARM since I don't see anything ARM-specific with it. Tomasz, could we 
have your thoughts on this?

>> diff --git a/arch/arm/include/asm/trusted_foundations.h b/arch/arm/include/asm/trusted_foundations.h
>> new file mode 100644
>> index 0000000..c6f20bd
>> --- /dev/null
>> +++ b/arch/arm/include/asm/trusted_foundations.h
>> @@ -0,0 +1,68 @@
>> +/*
>> + * Copyright (c) 2013, NVIDIA Corporation.
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful, but WITHOUT
>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
>> + * more details.
>> + */
>> +
>> +/*
>> + * Support for the Trusted Foundations secure monitor.
>> + *
>> + * Trusted Foundation comes active on some ARM consumer devices (most
>> + * Tegra-based devices sold on the market are concerned). Such devices can only
>> + * perform some basic operations, like setting the CPU reset vector, through
>> + * SMC calls to the secure monitor. The calls are completely specific to
>> + * Trusted Foundations, and do *not* follow the SMC calling convention or the
>> + * PSCI standard.
>> + */
>> +
>> +#ifndef __ASM_ARM_TRUSTED_FOUNDATIONS_H
>> +#define __ASM_ARM_TRUSTED_FOUNDATIONS_H
>> +
>> +#include <linux/kconfig.h>
>> +
>> +struct trusted_foundations_platform_data {
>> +	unsigned int version_major;
>> +	unsigned int version_minor;
>> +};
>> +
>> +#if IS_ENABLED(CONFIG_TRUSTED_FOUNDATIONS)
>> +
>> +void register_trusted_foundations(struct trusted_foundations_platform_data *pd);
>> +void of_register_trusted_foundations(void);
>> +
>> +#else /* CONFIG_TRUSTED_FOUNDATIONS */
>> +
>> +#include <linux/printk.h>
>> +#include <linux/of.h>
>> +#include <asm/bug.h>
>
> Please move these up along side the other #include - having includes depend
> on config symbols is an additional unnecessary source of fragility.
>
> Secondly, please use linux/*.h includes in preference to asm/*.h where the
> linux/*.h include picks up the corresponding asm/*.h include.  In this case,
> that should be linux/bug.h, not asm/bug.h.

Will do, thanks!

Alex.