On Wed, Oct 9, 2013 at 4:47 PM, Olof Johansson <olof@xxxxxxxxx> wrote:
> On Fri, Oct 4, 2013 at 9:37 AM, Alexandre Courbot <acourbot@xxxxxxxxxx> 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@xxxxxxxxxx>
>> Reviewed-by: Tomasz Figa <t.figa@xxxxxxxxxxx>
>> Reviewed-by: Stephen Warren <swarren@xxxxxxxxxx>
>> ---
>> .../arm/firmware/tl,trusted-foundations.txt | 17 +++++
>> .../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 | 77 ++++++++++++++++++++++
>> arch/arm/include/asm/trusted_foundations.h | 64 ++++++++++++++++++
>> 8 files changed, 191 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
>>
>> diff --git a/Documentation/devicetree/bindings/arm/firmware/tl,trusted-foundations.txt b/Documentation/devicetree/bindings/arm/firmware/tl,trusted-foundations.txt
>> new file mode 100644
>> index 0000000..3954bbd
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/firmware/tl,trusted-foundations.txt
>> @@ -0,0 +1,17 @@
>> +Trusted Foundations
>> +
>> +Boards that use the Trusted Foundations secure monitor can signal its
>> +presence by declaring a node compatible with "tl,trusted-foundations"
>> +under the root node.
>> +
>> +Required properties:
>> +- compatible : "tl,trusted-foundations"
>> +- version-major : major version number of Trusted Foundations firmware
>> +- version-minor: minor version number of Trusted Foundations firmware
>> +
>> +Example:
>> + firmware {
>> + compatible = "tl,trusted-foundations";
>> + version-major = <2>;
>> + version-minor = <8>;
>> + };
>> diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
>> index 2956800..a374eaa 100644
>> --- a/Documentation/devicetree/bindings/vendor-prefixes.txt
>> +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
>> @@ -66,6 +66,7 @@ ste ST-Ericsson
>> stericsson ST-Ericsson
>> toumaz Toumaz
>> ti Texas Instruments
>> +tl Trusted Logic
>> toshiba Toshiba Corporation
>> v3 V3 Semiconductor
>> via VIA Technologies, Inc.
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>> index 1ad6fb6..bf14cec 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -1076,6 +1076,8 @@ config ARM_TIMER_SP804
>> select CLKSRC_MMIO
>> select CLKSRC_OF if OF
>>
>> +source "arch/arm/firmware/Kconfig"
>> +
>> source arch/arm/mm/Kconfig
>>
>> config ARM_NR_BANKS
>> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
>> index a37a50f..f26712c 100644
>> --- a/arch/arm/Makefile
>> +++ b/arch/arm/Makefile
>> @@ -268,6 +268,7 @@ core-$(CONFIG_KVM_ARM_HOST) += arch/arm/kvm/
>> core-y += arch/arm/kernel/ arch/arm/mm/ arch/arm/common/
>> core-y += arch/arm/net/
>> core-y += arch/arm/crypto/
>> +core-y += arch/arm/firmware/
>> core-y += $(machdirs) $(platdirs)
>>
>> drivers-$(CONFIG_OPROFILE) += arch/arm/oprofile/
>> diff --git a/arch/arm/firmware/Kconfig b/arch/arm/firmware/Kconfig
>> new file mode 100644
>> index 0000000..bb00ccf
>> --- /dev/null
>> +++ b/arch/arm/firmware/Kconfig
>> @@ -0,0 +1,28 @@
>> +config ARCH_SUPPORTS_FIRMWARE
>> + bool
>> +
>> +config ARCH_SUPPORTS_TRUSTED_FOUNDATIONS
>> + bool
>> + select ARCH_SUPPORTS_FIRMWARE
>> +
>> +menu "Firmware options"
>> + depends on ARCH_SUPPORTS_FIRMWARE
>> +
>> +config TRUSTED_FOUNDATIONS
>> + bool "Trusted Foundations secure monitor support"
>> + depends on ARCH_SUPPORTS_TRUSTED_FOUNDATIONS
>> + help
>> + Some devices (including most Tegra-based consumer devices on the
>> + market) are booted with the Trusted Foundations secure monitor
>> + active, requiring some core operations to be performed by the secure
>> + monitor instead of the kernel.
>> +
>> + This option allows the kernel to invoke the secure monitor whenever
>> + required on devices using Trusted Foundations. See
>> + arch/arm/include/asm/trusted_foundations.h or the
>> + tl,trusted-foundations device tree binding documentation for details
>> + on how to use it.
>> +
>> + Say n if you don't know what this is about.
>> +
>> +endmenu
>> diff --git a/arch/arm/firmware/Makefile b/arch/arm/firmware/Makefile
>> new file mode 100644
>> index 0000000..a71f165
>> --- /dev/null
>> +++ b/arch/arm/firmware/Makefile
>> @@ -0,0 +1 @@
>> +obj-$(CONFIG_TRUSTED_FOUNDATIONS) += trusted_foundations.o
>> diff --git a/arch/arm/firmware/trusted_foundations.c b/arch/arm/firmware/trusted_foundations.c
>> new file mode 100644
>> index 0000000..c93c5e0
>> --- /dev/null
>> +++ b/arch/arm/firmware/trusted_foundations.c
>> @@ -0,0 +1,77 @@
>> +/*
>> + * Trusted Foundations support for ARM CPUs
>> + *
>> + * 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.
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/init.h>
>> +#include <linux/of.h>
>> +#include <asm/firmware.h>
>> +#include <asm/trusted_foundations.h>
>> +
>> +#define TF_SET_CPU_BOOT_ADDR_SMC 0xfffff200
>> +
>> +static void __naked tf_generic_smc(u32 type, u32 subtype, u32 arg)
>> +{
>> + asm volatile(
>> + ".arch_extension sec\n\t"
>> + "stmfd sp!, {r4 - r11, lr}\n\t"
>> + __asmeq("%0", "r0")
>> + __asmeq("%1", "r1")
>> + __asmeq("%2", "r2")
>> + "mov r3, #0\n\t"
>> + "mov r4, #0\n\t"
>> + "smc #0\n\t"
>> + "ldmfd sp!, {r4 - r11, pc}"
>> + :
>> + : "r" (type), "r" (subtype), "r" (arg)
>> + : "memory");
>> +}
>> +
>> +static int tf_set_cpu_boot_addr(int cpu, unsigned long boot_addr)
>> +{
>> + tf_generic_smc(TF_SET_CPU_BOOT_ADDR_SMC, boot_addr, 0);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct firmware_ops trusted_foundations_ops = {
>> + .set_cpu_boot_addr = tf_set_cpu_boot_addr,
>> +};
>> +
>> +void register_trusted_foundations(struct trusted_foundations_platform_data *pd)
>> +{
>> + /* we are not using version information for now since currently
>> + * supported SMCs are compatible with all TF releases */
>> + register_firmware_ops(&trusted_foundations_ops);
>> +}
>> +
>> +void of_register_trusted_foundations(void)
>> +{
>> + struct device_node *node;
>> + struct trusted_foundations_platform_data pdata;
>> + int err;
>> +
>> + node = of_find_compatible_node(NULL, NULL, "tl,trusted-foundations");
>> + if (!node)
>> + return;
>> +
>> + err = of_property_read_u32(node, "version-major", &pdata.version_major);
>> + if (err != 0)
>> + panic("Trusted Foundation: missing version-major property\n");
>> + err = of_property_read_u32(node, "version-minor", &pdata.version_minor);
>> + if (err != 0)
>> + panic("Trusted Foundation: missing version-minor property\n");
>> + register_trusted_foundations(&pdata);
>> +}
>> diff --git a/arch/arm/include/asm/trusted_foundations.h b/arch/arm/include/asm/trusted_foundations.h
>> new file mode 100644
>> index 0000000..749edbf
>> --- /dev/null
>> +++ b/arch/arm/include/asm/trusted_foundations.h
>> @@ -0,0 +1,64 @@
>> +/*
>> + * 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>
>> +
>> +static inline void register_trusted_foundations(
>> + struct trusted_foundations_platform_data *pd)
>> +{
>> + /* If we try to register TF, this means the system needs it to continue.
>> + * Its absence if thus a fatal error. */
>> + panic("No support for Trusted Foundations, stopping...\n");
>> +}
>> +
>> +static inline void of_register_trusted_foundations(void)
>> +{
>> + /* If we find the target should enable TF but does not support it,
>> + * fail as the system won't be able to do much anyway */
>> + if (of_find_compatible_node(NULL, NULL, "tl,trusted-foundations"))
>> + register_trusted_foundations(NULL);
>> +}
>> +#endif /* CONFIG_TRUSTED_FOUNDATIONS */
>
> The latter function can just be shortcut unto a local panic too.
>
> But do we really need to panic here? It's a PITA to debug since it'll
> be a very early panic. I'd rather have the system log errors in dmesg
> but continue booting with one cpu.
Actually the first version of this series continued on one CPU if TF
support was missing (as secondary CPUs would simply fail to boot), but
IIRC Stephen advocated for the current behavior (panic) instead. I
agree such an early panic is hard to debug, especially considering
that most devices using TF (Tegra retail devices) do not even feature
a serial port.
On the other hand, if we continue booting in these conditions the
system freezes as soon as cpuidle kicks in, so we won't be going very
far anyway. However the console is up when it happens.
Maybe if there is a way to disable the kernel features TF is supposed
to manage (SMP & cpuidle at the moment) when registration fails, the
system could continue more gracefully (even if on one leg) and warn
the user about this condition. Stephen, can I have your thoughts on
this?
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