linux_dsm_epyc7002/arch/arm/include/asm/trusted_foundations.h
Alexandre Courbot c3af6d6855 ARM: trusted_foundations: fallback when TF support is missing
When Trusted Foundations is detected as present on the system, but
Trusted Foundations support is not built into the kernel, the kernel
used to issue a panic very early during boot, leaving little clue to the
user as to what is going wrong.

It turns out that even without TF support built-in, the kernel can boot
on a TF-enabled system provided that SMP and cpuidle are disabled. This
patch does this and continue booting on one CPU, leaving the user with a
usable (however degraded) system.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
2014-02-18 13:46:32 -07:00

73 lines
2.3 KiB
C

/*
* 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>
#include <linux/printk.h>
#include <linux/bug.h>
#include <linux/of.h>
#include <linux/cpu.h>
#include <linux/smp.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 */
static inline void register_trusted_foundations(
struct trusted_foundations_platform_data *pd)
{
/*
* If the system requires TF and we cannot provide it, continue booting
* but disable features that cannot be provided.
*/
pr_err("No support for Trusted Foundations, continuing in degraded mode.\n");
pr_err("Secondary processors as well as CPU PM will be disabled.\n");
setup_max_cpus = 0;
cpu_idle_poll_ctrl(true);
}
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, "tlm,trusted-foundations"))
register_trusted_foundations(NULL);
}
#endif /* CONFIG_TRUSTED_FOUNDATIONS */
#endif