linux_dsm_epyc7002/arch/arm64/include/asm/cpu_ops.h
Sudeep Holla d55c5f28af arm64: smp: disable hotplug on trusted OS resident CPU
The trusted OS may reject CPU_OFF calls to its resident CPU, so we must
avoid issuing those. We never migrate a Trusted OS and we already take
care to prevent CPU_OFF PSCI call. However, this is not reflected
explicitly to the userspace. Any user can attempt to hotplug trusted OS
resident CPU. The entire motion of going through the various state
transitions in the CPU hotplug state machine gets executed and the
PSCI layer finally refuses to make CPU_OFF call.

This results is unnecessary unwinding of CPU hotplug state machine in
the kernel. Instead we can mark the trusted OS resident CPU as not
available for hotplug, so that the user attempt or request to do the
same will get immediately rejected.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
2019-08-15 11:12:03 +01:00

67 lines
2.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2013 ARM Ltd.
*/
#ifndef __ASM_CPU_OPS_H
#define __ASM_CPU_OPS_H
#include <linux/init.h>
#include <linux/threads.h>
/**
* struct cpu_operations - Callback operations for hotplugging CPUs.
*
* @name: Name of the property as appears in a devicetree cpu node's
* enable-method property. On systems booting with ACPI, @name
* identifies the struct cpu_operations entry corresponding to
* the boot protocol specified in the ACPI MADT table.
* @cpu_init: Reads any data necessary for a specific enable-method for a
* proposed logical id.
* @cpu_prepare: Early one-time preparation step for a cpu. If there is a
* mechanism for doing so, tests whether it is possible to boot
* the given CPU.
* @cpu_boot: Boots a cpu into the kernel.
* @cpu_postboot: Optionally, perform any post-boot cleanup or necesary
* synchronisation. Called from the cpu being booted.
* @cpu_can_disable: Determines whether a CPU can be disabled based on
* mechanism-specific information.
* @cpu_disable: Prepares a cpu to die. May fail for some mechanism-specific
* reason, which will cause the hot unplug to be aborted. Called
* from the cpu to be killed.
* @cpu_die: Makes a cpu leave the kernel. Must not fail. Called from the
* cpu being killed.
* @cpu_kill: Ensures a cpu has left the kernel. Called from another cpu.
* @cpu_init_idle: Reads any data necessary to initialize CPU idle states for
* a proposed logical id.
* @cpu_suspend: Suspends a cpu and saves the required context. May fail owing
* to wrong parameters or error conditions. Called from the
* CPU being suspended. Must be called with IRQs disabled.
*/
struct cpu_operations {
const char *name;
int (*cpu_init)(unsigned int);
int (*cpu_prepare)(unsigned int);
int (*cpu_boot)(unsigned int);
void (*cpu_postboot)(void);
#ifdef CONFIG_HOTPLUG_CPU
bool (*cpu_can_disable)(unsigned int cpu);
int (*cpu_disable)(unsigned int cpu);
void (*cpu_die)(unsigned int cpu);
int (*cpu_kill)(unsigned int cpu);
#endif
#ifdef CONFIG_CPU_IDLE
int (*cpu_init_idle)(unsigned int);
int (*cpu_suspend)(unsigned long);
#endif
};
extern const struct cpu_operations *cpu_ops[NR_CPUS];
int __init cpu_read_ops(int cpu);
static inline void __init cpu_read_bootcpu_ops(void)
{
cpu_read_ops(0);
}
#endif /* ifndef __ASM_CPU_OPS_H */