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0de0d64675
CPU hotplug and kexec rely on smp_ops.cpu_kill(), which is supposed to wait for the CPU to park or power down, and perform the last rites (such as disabling clocks etc., where the platform doesn't do this automatically). kexec in particular is unsafe without performing this synchronisation to park secondaries. Without it, the secondaries might not be parked when kexec trashes the kernel. There is no generic way to do this synchronisation, so a new mcpm platform_ops method power_down_finish() is added by this patch. The new method is mandatory. A platform which provides no way to detect when CPUs are parked is likely broken. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
104 lines
2.4 KiB
C
104 lines
2.4 KiB
C
/*
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* linux/arch/arm/mach-vexpress/mcpm_platsmp.c
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*
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* Created by: Nicolas Pitre, November 2012
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* Copyright: (C) 2012-2013 Linaro Limited
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Code to handle secondary CPU bringup and hotplug for the cluster power API.
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*/
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#include <linux/init.h>
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#include <linux/smp.h>
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#include <linux/spinlock.h>
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#include <asm/mcpm.h>
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#include <asm/smp.h>
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#include <asm/smp_plat.h>
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static void cpu_to_pcpu(unsigned int cpu,
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unsigned int *pcpu, unsigned int *pcluster)
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{
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unsigned int mpidr;
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mpidr = cpu_logical_map(cpu);
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*pcpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
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*pcluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
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}
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static int mcpm_boot_secondary(unsigned int cpu, struct task_struct *idle)
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{
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unsigned int pcpu, pcluster, ret;
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extern void secondary_startup(void);
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cpu_to_pcpu(cpu, &pcpu, &pcluster);
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pr_debug("%s: logical CPU %d is physical CPU %d cluster %d\n",
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__func__, cpu, pcpu, pcluster);
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mcpm_set_entry_vector(pcpu, pcluster, NULL);
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ret = mcpm_cpu_power_up(pcpu, pcluster);
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if (ret)
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return ret;
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mcpm_set_entry_vector(pcpu, pcluster, secondary_startup);
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arch_send_wakeup_ipi_mask(cpumask_of(cpu));
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dsb_sev();
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return 0;
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}
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static void mcpm_secondary_init(unsigned int cpu)
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{
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mcpm_cpu_powered_up();
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static int mcpm_cpu_kill(unsigned int cpu)
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{
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unsigned int pcpu, pcluster;
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cpu_to_pcpu(cpu, &pcpu, &pcluster);
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return !mcpm_cpu_power_down_finish(pcpu, pcluster);
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}
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static int mcpm_cpu_disable(unsigned int cpu)
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{
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/*
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* We assume all CPUs may be shut down.
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* This would be the hook to use for eventual Secure
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* OS migration requests as described in the PSCI spec.
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*/
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return 0;
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}
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static void mcpm_cpu_die(unsigned int cpu)
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{
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unsigned int mpidr, pcpu, pcluster;
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mpidr = read_cpuid_mpidr();
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pcpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
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pcluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
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mcpm_set_entry_vector(pcpu, pcluster, NULL);
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mcpm_cpu_power_down();
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}
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#endif
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static struct smp_operations __initdata mcpm_smp_ops = {
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.smp_boot_secondary = mcpm_boot_secondary,
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.smp_secondary_init = mcpm_secondary_init,
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#ifdef CONFIG_HOTPLUG_CPU
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.cpu_kill = mcpm_cpu_kill,
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.cpu_disable = mcpm_cpu_disable,
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.cpu_die = mcpm_cpu_die,
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#endif
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};
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void __init mcpm_smp_set_ops(void)
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{
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smp_set_ops(&mcpm_smp_ops);
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}
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