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/*
* Author: Kumar Gala <galak@kernel.crashing.org>
*
* Copyright 2009 Freescale Semiconductor Inc.
*
* 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.
*/
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/threads.h>
#include <linux/hardirq.h>
#include <asm/dbell.h>
#include <asm/irq_regs.h>
#include <asm/kvm_ppc.h>
#include <asm/trace.h>
#ifdef CONFIG_SMP
/*
* Doorbells must only be used if CPU_FTR_DBELL is available.
* msgsnd is used in HV, and msgsndp is used in !HV.
*
* These should be used by platform code that is aware of restrictions.
* Other arch code should use ->cause_ipi.
*
* doorbell_global_ipi() sends a dbell to any target CPU.
* Must be used only by architectures that address msgsnd target
* by PIR/get_hard_smp_processor_id.
*/
void doorbell_global_ipi(int cpu)
{
u32 tag = get_hard_smp_processor_id(cpu);
kvmppc_set_host_ipi(cpu, 1);
/* Order previous accesses vs. msgsnd, which is treated as a store */
ppc_msgsnd_sync();
ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
}
/*
* doorbell_core_ipi() sends a dbell to a target CPU in the same core.
* Must be used only by architectures that address msgsnd target
* by TIR/cpu_thread_in_core.
*/
void doorbell_core_ipi(int cpu)
{
u32 tag = cpu_thread_in_core(cpu);
kvmppc_set_host_ipi(cpu, 1);
/* Order previous accesses vs. msgsnd, which is treated as a store */
ppc_msgsnd_sync();
ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
}
/*
* Attempt to cause a core doorbell if destination is on the same core.
* Returns 1 on success, 0 on failure.
*/
int doorbell_try_core_ipi(int cpu)
{
int this_cpu = get_cpu();
int ret = 0;
if (cpumask_test_cpu(cpu, cpu_sibling_mask(this_cpu))) {
doorbell_core_ipi(cpu);
ret = 1;
}
put_cpu();
return ret;
}
void doorbell_exception(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
irq_enter();
trace_doorbell_entry(regs);
ppc_msgsync();
may_hard_irq_enable();
kvmppc_set_host_ipi(smp_processor_id(), 0);
__this_cpu_inc(irq_stat.doorbell_irqs);
smp_ipi_demux_relaxed(); /* already performed the barrier */
trace_doorbell_exit(regs);
irq_exit();
set_irq_regs(old_regs);
}
#else /* CONFIG_SMP */
void doorbell_exception(struct pt_regs *regs)
{
printk(KERN_WARNING "Received doorbell on non-smp system\n");
}
#endif /* CONFIG_SMP */
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