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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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755563bc79
Since we can now use hypervisor doorbells for host IPIs, this makes sure we clear the host IPI flag when taking a doorbell interrupt, and clears any pending doorbell IPI in pnv_smp_cpu_kill_self() (as we already do for IPIs sent via the XICS interrupt controller). Otherwise if there did happen to be a leftover pending doorbell interrupt for an offline CPU thread for any reason, it would prevent that thread from going into a power-saving mode; it would instead keep waking up because of the interrupt. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
/*
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* Author: Kumar Gala <galak@kernel.crashing.org>
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*
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* Copyright 2009 Freescale Semiconductor Inc.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/stddef.h>
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#include <linux/kernel.h>
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#include <linux/smp.h>
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#include <linux/threads.h>
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#include <linux/hardirq.h>
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#include <asm/dbell.h>
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#include <asm/irq_regs.h>
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#include <asm/kvm_ppc.h>
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#ifdef CONFIG_SMP
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void doorbell_setup_this_cpu(void)
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{
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unsigned long tag = mfspr(SPRN_DOORBELL_CPUTAG) & PPC_DBELL_TAG_MASK;
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smp_muxed_ipi_set_data(smp_processor_id(), tag);
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}
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void doorbell_cause_ipi(int cpu, unsigned long data)
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{
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/* Order previous accesses vs. msgsnd, which is treated as a store */
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mb();
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ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, data);
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}
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void doorbell_exception(struct pt_regs *regs)
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{
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struct pt_regs *old_regs = set_irq_regs(regs);
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irq_enter();
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may_hard_irq_enable();
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kvmppc_set_host_ipi(smp_processor_id(), 0);
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__this_cpu_inc(irq_stat.doorbell_irqs);
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smp_ipi_demux();
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irq_exit();
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set_irq_regs(old_regs);
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}
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#else /* CONFIG_SMP */
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void doorbell_exception(struct pt_regs *regs)
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{
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printk(KERN_WARNING "Received doorbell on non-smp system\n");
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}
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#endif /* CONFIG_SMP */
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