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0e37d25950
include/asm-generic/irq_regs.h declares per-cpu irq_regs variables and get_irq_regs() and set_irq_regs() helper functions to maintain them. These can be used to access the proper pt_regs structure related to the current interrupt entry (if any). In the powerpc arch code, this is used to maintain irq regs on decrementer and external interrupt exceptions. However, for the doorbell exceptions used by the msgsnd/msgrcv IPI mechanism of newer BookE CPUs, the irq_regs are not kept up to date. In particular this means that xmon will not work properly on SMP, because the secondary xmon instances started by IPI will blow up when they cannot retrieve the irq regs. This patch fixes the problem by adding calls to maintain the irq regs across doorbell exceptions. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
90 lines
2.1 KiB
C
90 lines
2.1 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/percpu.h>
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#include <asm/dbell.h>
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#include <asm/irq_regs.h>
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#ifdef CONFIG_SMP
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struct doorbell_cpu_info {
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unsigned long messages; /* current messages bits */
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unsigned int tag; /* tag value */
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};
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static DEFINE_PER_CPU(struct doorbell_cpu_info, doorbell_cpu_info);
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void doorbell_setup_this_cpu(void)
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{
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struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info);
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info->messages = 0;
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info->tag = mfspr(SPRN_PIR) & 0x3fff;
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}
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void doorbell_message_pass(int target, int msg)
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{
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struct doorbell_cpu_info *info;
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int i;
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if (target < NR_CPUS) {
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info = &per_cpu(doorbell_cpu_info, target);
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set_bit(msg, &info->messages);
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ppc_msgsnd(PPC_DBELL, 0, info->tag);
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}
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else if (target == MSG_ALL_BUT_SELF) {
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for_each_online_cpu(i) {
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if (i == smp_processor_id())
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continue;
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info = &per_cpu(doorbell_cpu_info, i);
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set_bit(msg, &info->messages);
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ppc_msgsnd(PPC_DBELL, 0, info->tag);
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}
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}
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else { /* target == MSG_ALL */
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for_each_online_cpu(i) {
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info = &per_cpu(doorbell_cpu_info, i);
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set_bit(msg, &info->messages);
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}
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ppc_msgsnd(PPC_DBELL, PPC_DBELL_MSG_BRDCAST, 0);
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}
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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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struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info);
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int msg;
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/* Warning: regs can be NULL when called from irq enable */
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if (!info->messages || (num_online_cpus() < 2))
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goto out;
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for (msg = 0; msg < 4; msg++)
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if (test_and_clear_bit(msg, &info->messages))
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smp_message_recv(msg);
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out:
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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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