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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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850f22d568
If we are soft disabled and receive a doorbell exception we don't process it immediately. This means we need to check on the way out of irq restore if there are any doorbell exceptions to process. The problem is at that point we don't know what our regs are, and that in turn makes xmon unhappy. To workaround the problem, instead of checking for and processing doorbells, we check for any doorbells and if there were any we send ourselves another. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
101 lines
2.3 KiB
C
101 lines
2.3 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/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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void doorbell_check_self(void)
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{
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struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info);
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if (!info->messages)
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return;
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ppc_msgsnd(PPC_DBELL, 0, info->tag);
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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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