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/*
* Based on arch/arm/kernel/irq.c
*
* Copyright (C) 1992 Linus Torvalds
* Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
* Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
* Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
* Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/kernel_stat.h>
#include <linux/irq.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irqchip.h>
#include <linux/seq_file.h>
unsigned long irq_err_count;
/*
* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned.
* irq_stack[0] is used as irq_count, a non-zero value indicates the stack
* is in use, and el?_irq() shouldn't switch to it. This is used to detect
* recursive use of the irq_stack, it is lazily updated by
* do_softirq_own_stack(), which is called on the irq_stack, before
* re-enabling interrupts to process softirqs.
*/
DEFINE_PER_CPU(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack) __aligned(16);
#define IRQ_COUNT() (*per_cpu(irq_stack, smp_processor_id()))
int arch_show_interrupts(struct seq_file *p, int prec)
{
show_ipi_list(p, prec);
seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
return 0;
}
void (*handle_arch_irq)(struct pt_regs *) = NULL;
void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
{
if (handle_arch_irq)
return;
handle_arch_irq = handle_irq;
}
void __init init_IRQ(void)
{
irqchip_init();
if (!handle_arch_irq)
panic("No interrupt controller found.");
}
/*
* do_softirq_own_stack() is called from irq_exit() before __do_softirq()
* re-enables interrupts, at which point we may re-enter el?_irq(). We
* increase irq_count here so that el1_irq() knows that it is already on the
* irq stack.
*
* Called with interrupts disabled, so we don't worry about moving cpu, or
* being interrupted while modifying irq_count.
*
* This function doesn't actually switch stack.
*/
void do_softirq_own_stack(void)
{
int cpu = smp_processor_id();
WARN_ON_ONCE(!irqs_disabled());
if (on_irq_stack(current_stack_pointer, cpu)) {
IRQ_COUNT()++;
__do_softirq();
IRQ_COUNT()--;
} else {
__do_softirq();
}
}
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