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