irq.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Based on arch/arm/kernel/irq.c
  4 *
  5 * Copyright (C) 1992 Linus Torvalds
  6 * Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
  7 * Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
  8 * Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
  9 * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
 10 * Copyright (C) 2012 ARM Ltd.
 11 */
 12
 13#include <linux/hardirq.h>
 14#include <linux/init.h>
 15#include <linux/irq.h>
 16#include <linux/irqchip.h>
 17#include <linux/kprobes.h>
 18#include <linux/memory.h>
 19#include <linux/scs.h>
 20#include <linux/seq_file.h>
 21#include <linux/smp.h>
 22#include <linux/vmalloc.h>
 23#include <asm/daifflags.h>
 24#include <asm/exception.h>
 25#include <asm/numa.h>
 26#include <asm/softirq_stack.h>
 27#include <asm/stacktrace.h>
 28#include <asm/vmap_stack.h>
 29
 30/* Only access this in an NMI enter/exit */
 31DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
 32
 33DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
 34
 35
 36DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
 37
 38#ifdef CONFIG_SHADOW_CALL_STACK
 39DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
 40#endif
 41
 42static void init_irq_scs(void)
 43{
 44	int cpu;
 45
 46	if (!scs_is_enabled())
 47		return;
 48
 49	for_each_possible_cpu(cpu)
 50		per_cpu(irq_shadow_call_stack_ptr, cpu) =
 51			scs_alloc(early_cpu_to_node(cpu));
 52}
 53
 54static void __init init_irq_stacks(void)
 55{
 56	int cpu;
 57	unsigned long *p;
 58
 59	for_each_possible_cpu(cpu) {
 60		p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, early_cpu_to_node(cpu));
 61		per_cpu(irq_stack_ptr, cpu) = p;
 62	}
 63}
 64
 65#ifdef CONFIG_SOFTIRQ_ON_OWN_STACK
 66static void ____do_softirq(struct pt_regs *regs)
 67{
 68	__do_softirq();
 69}
 70
 71void do_softirq_own_stack(void)
 72{
 73	call_on_irq_stack(NULL, ____do_softirq);
 74}
 75#endif
 76
 77static void default_handle_irq(struct pt_regs *regs)
 78{
 79	panic("IRQ taken without a root IRQ handler\n");
 80}
 81
 82static void default_handle_fiq(struct pt_regs *regs)
 83{
 84	panic("FIQ taken without a root FIQ handler\n");
 85}
 86
 87void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
 88void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
 89
 90int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 91{
 92	if (handle_arch_irq != default_handle_irq)
 93		return -EBUSY;
 94
 95	handle_arch_irq = handle_irq;
 96	pr_info("Root IRQ handler: %ps\n", handle_irq);
 97	return 0;
 98}
 99
100int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *))
101{
102	if (handle_arch_fiq != default_handle_fiq)
103		return -EBUSY;
104
105	handle_arch_fiq = handle_fiq;
106	pr_info("Root FIQ handler: %ps\n", handle_fiq);
107	return 0;
108}
109
110void __init init_IRQ(void)
111{
112	init_irq_stacks();
113	init_irq_scs();
114	irqchip_init();
115
116	if (system_uses_irq_prio_masking()) {
117		/*
118		 * Now that we have a stack for our IRQ handler, set
119		 * the PMR/PSR pair to a consistent state.
120		 */
121		WARN_ON(read_sysreg(daif) & PSR_A_BIT);
122		local_daif_restore(DAIF_PROCCTX_NOIRQ);
123	}
124}