LXR linux/arch/arm64/kernel/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/irq.h>
  14#include <linux/memory.h>
  15#include <linux/smp.h>
  16#include <linux/hardirq.h>
  17#include <linux/init.h>
  18#include <linux/irqchip.h>
  19#include <linux/kprobes.h>
  20#include <linux/scs.h>
  21#include <linux/seq_file.h>
  22#include <linux/vmalloc.h>
  23#include <asm/daifflags.h>
  24#include <asm/vmap_stack.h>
  25
  26/* Only access this in an NMI enter/exit */
  27DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
  28
  29DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
  30
  31
  32DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
  33
  34#ifdef CONFIG_SHADOW_CALL_STACK
  35DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
  36#endif
  37
  38static void init_irq_scs(void)
  39{
  40        int cpu;
  41
  42        if (!IS_ENABLED(CONFIG_SHADOW_CALL_STACK))
  43                return;
  44
  45        for_each_possible_cpu(cpu)
  46                per_cpu(irq_shadow_call_stack_ptr, cpu) =
  47                        scs_alloc(cpu_to_node(cpu));
  48}
  49
  50#ifdef CONFIG_VMAP_STACK
  51static void init_irq_stacks(void)
  52{
  53        int cpu;
  54        unsigned long *p;
  55
  56        for_each_possible_cpu(cpu) {
  57                p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, cpu_to_node(cpu));
  58                per_cpu(irq_stack_ptr, cpu) = p;
  59        }
  60}
  61#else
  62/* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */
  63DEFINE_PER_CPU_ALIGNED(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
  64
  65static void init_irq_stacks(void)
  66{
  67        int cpu;
  68
  69        for_each_possible_cpu(cpu)
  70                per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
  71}
  72#endif
  73
  74static void default_handle_irq(struct pt_regs *regs)
  75{
  76        panic("IRQ taken without a root IRQ handler\n");
  77}
  78
  79static void default_handle_fiq(struct pt_regs *regs)
  80{
  81        panic("FIQ taken without a root FIQ handler\n");
  82}
  83
  84void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
  85void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
  86
  87int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
  88{
  89        if (handle_arch_irq != default_handle_irq)
  90                return -EBUSY;
  91
  92        handle_arch_irq = handle_irq;
  93        pr_info("Root IRQ handler: %ps\n", handle_irq);
  94        return 0;
  95}
  96
  97int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *))
  98{
  99        if (handle_arch_fiq != default_handle_fiq)
 100                return -EBUSY;
 101
 102        handle_arch_fiq = handle_fiq;
 103        pr_info("Root FIQ handler: %ps\n", handle_fiq);
 104        return 0;
 105}
 106
 107void __init init_IRQ(void)
 108{
 109        init_irq_stacks();
 110        init_irq_scs();
 111        irqchip_init();
 112
 113        if (system_uses_irq_prio_masking()) {
 114                /*
 115                 * Now that we have a stack for our IRQ handler, set
 116                 * the PMR/PSR pair to a consistent state.
 117                 */
 118                WARN_ON(read_sysreg(daif) & PSR_A_BIT);
 119                local_daif_restore(DAIF_PROCCTX_NOIRQ);
 120        }
 121}
 122