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/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/softirq_stack.h>
  26 #include <asm/stacktrace.h>
  27 #include <asm/vmap_stack.h>
  28
  29 /* Only access this in an NMI enter/exit */
  30 DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
  31
  32 DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
  33
  34
  35 DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
  36
  37 #ifdef CONFIG_SHADOW_CALL_STACK
  38 DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
  39 #endif
  40
  41 static void init_irq_scs(void)
  42 {
  43         int cpu;
  44
  45         if (!scs_is_enabled())
  46                 return;
  47
  48         for_each_possible_cpu(cpu)
  49                 per_cpu(irq_shadow_call_stack_ptr, cpu) =
  50                         scs_alloc(cpu_to_node(cpu));
  51 }
  52
  53 #ifdef CONFIG_VMAP_STACK
  54 static void 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, cpu_to_node(cpu));
  61                 per_cpu(irq_stack_ptr, cpu) = p;
  62         }
  63 }
  64 #else
  65 /* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */
  66 DEFINE_PER_CPU_ALIGNED(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
  67
  68 static void init_irq_stacks(void)
  69 {
  70         int cpu;
  71
  72         for_each_possible_cpu(cpu)
  73                 per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
  74 }
  75 #endif
  76
  77 #ifndef CONFIG_PREEMPT_RT
  78 static void ____do_softirq(struct pt_regs *regs)
  79 {
  80         __do_softirq();
  81 }
  82
  83 void do_softirq_own_stack(void)
  84 {
  85         call_on_irq_stack(NULL, ____do_softirq);
  86 }
  87 #endif
  88
  89 static void default_handle_irq(struct pt_regs *regs)
  90 {
  91         panic("IRQ taken without a root IRQ handler\n");
  92 }
  93
  94 static void default_handle_fiq(struct pt_regs *regs)
  95 {
  96         panic("FIQ taken without a root FIQ handler\n");
  97 }
  98
  99 void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
 100 void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
 101
 102 int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 103 {
 104         if (handle_arch_irq != default_handle_irq)
 105                 return -EBUSY;
 106
 107         handle_arch_irq = handle_irq;
 108         pr_info("Root IRQ handler: %ps\n", handle_irq);
 109         return 0;
 110 }
 111
 112 int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *))
 113 {
 114         if (handle_arch_fiq != default_handle_fiq)
 115                 return -EBUSY;
 116
 117         handle_arch_fiq = handle_fiq;
 118         pr_info("Root FIQ handler: %ps\n", handle_fiq);
 119         return 0;
 120 }
 121
 122 void __init init_IRQ(void)
 123 {
 124         init_irq_stacks();
 125         init_irq_scs();
 126         irqchip_init();
 127
 128         if (system_uses_irq_prio_masking()) {
 129                 /*
 130                  * Now that we have a stack for our IRQ handler, set
 131                  * the PMR/PSR pair to a consistent state.
 132                  */
 133                 WARN_ON(read_sysreg(daif) & PSR_A_BIT);
 134                 local_daif_restore(DAIF_PROCCTX_NOIRQ);
 135         }
 136 }