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 */
  27 DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
  28
  29 DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
  30
  31
  32 DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
  33
  34 #ifdef CONFIG_SHADOW_CALL_STACK
  35 DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
  36 #endif
  37
  38 static 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
  51 static 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. */
  63 DEFINE_PER_CPU_ALIGNED(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
  64
  65 static 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
  74 static void default_handle_irq(struct pt_regs *regs)
  75 {
  76         panic("IRQ taken without a root IRQ handler\n");
  77 }
  78
  79 static void default_handle_fiq(struct pt_regs *regs)
  80 {
  81         panic("FIQ taken without a root FIQ handler\n");
  82 }
  83
  84 void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
  85 void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
  86
  87 int __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
  97 int __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
 107 void __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 }