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/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 */
  31 DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
  32
  33 DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
  34
  35
  36 DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
  37
  38 #ifdef CONFIG_SHADOW_CALL_STACK
  39 DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
  40 #endif
  41
  42 static 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
  54 #ifdef CONFIG_VMAP_STACK
  55 static void __init init_irq_stacks(void)
  56 {
  57         int cpu;
  58         unsigned long *p;
  59
  60         for_each_possible_cpu(cpu) {
  61                 p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, early_cpu_to_node(cpu));
  62                 per_cpu(irq_stack_ptr, cpu) = p;
  63         }
  64 }
  65 #else
  66 /* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */
  67 DEFINE_PER_CPU_ALIGNED(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
  68
  69 static void init_irq_stacks(void)
  70 {
  71         int cpu;
  72
  73         for_each_possible_cpu(cpu)
  74                 per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
  75 }
  76 #endif
  77
  78 #ifndef CONFIG_PREEMPT_RT
  79 static void ____do_softirq(struct pt_regs *regs)
  80 {
  81         __do_softirq();
  82 }
  83
  84 void do_softirq_own_stack(void)
  85 {
  86         call_on_irq_stack(NULL, ____do_softirq);
  87 }
  88 #endif
  89
  90 static void default_handle_irq(struct pt_regs *regs)
  91 {
  92         panic("IRQ taken without a root IRQ handler\n");
  93 }
  94
  95 static void default_handle_fiq(struct pt_regs *regs)
  96 {
  97         panic("FIQ taken without a root FIQ handler\n");
  98 }
  99
 100 void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
 101 void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
 102
 103 int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 104 {
 105         if (handle_arch_irq != default_handle_irq)
 106                 return -EBUSY;
 107
 108         handle_arch_irq = handle_irq;
 109         pr_info("Root IRQ handler: %ps\n", handle_irq);
 110         return 0;
 111 }
 112
 113 int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *))
 114 {
 115         if (handle_arch_fiq != default_handle_fiq)
 116                 return -EBUSY;
 117
 118         handle_arch_fiq = handle_fiq;
 119         pr_info("Root FIQ handler: %ps\n", handle_fiq);
 120         return 0;
 121 }
 122
 123 void __init init_IRQ(void)
 124 {
 125         init_irq_stacks();
 126         init_irq_scs();
 127         irqchip_init();
 128
 129         if (system_uses_irq_prio_masking()) {
 130                 /*
 131                  * Now that we have a stack for our IRQ handler, set
 132                  * the PMR/PSR pair to a consistent state.
 133                  */
 134                 WARN_ON(read_sysreg(daif) & PSR_A_BIT);
 135                 local_daif_restore(DAIF_PROCCTX_NOIRQ);
 136         }
 137 }