개념 설명 전체 · v6.18.37 / 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 <[email protected]> and
    9  * Tuukka Tikkanen <[email protected]>.
   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 static 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 #ifndef CONFIG_PREEMPT_RT
   66 static void ____do_softirq(struct pt_regs *regs)
   67 {
   68 	__do_softirq();
   69 }
   70 
   71 void do_softirq_own_stack(void)
   72 {
   73 	call_on_irq_stack(NULL, ____do_softirq);
   74 }
   75 #endif
   76 
   77 static void default_handle_irq(struct pt_regs *regs)
   78 {
   79 	panic("IRQ taken without a root IRQ handler\n");
   80 }
   81 
   82 static void default_handle_fiq(struct pt_regs *regs)
   83 {
   84 	panic("FIQ taken without a root FIQ handler\n");
   85 }
   86 
   87 void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
   88 void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
   89 
   90 int __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 
  100 int __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 
  110 void __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 }