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/seq_file.h>
  21 #include <linux/vmalloc.h>
  22 #include <asm/daifflags.h>
  23 #include <asm/vmap_stack.h>
  24
  25 /* Only access this in an NMI enter/exit */
  26 DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
  27
  28 DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
  29
  30 #ifdef CONFIG_VMAP_STACK
  31 static void init_irq_stacks(void)
  32 {
  33         int cpu;
  34         unsigned long *p;
  35
  36         for_each_possible_cpu(cpu) {
  37                 p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, cpu_to_node(cpu));
  38                 per_cpu(irq_stack_ptr, cpu) = p;
  39         }
  40 }
  41 #else
  42 /* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */
  43 DEFINE_PER_CPU_ALIGNED(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
  44
  45 static void init_irq_stacks(void)
  46 {
  47         int cpu;
  48
  49         for_each_possible_cpu(cpu)
  50                 per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
  51 }
  52 #endif
  53
  54 void __init init_IRQ(void)
  55 {
  56         init_irq_stacks();
  57         irqchip_init();
  58         if (!handle_arch_irq)
  59                 panic("No interrupt controller found.");
  60
  61         if (system_uses_irq_prio_masking()) {
  62                 /*
  63                  * Now that we have a stack for our IRQ handler, set
  64                  * the PMR/PSR pair to a consistent state.
  65                  */
  66                 WARN_ON(read_sysreg(daif) & PSR_A_BIT);
  67                 local_daif_restore(DAIF_PROCCTX_NOIRQ);
  68         }
  69 }
  70
  71 /*
  72  * Stubs to make nmi_enter/exit() code callable from ASM
  73  */
  74 asmlinkage void notrace asm_nmi_enter(void)
  75 {
  76         nmi_enter();
  77 }
  78 NOKPROBE_SYMBOL(asm_nmi_enter);
  79
  80 asmlinkage void notrace asm_nmi_exit(void)
  81 {
  82         nmi_exit();
  83 }
  84 NOKPROBE_SYMBOL(asm_nmi_exit);