1 /* 2 * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar 3 * 4 * This file contains the lowest level x86_64-specific interrupt 5 * entry and irq statistics code. All the remaining irq logic is 6 * done by the generic kernel/irq/ code and in the 7 * x86_64-specific irq controller code. (e.g. i8259.c and 8 * io_apic.c.) 9 */ 10 11 #include <linux/kernel_stat.h> 12 #include <linux/interrupt.h> 13 #include <linux/seq_file.h> 14 #include <linux/module.h> 15 #include <linux/delay.h> 16 #include <linux/ftrace.h> 17 #include <linux/uaccess.h> 18 #include <linux/smp.h> 19 #include <asm/io_apic.h> 20 #include <asm/idle.h> 21 #include <asm/apic.h> 22 23 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat); 24 EXPORT_PER_CPU_SYMBOL(irq_stat); 25 26 DEFINE_PER_CPU(struct pt_regs *, irq_regs); 27 EXPORT_PER_CPU_SYMBOL(irq_regs); 28 29 /* 30 * Probabilistic stack overflow check: 31 * 32 * Only check the stack in process context, because everything else 33 * runs on the big interrupt stacks. Checking reliably is too expensive, 34 * so we just check from interrupts. 35 */ 36 static inline void stack_overflow_check(struct pt_regs *regs) 37 { 38 #ifdef CONFIG_DEBUG_STACKOVERFLOW 39 u64 curbase = (u64)task_stack_page(current); 40 41 WARN_ONCE(regs->sp >= curbase && 42 regs->sp <= curbase + THREAD_SIZE && 43 regs->sp < curbase + sizeof(struct thread_info) + 44 sizeof(struct pt_regs) + 128, 45 46 "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n", 47 current->comm, curbase, regs->sp); 48 #endif 49 } 50 51 bool handle_irq(unsigned irq, struct pt_regs *regs) 52 { 53 struct irq_desc *desc; 54 55 stack_overflow_check(regs); 56 57 desc = irq_to_desc(irq); 58 if (unlikely(!desc)) 59 return false; 60 61 generic_handle_irq_desc(irq, desc); 62 return true; 63 } 64 65 66 extern void call_softirq(void); 67 68 asmlinkage void do_softirq(void) 69 { 70 __u32 pending; 71 unsigned long flags; 72 73 if (in_interrupt()) 74 return; 75 76 local_irq_save(flags); 77 pending = local_softirq_pending(); 78 /* Switch to interrupt stack */ 79 if (pending) { 80 call_softirq(); 81 WARN_ON_ONCE(softirq_count()); 82 } 83 local_irq_restore(flags); 84 } 85