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 if (user_mode_vm(regs)) 42 return; 43 44 WARN_ONCE(regs->sp >= curbase && 45 regs->sp <= curbase + THREAD_SIZE && 46 regs->sp < curbase + sizeof(struct thread_info) + 47 sizeof(struct pt_regs) + 128, 48 49 "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n", 50 current->comm, curbase, regs->sp); 51 #endif 52 } 53 54 bool handle_irq(unsigned irq, struct pt_regs *regs) 55 { 56 struct irq_desc *desc; 57 58 stack_overflow_check(regs); 59 60 desc = irq_to_desc(irq); 61 if (unlikely(!desc)) 62 return false; 63 64 generic_handle_irq_desc(irq, desc); 65 return true; 66 } 67 68 69 extern void call_softirq(void); 70 71 asmlinkage void do_softirq(void) 72 { 73 __u32 pending; 74 unsigned long flags; 75 76 if (in_interrupt()) 77 return; 78 79 local_irq_save(flags); 80 pending = local_softirq_pending(); 81 /* Switch to interrupt stack */ 82 if (pending) { 83 call_softirq(); 84 WARN_ON_ONCE(softirq_count()); 85 } 86 local_irq_restore(flags); 87 } 88