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 int sysctl_panic_on_stackoverflow; 30 31 /* 32 * Probabilistic stack overflow check: 33 * 34 * Only check the stack in process context, because everything else 35 * runs on the big interrupt stacks. Checking reliably is too expensive, 36 * so we just check from interrupts. 37 */ 38 static inline void stack_overflow_check(struct pt_regs *regs) 39 { 40 #ifdef CONFIG_DEBUG_STACKOVERFLOW 41 #define STACK_TOP_MARGIN 128 42 struct orig_ist *oist; 43 u64 irq_stack_top, irq_stack_bottom; 44 u64 estack_top, estack_bottom; 45 u64 curbase = (u64)task_stack_page(current); 46 47 if (user_mode(regs)) 48 return; 49 50 if (regs->sp >= curbase + sizeof(struct thread_info) + 51 sizeof(struct pt_regs) + STACK_TOP_MARGIN && 52 regs->sp <= curbase + THREAD_SIZE) 53 return; 54 55 irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) + 56 STACK_TOP_MARGIN; 57 irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr); 58 if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom) 59 return; 60 61 oist = this_cpu_ptr(&orig_ist); 62 estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN; 63 estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1]; 64 if (regs->sp >= estack_top && regs->sp <= estack_bottom) 65 return; 66 67 WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx)\n", 68 current->comm, curbase, regs->sp, 69 irq_stack_top, irq_stack_bottom, 70 estack_top, estack_bottom); 71 72 if (sysctl_panic_on_stackoverflow) 73 panic("low stack detected by irq handler - check messages\n"); 74 #endif 75 } 76 77 bool handle_irq(unsigned irq, struct pt_regs *regs) 78 { 79 struct irq_desc *desc; 80 81 stack_overflow_check(regs); 82 83 desc = irq_to_desc(irq); 84 if (unlikely(!desc)) 85 return false; 86 87 generic_handle_irq_desc(irq, desc); 88 return true; 89 } 90