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
 23DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
 24EXPORT_PER_CPU_SYMBOL(irq_stat);
 25
 26DEFINE_PER_CPU(struct pt_regs *, irq_regs);
 27EXPORT_PER_CPU_SYMBOL(irq_regs);
 28
 29int 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 */
 38static 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_vm(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)__get_cpu_var(irq_stack_union.irq_stack) +
 56			STACK_TOP_MARGIN;
 57	irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
 58	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
 59		return;
 60
 61	oist = &__get_cpu_var(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
 77bool 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
 
 
 
 
 91
 92extern void call_softirq(void);
 93
 94asmlinkage void do_softirq(void)
 95{
 96	__u32 pending;
 97	unsigned long flags;
 98
 99	if (in_interrupt())
100		return;
101
102	local_irq_save(flags);
103	pending = local_softirq_pending();
104	/* Switch to interrupt stack */
105	if (pending) {
106		call_softirq();
107		WARN_ON_ONCE(softirq_count());
108	}
109	local_irq_restore(flags);
110}

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 *	Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 4 *
 5 * This file contains the lowest level x86_64-specific interrupt
 6 * entry and irq statistics code. All the remaining irq logic is
 7 * done by the generic kernel/irq/ code and in the
 8 * x86_64-specific irq controller code. (e.g. i8259.c and
 9 * io_apic.c.)
10 */
11
12#include <linux/kernel_stat.h>
13#include <linux/interrupt.h>
14#include <linux/irq.h>
15#include <linux/seq_file.h>
 
16#include <linux/delay.h>
17#include <linux/ftrace.h>
18#include <linux/uaccess.h>
19#include <linux/smp.h>
20#include <linux/sched/task_stack.h>
21
22#include <asm/cpu_entry_area.h>
23#include <asm/irq_stack.h>
24#include <asm/io_apic.h>
 
25#include <asm/apic.h>
26
27DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible;
28DECLARE_INIT_PER_CPU(irq_stack_backing_store);
 
 
 
 
 
29
30#ifdef CONFIG_VMAP_STACK
31/*
32 * VMAP the backing store with guard pages
 
 
 
 
33 */
34static int map_irq_stack(unsigned int cpu)
35{
36	char *stack = (char *)per_cpu_ptr(&irq_stack_backing_store, cpu);
37	struct page *pages[IRQ_STACK_SIZE / PAGE_SIZE];
38	void *va;
39	int i;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
40
41	for (i = 0; i < IRQ_STACK_SIZE / PAGE_SIZE; i++) {
42		phys_addr_t pa = per_cpu_ptr_to_phys(stack + (i << PAGE_SHIFT));
 
43
44		pages[i] = pfn_to_page(pa >> PAGE_SHIFT);
45	}
46
47	va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, VM_MAP, PAGE_KERNEL);
48	if (!va)
49		return -ENOMEM;
50
51	per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
52	return 0;
53}
54#else
55/*
56 * If VMAP stacks are disabled due to KASAN, just use the per cpu
57 * backing store without guard pages.
58 */
59static int map_irq_stack(unsigned int cpu)
60{
61	void *va = per_cpu_ptr(&irq_stack_backing_store, cpu);
62
63	per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
64	return 0;
65}
66#endif
67
68int irq_init_percpu_irqstack(unsigned int cpu)
 
 
69{
70	if (per_cpu(hardirq_stack_ptr, cpu))
71		return 0;
72	return map_irq_stack(cpu);
73}
 
74
75void do_softirq_own_stack(void)
76{
77	run_on_irqstack_cond(__do_softirq, NULL);
 
 
 
 
 
78}