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 #include <asm/io_apic.h>
22 #include <asm/apic.h>
23
24 int sysctl_panic_on_stackoverflow;
25
26 /*
27 * Probabilistic stack overflow check:
28 *
29 * Only check the stack in process context, because everything else
30 * runs on the big interrupt stacks. Checking reliably is too expensive,
31 * so we just check from interrupts.
32 */
stack_overflow_check(struct pt_regs * regs)33 static inline void stack_overflow_check(struct pt_regs *regs)
34 {
35 #ifdef CONFIG_DEBUG_STACKOVERFLOW
36 #define STACK_TOP_MARGIN 128
37 struct orig_ist *oist;
38 u64 irq_stack_top, irq_stack_bottom;
39 u64 estack_top, estack_bottom;
40 u64 curbase = (u64)task_stack_page(current);
41
42 if (user_mode(regs))
43 return;
44
45 if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
46 regs->sp <= curbase + THREAD_SIZE)
47 return;
48
49 irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
50 STACK_TOP_MARGIN;
51 irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
52 if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
53 return;
54
55 oist = this_cpu_ptr(&orig_ist);
56 estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN;
57 estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
58 if (regs->sp >= estack_top && regs->sp <= estack_bottom)
59 return;
60
61 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,ip:%pF)\n",
62 current->comm, curbase, regs->sp,
63 irq_stack_top, irq_stack_bottom,
64 estack_top, estack_bottom, (void *)regs->ip);
65
66 if (sysctl_panic_on_stackoverflow)
67 panic("low stack detected by irq handler - check messages\n");
68 #endif
69 }
70
handle_irq(struct irq_desc * desc,struct pt_regs * regs)71 bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
72 {
73 stack_overflow_check(regs);
74
75 if (IS_ERR_OR_NULL(desc))
76 return false;
77
78 generic_handle_irq_desc(desc);
79 return true;
80 }
81
