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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
*
* This file contains the lowest level x86_64-specific interrupt
* entry and irq statistics code. All the remaining irq logic is
* done by the generic kernel/irq/ code and in the
* x86_64-specific irq controller code. (e.g. i8259.c and
* io_apic.c.)
*/
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <linux/smp.h>
#include <linux/sched/task_stack.h>
#include <asm/io_apic.h>
#include <asm/apic.h>
int sysctl_panic_on_stackoverflow;
/*
* Probabilistic stack overflow check:
*
* Regular device interrupts can enter on the following stacks:
*
* - User stack
*
* - Kernel task stack
*
* - Interrupt stack if a device driver reenables interrupts
* which should only happen in really old drivers.
*
* - Debug IST stack
*
* All other contexts are invalid.
*/
static inline void stack_overflow_check(struct pt_regs *regs)
{
#ifdef CONFIG_DEBUG_STACKOVERFLOW
#define STACK_TOP_MARGIN 128
struct orig_ist *oist;
u64 irq_stack_top, irq_stack_bottom;
u64 estack_top, estack_bottom;
u64 curbase = (u64)task_stack_page(current);
if (user_mode(regs))
return;
if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
regs->sp <= curbase + THREAD_SIZE)
return;
irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
STACK_TOP_MARGIN;
irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
return;
oist = this_cpu_ptr(&orig_ist);
estack_bottom = (u64)oist->ist[DEBUG_STACK];
estack_top = estack_bottom - DEBUG_STKSZ + STACK_TOP_MARGIN;
if (regs->sp >= estack_top && regs->sp <= estack_bottom)
return;
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",
current->comm, curbase, regs->sp,
irq_stack_top, irq_stack_bottom,
estack_top, estack_bottom, (void *)regs->ip);
if (sysctl_panic_on_stackoverflow)
panic("low stack detected by irq handler - check messages\n");
#endif
}
bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
{
stack_overflow_check(regs);
if (IS_ERR_OR_NULL(desc))
return false;
generic_handle_irq_desc(desc);
return true;
}
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