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