| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 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 | */ |
| 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 | |
| 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 | } |