Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
1da177e4 LT |
3 | * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar |
4 | * | |
5 | * This file contains the lowest level x86-specific interrupt | |
6 | * entry, irq-stacks and irq statistics code. All the remaining | |
7 | * irq logic is done by the generic kernel/irq/ code and | |
8 | * by the x86-specific irq controller code. (e.g. i8259.c and | |
9 | * io_apic.c.) | |
10 | */ | |
11 | ||
1da177e4 LT |
12 | #include <linux/seq_file.h> |
13 | #include <linux/interrupt.h> | |
447ae316 | 14 | #include <linux/irq.h> |
1da177e4 | 15 | #include <linux/kernel_stat.h> |
f3705136 ZM |
16 | #include <linux/notifier.h> |
17 | #include <linux/cpu.h> | |
18 | #include <linux/delay.h> | |
72ade5f9 | 19 | #include <linux/uaccess.h> |
42f8faec | 20 | #include <linux/percpu.h> |
5c1eb089 | 21 | #include <linux/mm.h> |
1da177e4 | 22 | |
e05d723f | 23 | #include <asm/apic.h> |
7614e913 | 24 | #include <asm/nospec-branch.h> |
db1cc7ae | 25 | #include <asm/softirq_stack.h> |
e05d723f | 26 | |
de9b10af | 27 | #ifdef CONFIG_DEBUG_STACKOVERFLOW |
53b56502 IM |
28 | |
29 | int sysctl_panic_on_stackoverflow __read_mostly; | |
30 | ||
de9b10af TG |
31 | /* Debugging check for stack overflow: is there less than 1KB free? */ |
32 | static int check_stack_overflow(void) | |
33 | { | |
34 | long sp; | |
35 | ||
36 | __asm__ __volatile__("andl %%esp,%0" : | |
37 | "=r" (sp) : "0" (THREAD_SIZE - 1)); | |
38 | ||
39 | return sp < (sizeof(struct thread_info) + STACK_WARN); | |
40 | } | |
41 | ||
42 | static void print_stack_overflow(void) | |
43 | { | |
44 | printk(KERN_WARNING "low stack detected by irq handler\n"); | |
45 | dump_stack(); | |
55af7796 MH |
46 | if (sysctl_panic_on_stackoverflow) |
47 | panic("low stack detected by irq handler - check messages\n"); | |
de9b10af TG |
48 | } |
49 | ||
50 | #else | |
51 | static inline int check_stack_overflow(void) { return 0; } | |
52 | static inline void print_stack_overflow(void) { } | |
53 | #endif | |
54 | ||
403d8efc | 55 | static void call_on_stack(void *func, void *stack) |
04b361ab | 56 | { |
403d8efc | 57 | asm volatile("xchgl %%ebx,%%esp \n" |
7614e913 | 58 | CALL_NOSPEC |
403d8efc TG |
59 | "movl %%ebx,%%esp \n" |
60 | : "=b" (stack) | |
61 | : "0" (stack), | |
7614e913 | 62 | [thunk_target] "D"(func) |
403d8efc | 63 | : "memory", "cc", "edx", "ecx", "eax"); |
04b361ab | 64 | } |
1da177e4 | 65 | |
198d208d SR |
66 | static inline void *current_stack(void) |
67 | { | |
196bd485 | 68 | return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1)); |
198d208d SR |
69 | } |
70 | ||
bd0b9ac4 | 71 | static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc) |
de9b10af | 72 | { |
198d208d | 73 | struct irq_stack *curstk, *irqstk; |
bd0b9ac4 | 74 | u32 *isp, *prev_esp, arg1; |
1da177e4 | 75 | |
198d208d | 76 | curstk = (struct irq_stack *) current_stack(); |
d7b6d709 | 77 | irqstk = __this_cpu_read(pcpu_hot.hardirq_stack_ptr); |
1da177e4 LT |
78 | |
79 | /* | |
80 | * this is where we switch to the IRQ stack. However, if we are | |
81 | * already using the IRQ stack (because we interrupted a hardirq | |
82 | * handler) we can't do that and just have to keep using the | |
83 | * current stack (which is the irq stack already after all) | |
84 | */ | |
198d208d | 85 | if (unlikely(curstk == irqstk)) |
de9b10af | 86 | return 0; |
1da177e4 | 87 | |
198d208d SR |
88 | isp = (u32 *) ((char *)irqstk + sizeof(*irqstk)); |
89 | ||
90 | /* Save the next esp at the bottom of the stack */ | |
91 | prev_esp = (u32 *)irqstk; | |
196bd485 | 92 | *prev_esp = current_stack_pointer; |
1da177e4 | 93 | |
de9b10af | 94 | if (unlikely(overflow)) |
403d8efc TG |
95 | call_on_stack(print_stack_overflow, isp); |
96 | ||
97 | asm volatile("xchgl %%ebx,%%esp \n" | |
7614e913 | 98 | CALL_NOSPEC |
403d8efc | 99 | "movl %%ebx,%%esp \n" |
bd0b9ac4 TG |
100 | : "=a" (arg1), "=b" (isp) |
101 | : "0" (desc), "1" (isp), | |
7614e913 | 102 | [thunk_target] "D" (desc->handle_irq) |
403d8efc | 103 | : "memory", "cc", "ecx"); |
1da177e4 LT |
104 | return 1; |
105 | } | |
106 | ||
1da177e4 | 107 | /* |
66c7ceb4 | 108 | * Allocate per-cpu stacks for hardirq and softirq processing |
1da177e4 | 109 | */ |
66c7ceb4 | 110 | int irq_init_percpu_irqstack(unsigned int cpu) |
1da177e4 | 111 | { |
66c7ceb4 TG |
112 | int node = cpu_to_node(cpu); |
113 | struct page *ph, *ps; | |
1da177e4 | 114 | |
d7b6d709 | 115 | if (per_cpu(pcpu_hot.hardirq_stack_ptr, cpu)) |
66c7ceb4 | 116 | return 0; |
1da177e4 | 117 | |
66c7ceb4 TG |
118 | ph = alloc_pages_node(node, THREADINFO_GFP, THREAD_SIZE_ORDER); |
119 | if (!ph) | |
120 | return -ENOMEM; | |
121 | ps = alloc_pages_node(node, THREADINFO_GFP, THREAD_SIZE_ORDER); | |
122 | if (!ps) { | |
123 | __free_pages(ph, THREAD_SIZE_ORDER); | |
124 | return -ENOMEM; | |
125 | } | |
1da177e4 | 126 | |
d7b6d709 TG |
127 | per_cpu(pcpu_hot.hardirq_stack_ptr, cpu) = page_address(ph); |
128 | per_cpu(pcpu_hot.softirq_stack_ptr, cpu) = page_address(ps); | |
66c7ceb4 | 129 | return 0; |
1da177e4 LT |
130 | } |
131 | ||
8cbb2b50 | 132 | #ifdef CONFIG_SOFTIRQ_ON_OWN_STACK |
7d65f4a6 | 133 | void do_softirq_own_stack(void) |
1da177e4 | 134 | { |
198d208d | 135 | struct irq_stack *irqstk; |
0788aa6a | 136 | u32 *isp, *prev_esp; |
1da177e4 | 137 | |
d7b6d709 | 138 | irqstk = __this_cpu_read(pcpu_hot.softirq_stack_ptr); |
1da177e4 | 139 | |
7d65f4a6 | 140 | /* build the stack frame on the softirq stack */ |
198d208d | 141 | isp = (u32 *) ((char *)irqstk + sizeof(*irqstk)); |
1da177e4 | 142 | |
0788aa6a | 143 | /* Push the previous esp onto the stack */ |
198d208d | 144 | prev_esp = (u32 *)irqstk; |
196bd485 | 145 | *prev_esp = current_stack_pointer; |
0788aa6a | 146 | |
7d65f4a6 | 147 | call_on_stack(__do_softirq, isp); |
1da177e4 | 148 | } |
441e9036 | 149 | #endif |
403d8efc | 150 | |
7c2a5736 | 151 | void __handle_irq(struct irq_desc *desc, struct pt_regs *regs) |
9b2b76a3 | 152 | { |
bd0b9ac4 | 153 | int overflow = check_stack_overflow(); |
9b2b76a3 | 154 | |
bd0b9ac4 | 155 | if (user_mode(regs) || !execute_on_irq_stack(overflow, desc)) { |
9b2b76a3 JF |
156 | if (unlikely(overflow)) |
157 | print_stack_overflow(); | |
bd0b9ac4 | 158 | generic_handle_irq_desc(desc); |
9b2b76a3 | 159 | } |
9b2b76a3 | 160 | } |