Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar |
3 | * | |
4 | * This file contains the lowest level x86-specific interrupt | |
5 | * entry, irq-stacks and irq statistics code. All the remaining | |
6 | * irq logic is done by the generic kernel/irq/ code and | |
7 | * by the x86-specific irq controller code. (e.g. i8259.c and | |
8 | * io_apic.c.) | |
9 | */ | |
10 | ||
1da177e4 LT |
11 | #include <linux/module.h> |
12 | #include <linux/seq_file.h> | |
13 | #include <linux/interrupt.h> | |
14 | #include <linux/kernel_stat.h> | |
f3705136 ZM |
15 | #include <linux/notifier.h> |
16 | #include <linux/cpu.h> | |
17 | #include <linux/delay.h> | |
72ade5f9 | 18 | #include <linux/uaccess.h> |
42f8faec | 19 | #include <linux/percpu.h> |
5c1eb089 | 20 | #include <linux/mm.h> |
1da177e4 | 21 | |
e05d723f | 22 | #include <asm/apic.h> |
e05d723f | 23 | |
f34e3b61 | 24 | DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat); |
1da177e4 LT |
25 | EXPORT_PER_CPU_SYMBOL(irq_stat); |
26 | ||
7c3576d2 JF |
27 | DEFINE_PER_CPU(struct pt_regs *, irq_regs); |
28 | EXPORT_PER_CPU_SYMBOL(irq_regs); | |
29 | ||
de9b10af | 30 | #ifdef CONFIG_DEBUG_STACKOVERFLOW |
53b56502 IM |
31 | |
32 | int sysctl_panic_on_stackoverflow __read_mostly; | |
33 | ||
de9b10af TG |
34 | /* Debugging check for stack overflow: is there less than 1KB free? */ |
35 | static int check_stack_overflow(void) | |
36 | { | |
37 | long sp; | |
38 | ||
39 | __asm__ __volatile__("andl %%esp,%0" : | |
40 | "=r" (sp) : "0" (THREAD_SIZE - 1)); | |
41 | ||
42 | return sp < (sizeof(struct thread_info) + STACK_WARN); | |
43 | } | |
44 | ||
45 | static void print_stack_overflow(void) | |
46 | { | |
47 | printk(KERN_WARNING "low stack detected by irq handler\n"); | |
48 | dump_stack(); | |
55af7796 MH |
49 | if (sysctl_panic_on_stackoverflow) |
50 | panic("low stack detected by irq handler - check messages\n"); | |
de9b10af TG |
51 | } |
52 | ||
53 | #else | |
54 | static inline int check_stack_overflow(void) { return 0; } | |
55 | static inline void print_stack_overflow(void) { } | |
56 | #endif | |
57 | ||
198d208d SR |
58 | DEFINE_PER_CPU(struct irq_stack *, hardirq_stack); |
59 | DEFINE_PER_CPU(struct irq_stack *, softirq_stack); | |
1da177e4 | 60 | |
403d8efc | 61 | static void call_on_stack(void *func, void *stack) |
04b361ab | 62 | { |
403d8efc TG |
63 | asm volatile("xchgl %%ebx,%%esp \n" |
64 | "call *%%edi \n" | |
65 | "movl %%ebx,%%esp \n" | |
66 | : "=b" (stack) | |
67 | : "0" (stack), | |
68 | "D"(func) | |
69 | : "memory", "cc", "edx", "ecx", "eax"); | |
04b361ab | 70 | } |
1da177e4 | 71 | |
198d208d | 72 | /* how to get the current stack pointer from C */ |
6cce16f9 MK |
73 | #define current_stack_pointer ({ \ |
74 | unsigned long sp; \ | |
75 | asm("mov %%esp,%0" : "=g" (sp)); \ | |
76 | sp; \ | |
77 | }) | |
198d208d SR |
78 | |
79 | static inline void *current_stack(void) | |
80 | { | |
81 | return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1)); | |
82 | } | |
83 | ||
de9b10af TG |
84 | static inline int |
85 | execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) | |
86 | { | |
198d208d | 87 | struct irq_stack *curstk, *irqstk; |
0788aa6a | 88 | u32 *isp, *prev_esp, arg1, arg2; |
1da177e4 | 89 | |
198d208d SR |
90 | curstk = (struct irq_stack *) current_stack(); |
91 | irqstk = __this_cpu_read(hardirq_stack); | |
1da177e4 LT |
92 | |
93 | /* | |
94 | * this is where we switch to the IRQ stack. However, if we are | |
95 | * already using the IRQ stack (because we interrupted a hardirq | |
96 | * handler) we can't do that and just have to keep using the | |
97 | * current stack (which is the irq stack already after all) | |
98 | */ | |
198d208d | 99 | if (unlikely(curstk == irqstk)) |
de9b10af | 100 | return 0; |
1da177e4 | 101 | |
198d208d SR |
102 | isp = (u32 *) ((char *)irqstk + sizeof(*irqstk)); |
103 | ||
104 | /* Save the next esp at the bottom of the stack */ | |
105 | prev_esp = (u32 *)irqstk; | |
0788aa6a | 106 | *prev_esp = current_stack_pointer; |
1da177e4 | 107 | |
de9b10af | 108 | if (unlikely(overflow)) |
403d8efc TG |
109 | call_on_stack(print_stack_overflow, isp); |
110 | ||
111 | asm volatile("xchgl %%ebx,%%esp \n" | |
112 | "call *%%edi \n" | |
113 | "movl %%ebx,%%esp \n" | |
114 | : "=a" (arg1), "=d" (arg2), "=b" (isp) | |
115 | : "0" (irq), "1" (desc), "2" (isp), | |
116 | "D" (desc->handle_irq) | |
117 | : "memory", "cc", "ecx"); | |
1da177e4 LT |
118 | return 1; |
119 | } | |
120 | ||
1da177e4 LT |
121 | /* |
122 | * allocate per-cpu stacks for hardirq and for softirq processing | |
123 | */ | |
148f9bb8 | 124 | void irq_ctx_init(int cpu) |
1da177e4 | 125 | { |
198d208d | 126 | struct irq_stack *irqstk; |
1da177e4 | 127 | |
198d208d | 128 | if (per_cpu(hardirq_stack, cpu)) |
1da177e4 LT |
129 | return; |
130 | ||
198d208d | 131 | irqstk = page_address(alloc_pages_node(cpu_to_node(cpu), |
38e7c572 TG |
132 | THREADINFO_GFP, |
133 | THREAD_SIZE_ORDER)); | |
198d208d | 134 | per_cpu(hardirq_stack, cpu) = irqstk; |
1da177e4 | 135 | |
198d208d | 136 | irqstk = page_address(alloc_pages_node(cpu_to_node(cpu), |
38e7c572 TG |
137 | THREADINFO_GFP, |
138 | THREAD_SIZE_ORDER)); | |
198d208d | 139 | per_cpu(softirq_stack, cpu) = irqstk; |
1da177e4 | 140 | |
403d8efc | 141 | printk(KERN_DEBUG "CPU %u irqstacks, hard=%p soft=%p\n", |
198d208d | 142 | cpu, per_cpu(hardirq_stack, cpu), per_cpu(softirq_stack, cpu)); |
1da177e4 LT |
143 | } |
144 | ||
7d65f4a6 | 145 | void do_softirq_own_stack(void) |
1da177e4 | 146 | { |
198d208d SR |
147 | struct thread_info *curstk; |
148 | struct irq_stack *irqstk; | |
0788aa6a | 149 | u32 *isp, *prev_esp; |
1da177e4 | 150 | |
198d208d SR |
151 | curstk = current_stack(); |
152 | irqstk = __this_cpu_read(softirq_stack); | |
1da177e4 | 153 | |
7d65f4a6 | 154 | /* build the stack frame on the softirq stack */ |
198d208d | 155 | isp = (u32 *) ((char *)irqstk + sizeof(*irqstk)); |
1da177e4 | 156 | |
0788aa6a | 157 | /* Push the previous esp onto the stack */ |
198d208d | 158 | prev_esp = (u32 *)irqstk; |
0788aa6a SR |
159 | *prev_esp = current_stack_pointer; |
160 | ||
7d65f4a6 | 161 | call_on_stack(__do_softirq, isp); |
1da177e4 | 162 | } |
403d8efc | 163 | |
9b2b76a3 JF |
164 | bool handle_irq(unsigned irq, struct pt_regs *regs) |
165 | { | |
166 | struct irq_desc *desc; | |
167 | int overflow; | |
168 | ||
169 | overflow = check_stack_overflow(); | |
170 | ||
171 | desc = irq_to_desc(irq); | |
172 | if (unlikely(!desc)) | |
173 | return false; | |
174 | ||
986cb48c | 175 | if (user_mode_vm(regs) || !execute_on_irq_stack(overflow, desc, irq)) { |
9b2b76a3 JF |
176 | if (unlikely(overflow)) |
177 | print_stack_overflow(); | |
178 | desc->handle_irq(irq, desc); | |
179 | } | |
180 | ||
181 | return true; | |
182 | } |