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 | ||
1da177e4 LT |
58 | /* |
59 | * per-CPU IRQ handling contexts (thread information and stack) | |
60 | */ | |
61 | union irq_ctx { | |
62 | struct thread_info tinfo; | |
63 | u32 stack[THREAD_SIZE/sizeof(u32)]; | |
25897374 | 64 | } __attribute__((aligned(THREAD_SIZE))); |
1da177e4 | 65 | |
42f8faec LJ |
66 | static DEFINE_PER_CPU(union irq_ctx *, hardirq_ctx); |
67 | static DEFINE_PER_CPU(union irq_ctx *, softirq_ctx); | |
1da177e4 | 68 | |
403d8efc | 69 | static void call_on_stack(void *func, void *stack) |
04b361ab | 70 | { |
403d8efc TG |
71 | asm volatile("xchgl %%ebx,%%esp \n" |
72 | "call *%%edi \n" | |
73 | "movl %%ebx,%%esp \n" | |
74 | : "=b" (stack) | |
75 | : "0" (stack), | |
76 | "D"(func) | |
77 | : "memory", "cc", "edx", "ecx", "eax"); | |
04b361ab | 78 | } |
1da177e4 | 79 | |
de9b10af TG |
80 | static inline int |
81 | execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) | |
82 | { | |
83 | union irq_ctx *curctx, *irqctx; | |
403d8efc | 84 | u32 *isp, arg1, arg2; |
1da177e4 LT |
85 | |
86 | curctx = (union irq_ctx *) current_thread_info(); | |
0a3aee0d | 87 | irqctx = __this_cpu_read(hardirq_ctx); |
1da177e4 LT |
88 | |
89 | /* | |
90 | * this is where we switch to the IRQ stack. However, if we are | |
91 | * already using the IRQ stack (because we interrupted a hardirq | |
92 | * handler) we can't do that and just have to keep using the | |
93 | * current stack (which is the irq stack already after all) | |
94 | */ | |
de9b10af TG |
95 | if (unlikely(curctx == irqctx)) |
96 | return 0; | |
1da177e4 | 97 | |
de9b10af | 98 | /* build the stack frame on the IRQ stack */ |
72ade5f9 | 99 | isp = (u32 *) ((char *)irqctx + sizeof(*irqctx)); |
de9b10af TG |
100 | irqctx->tinfo.task = curctx->tinfo.task; |
101 | irqctx->tinfo.previous_esp = current_stack_pointer; | |
1da177e4 | 102 | |
986cb48c LT |
103 | /* Copy the preempt_count so that the [soft]irq checks work. */ |
104 | irqctx->tinfo.preempt_count = curctx->tinfo.preempt_count; | |
de9b10af TG |
105 | |
106 | if (unlikely(overflow)) | |
403d8efc TG |
107 | call_on_stack(print_stack_overflow, isp); |
108 | ||
109 | asm volatile("xchgl %%ebx,%%esp \n" | |
110 | "call *%%edi \n" | |
111 | "movl %%ebx,%%esp \n" | |
112 | : "=a" (arg1), "=d" (arg2), "=b" (isp) | |
113 | : "0" (irq), "1" (desc), "2" (isp), | |
114 | "D" (desc->handle_irq) | |
115 | : "memory", "cc", "ecx"); | |
1da177e4 LT |
116 | return 1; |
117 | } | |
118 | ||
1da177e4 LT |
119 | /* |
120 | * allocate per-cpu stacks for hardirq and for softirq processing | |
121 | */ | |
148f9bb8 | 122 | void irq_ctx_init(int cpu) |
1da177e4 LT |
123 | { |
124 | union irq_ctx *irqctx; | |
125 | ||
42f8faec | 126 | if (per_cpu(hardirq_ctx, cpu)) |
1da177e4 LT |
127 | return; |
128 | ||
5c1eb089 | 129 | irqctx = page_address(alloc_pages_node(cpu_to_node(cpu), |
38e7c572 TG |
130 | THREADINFO_GFP, |
131 | THREAD_SIZE_ORDER)); | |
7b698ea3 | 132 | memset(&irqctx->tinfo, 0, sizeof(struct thread_info)); |
403d8efc TG |
133 | irqctx->tinfo.cpu = cpu; |
134 | irqctx->tinfo.preempt_count = HARDIRQ_OFFSET; | |
135 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); | |
1da177e4 | 136 | |
42f8faec | 137 | per_cpu(hardirq_ctx, cpu) = irqctx; |
1da177e4 | 138 | |
5c1eb089 | 139 | irqctx = page_address(alloc_pages_node(cpu_to_node(cpu), |
38e7c572 TG |
140 | THREADINFO_GFP, |
141 | THREAD_SIZE_ORDER)); | |
7b698ea3 | 142 | memset(&irqctx->tinfo, 0, sizeof(struct thread_info)); |
403d8efc | 143 | irqctx->tinfo.cpu = cpu; |
403d8efc | 144 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); |
1da177e4 | 145 | |
42f8faec | 146 | per_cpu(softirq_ctx, cpu) = irqctx; |
1da177e4 | 147 | |
403d8efc | 148 | printk(KERN_DEBUG "CPU %u irqstacks, hard=%p soft=%p\n", |
42f8faec | 149 | cpu, per_cpu(hardirq_ctx, cpu), per_cpu(softirq_ctx, cpu)); |
1da177e4 LT |
150 | } |
151 | ||
1da177e4 LT |
152 | asmlinkage void do_softirq(void) |
153 | { | |
154 | unsigned long flags; | |
155 | struct thread_info *curctx; | |
156 | union irq_ctx *irqctx; | |
157 | u32 *isp; | |
158 | ||
159 | if (in_interrupt()) | |
160 | return; | |
161 | ||
162 | local_irq_save(flags); | |
163 | ||
164 | if (local_softirq_pending()) { | |
165 | curctx = current_thread_info(); | |
0a3aee0d | 166 | irqctx = __this_cpu_read(softirq_ctx); |
1da177e4 LT |
167 | irqctx->tinfo.task = curctx->task; |
168 | irqctx->tinfo.previous_esp = current_stack_pointer; | |
169 | ||
170 | /* build the stack frame on the softirq stack */ | |
72ade5f9 | 171 | isp = (u32 *) ((char *)irqctx + sizeof(*irqctx)); |
1da177e4 | 172 | |
403d8efc | 173 | call_on_stack(__do_softirq, isp); |
55f327fa | 174 | /* |
0d2eb44f | 175 | * Shouldn't happen, we returned above if in_interrupt(): |
403d8efc | 176 | */ |
55f327fa | 177 | WARN_ON_ONCE(softirq_count()); |
1da177e4 LT |
178 | } |
179 | ||
180 | local_irq_restore(flags); | |
181 | } | |
403d8efc | 182 | |
9b2b76a3 JF |
183 | bool handle_irq(unsigned irq, struct pt_regs *regs) |
184 | { | |
185 | struct irq_desc *desc; | |
186 | int overflow; | |
187 | ||
188 | overflow = check_stack_overflow(); | |
189 | ||
190 | desc = irq_to_desc(irq); | |
191 | if (unlikely(!desc)) | |
192 | return false; | |
193 | ||
986cb48c | 194 | if (user_mode_vm(regs) || !execute_on_irq_stack(overflow, desc, irq)) { |
9b2b76a3 JF |
195 | if (unlikely(overflow)) |
196 | print_stack_overflow(); | |
197 | desc->handle_irq(irq, desc); | |
198 | } | |
199 | ||
200 | return true; | |
201 | } |