Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/arch/i386/kernel/irq.c | |
3 | * | |
4 | * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar | |
5 | * | |
6 | * This file contains the lowest level x86-specific interrupt | |
7 | * entry, irq-stacks and irq statistics code. All the remaining | |
8 | * irq logic is done by the generic kernel/irq/ code and | |
9 | * by the x86-specific irq controller code. (e.g. i8259.c and | |
10 | * io_apic.c.) | |
11 | */ | |
12 | ||
13 | #include <asm/uaccess.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/seq_file.h> | |
16 | #include <linux/interrupt.h> | |
17 | #include <linux/kernel_stat.h> | |
18 | ||
19 | DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_maxaligned_in_smp; | |
20 | EXPORT_PER_CPU_SYMBOL(irq_stat); | |
21 | ||
22 | #ifndef CONFIG_X86_LOCAL_APIC | |
23 | /* | |
24 | * 'what should we do if we get a hw irq event on an illegal vector'. | |
25 | * each architecture has to answer this themselves. | |
26 | */ | |
27 | void ack_bad_irq(unsigned int irq) | |
28 | { | |
29 | printk("unexpected IRQ trap at vector %02x\n", irq); | |
30 | } | |
31 | #endif | |
32 | ||
33 | #ifdef CONFIG_4KSTACKS | |
34 | /* | |
35 | * per-CPU IRQ handling contexts (thread information and stack) | |
36 | */ | |
37 | union irq_ctx { | |
38 | struct thread_info tinfo; | |
39 | u32 stack[THREAD_SIZE/sizeof(u32)]; | |
40 | }; | |
41 | ||
42 | static union irq_ctx *hardirq_ctx[NR_CPUS]; | |
43 | static union irq_ctx *softirq_ctx[NR_CPUS]; | |
44 | #endif | |
45 | ||
46 | /* | |
47 | * do_IRQ handles all normal device IRQ's (the special | |
48 | * SMP cross-CPU interrupts have their own specific | |
49 | * handlers). | |
50 | */ | |
51 | fastcall unsigned int do_IRQ(struct pt_regs *regs) | |
52 | { | |
53 | /* high bits used in ret_from_ code */ | |
54 | int irq = regs->orig_eax & 0xff; | |
55 | #ifdef CONFIG_4KSTACKS | |
56 | union irq_ctx *curctx, *irqctx; | |
57 | u32 *isp; | |
58 | #endif | |
59 | ||
60 | irq_enter(); | |
61 | #ifdef CONFIG_DEBUG_STACKOVERFLOW | |
62 | /* Debugging check for stack overflow: is there less than 1KB free? */ | |
63 | { | |
64 | long esp; | |
65 | ||
66 | __asm__ __volatile__("andl %%esp,%0" : | |
67 | "=r" (esp) : "0" (THREAD_SIZE - 1)); | |
68 | if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) { | |
69 | printk("do_IRQ: stack overflow: %ld\n", | |
70 | esp - sizeof(struct thread_info)); | |
71 | dump_stack(); | |
72 | } | |
73 | } | |
74 | #endif | |
75 | ||
76 | #ifdef CONFIG_4KSTACKS | |
77 | ||
78 | curctx = (union irq_ctx *) current_thread_info(); | |
79 | irqctx = hardirq_ctx[smp_processor_id()]; | |
80 | ||
81 | /* | |
82 | * this is where we switch to the IRQ stack. However, if we are | |
83 | * already using the IRQ stack (because we interrupted a hardirq | |
84 | * handler) we can't do that and just have to keep using the | |
85 | * current stack (which is the irq stack already after all) | |
86 | */ | |
87 | if (curctx != irqctx) { | |
88 | int arg1, arg2, ebx; | |
89 | ||
90 | /* build the stack frame on the IRQ stack */ | |
91 | isp = (u32*) ((char*)irqctx + sizeof(*irqctx)); | |
92 | irqctx->tinfo.task = curctx->tinfo.task; | |
93 | irqctx->tinfo.previous_esp = current_stack_pointer; | |
94 | ||
95 | asm volatile( | |
96 | " xchgl %%ebx,%%esp \n" | |
97 | " call __do_IRQ \n" | |
98 | " movl %%ebx,%%esp \n" | |
99 | : "=a" (arg1), "=d" (arg2), "=b" (ebx) | |
100 | : "0" (irq), "1" (regs), "2" (isp) | |
101 | : "memory", "cc", "ecx" | |
102 | ); | |
103 | } else | |
104 | #endif | |
105 | __do_IRQ(irq, regs); | |
106 | ||
107 | irq_exit(); | |
108 | ||
109 | return 1; | |
110 | } | |
111 | ||
112 | #ifdef CONFIG_4KSTACKS | |
113 | ||
114 | /* | |
115 | * These should really be __section__(".bss.page_aligned") as well, but | |
116 | * gcc's 3.0 and earlier don't handle that correctly. | |
117 | */ | |
118 | static char softirq_stack[NR_CPUS * THREAD_SIZE] | |
119 | __attribute__((__aligned__(THREAD_SIZE))); | |
120 | ||
121 | static char hardirq_stack[NR_CPUS * THREAD_SIZE] | |
122 | __attribute__((__aligned__(THREAD_SIZE))); | |
123 | ||
124 | /* | |
125 | * allocate per-cpu stacks for hardirq and for softirq processing | |
126 | */ | |
127 | void irq_ctx_init(int cpu) | |
128 | { | |
129 | union irq_ctx *irqctx; | |
130 | ||
131 | if (hardirq_ctx[cpu]) | |
132 | return; | |
133 | ||
134 | irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE]; | |
135 | irqctx->tinfo.task = NULL; | |
136 | irqctx->tinfo.exec_domain = NULL; | |
137 | irqctx->tinfo.cpu = cpu; | |
138 | irqctx->tinfo.preempt_count = HARDIRQ_OFFSET; | |
139 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); | |
140 | ||
141 | hardirq_ctx[cpu] = irqctx; | |
142 | ||
143 | irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE]; | |
144 | irqctx->tinfo.task = NULL; | |
145 | irqctx->tinfo.exec_domain = NULL; | |
146 | irqctx->tinfo.cpu = cpu; | |
147 | irqctx->tinfo.preempt_count = SOFTIRQ_OFFSET; | |
148 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); | |
149 | ||
150 | softirq_ctx[cpu] = irqctx; | |
151 | ||
152 | printk("CPU %u irqstacks, hard=%p soft=%p\n", | |
153 | cpu,hardirq_ctx[cpu],softirq_ctx[cpu]); | |
154 | } | |
155 | ||
156 | extern asmlinkage void __do_softirq(void); | |
157 | ||
158 | asmlinkage void do_softirq(void) | |
159 | { | |
160 | unsigned long flags; | |
161 | struct thread_info *curctx; | |
162 | union irq_ctx *irqctx; | |
163 | u32 *isp; | |
164 | ||
165 | if (in_interrupt()) | |
166 | return; | |
167 | ||
168 | local_irq_save(flags); | |
169 | ||
170 | if (local_softirq_pending()) { | |
171 | curctx = current_thread_info(); | |
172 | irqctx = softirq_ctx[smp_processor_id()]; | |
173 | irqctx->tinfo.task = curctx->task; | |
174 | irqctx->tinfo.previous_esp = current_stack_pointer; | |
175 | ||
176 | /* build the stack frame on the softirq stack */ | |
177 | isp = (u32*) ((char*)irqctx + sizeof(*irqctx)); | |
178 | ||
179 | asm volatile( | |
180 | " xchgl %%ebx,%%esp \n" | |
181 | " call __do_softirq \n" | |
182 | " movl %%ebx,%%esp \n" | |
183 | : "=b"(isp) | |
184 | : "0"(isp) | |
185 | : "memory", "cc", "edx", "ecx", "eax" | |
186 | ); | |
187 | } | |
188 | ||
189 | local_irq_restore(flags); | |
190 | } | |
191 | ||
192 | EXPORT_SYMBOL(do_softirq); | |
193 | #endif | |
194 | ||
195 | /* | |
196 | * Interrupt statistics: | |
197 | */ | |
198 | ||
199 | atomic_t irq_err_count; | |
200 | ||
201 | /* | |
202 | * /proc/interrupts printing: | |
203 | */ | |
204 | ||
205 | int show_interrupts(struct seq_file *p, void *v) | |
206 | { | |
207 | int i = *(loff_t *) v, j; | |
208 | struct irqaction * action; | |
209 | unsigned long flags; | |
210 | ||
211 | if (i == 0) { | |
212 | seq_printf(p, " "); | |
213 | for (j=0; j<NR_CPUS; j++) | |
214 | if (cpu_online(j)) | |
215 | seq_printf(p, "CPU%d ",j); | |
216 | seq_putc(p, '\n'); | |
217 | } | |
218 | ||
219 | if (i < NR_IRQS) { | |
220 | spin_lock_irqsave(&irq_desc[i].lock, flags); | |
221 | action = irq_desc[i].action; | |
222 | if (!action) | |
223 | goto skip; | |
224 | seq_printf(p, "%3d: ",i); | |
225 | #ifndef CONFIG_SMP | |
226 | seq_printf(p, "%10u ", kstat_irqs(i)); | |
227 | #else | |
228 | for (j = 0; j < NR_CPUS; j++) | |
229 | if (cpu_online(j)) | |
230 | seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]); | |
231 | #endif | |
232 | seq_printf(p, " %14s", irq_desc[i].handler->typename); | |
233 | seq_printf(p, " %s", action->name); | |
234 | ||
235 | for (action=action->next; action; action = action->next) | |
236 | seq_printf(p, ", %s", action->name); | |
237 | ||
238 | seq_putc(p, '\n'); | |
239 | skip: | |
240 | spin_unlock_irqrestore(&irq_desc[i].lock, flags); | |
241 | } else if (i == NR_IRQS) { | |
242 | seq_printf(p, "NMI: "); | |
243 | for (j = 0; j < NR_CPUS; j++) | |
244 | if (cpu_online(j)) | |
245 | seq_printf(p, "%10u ", nmi_count(j)); | |
246 | seq_putc(p, '\n'); | |
247 | #ifdef CONFIG_X86_LOCAL_APIC | |
248 | seq_printf(p, "LOC: "); | |
249 | for (j = 0; j < NR_CPUS; j++) | |
250 | if (cpu_online(j)) | |
251 | seq_printf(p, "%10u ", | |
252 | per_cpu(irq_stat,j).apic_timer_irqs); | |
253 | seq_putc(p, '\n'); | |
254 | #endif | |
255 | seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count)); | |
256 | #if defined(CONFIG_X86_IO_APIC) | |
257 | seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count)); | |
258 | #endif | |
259 | } | |
260 | return 0; | |
261 | } |