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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 | ||
1da177e4 LT |
13 | #include <linux/module.h> |
14 | #include <linux/seq_file.h> | |
15 | #include <linux/interrupt.h> | |
16 | #include <linux/kernel_stat.h> | |
f3705136 ZM |
17 | #include <linux/notifier.h> |
18 | #include <linux/cpu.h> | |
19 | #include <linux/delay.h> | |
1da177e4 | 20 | |
e05d723f TG |
21 | #include <asm/apic.h> |
22 | #include <asm/uaccess.h> | |
23 | ||
22fc6ecc | 24 | DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_internodealigned_in_smp; |
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 | ||
1da177e4 LT |
30 | /* |
31 | * 'what should we do if we get a hw irq event on an illegal vector'. | |
32 | * each architecture has to answer this themselves. | |
33 | */ | |
34 | void ack_bad_irq(unsigned int irq) | |
35 | { | |
e05d723f TG |
36 | printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq); |
37 | ||
38 | #ifdef CONFIG_X86_LOCAL_APIC | |
39 | /* | |
40 | * Currently unexpected vectors happen only on SMP and APIC. | |
41 | * We _must_ ack these because every local APIC has only N | |
42 | * irq slots per priority level, and a 'hanging, unacked' IRQ | |
43 | * holds up an irq slot - in excessive cases (when multiple | |
44 | * unexpected vectors occur) that might lock up the APIC | |
45 | * completely. | |
46 | * But only ack when the APIC is enabled -AK | |
47 | */ | |
48 | if (cpu_has_apic) | |
49 | ack_APIC_irq(); | |
1da177e4 | 50 | #endif |
e05d723f | 51 | } |
1da177e4 LT |
52 | |
53 | #ifdef CONFIG_4KSTACKS | |
54 | /* | |
55 | * per-CPU IRQ handling contexts (thread information and stack) | |
56 | */ | |
57 | union irq_ctx { | |
58 | struct thread_info tinfo; | |
59 | u32 stack[THREAD_SIZE/sizeof(u32)]; | |
60 | }; | |
61 | ||
22722051 AM |
62 | static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly; |
63 | static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly; | |
1da177e4 LT |
64 | #endif |
65 | ||
66 | /* | |
67 | * do_IRQ handles all normal device IRQ's (the special | |
68 | * SMP cross-CPU interrupts have their own specific | |
69 | * handlers). | |
70 | */ | |
71 | fastcall unsigned int do_IRQ(struct pt_regs *regs) | |
72 | { | |
7d12e780 | 73 | struct pt_regs *old_regs; |
19eadf98 RR |
74 | /* high bit used in ret_from_ code */ |
75 | int irq = ~regs->orig_eax; | |
f5b9ed7a | 76 | struct irq_desc *desc = irq_desc + irq; |
1da177e4 LT |
77 | #ifdef CONFIG_4KSTACKS |
78 | union irq_ctx *curctx, *irqctx; | |
79 | u32 *isp; | |
80 | #endif | |
81 | ||
a052b68b AM |
82 | if (unlikely((unsigned)irq >= NR_IRQS)) { |
83 | printk(KERN_EMERG "%s: cannot handle IRQ %d\n", | |
84 | __FUNCTION__, irq); | |
85 | BUG(); | |
86 | } | |
87 | ||
7d12e780 | 88 | old_regs = set_irq_regs(regs); |
1da177e4 LT |
89 | irq_enter(); |
90 | #ifdef CONFIG_DEBUG_STACKOVERFLOW | |
91 | /* Debugging check for stack overflow: is there less than 1KB free? */ | |
92 | { | |
93 | long esp; | |
94 | ||
95 | __asm__ __volatile__("andl %%esp,%0" : | |
96 | "=r" (esp) : "0" (THREAD_SIZE - 1)); | |
97 | if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) { | |
98 | printk("do_IRQ: stack overflow: %ld\n", | |
99 | esp - sizeof(struct thread_info)); | |
100 | dump_stack(); | |
101 | } | |
102 | } | |
103 | #endif | |
104 | ||
105 | #ifdef CONFIG_4KSTACKS | |
106 | ||
107 | curctx = (union irq_ctx *) current_thread_info(); | |
108 | irqctx = hardirq_ctx[smp_processor_id()]; | |
109 | ||
110 | /* | |
111 | * this is where we switch to the IRQ stack. However, if we are | |
112 | * already using the IRQ stack (because we interrupted a hardirq | |
113 | * handler) we can't do that and just have to keep using the | |
114 | * current stack (which is the irq stack already after all) | |
115 | */ | |
116 | if (curctx != irqctx) { | |
7d12e780 | 117 | int arg1, arg2, ebx; |
1da177e4 LT |
118 | |
119 | /* build the stack frame on the IRQ stack */ | |
120 | isp = (u32*) ((char*)irqctx + sizeof(*irqctx)); | |
121 | irqctx->tinfo.task = curctx->tinfo.task; | |
122 | irqctx->tinfo.previous_esp = current_stack_pointer; | |
123 | ||
a5d157e0 BS |
124 | /* |
125 | * Copy the softirq bits in preempt_count so that the | |
126 | * softirq checks work in the hardirq context. | |
127 | */ | |
128 | irqctx->tinfo.preempt_count = | |
91bf4602 AM |
129 | (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) | |
130 | (curctx->tinfo.preempt_count & SOFTIRQ_MASK); | |
a5d157e0 | 131 | |
1da177e4 | 132 | asm volatile( |
f5b9ed7a IM |
133 | " xchgl %%ebx,%%esp \n" |
134 | " call *%%edi \n" | |
1da177e4 | 135 | " movl %%ebx,%%esp \n" |
7d12e780 DH |
136 | : "=a" (arg1), "=d" (arg2), "=b" (ebx) |
137 | : "0" (irq), "1" (desc), "2" (isp), | |
f5b9ed7a IM |
138 | "D" (desc->handle_irq) |
139 | : "memory", "cc" | |
1da177e4 LT |
140 | ); |
141 | } else | |
142 | #endif | |
7d12e780 | 143 | desc->handle_irq(irq, desc); |
1da177e4 LT |
144 | |
145 | irq_exit(); | |
7d12e780 | 146 | set_irq_regs(old_regs); |
1da177e4 LT |
147 | return 1; |
148 | } | |
149 | ||
150 | #ifdef CONFIG_4KSTACKS | |
151 | ||
152 | /* | |
153 | * These should really be __section__(".bss.page_aligned") as well, but | |
154 | * gcc's 3.0 and earlier don't handle that correctly. | |
155 | */ | |
156 | static char softirq_stack[NR_CPUS * THREAD_SIZE] | |
157 | __attribute__((__aligned__(THREAD_SIZE))); | |
158 | ||
159 | static char hardirq_stack[NR_CPUS * THREAD_SIZE] | |
160 | __attribute__((__aligned__(THREAD_SIZE))); | |
161 | ||
162 | /* | |
163 | * allocate per-cpu stacks for hardirq and for softirq processing | |
164 | */ | |
165 | void irq_ctx_init(int cpu) | |
166 | { | |
167 | union irq_ctx *irqctx; | |
168 | ||
169 | if (hardirq_ctx[cpu]) | |
170 | return; | |
171 | ||
172 | irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE]; | |
173 | irqctx->tinfo.task = NULL; | |
174 | irqctx->tinfo.exec_domain = NULL; | |
175 | irqctx->tinfo.cpu = cpu; | |
176 | irqctx->tinfo.preempt_count = HARDIRQ_OFFSET; | |
177 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); | |
178 | ||
179 | hardirq_ctx[cpu] = irqctx; | |
180 | ||
181 | irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE]; | |
182 | irqctx->tinfo.task = NULL; | |
183 | irqctx->tinfo.exec_domain = NULL; | |
184 | irqctx->tinfo.cpu = cpu; | |
55f327fa | 185 | irqctx->tinfo.preempt_count = 0; |
1da177e4 LT |
186 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); |
187 | ||
188 | softirq_ctx[cpu] = irqctx; | |
189 | ||
190 | printk("CPU %u irqstacks, hard=%p soft=%p\n", | |
191 | cpu,hardirq_ctx[cpu],softirq_ctx[cpu]); | |
192 | } | |
193 | ||
e1367daf LS |
194 | void irq_ctx_exit(int cpu) |
195 | { | |
196 | hardirq_ctx[cpu] = NULL; | |
197 | } | |
198 | ||
1da177e4 LT |
199 | extern asmlinkage void __do_softirq(void); |
200 | ||
201 | asmlinkage void do_softirq(void) | |
202 | { | |
203 | unsigned long flags; | |
204 | struct thread_info *curctx; | |
205 | union irq_ctx *irqctx; | |
206 | u32 *isp; | |
207 | ||
208 | if (in_interrupt()) | |
209 | return; | |
210 | ||
211 | local_irq_save(flags); | |
212 | ||
213 | if (local_softirq_pending()) { | |
214 | curctx = current_thread_info(); | |
215 | irqctx = softirq_ctx[smp_processor_id()]; | |
216 | irqctx->tinfo.task = curctx->task; | |
217 | irqctx->tinfo.previous_esp = current_stack_pointer; | |
218 | ||
219 | /* build the stack frame on the softirq stack */ | |
220 | isp = (u32*) ((char*)irqctx + sizeof(*irqctx)); | |
221 | ||
222 | asm volatile( | |
223 | " xchgl %%ebx,%%esp \n" | |
224 | " call __do_softirq \n" | |
225 | " movl %%ebx,%%esp \n" | |
226 | : "=b"(isp) | |
227 | : "0"(isp) | |
228 | : "memory", "cc", "edx", "ecx", "eax" | |
229 | ); | |
55f327fa IM |
230 | /* |
231 | * Shouldnt happen, we returned above if in_interrupt(): | |
232 | */ | |
233 | WARN_ON_ONCE(softirq_count()); | |
1da177e4 LT |
234 | } |
235 | ||
236 | local_irq_restore(flags); | |
237 | } | |
238 | ||
239 | EXPORT_SYMBOL(do_softirq); | |
240 | #endif | |
241 | ||
242 | /* | |
243 | * Interrupt statistics: | |
244 | */ | |
245 | ||
246 | atomic_t irq_err_count; | |
247 | ||
248 | /* | |
249 | * /proc/interrupts printing: | |
250 | */ | |
251 | ||
252 | int show_interrupts(struct seq_file *p, void *v) | |
253 | { | |
254 | int i = *(loff_t *) v, j; | |
255 | struct irqaction * action; | |
256 | unsigned long flags; | |
257 | ||
258 | if (i == 0) { | |
259 | seq_printf(p, " "); | |
9f40a72a | 260 | for_each_online_cpu(j) |
bdbdaa79 | 261 | seq_printf(p, "CPU%-8d",j); |
1da177e4 LT |
262 | seq_putc(p, '\n'); |
263 | } | |
264 | ||
265 | if (i < NR_IRQS) { | |
266 | spin_lock_irqsave(&irq_desc[i].lock, flags); | |
267 | action = irq_desc[i].action; | |
268 | if (!action) | |
269 | goto skip; | |
270 | seq_printf(p, "%3d: ",i); | |
271 | #ifndef CONFIG_SMP | |
272 | seq_printf(p, "%10u ", kstat_irqs(i)); | |
273 | #else | |
9f40a72a | 274 | for_each_online_cpu(j) |
f3705136 | 275 | seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]); |
1da177e4 | 276 | #endif |
f5b9ed7a | 277 | seq_printf(p, " %8s", irq_desc[i].chip->name); |
a460e745 | 278 | seq_printf(p, "-%-8s", irq_desc[i].name); |
1da177e4 LT |
279 | seq_printf(p, " %s", action->name); |
280 | ||
281 | for (action=action->next; action; action = action->next) | |
282 | seq_printf(p, ", %s", action->name); | |
283 | ||
284 | seq_putc(p, '\n'); | |
285 | skip: | |
286 | spin_unlock_irqrestore(&irq_desc[i].lock, flags); | |
287 | } else if (i == NR_IRQS) { | |
288 | seq_printf(p, "NMI: "); | |
9f40a72a | 289 | for_each_online_cpu(j) |
f3705136 | 290 | seq_printf(p, "%10u ", nmi_count(j)); |
1da177e4 LT |
291 | seq_putc(p, '\n'); |
292 | #ifdef CONFIG_X86_LOCAL_APIC | |
293 | seq_printf(p, "LOC: "); | |
9f40a72a | 294 | for_each_online_cpu(j) |
f3705136 ZM |
295 | seq_printf(p, "%10u ", |
296 | per_cpu(irq_stat,j).apic_timer_irqs); | |
1da177e4 LT |
297 | seq_putc(p, '\n'); |
298 | #endif | |
299 | seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count)); | |
300 | #if defined(CONFIG_X86_IO_APIC) | |
301 | seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count)); | |
302 | #endif | |
303 | } | |
304 | return 0; | |
305 | } | |
f3705136 ZM |
306 | |
307 | #ifdef CONFIG_HOTPLUG_CPU | |
308 | #include <mach_apic.h> | |
309 | ||
310 | void fixup_irqs(cpumask_t map) | |
311 | { | |
312 | unsigned int irq; | |
313 | static int warned; | |
314 | ||
315 | for (irq = 0; irq < NR_IRQS; irq++) { | |
316 | cpumask_t mask; | |
317 | if (irq == 2) | |
318 | continue; | |
319 | ||
a53da52f | 320 | cpus_and(mask, irq_desc[irq].affinity, map); |
f3705136 ZM |
321 | if (any_online_cpu(mask) == NR_CPUS) { |
322 | printk("Breaking affinity for irq %i\n", irq); | |
323 | mask = map; | |
324 | } | |
d1bef4ed IM |
325 | if (irq_desc[irq].chip->set_affinity) |
326 | irq_desc[irq].chip->set_affinity(irq, mask); | |
f3705136 ZM |
327 | else if (irq_desc[irq].action && !(warned++)) |
328 | printk("Cannot set affinity for irq %i\n", irq); | |
329 | } | |
330 | ||
331 | #if 0 | |
332 | barrier(); | |
333 | /* Ingo Molnar says: "after the IO-APIC masks have been redirected | |
334 | [note the nop - the interrupt-enable boundary on x86 is two | |
335 | instructions from sti] - to flush out pending hardirqs and | |
336 | IPIs. After this point nothing is supposed to reach this CPU." */ | |
337 | __asm__ __volatile__("sti; nop; cli"); | |
338 | barrier(); | |
339 | #else | |
340 | /* That doesn't seem sufficient. Give it 1ms. */ | |
341 | local_irq_enable(); | |
342 | mdelay(1); | |
343 | local_irq_disable(); | |
344 | #endif | |
345 | } | |
346 | #endif | |
347 |