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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 | ||
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> | |
f3705136 ZM |
18 | #include <linux/notifier.h> |
19 | #include <linux/cpu.h> | |
20 | #include <linux/delay.h> | |
1da177e4 | 21 | |
22fc6ecc | 22 | DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_internodealigned_in_smp; |
1da177e4 LT |
23 | EXPORT_PER_CPU_SYMBOL(irq_stat); |
24 | ||
25 | #ifndef CONFIG_X86_LOCAL_APIC | |
26 | /* | |
27 | * 'what should we do if we get a hw irq event on an illegal vector'. | |
28 | * each architecture has to answer this themselves. | |
29 | */ | |
30 | void ack_bad_irq(unsigned int irq) | |
31 | { | |
32 | printk("unexpected IRQ trap at vector %02x\n", irq); | |
33 | } | |
34 | #endif | |
35 | ||
36 | #ifdef CONFIG_4KSTACKS | |
37 | /* | |
38 | * per-CPU IRQ handling contexts (thread information and stack) | |
39 | */ | |
40 | union irq_ctx { | |
41 | struct thread_info tinfo; | |
42 | u32 stack[THREAD_SIZE/sizeof(u32)]; | |
43 | }; | |
44 | ||
22722051 AM |
45 | static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly; |
46 | static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly; | |
1da177e4 LT |
47 | #endif |
48 | ||
49 | /* | |
50 | * do_IRQ handles all normal device IRQ's (the special | |
51 | * SMP cross-CPU interrupts have their own specific | |
52 | * handlers). | |
53 | */ | |
54 | fastcall unsigned int do_IRQ(struct pt_regs *regs) | |
55 | { | |
19eadf98 RR |
56 | /* high bit used in ret_from_ code */ |
57 | int irq = ~regs->orig_eax; | |
1da177e4 LT |
58 | #ifdef CONFIG_4KSTACKS |
59 | union irq_ctx *curctx, *irqctx; | |
60 | u32 *isp; | |
61 | #endif | |
62 | ||
a052b68b AM |
63 | if (unlikely((unsigned)irq >= NR_IRQS)) { |
64 | printk(KERN_EMERG "%s: cannot handle IRQ %d\n", | |
65 | __FUNCTION__, irq); | |
66 | BUG(); | |
67 | } | |
68 | ||
1da177e4 LT |
69 | irq_enter(); |
70 | #ifdef CONFIG_DEBUG_STACKOVERFLOW | |
71 | /* Debugging check for stack overflow: is there less than 1KB free? */ | |
72 | { | |
73 | long esp; | |
74 | ||
75 | __asm__ __volatile__("andl %%esp,%0" : | |
76 | "=r" (esp) : "0" (THREAD_SIZE - 1)); | |
77 | if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) { | |
78 | printk("do_IRQ: stack overflow: %ld\n", | |
79 | esp - sizeof(struct thread_info)); | |
80 | dump_stack(); | |
81 | } | |
82 | } | |
83 | #endif | |
84 | ||
85 | #ifdef CONFIG_4KSTACKS | |
86 | ||
87 | curctx = (union irq_ctx *) current_thread_info(); | |
88 | irqctx = hardirq_ctx[smp_processor_id()]; | |
89 | ||
90 | /* | |
91 | * this is where we switch to the IRQ stack. However, if we are | |
92 | * already using the IRQ stack (because we interrupted a hardirq | |
93 | * handler) we can't do that and just have to keep using the | |
94 | * current stack (which is the irq stack already after all) | |
95 | */ | |
96 | if (curctx != irqctx) { | |
97 | int arg1, arg2, ebx; | |
98 | ||
99 | /* build the stack frame on the IRQ stack */ | |
100 | isp = (u32*) ((char*)irqctx + sizeof(*irqctx)); | |
101 | irqctx->tinfo.task = curctx->tinfo.task; | |
102 | irqctx->tinfo.previous_esp = current_stack_pointer; | |
103 | ||
a5d157e0 BS |
104 | /* |
105 | * Copy the softirq bits in preempt_count so that the | |
106 | * softirq checks work in the hardirq context. | |
107 | */ | |
108 | irqctx->tinfo.preempt_count = | |
91bf4602 AM |
109 | (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) | |
110 | (curctx->tinfo.preempt_count & SOFTIRQ_MASK); | |
a5d157e0 | 111 | |
1da177e4 LT |
112 | asm volatile( |
113 | " xchgl %%ebx,%%esp \n" | |
114 | " call __do_IRQ \n" | |
115 | " movl %%ebx,%%esp \n" | |
116 | : "=a" (arg1), "=d" (arg2), "=b" (ebx) | |
117 | : "0" (irq), "1" (regs), "2" (isp) | |
118 | : "memory", "cc", "ecx" | |
119 | ); | |
120 | } else | |
121 | #endif | |
122 | __do_IRQ(irq, regs); | |
123 | ||
124 | irq_exit(); | |
125 | ||
126 | return 1; | |
127 | } | |
128 | ||
129 | #ifdef CONFIG_4KSTACKS | |
130 | ||
131 | /* | |
132 | * These should really be __section__(".bss.page_aligned") as well, but | |
133 | * gcc's 3.0 and earlier don't handle that correctly. | |
134 | */ | |
135 | static char softirq_stack[NR_CPUS * THREAD_SIZE] | |
136 | __attribute__((__aligned__(THREAD_SIZE))); | |
137 | ||
138 | static char hardirq_stack[NR_CPUS * THREAD_SIZE] | |
139 | __attribute__((__aligned__(THREAD_SIZE))); | |
140 | ||
141 | /* | |
142 | * allocate per-cpu stacks for hardirq and for softirq processing | |
143 | */ | |
144 | void irq_ctx_init(int cpu) | |
145 | { | |
146 | union irq_ctx *irqctx; | |
147 | ||
148 | if (hardirq_ctx[cpu]) | |
149 | return; | |
150 | ||
151 | irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE]; | |
152 | irqctx->tinfo.task = NULL; | |
153 | irqctx->tinfo.exec_domain = NULL; | |
154 | irqctx->tinfo.cpu = cpu; | |
155 | irqctx->tinfo.preempt_count = HARDIRQ_OFFSET; | |
156 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); | |
157 | ||
158 | hardirq_ctx[cpu] = irqctx; | |
159 | ||
160 | irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE]; | |
161 | irqctx->tinfo.task = NULL; | |
162 | irqctx->tinfo.exec_domain = NULL; | |
163 | irqctx->tinfo.cpu = cpu; | |
55f327fa | 164 | irqctx->tinfo.preempt_count = 0; |
1da177e4 LT |
165 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); |
166 | ||
167 | softirq_ctx[cpu] = irqctx; | |
168 | ||
169 | printk("CPU %u irqstacks, hard=%p soft=%p\n", | |
170 | cpu,hardirq_ctx[cpu],softirq_ctx[cpu]); | |
171 | } | |
172 | ||
e1367daf LS |
173 | void irq_ctx_exit(int cpu) |
174 | { | |
175 | hardirq_ctx[cpu] = NULL; | |
176 | } | |
177 | ||
1da177e4 LT |
178 | extern asmlinkage void __do_softirq(void); |
179 | ||
180 | asmlinkage void do_softirq(void) | |
181 | { | |
182 | unsigned long flags; | |
183 | struct thread_info *curctx; | |
184 | union irq_ctx *irqctx; | |
185 | u32 *isp; | |
186 | ||
187 | if (in_interrupt()) | |
188 | return; | |
189 | ||
190 | local_irq_save(flags); | |
191 | ||
192 | if (local_softirq_pending()) { | |
193 | curctx = current_thread_info(); | |
194 | irqctx = softirq_ctx[smp_processor_id()]; | |
195 | irqctx->tinfo.task = curctx->task; | |
196 | irqctx->tinfo.previous_esp = current_stack_pointer; | |
197 | ||
198 | /* build the stack frame on the softirq stack */ | |
199 | isp = (u32*) ((char*)irqctx + sizeof(*irqctx)); | |
200 | ||
201 | asm volatile( | |
202 | " xchgl %%ebx,%%esp \n" | |
203 | " call __do_softirq \n" | |
204 | " movl %%ebx,%%esp \n" | |
205 | : "=b"(isp) | |
206 | : "0"(isp) | |
207 | : "memory", "cc", "edx", "ecx", "eax" | |
208 | ); | |
55f327fa IM |
209 | /* |
210 | * Shouldnt happen, we returned above if in_interrupt(): | |
211 | */ | |
212 | WARN_ON_ONCE(softirq_count()); | |
1da177e4 LT |
213 | } |
214 | ||
215 | local_irq_restore(flags); | |
216 | } | |
217 | ||
218 | EXPORT_SYMBOL(do_softirq); | |
219 | #endif | |
220 | ||
221 | /* | |
222 | * Interrupt statistics: | |
223 | */ | |
224 | ||
225 | atomic_t irq_err_count; | |
226 | ||
227 | /* | |
228 | * /proc/interrupts printing: | |
229 | */ | |
230 | ||
231 | int show_interrupts(struct seq_file *p, void *v) | |
232 | { | |
233 | int i = *(loff_t *) v, j; | |
234 | struct irqaction * action; | |
235 | unsigned long flags; | |
236 | ||
237 | if (i == 0) { | |
238 | seq_printf(p, " "); | |
9f40a72a | 239 | for_each_online_cpu(j) |
bdbdaa79 | 240 | seq_printf(p, "CPU%-8d",j); |
1da177e4 LT |
241 | seq_putc(p, '\n'); |
242 | } | |
243 | ||
244 | if (i < NR_IRQS) { | |
245 | spin_lock_irqsave(&irq_desc[i].lock, flags); | |
246 | action = irq_desc[i].action; | |
247 | if (!action) | |
248 | goto skip; | |
249 | seq_printf(p, "%3d: ",i); | |
250 | #ifndef CONFIG_SMP | |
251 | seq_printf(p, "%10u ", kstat_irqs(i)); | |
252 | #else | |
9f40a72a | 253 | for_each_online_cpu(j) |
f3705136 | 254 | seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]); |
1da177e4 | 255 | #endif |
d1bef4ed | 256 | seq_printf(p, " %14s", irq_desc[i].chip->typename); |
1da177e4 LT |
257 | seq_printf(p, " %s", action->name); |
258 | ||
259 | for (action=action->next; action; action = action->next) | |
260 | seq_printf(p, ", %s", action->name); | |
261 | ||
262 | seq_putc(p, '\n'); | |
263 | skip: | |
264 | spin_unlock_irqrestore(&irq_desc[i].lock, flags); | |
265 | } else if (i == NR_IRQS) { | |
266 | seq_printf(p, "NMI: "); | |
9f40a72a | 267 | for_each_online_cpu(j) |
f3705136 | 268 | seq_printf(p, "%10u ", nmi_count(j)); |
1da177e4 LT |
269 | seq_putc(p, '\n'); |
270 | #ifdef CONFIG_X86_LOCAL_APIC | |
271 | seq_printf(p, "LOC: "); | |
9f40a72a | 272 | for_each_online_cpu(j) |
f3705136 ZM |
273 | seq_printf(p, "%10u ", |
274 | per_cpu(irq_stat,j).apic_timer_irqs); | |
1da177e4 LT |
275 | seq_putc(p, '\n'); |
276 | #endif | |
277 | seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count)); | |
278 | #if defined(CONFIG_X86_IO_APIC) | |
279 | seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count)); | |
280 | #endif | |
281 | } | |
282 | return 0; | |
283 | } | |
f3705136 ZM |
284 | |
285 | #ifdef CONFIG_HOTPLUG_CPU | |
286 | #include <mach_apic.h> | |
287 | ||
288 | void fixup_irqs(cpumask_t map) | |
289 | { | |
290 | unsigned int irq; | |
291 | static int warned; | |
292 | ||
293 | for (irq = 0; irq < NR_IRQS; irq++) { | |
294 | cpumask_t mask; | |
295 | if (irq == 2) | |
296 | continue; | |
297 | ||
a53da52f | 298 | cpus_and(mask, irq_desc[irq].affinity, map); |
f3705136 ZM |
299 | if (any_online_cpu(mask) == NR_CPUS) { |
300 | printk("Breaking affinity for irq %i\n", irq); | |
301 | mask = map; | |
302 | } | |
d1bef4ed IM |
303 | if (irq_desc[irq].chip->set_affinity) |
304 | irq_desc[irq].chip->set_affinity(irq, mask); | |
f3705136 ZM |
305 | else if (irq_desc[irq].action && !(warned++)) |
306 | printk("Cannot set affinity for irq %i\n", irq); | |
307 | } | |
308 | ||
309 | #if 0 | |
310 | barrier(); | |
311 | /* Ingo Molnar says: "after the IO-APIC masks have been redirected | |
312 | [note the nop - the interrupt-enable boundary on x86 is two | |
313 | instructions from sti] - to flush out pending hardirqs and | |
314 | IPIs. After this point nothing is supposed to reach this CPU." */ | |
315 | __asm__ __volatile__("sti; nop; cli"); | |
316 | barrier(); | |
317 | #else | |
318 | /* That doesn't seem sufficient. Give it 1ms. */ | |
319 | local_irq_enable(); | |
320 | mdelay(1); | |
321 | local_irq_disable(); | |
322 | #endif | |
323 | } | |
324 | #endif | |
325 |