1 /*
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
11 #include <linux/module.h>
12 #include <linux/seq_file.h>
13 #include <linux/interrupt.h>
14 #include <linux/kernel_stat.h>
15 #include <linux/notifier.h>
16 #include <linux/cpu.h>
17 #include <linux/delay.h>
18
19 #include <linux/ftrace.h>
20
21 #include <asm/apic.h>
22 #include <asm/uaccess.h>
23
24 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
25 EXPORT_PER_CPU_SYMBOL(irq_stat);
26
27 DEFINE_PER_CPU(struct pt_regs *, irq_regs);
28 EXPORT_PER_CPU_SYMBOL(irq_regs);
29
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 {
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();
50 #endif
51 }
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
62 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
63 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
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 unsigned int do_IRQ(struct pt_regs *regs)
72 {
73 struct pt_regs *old_regs;
74 /* high bit used in ret_from_ code */
75 int irq = ~regs->orig_ax;
76 struct irq_desc *desc = irq_desc + irq;
77 #ifdef CONFIG_4KSTACKS
78 union irq_ctx *curctx, *irqctx;
79 u32 *isp;
80 #endif
81
82 #ifdef CONFIG_X86_LOCAL_APIC
83 irq_show_regs_callback(smp_processor_id(), regs);
84 #endif
85
86 if (unlikely((unsigned)irq >= NR_IRQS)) {
87 printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
88 __FUNCTION__, irq);
89 BUG();
90 }
91
92 old_regs = set_irq_regs(regs);
93 irq_enter();
94 ftrace_event_irq(irq, user_mode(regs), regs->ip);
95 #ifdef CONFIG_DEBUG_STACKOVERFLOW
96 /* Debugging check for stack overflow: is there less than 1KB free? */
97 {
98 long sp;
99
100 __asm__ __volatile__("andl %%esp,%0" :
101 "=r" (sp) : "" (THREAD_SIZE - 1));
102 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
103 printk("BUG: do_IRQ: stack overflow: %ld\n",
104 sp - sizeof(struct thread_info));
105 dump_stack();
106 }
107 }
108 #endif
109
110 #ifdef CONFIG_4KSTACKS
111
112 curctx = (union irq_ctx *) current_thread_info();
113 irqctx = hardirq_ctx[smp_processor_id()];
114
115 /*
116 * this is where we switch to the IRQ stack. However, if we are
117 * already using the IRQ stack (because we interrupted a hardirq
118 * handler) we can't do that and just have to keep using the
119 * current stack (which is the irq stack already after all)
120 */
121 if (curctx != irqctx) {
122 int arg1, arg2, bx;
123
124 /* build the stack frame on the IRQ stack */
125 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
126 irqctx->tinfo.task = curctx->tinfo.task;
127 irqctx->tinfo.previous_esp = current_stack_pointer;
128
129 /*
130 * Copy the softirq bits in preempt_count so that the
131 * softirq checks work in the hardirq context.
132 */
133 irqctx->tinfo.preempt_count =
134 (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
135 (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
136
137 asm volatile(
138 " xchgl %%ebx,%%esp \n"
139 " call *%%edi \n"
140 " movl %%ebx,%%esp \n"
141 : "=a" (arg1), "=d" (arg2), "=b" (bx)
142 : "" (irq), "1" (desc), "2" (isp),
143 "D" (desc->handle_irq)
144 : "memory", "cc", "ecx"
145 );
146 } else
147 #endif
148 desc->handle_irq(irq, desc);
149
150 irq_exit();
151 set_irq_regs(old_regs);
152 return 1;
153 }
154
155 #ifdef CONFIG_4KSTACKS
156
157 static char softirq_stack[NR_CPUS * THREAD_SIZE]
158 __attribute__((__section__(".bss.page_aligned")));
159
160 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
161 __attribute__((__section__(".bss.page_aligned")));
162
163 /*
164 * allocate per-cpu stacks for hardirq and for softirq processing
165 */
166 void irq_ctx_init(int cpu)
167 {
168 union irq_ctx *irqctx;
169
170 if (hardirq_ctx[cpu])
171 return;
172
173 irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE];
174 irqctx->tinfo.task = NULL;
175 irqctx->tinfo.exec_domain = NULL;
176 irqctx->tinfo.cpu = cpu;
177 irqctx->tinfo.preempt_count = HARDIRQ_OFFSET;
178 irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
179
180 hardirq_ctx[cpu] = irqctx;
181
182 irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE];
183 irqctx->tinfo.task = NULL;
184 irqctx->tinfo.exec_domain = NULL;
185 irqctx->tinfo.cpu = cpu;
186 irqctx->tinfo.preempt_count = 0;
187 irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
188
189 softirq_ctx[cpu] = irqctx;
190
191 printk("CPU %u irqstacks, hard=%p soft=%p\n",
192 cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
193 }
194
195 void irq_ctx_exit(int cpu)
196 {
197 hardirq_ctx[cpu] = NULL;
198 }
199
200 extern asmlinkage void __do_softirq(void);
201
202 asmlinkage void do_softirq(void)
203 {
204 unsigned long flags;
205 struct thread_info *curctx;
206 union irq_ctx *irqctx;
207 u32 *isp;
208
209 if (in_interrupt())
210 return;
211
212 local_irq_save(flags);
213
214 if (local_softirq_pending()) {
215 curctx = current_thread_info();
216 irqctx = softirq_ctx[smp_processor_id()];
217 irqctx->tinfo.task = curctx->task;
218 irqctx->tinfo.previous_esp = current_stack_pointer;
219
220 /* build the stack frame on the softirq stack */
221 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
222
223 asm volatile(
224 " xchgl %%ebx,%%esp \n"
225 " call __do_softirq \n"
226 " movl %%ebx,%%esp \n"
227 : "=b"(isp)
228 : ""(isp)
229 : "memory", "cc", "edx", "ecx", "eax"
230 );
231 /*
232 * Shouldnt happen, we returned above if in_interrupt():
233 */
234 WARN_ON_ONCE(softirq_count());
235 }
236
237 local_irq_restore(flags);
238 }
239 #endif
240
241 /*
242 * Interrupt statistics:
243 */
244
245 atomic_t irq_err_count;
246
247 /*
248 * /proc/interrupts printing:
249 */
250
251 int show_interrupts(struct seq_file *p, void *v)
252 {
253 int i = *(loff_t *) v, j;
254 struct irqaction * action;
255 unsigned long flags;
256
257 if (i == 0) {
258 seq_printf(p, " ");
259 for_each_online_cpu(j)
260 seq_printf(p, "CPU%-8d",j);
261 seq_putc(p, '\n');
262 }
263
264 if (i < NR_IRQS) {
265 unsigned any_count = 0;
266
267 spin_lock_irqsave(&irq_desc[i].lock, flags);
268 #ifndef CONFIG_SMP
269 any_count = kstat_irqs(i);
270 #else
271 for_each_online_cpu(j)
272 any_count |= kstat_cpu(j).irqs[i];
273 #endif
274 action = irq_desc[i].action;
275 if (!action && !any_count)
276 goto skip;
277 seq_printf(p, "%3d: ",i);
278 #ifndef CONFIG_SMP
279 seq_printf(p, "%10u ", kstat_irqs(i));
280 #else
281 for_each_online_cpu(j)
282 seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
283 #endif
284 seq_printf(p, " %8s", irq_desc[i].chip->name);
285 seq_printf(p, "-%-8s", irq_desc[i].name);
286
287 if (action) {
288 seq_printf(p, " %s", action->name);
289 while ((action = action->next) != NULL)
290 seq_printf(p, ", %s", action->name);
291 }
292
293 seq_putc(p, '\n');
294 skip:
295 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
296 } else if (i == NR_IRQS) {
297 seq_printf(p, "NMI: ");
298 for_each_online_cpu(j)
299 seq_printf(p, "%10u ", nmi_count(j));
300 seq_printf(p, " Non-maskable interrupts\n");
301 #ifdef CONFIG_X86_LOCAL_APIC
302 seq_printf(p, "LOC: ");
303 for_each_online_cpu(j)
304 seq_printf(p, "%10u ",
305 per_cpu(irq_stat,j).apic_timer_irqs);
306 seq_printf(p, " Local timer interrupts\n");
307 #endif
308 #ifdef CONFIG_SMP
309 seq_printf(p, "RES: ");
310 for_each_online_cpu(j)
311 seq_printf(p, "%10u ",
312 per_cpu(irq_stat,j).irq_resched_count);
313 seq_printf(p, " Rescheduling interrupts\n");
314 seq_printf(p, "CAL: ");
315 for_each_online_cpu(j)
316 seq_printf(p, "%10u ",
317 per_cpu(irq_stat,j).irq_call_count);
318 seq_printf(p, " function call interrupts\n");
319 seq_printf(p, "TLB: ");
320 for_each_online_cpu(j)
321 seq_printf(p, "%10u ",
322 per_cpu(irq_stat,j).irq_tlb_count);
323 seq_printf(p, " TLB shootdowns\n");
324 #endif
325 seq_printf(p, "TRM: ");
326 for_each_online_cpu(j)
327 seq_printf(p, "%10u ",
328 per_cpu(irq_stat,j).irq_thermal_count);
329 seq_printf(p, " Thermal event interrupts\n");
330 seq_printf(p, "SPU: ");
331 for_each_online_cpu(j)
332 seq_printf(p, "%10u ",
333 per_cpu(irq_stat,j).irq_spurious_count);
334 seq_printf(p, " Spurious interrupts\n");
335 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
336 #if defined(CONFIG_X86_IO_APIC)
337 seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
338 #endif
339 }
340 return 0;
341 }
342
343 #ifdef CONFIG_HOTPLUG_CPU
344 #include <mach_apic.h>
345
346 void fixup_irqs(cpumask_t map)
347 {
348 unsigned int irq;
349 static int warned;
350
351 for (irq = 0; irq < NR_IRQS; irq++) {
352 cpumask_t mask;
353 if (irq == 2)
354 continue;
355
356 cpus_and(mask, irq_desc[irq].affinity, map);
357 if (any_online_cpu(mask) == NR_CPUS) {
358 printk("Breaking affinity for irq %i\n", irq);
359 mask = map;
360 }
361 if (irq_desc[irq].chip->set_affinity)
362 irq_desc[irq].chip->set_affinity(irq, mask);
363 else if (irq_desc[irq].action && !(warned++))
364 printk("Cannot set affinity for irq %i\n", irq);
365 }
366
367 #if 0
368 barrier();
369 /* Ingo Molnar says: "after the IO-APIC masks have been redirected
370 [note the nop - the interrupt-enable boundary on x86 is two
371 instructions from sti] - to flush out pending hardirqs and
372 IPIs. After this point nothing is supposed to reach this CPU." */
373 __asm__ __volatile__("sti; nop; cli");
374 barrier();
375 #else
376 /* That doesn't seem sufficient. Give it 1ms. */
377 local_irq_enable();
378 mdelay(1);
379 local_irq_disable();
380 #endif
381 }
382 #endif
383
384
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