xref: /linux/arch/x86/kernel/irq.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
1 /*
2  * Common interrupt code for 32 and 64 bit
3  */
4 #include <linux/cpu.h>
5 #include <linux/interrupt.h>
6 #include <linux/kernel_stat.h>
7 #include <linux/seq_file.h>
8 #include <linux/smp.h>
9 #include <linux/ftrace.h>
10 
11 #include <asm/apic.h>
12 #include <asm/io_apic.h>
13 #include <asm/irq.h>
14 #include <asm/idle.h>
15 #include <asm/mce.h>
16 #include <asm/hw_irq.h>
17 
18 atomic_t irq_err_count;
19 
20 /* Function pointer for generic interrupt vector handling */
21 void (*x86_platform_ipi_callback)(void) = NULL;
22 
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 	if (printk_ratelimit())
30 		pr_err("unexpected IRQ trap at vector %02x\n", irq);
31 
32 	/*
33 	 * Currently unexpected vectors happen only on SMP and APIC.
34 	 * We _must_ ack these because every local APIC has only N
35 	 * irq slots per priority level, and a 'hanging, unacked' IRQ
36 	 * holds up an irq slot - in excessive cases (when multiple
37 	 * unexpected vectors occur) that might lock up the APIC
38 	 * completely.
39 	 * But only ack when the APIC is enabled -AK
40 	 */
41 	ack_APIC_irq();
42 }
43 
44 #define irq_stats(x)		(&per_cpu(irq_stat, x))
45 /*
46  * /proc/interrupts printing:
47  */
48 static int show_other_interrupts(struct seq_file *p, int prec)
49 {
50 	int j;
51 
52 	seq_printf(p, "%*s: ", prec, "NMI");
53 	for_each_online_cpu(j)
54 		seq_printf(p, "%10u ", irq_stats(j)->__nmi_count);
55 	seq_printf(p, "  Non-maskable interrupts\n");
56 #ifdef CONFIG_X86_LOCAL_APIC
57 	seq_printf(p, "%*s: ", prec, "LOC");
58 	for_each_online_cpu(j)
59 		seq_printf(p, "%10u ", irq_stats(j)->apic_timer_irqs);
60 	seq_printf(p, "  Local timer interrupts\n");
61 
62 	seq_printf(p, "%*s: ", prec, "SPU");
63 	for_each_online_cpu(j)
64 		seq_printf(p, "%10u ", irq_stats(j)->irq_spurious_count);
65 	seq_printf(p, "  Spurious interrupts\n");
66 	seq_printf(p, "%*s: ", prec, "PMI");
67 	for_each_online_cpu(j)
68 		seq_printf(p, "%10u ", irq_stats(j)->apic_perf_irqs);
69 	seq_printf(p, "  Performance monitoring interrupts\n");
70 	seq_printf(p, "%*s: ", prec, "PND");
71 	for_each_online_cpu(j)
72 		seq_printf(p, "%10u ", irq_stats(j)->apic_pending_irqs);
73 	seq_printf(p, "  Performance pending work\n");
74 #endif
75 	if (x86_platform_ipi_callback) {
76 		seq_printf(p, "%*s: ", prec, "PLT");
77 		for_each_online_cpu(j)
78 			seq_printf(p, "%10u ", irq_stats(j)->x86_platform_ipis);
79 		seq_printf(p, "  Platform interrupts\n");
80 	}
81 #ifdef CONFIG_SMP
82 	seq_printf(p, "%*s: ", prec, "RES");
83 	for_each_online_cpu(j)
84 		seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
85 	seq_printf(p, "  Rescheduling interrupts\n");
86 	seq_printf(p, "%*s: ", prec, "CAL");
87 	for_each_online_cpu(j)
88 		seq_printf(p, "%10u ", irq_stats(j)->irq_call_count);
89 	seq_printf(p, "  Function call interrupts\n");
90 	seq_printf(p, "%*s: ", prec, "TLB");
91 	for_each_online_cpu(j)
92 		seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
93 	seq_printf(p, "  TLB shootdowns\n");
94 #endif
95 #ifdef CONFIG_X86_THERMAL_VECTOR
96 	seq_printf(p, "%*s: ", prec, "TRM");
97 	for_each_online_cpu(j)
98 		seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
99 	seq_printf(p, "  Thermal event interrupts\n");
100 #endif
101 #ifdef CONFIG_X86_MCE_THRESHOLD
102 	seq_printf(p, "%*s: ", prec, "THR");
103 	for_each_online_cpu(j)
104 		seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
105 	seq_printf(p, "  Threshold APIC interrupts\n");
106 #endif
107 #ifdef CONFIG_X86_MCE
108 	seq_printf(p, "%*s: ", prec, "MCE");
109 	for_each_online_cpu(j)
110 		seq_printf(p, "%10u ", per_cpu(mce_exception_count, j));
111 	seq_printf(p, "  Machine check exceptions\n");
112 	seq_printf(p, "%*s: ", prec, "MCP");
113 	for_each_online_cpu(j)
114 		seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
115 	seq_printf(p, "  Machine check polls\n");
116 #endif
117 	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
118 #if defined(CONFIG_X86_IO_APIC)
119 	seq_printf(p, "%*s: %10u\n", prec, "MIS", atomic_read(&irq_mis_count));
120 #endif
121 	return 0;
122 }
123 
124 int show_interrupts(struct seq_file *p, void *v)
125 {
126 	unsigned long flags, any_count = 0;
127 	int i = *(loff_t *) v, j, prec;
128 	struct irqaction *action;
129 	struct irq_desc *desc;
130 
131 	if (i > nr_irqs)
132 		return 0;
133 
134 	for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
135 		j *= 10;
136 
137 	if (i == nr_irqs)
138 		return show_other_interrupts(p, prec);
139 
140 	/* print header */
141 	if (i == 0) {
142 		seq_printf(p, "%*s", prec + 8, "");
143 		for_each_online_cpu(j)
144 			seq_printf(p, "CPU%-8d", j);
145 		seq_putc(p, '\n');
146 	}
147 
148 	desc = irq_to_desc(i);
149 	if (!desc)
150 		return 0;
151 
152 	raw_spin_lock_irqsave(&desc->lock, flags);
153 	for_each_online_cpu(j)
154 		any_count |= kstat_irqs_cpu(i, j);
155 	action = desc->action;
156 	if (!action && !any_count)
157 		goto out;
158 
159 	seq_printf(p, "%*d: ", prec, i);
160 	for_each_online_cpu(j)
161 		seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
162 	seq_printf(p, " %8s", desc->chip->name);
163 	seq_printf(p, "-%-8s", desc->name);
164 
165 	if (action) {
166 		seq_printf(p, "  %s", action->name);
167 		while ((action = action->next) != NULL)
168 			seq_printf(p, ", %s", action->name);
169 	}
170 
171 	seq_putc(p, '\n');
172 out:
173 	raw_spin_unlock_irqrestore(&desc->lock, flags);
174 	return 0;
175 }
176 
177 /*
178  * /proc/stat helpers
179  */
180 u64 arch_irq_stat_cpu(unsigned int cpu)
181 {
182 	u64 sum = irq_stats(cpu)->__nmi_count;
183 
184 #ifdef CONFIG_X86_LOCAL_APIC
185 	sum += irq_stats(cpu)->apic_timer_irqs;
186 	sum += irq_stats(cpu)->irq_spurious_count;
187 	sum += irq_stats(cpu)->apic_perf_irqs;
188 	sum += irq_stats(cpu)->apic_pending_irqs;
189 #endif
190 	if (x86_platform_ipi_callback)
191 		sum += irq_stats(cpu)->x86_platform_ipis;
192 #ifdef CONFIG_SMP
193 	sum += irq_stats(cpu)->irq_resched_count;
194 	sum += irq_stats(cpu)->irq_call_count;
195 	sum += irq_stats(cpu)->irq_tlb_count;
196 #endif
197 #ifdef CONFIG_X86_THERMAL_VECTOR
198 	sum += irq_stats(cpu)->irq_thermal_count;
199 #endif
200 #ifdef CONFIG_X86_MCE_THRESHOLD
201 	sum += irq_stats(cpu)->irq_threshold_count;
202 #endif
203 #ifdef CONFIG_X86_MCE
204 	sum += per_cpu(mce_exception_count, cpu);
205 	sum += per_cpu(mce_poll_count, cpu);
206 #endif
207 	return sum;
208 }
209 
210 u64 arch_irq_stat(void)
211 {
212 	u64 sum = atomic_read(&irq_err_count);
213 
214 #ifdef CONFIG_X86_IO_APIC
215 	sum += atomic_read(&irq_mis_count);
216 #endif
217 	return sum;
218 }
219 
220 
221 /*
222  * do_IRQ handles all normal device IRQ's (the special
223  * SMP cross-CPU interrupts have their own specific
224  * handlers).
225  */
226 unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
227 {
228 	struct pt_regs *old_regs = set_irq_regs(regs);
229 
230 	/* high bit used in ret_from_ code  */
231 	unsigned vector = ~regs->orig_ax;
232 	unsigned irq;
233 
234 	exit_idle();
235 	irq_enter();
236 
237 	irq = __get_cpu_var(vector_irq)[vector];
238 
239 	if (!handle_irq(irq, regs)) {
240 		ack_APIC_irq();
241 
242 		if (printk_ratelimit())
243 			pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n",
244 				__func__, smp_processor_id(), vector, irq);
245 	}
246 
247 	irq_exit();
248 
249 	set_irq_regs(old_regs);
250 	return 1;
251 }
252 
253 /*
254  * Handler for X86_PLATFORM_IPI_VECTOR.
255  */
256 void smp_x86_platform_ipi(struct pt_regs *regs)
257 {
258 	struct pt_regs *old_regs = set_irq_regs(regs);
259 
260 	ack_APIC_irq();
261 
262 	exit_idle();
263 
264 	irq_enter();
265 
266 	inc_irq_stat(x86_platform_ipis);
267 
268 	if (x86_platform_ipi_callback)
269 		x86_platform_ipi_callback();
270 
271 	irq_exit();
272 
273 	set_irq_regs(old_regs);
274 }
275 
276 EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
277 
278 #ifdef CONFIG_HOTPLUG_CPU
279 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
280 void fixup_irqs(void)
281 {
282 	unsigned int irq, vector;
283 	static int warned;
284 	struct irq_desc *desc;
285 
286 	for_each_irq_desc(irq, desc) {
287 		int break_affinity = 0;
288 		int set_affinity = 1;
289 		const struct cpumask *affinity;
290 
291 		if (!desc)
292 			continue;
293 		if (irq == 2)
294 			continue;
295 
296 		/* interrupt's are disabled at this point */
297 		raw_spin_lock(&desc->lock);
298 
299 		affinity = desc->affinity;
300 		if (!irq_has_action(irq) ||
301 		    cpumask_equal(affinity, cpu_online_mask)) {
302 			raw_spin_unlock(&desc->lock);
303 			continue;
304 		}
305 
306 		/*
307 		 * Complete the irq move. This cpu is going down and for
308 		 * non intr-remapping case, we can't wait till this interrupt
309 		 * arrives at this cpu before completing the irq move.
310 		 */
311 		irq_force_complete_move(irq);
312 
313 		if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
314 			break_affinity = 1;
315 			affinity = cpu_all_mask;
316 		}
317 
318 		if (!(desc->status & IRQ_MOVE_PCNTXT) && desc->chip->mask)
319 			desc->chip->mask(irq);
320 
321 		if (desc->chip->set_affinity)
322 			desc->chip->set_affinity(irq, affinity);
323 		else if (!(warned++))
324 			set_affinity = 0;
325 
326 		if (!(desc->status & IRQ_MOVE_PCNTXT) && desc->chip->unmask)
327 			desc->chip->unmask(irq);
328 
329 		raw_spin_unlock(&desc->lock);
330 
331 		if (break_affinity && set_affinity)
332 			printk("Broke affinity for irq %i\n", irq);
333 		else if (!set_affinity)
334 			printk("Cannot set affinity for irq %i\n", irq);
335 	}
336 
337 	/*
338 	 * We can remove mdelay() and then send spuriuous interrupts to
339 	 * new cpu targets for all the irqs that were handled previously by
340 	 * this cpu. While it works, I have seen spurious interrupt messages
341 	 * (nothing wrong but still...).
342 	 *
343 	 * So for now, retain mdelay(1) and check the IRR and then send those
344 	 * interrupts to new targets as this cpu is already offlined...
345 	 */
346 	mdelay(1);
347 
348 	for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
349 		unsigned int irr;
350 
351 		if (__get_cpu_var(vector_irq)[vector] < 0)
352 			continue;
353 
354 		irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
355 		if (irr  & (1 << (vector % 32))) {
356 			irq = __get_cpu_var(vector_irq)[vector];
357 
358 			desc = irq_to_desc(irq);
359 			raw_spin_lock(&desc->lock);
360 			if (desc->chip->retrigger)
361 				desc->chip->retrigger(irq);
362 			raw_spin_unlock(&desc->lock);
363 		}
364 	}
365 }
366 #endif
367