xref: /openbmc/linux/arch/x86/kernel/irq.c (revision 565d76cb)
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/of.h>
8 #include <linux/seq_file.h>
9 #include <linux/smp.h>
10 #include <linux/ftrace.h>
11 
12 #include <asm/apic.h>
13 #include <asm/io_apic.h>
14 #include <asm/irq.h>
15 #include <asm/idle.h>
16 #include <asm/mce.h>
17 #include <asm/hw_irq.h>
18 
19 atomic_t irq_err_count;
20 
21 /* Function pointer for generic interrupt vector handling */
22 void (*x86_platform_ipi_callback)(void) = NULL;
23 
24 /*
25  * 'what should we do if we get a hw irq event on an illegal vector'.
26  * each architecture has to answer this themselves.
27  */
28 void ack_bad_irq(unsigned int irq)
29 {
30 	if (printk_ratelimit())
31 		pr_err("unexpected IRQ trap at vector %02x\n", irq);
32 
33 	/*
34 	 * Currently unexpected vectors happen only on SMP and APIC.
35 	 * We _must_ ack these because every local APIC has only N
36 	 * irq slots per priority level, and a 'hanging, unacked' IRQ
37 	 * holds up an irq slot - in excessive cases (when multiple
38 	 * unexpected vectors occur) that might lock up the APIC
39 	 * completely.
40 	 * But only ack when the APIC is enabled -AK
41 	 */
42 	ack_APIC_irq();
43 }
44 
45 #define irq_stats(x)		(&per_cpu(irq_stat, x))
46 /*
47  * /proc/interrupts printing for arch specific interrupts
48  */
49 int arch_show_interrupts(struct seq_file *p, int prec)
50 {
51 	int j;
52 
53 	seq_printf(p, "%*s: ", prec, "NMI");
54 	for_each_online_cpu(j)
55 		seq_printf(p, "%10u ", irq_stats(j)->__nmi_count);
56 	seq_printf(p, "  Non-maskable interrupts\n");
57 #ifdef CONFIG_X86_LOCAL_APIC
58 	seq_printf(p, "%*s: ", prec, "LOC");
59 	for_each_online_cpu(j)
60 		seq_printf(p, "%10u ", irq_stats(j)->apic_timer_irqs);
61 	seq_printf(p, "  Local timer interrupts\n");
62 
63 	seq_printf(p, "%*s: ", prec, "SPU");
64 	for_each_online_cpu(j)
65 		seq_printf(p, "%10u ", irq_stats(j)->irq_spurious_count);
66 	seq_printf(p, "  Spurious interrupts\n");
67 	seq_printf(p, "%*s: ", prec, "PMI");
68 	for_each_online_cpu(j)
69 		seq_printf(p, "%10u ", irq_stats(j)->apic_perf_irqs);
70 	seq_printf(p, "  Performance monitoring interrupts\n");
71 	seq_printf(p, "%*s: ", prec, "IWI");
72 	for_each_online_cpu(j)
73 		seq_printf(p, "%10u ", irq_stats(j)->apic_irq_work_irqs);
74 	seq_printf(p, "  IRQ work interrupts\n");
75 #endif
76 	if (x86_platform_ipi_callback) {
77 		seq_printf(p, "%*s: ", prec, "PLT");
78 		for_each_online_cpu(j)
79 			seq_printf(p, "%10u ", irq_stats(j)->x86_platform_ipis);
80 		seq_printf(p, "  Platform interrupts\n");
81 	}
82 #ifdef CONFIG_SMP
83 	seq_printf(p, "%*s: ", prec, "RES");
84 	for_each_online_cpu(j)
85 		seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
86 	seq_printf(p, "  Rescheduling interrupts\n");
87 	seq_printf(p, "%*s: ", prec, "CAL");
88 	for_each_online_cpu(j)
89 		seq_printf(p, "%10u ", irq_stats(j)->irq_call_count);
90 	seq_printf(p, "  Function call interrupts\n");
91 	seq_printf(p, "%*s: ", prec, "TLB");
92 	for_each_online_cpu(j)
93 		seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
94 	seq_printf(p, "  TLB shootdowns\n");
95 #endif
96 #ifdef CONFIG_X86_THERMAL_VECTOR
97 	seq_printf(p, "%*s: ", prec, "TRM");
98 	for_each_online_cpu(j)
99 		seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
100 	seq_printf(p, "  Thermal event interrupts\n");
101 #endif
102 #ifdef CONFIG_X86_MCE_THRESHOLD
103 	seq_printf(p, "%*s: ", prec, "THR");
104 	for_each_online_cpu(j)
105 		seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
106 	seq_printf(p, "  Threshold APIC interrupts\n");
107 #endif
108 #ifdef CONFIG_X86_MCE
109 	seq_printf(p, "%*s: ", prec, "MCE");
110 	for_each_online_cpu(j)
111 		seq_printf(p, "%10u ", per_cpu(mce_exception_count, j));
112 	seq_printf(p, "  Machine check exceptions\n");
113 	seq_printf(p, "%*s: ", prec, "MCP");
114 	for_each_online_cpu(j)
115 		seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
116 	seq_printf(p, "  Machine check polls\n");
117 #endif
118 	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
119 #if defined(CONFIG_X86_IO_APIC)
120 	seq_printf(p, "%*s: %10u\n", prec, "MIS", atomic_read(&irq_mis_count));
121 #endif
122 	return 0;
123 }
124 
125 /*
126  * /proc/stat helpers
127  */
128 u64 arch_irq_stat_cpu(unsigned int cpu)
129 {
130 	u64 sum = irq_stats(cpu)->__nmi_count;
131 
132 #ifdef CONFIG_X86_LOCAL_APIC
133 	sum += irq_stats(cpu)->apic_timer_irqs;
134 	sum += irq_stats(cpu)->irq_spurious_count;
135 	sum += irq_stats(cpu)->apic_perf_irqs;
136 	sum += irq_stats(cpu)->apic_irq_work_irqs;
137 #endif
138 	if (x86_platform_ipi_callback)
139 		sum += irq_stats(cpu)->x86_platform_ipis;
140 #ifdef CONFIG_SMP
141 	sum += irq_stats(cpu)->irq_resched_count;
142 	sum += irq_stats(cpu)->irq_call_count;
143 	sum += irq_stats(cpu)->irq_tlb_count;
144 #endif
145 #ifdef CONFIG_X86_THERMAL_VECTOR
146 	sum += irq_stats(cpu)->irq_thermal_count;
147 #endif
148 #ifdef CONFIG_X86_MCE_THRESHOLD
149 	sum += irq_stats(cpu)->irq_threshold_count;
150 #endif
151 #ifdef CONFIG_X86_MCE
152 	sum += per_cpu(mce_exception_count, cpu);
153 	sum += per_cpu(mce_poll_count, cpu);
154 #endif
155 	return sum;
156 }
157 
158 u64 arch_irq_stat(void)
159 {
160 	u64 sum = atomic_read(&irq_err_count);
161 
162 #ifdef CONFIG_X86_IO_APIC
163 	sum += atomic_read(&irq_mis_count);
164 #endif
165 	return sum;
166 }
167 
168 
169 /*
170  * do_IRQ handles all normal device IRQ's (the special
171  * SMP cross-CPU interrupts have their own specific
172  * handlers).
173  */
174 unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
175 {
176 	struct pt_regs *old_regs = set_irq_regs(regs);
177 
178 	/* high bit used in ret_from_ code  */
179 	unsigned vector = ~regs->orig_ax;
180 	unsigned irq;
181 
182 	exit_idle();
183 	irq_enter();
184 
185 	irq = __this_cpu_read(vector_irq[vector]);
186 
187 	if (!handle_irq(irq, regs)) {
188 		ack_APIC_irq();
189 
190 		if (printk_ratelimit())
191 			pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n",
192 				__func__, smp_processor_id(), vector, irq);
193 	}
194 
195 	irq_exit();
196 
197 	set_irq_regs(old_regs);
198 	return 1;
199 }
200 
201 /*
202  * Handler for X86_PLATFORM_IPI_VECTOR.
203  */
204 void smp_x86_platform_ipi(struct pt_regs *regs)
205 {
206 	struct pt_regs *old_regs = set_irq_regs(regs);
207 
208 	ack_APIC_irq();
209 
210 	exit_idle();
211 
212 	irq_enter();
213 
214 	inc_irq_stat(x86_platform_ipis);
215 
216 	if (x86_platform_ipi_callback)
217 		x86_platform_ipi_callback();
218 
219 	irq_exit();
220 
221 	set_irq_regs(old_regs);
222 }
223 
224 EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
225 
226 #ifdef CONFIG_HOTPLUG_CPU
227 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
228 void fixup_irqs(void)
229 {
230 	unsigned int irq, vector;
231 	static int warned;
232 	struct irq_desc *desc;
233 	struct irq_data *data;
234 	struct irq_chip *chip;
235 
236 	for_each_irq_desc(irq, desc) {
237 		int break_affinity = 0;
238 		int set_affinity = 1;
239 		const struct cpumask *affinity;
240 
241 		if (!desc)
242 			continue;
243 		if (irq == 2)
244 			continue;
245 
246 		/* interrupt's are disabled at this point */
247 		raw_spin_lock(&desc->lock);
248 
249 		data = irq_desc_get_irq_data(desc);
250 		affinity = data->affinity;
251 		if (!irq_has_action(irq) ||
252 		    cpumask_subset(affinity, cpu_online_mask)) {
253 			raw_spin_unlock(&desc->lock);
254 			continue;
255 		}
256 
257 		/*
258 		 * Complete the irq move. This cpu is going down and for
259 		 * non intr-remapping case, we can't wait till this interrupt
260 		 * arrives at this cpu before completing the irq move.
261 		 */
262 		irq_force_complete_move(irq);
263 
264 		if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
265 			break_affinity = 1;
266 			affinity = cpu_all_mask;
267 		}
268 
269 		chip = irq_data_get_irq_chip(data);
270 		if (!irqd_can_move_in_process_context(data) && chip->irq_mask)
271 			chip->irq_mask(data);
272 
273 		if (chip->irq_set_affinity)
274 			chip->irq_set_affinity(data, affinity, true);
275 		else if (!(warned++))
276 			set_affinity = 0;
277 
278 		if (!irqd_can_move_in_process_context(data) && chip->irq_unmask)
279 			chip->irq_unmask(data);
280 
281 		raw_spin_unlock(&desc->lock);
282 
283 		if (break_affinity && set_affinity)
284 			printk("Broke affinity for irq %i\n", irq);
285 		else if (!set_affinity)
286 			printk("Cannot set affinity for irq %i\n", irq);
287 	}
288 
289 	/*
290 	 * We can remove mdelay() and then send spuriuous interrupts to
291 	 * new cpu targets for all the irqs that were handled previously by
292 	 * this cpu. While it works, I have seen spurious interrupt messages
293 	 * (nothing wrong but still...).
294 	 *
295 	 * So for now, retain mdelay(1) and check the IRR and then send those
296 	 * interrupts to new targets as this cpu is already offlined...
297 	 */
298 	mdelay(1);
299 
300 	for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
301 		unsigned int irr;
302 
303 		if (__this_cpu_read(vector_irq[vector]) < 0)
304 			continue;
305 
306 		irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
307 		if (irr  & (1 << (vector % 32))) {
308 			irq = __this_cpu_read(vector_irq[vector]);
309 
310 			desc = irq_to_desc(irq);
311 			data = irq_desc_get_irq_data(desc);
312 			chip = irq_data_get_irq_chip(data);
313 			raw_spin_lock(&desc->lock);
314 			if (chip->irq_retrigger)
315 				chip->irq_retrigger(data);
316 			raw_spin_unlock(&desc->lock);
317 		}
318 	}
319 }
320 #endif
321