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1/*
2 * Copyright (C) 2017 Thomas Gleixner <tglx@linutronix.de>
3 *
4 * SPDX-License-Identifier: GPL-2.0
5 */
6#include <linux/spinlock.h>
7#include <linux/seq_file.h>
8#include <linux/bitmap.h>
9#include <linux/percpu.h>
10#include <linux/cpu.h>
11#include <linux/irq.h>
12
13#define IRQ_MATRIX_SIZE (BITS_TO_LONGS(IRQ_MATRIX_BITS) * sizeof(unsigned long))
14
15struct cpumap {
16 unsigned int available;
17 unsigned int allocated;
18 unsigned int managed;
19 bool online;
20 unsigned long alloc_map[IRQ_MATRIX_SIZE];
21 unsigned long managed_map[IRQ_MATRIX_SIZE];
22};
23
24struct irq_matrix {
25 unsigned int matrix_bits;
26 unsigned int alloc_start;
27 unsigned int alloc_end;
28 unsigned int alloc_size;
29 unsigned int global_available;
30 unsigned int global_reserved;
31 unsigned int systembits_inalloc;
32 unsigned int total_allocated;
33 unsigned int online_maps;
34 struct cpumap __percpu *maps;
35 unsigned long scratch_map[IRQ_MATRIX_SIZE];
36 unsigned long system_map[IRQ_MATRIX_SIZE];
37};
38
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39#define CREATE_TRACE_POINTS
40#include <trace/events/irq_matrix.h>
41
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42/**
43 * irq_alloc_matrix - Allocate a irq_matrix structure and initialize it
44 * @matrix_bits: Number of matrix bits must be <= IRQ_MATRIX_BITS
45 * @alloc_start: From which bit the allocation search starts
46 * @alloc_end: At which bit the allocation search ends, i.e first
47 * invalid bit
48 */
49__init struct irq_matrix *irq_alloc_matrix(unsigned int matrix_bits,
50 unsigned int alloc_start,
51 unsigned int alloc_end)
52{
53 struct irq_matrix *m;
54
55 if (matrix_bits > IRQ_MATRIX_BITS)
56 return NULL;
57
58 m = kzalloc(sizeof(*m), GFP_KERNEL);
59 if (!m)
60 return NULL;
61
62 m->matrix_bits = matrix_bits;
63 m->alloc_start = alloc_start;
64 m->alloc_end = alloc_end;
65 m->alloc_size = alloc_end - alloc_start;
66 m->maps = alloc_percpu(*m->maps);
67 if (!m->maps) {
68 kfree(m);
69 return NULL;
70 }
71 return m;
72}
73
74/**
75 * irq_matrix_online - Bring the local CPU matrix online
76 * @m: Matrix pointer
77 */
78void irq_matrix_online(struct irq_matrix *m)
79{
80 struct cpumap *cm = this_cpu_ptr(m->maps);
81
82 BUG_ON(cm->online);
83
84 bitmap_zero(cm->alloc_map, m->matrix_bits);
85 cm->available = m->alloc_size - (cm->managed + m->systembits_inalloc);
86 cm->allocated = 0;
87 m->global_available += cm->available;
88 cm->online = true;
89 m->online_maps++;
ec0f7cd2 90 trace_irq_matrix_online(m);
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91}
92
93/**
94 * irq_matrix_offline - Bring the local CPU matrix offline
95 * @m: Matrix pointer
96 */
97void irq_matrix_offline(struct irq_matrix *m)
98{
99 struct cpumap *cm = this_cpu_ptr(m->maps);
100
101 /* Update the global available size */
102 m->global_available -= cm->available;
103 cm->online = false;
104 m->online_maps--;
ec0f7cd2 105 trace_irq_matrix_offline(m);
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106}
107
108static unsigned int matrix_alloc_area(struct irq_matrix *m, struct cpumap *cm,
109 unsigned int num, bool managed)
110{
111 unsigned int area, start = m->alloc_start;
112 unsigned int end = m->alloc_end;
113
114 bitmap_or(m->scratch_map, cm->managed_map, m->system_map, end);
115 bitmap_or(m->scratch_map, m->scratch_map, cm->alloc_map, end);
116 area = bitmap_find_next_zero_area(m->scratch_map, end, start, num, 0);
117 if (area >= end)
118 return area;
119 if (managed)
120 bitmap_set(cm->managed_map, area, num);
121 else
122 bitmap_set(cm->alloc_map, area, num);
123 return area;
124}
125
126/**
127 * irq_matrix_assign_system - Assign system wide entry in the matrix
128 * @m: Matrix pointer
129 * @bit: Which bit to reserve
130 * @replace: Replace an already allocated vector with a system
131 * vector at the same bit position.
132 *
133 * The BUG_ON()s below are on purpose. If this goes wrong in the
134 * early boot process, then the chance to survive is about zero.
135 * If this happens when the system is life, it's not much better.
136 */
137void irq_matrix_assign_system(struct irq_matrix *m, unsigned int bit,
138 bool replace)
139{
140 struct cpumap *cm = this_cpu_ptr(m->maps);
141
142 BUG_ON(bit > m->matrix_bits);
143 BUG_ON(m->online_maps > 1 || (m->online_maps && !replace));
144
145 set_bit(bit, m->system_map);
146 if (replace) {
147 BUG_ON(!test_and_clear_bit(bit, cm->alloc_map));
148 cm->allocated--;
149 m->total_allocated--;
150 }
151 if (bit >= m->alloc_start && bit < m->alloc_end)
152 m->systembits_inalloc++;
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153
154 trace_irq_matrix_assign_system(bit, m);
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155}
156
157/**
158 * irq_matrix_reserve_managed - Reserve a managed interrupt in a CPU map
159 * @m: Matrix pointer
160 * @msk: On which CPUs the bits should be reserved.
161 *
162 * Can be called for offline CPUs. Note, this will only reserve one bit
163 * on all CPUs in @msk, but it's not guaranteed that the bits are at the
164 * same offset on all CPUs
165 */
166int irq_matrix_reserve_managed(struct irq_matrix *m, const struct cpumask *msk)
167{
168 unsigned int cpu, failed_cpu;
169
170 for_each_cpu(cpu, msk) {
171 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
172 unsigned int bit;
173
174 bit = matrix_alloc_area(m, cm, 1, true);
175 if (bit >= m->alloc_end)
176 goto cleanup;
177 cm->managed++;
178 if (cm->online) {
179 cm->available--;
180 m->global_available--;
181 }
ec0f7cd2 182 trace_irq_matrix_reserve_managed(bit, cpu, m, cm);
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183 }
184 return 0;
185cleanup:
186 failed_cpu = cpu;
187 for_each_cpu(cpu, msk) {
188 if (cpu == failed_cpu)
189 break;
190 irq_matrix_remove_managed(m, cpumask_of(cpu));
191 }
192 return -ENOSPC;
193}
194
195/**
196 * irq_matrix_remove_managed - Remove managed interrupts in a CPU map
197 * @m: Matrix pointer
198 * @msk: On which CPUs the bits should be removed
199 *
200 * Can be called for offline CPUs
201 *
202 * This removes not allocated managed interrupts from the map. It does
203 * not matter which one because the managed interrupts free their
204 * allocation when they shut down. If not, the accounting is screwed,
205 * but all what can be done at this point is warn about it.
206 */
207void irq_matrix_remove_managed(struct irq_matrix *m, const struct cpumask *msk)
208{
209 unsigned int cpu;
210
211 for_each_cpu(cpu, msk) {
212 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
213 unsigned int bit, end = m->alloc_end;
214
215 if (WARN_ON_ONCE(!cm->managed))
216 continue;
217
218 /* Get managed bit which are not allocated */
219 bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
220
221 bit = find_first_bit(m->scratch_map, end);
222 if (WARN_ON_ONCE(bit >= end))
223 continue;
224
225 clear_bit(bit, cm->managed_map);
226
227 cm->managed--;
228 if (cm->online) {
229 cm->available++;
230 m->global_available++;
231 }
ec0f7cd2 232 trace_irq_matrix_remove_managed(bit, cpu, m, cm);
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233 }
234}
235
236/**
237 * irq_matrix_alloc_managed - Allocate a managed interrupt in a CPU map
238 * @m: Matrix pointer
239 * @cpu: On which CPU the interrupt should be allocated
240 */
241int irq_matrix_alloc_managed(struct irq_matrix *m, unsigned int cpu)
242{
243 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
244 unsigned int bit, end = m->alloc_end;
245
246 /* Get managed bit which are not allocated */
247 bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
248 bit = find_first_bit(m->scratch_map, end);
249 if (bit >= end)
250 return -ENOSPC;
251 set_bit(bit, cm->alloc_map);
252 cm->allocated++;
253 m->total_allocated++;
ec0f7cd2 254 trace_irq_matrix_alloc_managed(bit, cpu, m, cm);
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255 return bit;
256}
257
258/**
259 * irq_matrix_assign - Assign a preallocated interrupt in the local CPU map
260 * @m: Matrix pointer
261 * @bit: Which bit to mark
262 *
263 * This should only be used to mark preallocated vectors
264 */
265void irq_matrix_assign(struct irq_matrix *m, unsigned int bit)
266{
267 struct cpumap *cm = this_cpu_ptr(m->maps);
268
269 if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
270 return;
271 if (WARN_ON_ONCE(test_and_set_bit(bit, cm->alloc_map)))
272 return;
273 cm->allocated++;
274 m->total_allocated++;
275 cm->available--;
276 m->global_available--;
ec0f7cd2 277 trace_irq_matrix_assign(bit, smp_processor_id(), m, cm);
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278}
279
280/**
281 * irq_matrix_reserve - Reserve interrupts
282 * @m: Matrix pointer
283 *
284 * This is merily a book keeping call. It increments the number of globally
285 * reserved interrupt bits w/o actually allocating them. This allows to
286 * setup interrupt descriptors w/o assigning low level resources to it.
287 * The actual allocation happens when the interrupt gets activated.
288 */
289void irq_matrix_reserve(struct irq_matrix *m)
290{
291 if (m->global_reserved <= m->global_available &&
292 m->global_reserved + 1 > m->global_available)
293 pr_warn("Interrupt reservation exceeds available resources\n");
294
295 m->global_reserved++;
ec0f7cd2 296 trace_irq_matrix_reserve(m);
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297}
298
299/**
300 * irq_matrix_remove_reserved - Remove interrupt reservation
301 * @m: Matrix pointer
302 *
303 * This is merily a book keeping call. It decrements the number of globally
304 * reserved interrupt bits. This is used to undo irq_matrix_reserve() when the
305 * interrupt was never in use and a real vector allocated, which undid the
306 * reservation.
307 */
308void irq_matrix_remove_reserved(struct irq_matrix *m)
309{
310 m->global_reserved--;
ec0f7cd2 311 trace_irq_matrix_remove_reserved(m);
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312}
313
314/**
315 * irq_matrix_alloc - Allocate a regular interrupt in a CPU map
316 * @m: Matrix pointer
317 * @msk: Which CPUs to search in
318 * @reserved: Allocate previously reserved interrupts
319 * @mapped_cpu: Pointer to store the CPU for which the irq was allocated
320 */
321int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
322 bool reserved, unsigned int *mapped_cpu)
323{
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324 unsigned int cpu, best_cpu, maxavl = 0;
325 struct cpumap *cm;
326 unsigned int bit;
2f75d9e1 327
a0c9259d 328 best_cpu = UINT_MAX;
2f75d9e1 329 for_each_cpu(cpu, msk) {
a0c9259d 330 cm = per_cpu_ptr(m->maps, cpu);
2f75d9e1 331
a0c9259d 332 if (!cm->online || cm->available <= maxavl)
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333 continue;
334
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335 best_cpu = cpu;
336 maxavl = cm->available;
337 }
338
339 if (maxavl) {
340 cm = per_cpu_ptr(m->maps, best_cpu);
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341 bit = matrix_alloc_area(m, cm, 1, false);
342 if (bit < m->alloc_end) {
343 cm->allocated++;
344 cm->available--;
345 m->total_allocated++;
346 m->global_available--;
347 if (reserved)
348 m->global_reserved--;
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349 *mapped_cpu = best_cpu;
350 trace_irq_matrix_alloc(bit, best_cpu, m, cm);
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351 return bit;
352 }
353 }
354 return -ENOSPC;
355}
356
357/**
358 * irq_matrix_free - Free allocated interrupt in the matrix
359 * @m: Matrix pointer
360 * @cpu: Which CPU map needs be updated
361 * @bit: The bit to remove
362 * @managed: If true, the interrupt is managed and not accounted
363 * as available.
364 */
365void irq_matrix_free(struct irq_matrix *m, unsigned int cpu,
366 unsigned int bit, bool managed)
367{
368 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
369
370 if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
371 return;
372
373 if (cm->online) {
374 clear_bit(bit, cm->alloc_map);
375 cm->allocated--;
376 m->total_allocated--;
377 if (!managed) {
378 cm->available++;
379 m->global_available++;
380 }
381 }
ec0f7cd2 382 trace_irq_matrix_free(bit, cpu, m, cm);
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383}
384
385/**
386 * irq_matrix_available - Get the number of globally available irqs
387 * @m: Pointer to the matrix to query
388 * @cpudown: If true, the local CPU is about to go down, adjust
389 * the number of available irqs accordingly
390 */
391unsigned int irq_matrix_available(struct irq_matrix *m, bool cpudown)
392{
393 struct cpumap *cm = this_cpu_ptr(m->maps);
394
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395 if (!cpudown)
396 return m->global_available;
397 return m->global_available - cm->available;
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398}
399
400/**
401 * irq_matrix_reserved - Get the number of globally reserved irqs
402 * @m: Pointer to the matrix to query
403 */
404unsigned int irq_matrix_reserved(struct irq_matrix *m)
405{
406 return m->global_reserved;
407}
408
409/**
410 * irq_matrix_allocated - Get the number of allocated irqs on the local cpu
411 * @m: Pointer to the matrix to search
412 *
413 * This returns number of allocated irqs
414 */
415unsigned int irq_matrix_allocated(struct irq_matrix *m)
416{
417 struct cpumap *cm = this_cpu_ptr(m->maps);
418
419 return cm->allocated;
420}
421
422#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
423/**
424 * irq_matrix_debug_show - Show detailed allocation information
425 * @sf: Pointer to the seq_file to print to
426 * @m: Pointer to the matrix allocator
427 * @ind: Indentation for the print format
428 *
429 * Note, this is a lockless snapshot.
430 */
431void irq_matrix_debug_show(struct seq_file *sf, struct irq_matrix *m, int ind)
432{
433 unsigned int nsys = bitmap_weight(m->system_map, m->matrix_bits);
434 int cpu;
435
436 seq_printf(sf, "Online bitmaps: %6u\n", m->online_maps);
437 seq_printf(sf, "Global available: %6u\n", m->global_available);
438 seq_printf(sf, "Global reserved: %6u\n", m->global_reserved);
439 seq_printf(sf, "Total allocated: %6u\n", m->total_allocated);
440 seq_printf(sf, "System: %u: %*pbl\n", nsys, m->matrix_bits,
441 m->system_map);
442 seq_printf(sf, "%*s| CPU | avl | man | act | vectors\n", ind, " ");
443 cpus_read_lock();
444 for_each_online_cpu(cpu) {
445 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
446
447 seq_printf(sf, "%*s %4d %4u %4u %4u %*pbl\n", ind, " ",
448 cpu, cm->available, cm->managed, cm->allocated,
449 m->matrix_bits, cm->alloc_map);
450 }
451 cpus_read_unlock();
452}
453#endif