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90cafdd5 TG |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | // Copyright (C) 2017 Thomas Gleixner <tglx@linutronix.de> | |
3 | ||
2f75d9e1 TG |
4 | #include <linux/spinlock.h> |
5 | #include <linux/seq_file.h> | |
6 | #include <linux/bitmap.h> | |
7 | #include <linux/percpu.h> | |
8 | #include <linux/cpu.h> | |
9 | #include <linux/irq.h> | |
10 | ||
57f01796 | 11 | #define IRQ_MATRIX_SIZE (BITS_TO_LONGS(IRQ_MATRIX_BITS)) |
2f75d9e1 TG |
12 | |
13 | struct cpumap { | |
14 | unsigned int available; | |
15 | unsigned int allocated; | |
16 | unsigned int managed; | |
e8da8794 | 17 | unsigned int managed_allocated; |
651ca2c0 | 18 | bool initialized; |
2f75d9e1 TG |
19 | bool online; |
20 | unsigned long alloc_map[IRQ_MATRIX_SIZE]; | |
21 | unsigned long managed_map[IRQ_MATRIX_SIZE]; | |
22 | }; | |
23 | ||
24 | struct 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 | ||
ec0f7cd2 TG |
39 | #define CREATE_TRACE_POINTS |
40 | #include <trace/events/irq_matrix.h> | |
41 | ||
2f75d9e1 TG |
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 | */ | |
78 | void irq_matrix_online(struct irq_matrix *m) | |
79 | { | |
80 | struct cpumap *cm = this_cpu_ptr(m->maps); | |
81 | ||
82 | BUG_ON(cm->online); | |
83 | ||
651ca2c0 TG |
84 | if (!cm->initialized) { |
85 | cm->available = m->alloc_size; | |
86 | cm->available -= cm->managed + m->systembits_inalloc; | |
87 | cm->initialized = true; | |
88 | } | |
2f75d9e1 TG |
89 | m->global_available += cm->available; |
90 | cm->online = true; | |
91 | m->online_maps++; | |
ec0f7cd2 | 92 | trace_irq_matrix_online(m); |
2f75d9e1 TG |
93 | } |
94 | ||
95 | /** | |
96 | * irq_matrix_offline - Bring the local CPU matrix offline | |
97 | * @m: Matrix pointer | |
98 | */ | |
99 | void irq_matrix_offline(struct irq_matrix *m) | |
100 | { | |
101 | struct cpumap *cm = this_cpu_ptr(m->maps); | |
102 | ||
103 | /* Update the global available size */ | |
104 | m->global_available -= cm->available; | |
105 | cm->online = false; | |
106 | m->online_maps--; | |
ec0f7cd2 | 107 | trace_irq_matrix_offline(m); |
2f75d9e1 TG |
108 | } |
109 | ||
110 | static unsigned int matrix_alloc_area(struct irq_matrix *m, struct cpumap *cm, | |
111 | unsigned int num, bool managed) | |
112 | { | |
113 | unsigned int area, start = m->alloc_start; | |
114 | unsigned int end = m->alloc_end; | |
115 | ||
116 | bitmap_or(m->scratch_map, cm->managed_map, m->system_map, end); | |
117 | bitmap_or(m->scratch_map, m->scratch_map, cm->alloc_map, end); | |
118 | area = bitmap_find_next_zero_area(m->scratch_map, end, start, num, 0); | |
119 | if (area >= end) | |
120 | return area; | |
121 | if (managed) | |
122 | bitmap_set(cm->managed_map, area, num); | |
123 | else | |
124 | bitmap_set(cm->alloc_map, area, num); | |
125 | return area; | |
126 | } | |
127 | ||
8ffe4e61 DL |
128 | /* Find the best CPU which has the lowest vector allocation count */ |
129 | static unsigned int matrix_find_best_cpu(struct irq_matrix *m, | |
130 | const struct cpumask *msk) | |
131 | { | |
132 | unsigned int cpu, best_cpu, maxavl = 0; | |
133 | struct cpumap *cm; | |
134 | ||
135 | best_cpu = UINT_MAX; | |
136 | ||
137 | for_each_cpu(cpu, msk) { | |
138 | cm = per_cpu_ptr(m->maps, cpu); | |
139 | ||
140 | if (!cm->online || cm->available <= maxavl) | |
141 | continue; | |
142 | ||
143 | best_cpu = cpu; | |
144 | maxavl = cm->available; | |
145 | } | |
146 | return best_cpu; | |
147 | } | |
148 | ||
e8da8794 LL |
149 | /* Find the best CPU which has the lowest number of managed IRQs allocated */ |
150 | static unsigned int matrix_find_best_cpu_managed(struct irq_matrix *m, | |
151 | const struct cpumask *msk) | |
152 | { | |
153 | unsigned int cpu, best_cpu, allocated = UINT_MAX; | |
154 | struct cpumap *cm; | |
155 | ||
156 | best_cpu = UINT_MAX; | |
157 | ||
158 | for_each_cpu(cpu, msk) { | |
159 | cm = per_cpu_ptr(m->maps, cpu); | |
160 | ||
161 | if (!cm->online || cm->managed_allocated > allocated) | |
162 | continue; | |
163 | ||
164 | best_cpu = cpu; | |
165 | allocated = cm->managed_allocated; | |
166 | } | |
167 | return best_cpu; | |
168 | } | |
169 | ||
2f75d9e1 TG |
170 | /** |
171 | * irq_matrix_assign_system - Assign system wide entry in the matrix | |
172 | * @m: Matrix pointer | |
173 | * @bit: Which bit to reserve | |
174 | * @replace: Replace an already allocated vector with a system | |
175 | * vector at the same bit position. | |
176 | * | |
177 | * The BUG_ON()s below are on purpose. If this goes wrong in the | |
178 | * early boot process, then the chance to survive is about zero. | |
179 | * If this happens when the system is life, it's not much better. | |
180 | */ | |
181 | void irq_matrix_assign_system(struct irq_matrix *m, unsigned int bit, | |
182 | bool replace) | |
183 | { | |
184 | struct cpumap *cm = this_cpu_ptr(m->maps); | |
185 | ||
186 | BUG_ON(bit > m->matrix_bits); | |
187 | BUG_ON(m->online_maps > 1 || (m->online_maps && !replace)); | |
188 | ||
189 | set_bit(bit, m->system_map); | |
190 | if (replace) { | |
191 | BUG_ON(!test_and_clear_bit(bit, cm->alloc_map)); | |
192 | cm->allocated--; | |
193 | m->total_allocated--; | |
194 | } | |
195 | if (bit >= m->alloc_start && bit < m->alloc_end) | |
196 | m->systembits_inalloc++; | |
ec0f7cd2 TG |
197 | |
198 | trace_irq_matrix_assign_system(bit, m); | |
2f75d9e1 TG |
199 | } |
200 | ||
201 | /** | |
202 | * irq_matrix_reserve_managed - Reserve a managed interrupt in a CPU map | |
203 | * @m: Matrix pointer | |
204 | * @msk: On which CPUs the bits should be reserved. | |
205 | * | |
206 | * Can be called for offline CPUs. Note, this will only reserve one bit | |
207 | * on all CPUs in @msk, but it's not guaranteed that the bits are at the | |
208 | * same offset on all CPUs | |
209 | */ | |
210 | int irq_matrix_reserve_managed(struct irq_matrix *m, const struct cpumask *msk) | |
211 | { | |
212 | unsigned int cpu, failed_cpu; | |
213 | ||
214 | for_each_cpu(cpu, msk) { | |
215 | struct cpumap *cm = per_cpu_ptr(m->maps, cpu); | |
216 | unsigned int bit; | |
217 | ||
218 | bit = matrix_alloc_area(m, cm, 1, true); | |
219 | if (bit >= m->alloc_end) | |
220 | goto cleanup; | |
221 | cm->managed++; | |
222 | if (cm->online) { | |
223 | cm->available--; | |
224 | m->global_available--; | |
225 | } | |
ec0f7cd2 | 226 | trace_irq_matrix_reserve_managed(bit, cpu, m, cm); |
2f75d9e1 TG |
227 | } |
228 | return 0; | |
229 | cleanup: | |
230 | failed_cpu = cpu; | |
231 | for_each_cpu(cpu, msk) { | |
232 | if (cpu == failed_cpu) | |
233 | break; | |
234 | irq_matrix_remove_managed(m, cpumask_of(cpu)); | |
235 | } | |
236 | return -ENOSPC; | |
237 | } | |
238 | ||
239 | /** | |
240 | * irq_matrix_remove_managed - Remove managed interrupts in a CPU map | |
241 | * @m: Matrix pointer | |
242 | * @msk: On which CPUs the bits should be removed | |
243 | * | |
244 | * Can be called for offline CPUs | |
245 | * | |
246 | * This removes not allocated managed interrupts from the map. It does | |
247 | * not matter which one because the managed interrupts free their | |
248 | * allocation when they shut down. If not, the accounting is screwed, | |
249 | * but all what can be done at this point is warn about it. | |
250 | */ | |
251 | void irq_matrix_remove_managed(struct irq_matrix *m, const struct cpumask *msk) | |
252 | { | |
253 | unsigned int cpu; | |
254 | ||
255 | for_each_cpu(cpu, msk) { | |
256 | struct cpumap *cm = per_cpu_ptr(m->maps, cpu); | |
257 | unsigned int bit, end = m->alloc_end; | |
258 | ||
259 | if (WARN_ON_ONCE(!cm->managed)) | |
260 | continue; | |
261 | ||
262 | /* Get managed bit which are not allocated */ | |
263 | bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end); | |
264 | ||
265 | bit = find_first_bit(m->scratch_map, end); | |
266 | if (WARN_ON_ONCE(bit >= end)) | |
267 | continue; | |
268 | ||
269 | clear_bit(bit, cm->managed_map); | |
270 | ||
271 | cm->managed--; | |
272 | if (cm->online) { | |
273 | cm->available++; | |
274 | m->global_available++; | |
275 | } | |
ec0f7cd2 | 276 | trace_irq_matrix_remove_managed(bit, cpu, m, cm); |
2f75d9e1 TG |
277 | } |
278 | } | |
279 | ||
280 | /** | |
281 | * irq_matrix_alloc_managed - Allocate a managed interrupt in a CPU map | |
282 | * @m: Matrix pointer | |
283 | * @cpu: On which CPU the interrupt should be allocated | |
284 | */ | |
76f99ae5 DL |
285 | int irq_matrix_alloc_managed(struct irq_matrix *m, const struct cpumask *msk, |
286 | unsigned int *mapped_cpu) | |
2f75d9e1 | 287 | { |
76f99ae5 DL |
288 | unsigned int bit, cpu, end = m->alloc_end; |
289 | struct cpumap *cm; | |
290 | ||
291 | if (cpumask_empty(msk)) | |
292 | return -EINVAL; | |
293 | ||
e8da8794 | 294 | cpu = matrix_find_best_cpu_managed(m, msk); |
76f99ae5 DL |
295 | if (cpu == UINT_MAX) |
296 | return -ENOSPC; | |
2f75d9e1 | 297 | |
76f99ae5 DL |
298 | cm = per_cpu_ptr(m->maps, cpu); |
299 | end = m->alloc_end; | |
2f75d9e1 TG |
300 | /* Get managed bit which are not allocated */ |
301 | bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end); | |
302 | bit = find_first_bit(m->scratch_map, end); | |
303 | if (bit >= end) | |
304 | return -ENOSPC; | |
305 | set_bit(bit, cm->alloc_map); | |
306 | cm->allocated++; | |
e8da8794 | 307 | cm->managed_allocated++; |
2f75d9e1 | 308 | m->total_allocated++; |
76f99ae5 | 309 | *mapped_cpu = cpu; |
ec0f7cd2 | 310 | trace_irq_matrix_alloc_managed(bit, cpu, m, cm); |
2f75d9e1 TG |
311 | return bit; |
312 | } | |
313 | ||
314 | /** | |
315 | * irq_matrix_assign - Assign a preallocated interrupt in the local CPU map | |
316 | * @m: Matrix pointer | |
317 | * @bit: Which bit to mark | |
318 | * | |
319 | * This should only be used to mark preallocated vectors | |
320 | */ | |
321 | void irq_matrix_assign(struct irq_matrix *m, unsigned int bit) | |
322 | { | |
323 | struct cpumap *cm = this_cpu_ptr(m->maps); | |
324 | ||
325 | if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end)) | |
326 | return; | |
327 | if (WARN_ON_ONCE(test_and_set_bit(bit, cm->alloc_map))) | |
328 | return; | |
329 | cm->allocated++; | |
330 | m->total_allocated++; | |
331 | cm->available--; | |
332 | m->global_available--; | |
ec0f7cd2 | 333 | trace_irq_matrix_assign(bit, smp_processor_id(), m, cm); |
2f75d9e1 TG |
334 | } |
335 | ||
336 | /** | |
337 | * irq_matrix_reserve - Reserve interrupts | |
338 | * @m: Matrix pointer | |
339 | * | |
340 | * This is merily a book keeping call. It increments the number of globally | |
341 | * reserved interrupt bits w/o actually allocating them. This allows to | |
342 | * setup interrupt descriptors w/o assigning low level resources to it. | |
343 | * The actual allocation happens when the interrupt gets activated. | |
344 | */ | |
345 | void irq_matrix_reserve(struct irq_matrix *m) | |
346 | { | |
347 | if (m->global_reserved <= m->global_available && | |
348 | m->global_reserved + 1 > m->global_available) | |
349 | pr_warn("Interrupt reservation exceeds available resources\n"); | |
350 | ||
351 | m->global_reserved++; | |
ec0f7cd2 | 352 | trace_irq_matrix_reserve(m); |
2f75d9e1 TG |
353 | } |
354 | ||
355 | /** | |
356 | * irq_matrix_remove_reserved - Remove interrupt reservation | |
357 | * @m: Matrix pointer | |
358 | * | |
359 | * This is merily a book keeping call. It decrements the number of globally | |
360 | * reserved interrupt bits. This is used to undo irq_matrix_reserve() when the | |
361 | * interrupt was never in use and a real vector allocated, which undid the | |
362 | * reservation. | |
363 | */ | |
364 | void irq_matrix_remove_reserved(struct irq_matrix *m) | |
365 | { | |
366 | m->global_reserved--; | |
ec0f7cd2 | 367 | trace_irq_matrix_remove_reserved(m); |
2f75d9e1 TG |
368 | } |
369 | ||
370 | /** | |
371 | * irq_matrix_alloc - Allocate a regular interrupt in a CPU map | |
372 | * @m: Matrix pointer | |
373 | * @msk: Which CPUs to search in | |
374 | * @reserved: Allocate previously reserved interrupts | |
375 | * @mapped_cpu: Pointer to store the CPU for which the irq was allocated | |
376 | */ | |
377 | int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk, | |
378 | bool reserved, unsigned int *mapped_cpu) | |
379 | { | |
8ffe4e61 | 380 | unsigned int cpu, bit; |
a0c9259d | 381 | struct cpumap *cm; |
2f75d9e1 | 382 | |
8ffe4e61 DL |
383 | cpu = matrix_find_best_cpu(m, msk); |
384 | if (cpu == UINT_MAX) | |
385 | return -ENOSPC; | |
2f75d9e1 | 386 | |
8ffe4e61 DL |
387 | cm = per_cpu_ptr(m->maps, cpu); |
388 | bit = matrix_alloc_area(m, cm, 1, false); | |
389 | if (bit >= m->alloc_end) | |
390 | return -ENOSPC; | |
391 | cm->allocated++; | |
392 | cm->available--; | |
393 | m->total_allocated++; | |
394 | m->global_available--; | |
395 | if (reserved) | |
396 | m->global_reserved--; | |
397 | *mapped_cpu = cpu; | |
398 | trace_irq_matrix_alloc(bit, cpu, m, cm); | |
399 | return bit; | |
a0c9259d | 400 | |
2f75d9e1 TG |
401 | } |
402 | ||
403 | /** | |
404 | * irq_matrix_free - Free allocated interrupt in the matrix | |
405 | * @m: Matrix pointer | |
406 | * @cpu: Which CPU map needs be updated | |
407 | * @bit: The bit to remove | |
408 | * @managed: If true, the interrupt is managed and not accounted | |
409 | * as available. | |
410 | */ | |
411 | void irq_matrix_free(struct irq_matrix *m, unsigned int cpu, | |
412 | unsigned int bit, bool managed) | |
413 | { | |
414 | struct cpumap *cm = per_cpu_ptr(m->maps, cpu); | |
415 | ||
416 | if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end)) | |
417 | return; | |
418 | ||
651ca2c0 TG |
419 | clear_bit(bit, cm->alloc_map); |
420 | cm->allocated--; | |
e8da8794 LL |
421 | if(managed) |
422 | cm->managed_allocated--; | |
651ca2c0 TG |
423 | |
424 | if (cm->online) | |
2f75d9e1 | 425 | m->total_allocated--; |
651ca2c0 TG |
426 | |
427 | if (!managed) { | |
428 | cm->available++; | |
429 | if (cm->online) | |
2f75d9e1 | 430 | m->global_available++; |
2f75d9e1 | 431 | } |
ec0f7cd2 | 432 | trace_irq_matrix_free(bit, cpu, m, cm); |
2f75d9e1 TG |
433 | } |
434 | ||
435 | /** | |
436 | * irq_matrix_available - Get the number of globally available irqs | |
437 | * @m: Pointer to the matrix to query | |
438 | * @cpudown: If true, the local CPU is about to go down, adjust | |
439 | * the number of available irqs accordingly | |
440 | */ | |
441 | unsigned int irq_matrix_available(struct irq_matrix *m, bool cpudown) | |
442 | { | |
443 | struct cpumap *cm = this_cpu_ptr(m->maps); | |
444 | ||
bb5c4342 TG |
445 | if (!cpudown) |
446 | return m->global_available; | |
447 | return m->global_available - cm->available; | |
2f75d9e1 TG |
448 | } |
449 | ||
450 | /** | |
451 | * irq_matrix_reserved - Get the number of globally reserved irqs | |
452 | * @m: Pointer to the matrix to query | |
453 | */ | |
454 | unsigned int irq_matrix_reserved(struct irq_matrix *m) | |
455 | { | |
456 | return m->global_reserved; | |
457 | } | |
458 | ||
459 | /** | |
460 | * irq_matrix_allocated - Get the number of allocated irqs on the local cpu | |
461 | * @m: Pointer to the matrix to search | |
462 | * | |
463 | * This returns number of allocated irqs | |
464 | */ | |
465 | unsigned int irq_matrix_allocated(struct irq_matrix *m) | |
466 | { | |
467 | struct cpumap *cm = this_cpu_ptr(m->maps); | |
468 | ||
469 | return cm->allocated; | |
470 | } | |
471 | ||
472 | #ifdef CONFIG_GENERIC_IRQ_DEBUGFS | |
473 | /** | |
474 | * irq_matrix_debug_show - Show detailed allocation information | |
475 | * @sf: Pointer to the seq_file to print to | |
476 | * @m: Pointer to the matrix allocator | |
477 | * @ind: Indentation for the print format | |
478 | * | |
479 | * Note, this is a lockless snapshot. | |
480 | */ | |
481 | void irq_matrix_debug_show(struct seq_file *sf, struct irq_matrix *m, int ind) | |
482 | { | |
483 | unsigned int nsys = bitmap_weight(m->system_map, m->matrix_bits); | |
484 | int cpu; | |
485 | ||
486 | seq_printf(sf, "Online bitmaps: %6u\n", m->online_maps); | |
487 | seq_printf(sf, "Global available: %6u\n", m->global_available); | |
488 | seq_printf(sf, "Global reserved: %6u\n", m->global_reserved); | |
489 | seq_printf(sf, "Total allocated: %6u\n", m->total_allocated); | |
490 | seq_printf(sf, "System: %u: %*pbl\n", nsys, m->matrix_bits, | |
491 | m->system_map); | |
e8da8794 | 492 | seq_printf(sf, "%*s| CPU | avl | man | mac | act | vectors\n", ind, " "); |
2f75d9e1 TG |
493 | cpus_read_lock(); |
494 | for_each_online_cpu(cpu) { | |
495 | struct cpumap *cm = per_cpu_ptr(m->maps, cpu); | |
496 | ||
e8da8794 LL |
497 | seq_printf(sf, "%*s %4d %4u %4u %4u %4u %*pbl\n", ind, " ", |
498 | cpu, cm->available, cm->managed, | |
499 | cm->managed_allocated, cm->allocated, | |
2f75d9e1 TG |
500 | m->matrix_bits, cm->alloc_map); |
501 | } | |
502 | cpus_read_unlock(); | |
503 | } | |
504 | #endif |