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1// SPDX-License-Identifier: GPL-2.0
2// Copyright (C) 2017 Thomas Gleixner <tglx@linutronix.de>
3
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
11#define IRQ_MATRIX_SIZE (BITS_TO_LONGS(IRQ_MATRIX_BITS) * sizeof(unsigned long))
12
13struct cpumap {
14 unsigned int available;
15 unsigned int allocated;
16 unsigned int managed;
17 bool initialized;
18 bool online;
19 unsigned long alloc_map[IRQ_MATRIX_SIZE];
20 unsigned long managed_map[IRQ_MATRIX_SIZE];
21};
22
23struct irq_matrix {
24 unsigned int matrix_bits;
25 unsigned int alloc_start;
26 unsigned int alloc_end;
27 unsigned int alloc_size;
28 unsigned int global_available;
29 unsigned int global_reserved;
30 unsigned int systembits_inalloc;
31 unsigned int total_allocated;
32 unsigned int online_maps;
33 struct cpumap __percpu *maps;
34 unsigned long scratch_map[IRQ_MATRIX_SIZE];
35 unsigned long system_map[IRQ_MATRIX_SIZE];
36};
37
38#define CREATE_TRACE_POINTS
39#include <trace/events/irq_matrix.h>
40
41/**
42 * irq_alloc_matrix - Allocate a irq_matrix structure and initialize it
43 * @matrix_bits: Number of matrix bits must be <= IRQ_MATRIX_BITS
44 * @alloc_start: From which bit the allocation search starts
45 * @alloc_end: At which bit the allocation search ends, i.e first
46 * invalid bit
47 */
48__init struct irq_matrix *irq_alloc_matrix(unsigned int matrix_bits,
49 unsigned int alloc_start,
50 unsigned int alloc_end)
51{
52 struct irq_matrix *m;
53
54 if (matrix_bits > IRQ_MATRIX_BITS)
55 return NULL;
56
57 m = kzalloc(sizeof(*m), GFP_KERNEL);
58 if (!m)
59 return NULL;
60
61 m->matrix_bits = matrix_bits;
62 m->alloc_start = alloc_start;
63 m->alloc_end = alloc_end;
64 m->alloc_size = alloc_end - alloc_start;
65 m->maps = alloc_percpu(*m->maps);
66 if (!m->maps) {
67 kfree(m);
68 return NULL;
69 }
70 return m;
71}
72
73/**
74 * irq_matrix_online - Bring the local CPU matrix online
75 * @m: Matrix pointer
76 */
77void irq_matrix_online(struct irq_matrix *m)
78{
79 struct cpumap *cm = this_cpu_ptr(m->maps);
80
81 BUG_ON(cm->online);
82
83 if (!cm->initialized) {
84 cm->available = m->alloc_size;
85 cm->available -= cm->managed + m->systembits_inalloc;
86 cm->initialized = true;
87 }
88 m->global_available += cm->available;
89 cm->online = true;
90 m->online_maps++;
91 trace_irq_matrix_online(m);
92}
93
94/**
95 * irq_matrix_offline - Bring the local CPU matrix offline
96 * @m: Matrix pointer
97 */
98void irq_matrix_offline(struct irq_matrix *m)
99{
100 struct cpumap *cm = this_cpu_ptr(m->maps);
101
102 /* Update the global available size */
103 m->global_available -= cm->available;
104 cm->online = false;
105 m->online_maps--;
106 trace_irq_matrix_offline(m);
107}
108
109static unsigned int matrix_alloc_area(struct irq_matrix *m, struct cpumap *cm,
110 unsigned int num, bool managed)
111{
112 unsigned int area, start = m->alloc_start;
113 unsigned int end = m->alloc_end;
114
115 bitmap_or(m->scratch_map, cm->managed_map, m->system_map, end);
116 bitmap_or(m->scratch_map, m->scratch_map, cm->alloc_map, end);
117 area = bitmap_find_next_zero_area(m->scratch_map, end, start, num, 0);
118 if (area >= end)
119 return area;
120 if (managed)
121 bitmap_set(cm->managed_map, area, num);
122 else
123 bitmap_set(cm->alloc_map, area, num);
124 return area;
125}
126
127/**
128 * irq_matrix_assign_system - Assign system wide entry in the matrix
129 * @m: Matrix pointer
130 * @bit: Which bit to reserve
131 * @replace: Replace an already allocated vector with a system
132 * vector at the same bit position.
133 *
134 * The BUG_ON()s below are on purpose. If this goes wrong in the
135 * early boot process, then the chance to survive is about zero.
136 * If this happens when the system is life, it's not much better.
137 */
138void irq_matrix_assign_system(struct irq_matrix *m, unsigned int bit,
139 bool replace)
140{
141 struct cpumap *cm = this_cpu_ptr(m->maps);
142
143 BUG_ON(bit > m->matrix_bits);
144 BUG_ON(m->online_maps > 1 || (m->online_maps && !replace));
145
146 set_bit(bit, m->system_map);
147 if (replace) {
148 BUG_ON(!test_and_clear_bit(bit, cm->alloc_map));
149 cm->allocated--;
150 m->total_allocated--;
151 }
152 if (bit >= m->alloc_start && bit < m->alloc_end)
153 m->systembits_inalloc++;
154
155 trace_irq_matrix_assign_system(bit, m);
156}
157
158/**
159 * irq_matrix_reserve_managed - Reserve a managed interrupt in a CPU map
160 * @m: Matrix pointer
161 * @msk: On which CPUs the bits should be reserved.
162 *
163 * Can be called for offline CPUs. Note, this will only reserve one bit
164 * on all CPUs in @msk, but it's not guaranteed that the bits are at the
165 * same offset on all CPUs
166 */
167int irq_matrix_reserve_managed(struct irq_matrix *m, const struct cpumask *msk)
168{
169 unsigned int cpu, failed_cpu;
170
171 for_each_cpu(cpu, msk) {
172 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
173 unsigned int bit;
174
175 bit = matrix_alloc_area(m, cm, 1, true);
176 if (bit >= m->alloc_end)
177 goto cleanup;
178 cm->managed++;
179 if (cm->online) {
180 cm->available--;
181 m->global_available--;
182 }
183 trace_irq_matrix_reserve_managed(bit, cpu, m, cm);
184 }
185 return 0;
186cleanup:
187 failed_cpu = cpu;
188 for_each_cpu(cpu, msk) {
189 if (cpu == failed_cpu)
190 break;
191 irq_matrix_remove_managed(m, cpumask_of(cpu));
192 }
193 return -ENOSPC;
194}
195
196/**
197 * irq_matrix_remove_managed - Remove managed interrupts in a CPU map
198 * @m: Matrix pointer
199 * @msk: On which CPUs the bits should be removed
200 *
201 * Can be called for offline CPUs
202 *
203 * This removes not allocated managed interrupts from the map. It does
204 * not matter which one because the managed interrupts free their
205 * allocation when they shut down. If not, the accounting is screwed,
206 * but all what can be done at this point is warn about it.
207 */
208void irq_matrix_remove_managed(struct irq_matrix *m, const struct cpumask *msk)
209{
210 unsigned int cpu;
211
212 for_each_cpu(cpu, msk) {
213 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
214 unsigned int bit, end = m->alloc_end;
215
216 if (WARN_ON_ONCE(!cm->managed))
217 continue;
218
219 /* Get managed bit which are not allocated */
220 bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
221
222 bit = find_first_bit(m->scratch_map, end);
223 if (WARN_ON_ONCE(bit >= end))
224 continue;
225
226 clear_bit(bit, cm->managed_map);
227
228 cm->managed--;
229 if (cm->online) {
230 cm->available++;
231 m->global_available++;
232 }
233 trace_irq_matrix_remove_managed(bit, cpu, m, cm);
234 }
235}
236
237/**
238 * irq_matrix_alloc_managed - Allocate a managed interrupt in a CPU map
239 * @m: Matrix pointer
240 * @cpu: On which CPU the interrupt should be allocated
241 */
242int irq_matrix_alloc_managed(struct irq_matrix *m, unsigned int cpu)
243{
244 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
245 unsigned int bit, end = m->alloc_end;
246
247 /* Get managed bit which are not allocated */
248 bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
249 bit = find_first_bit(m->scratch_map, end);
250 if (bit >= end)
251 return -ENOSPC;
252 set_bit(bit, cm->alloc_map);
253 cm->allocated++;
254 m->total_allocated++;
255 trace_irq_matrix_alloc_managed(bit, cpu, m, cm);
256 return bit;
257}
258
259/**
260 * irq_matrix_assign - Assign a preallocated interrupt in the local CPU map
261 * @m: Matrix pointer
262 * @bit: Which bit to mark
263 *
264 * This should only be used to mark preallocated vectors
265 */
266void irq_matrix_assign(struct irq_matrix *m, unsigned int bit)
267{
268 struct cpumap *cm = this_cpu_ptr(m->maps);
269
270 if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
271 return;
272 if (WARN_ON_ONCE(test_and_set_bit(bit, cm->alloc_map)))
273 return;
274 cm->allocated++;
275 m->total_allocated++;
276 cm->available--;
277 m->global_available--;
278 trace_irq_matrix_assign(bit, smp_processor_id(), m, cm);
279}
280
281/**
282 * irq_matrix_reserve - Reserve interrupts
283 * @m: Matrix pointer
284 *
285 * This is merily a book keeping call. It increments the number of globally
286 * reserved interrupt bits w/o actually allocating them. This allows to
287 * setup interrupt descriptors w/o assigning low level resources to it.
288 * The actual allocation happens when the interrupt gets activated.
289 */
290void irq_matrix_reserve(struct irq_matrix *m)
291{
292 if (m->global_reserved <= m->global_available &&
293 m->global_reserved + 1 > m->global_available)
294 pr_warn("Interrupt reservation exceeds available resources\n");
295
296 m->global_reserved++;
297 trace_irq_matrix_reserve(m);
298}
299
300/**
301 * irq_matrix_remove_reserved - Remove interrupt reservation
302 * @m: Matrix pointer
303 *
304 * This is merily a book keeping call. It decrements the number of globally
305 * reserved interrupt bits. This is used to undo irq_matrix_reserve() when the
306 * interrupt was never in use and a real vector allocated, which undid the
307 * reservation.
308 */
309void irq_matrix_remove_reserved(struct irq_matrix *m)
310{
311 m->global_reserved--;
312 trace_irq_matrix_remove_reserved(m);
313}
314
315/**
316 * irq_matrix_alloc - Allocate a regular interrupt in a CPU map
317 * @m: Matrix pointer
318 * @msk: Which CPUs to search in
319 * @reserved: Allocate previously reserved interrupts
320 * @mapped_cpu: Pointer to store the CPU for which the irq was allocated
321 */
322int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
323 bool reserved, unsigned int *mapped_cpu)
324{
325 unsigned int cpu, best_cpu, maxavl = 0;
326 struct cpumap *cm;
327 unsigned int bit;
328
329 best_cpu = UINT_MAX;
330 for_each_cpu(cpu, msk) {
331 cm = per_cpu_ptr(m->maps, cpu);
332
333 if (!cm->online || cm->available <= maxavl)
334 continue;
335
336 best_cpu = cpu;
337 maxavl = cm->available;
338 }
339
340 if (maxavl) {
341 cm = per_cpu_ptr(m->maps, best_cpu);
342 bit = matrix_alloc_area(m, cm, 1, false);
343 if (bit < m->alloc_end) {
344 cm->allocated++;
345 cm->available--;
346 m->total_allocated++;
347 m->global_available--;
348 if (reserved)
349 m->global_reserved--;
350 *mapped_cpu = best_cpu;
351 trace_irq_matrix_alloc(bit, best_cpu, m, cm);
352 return bit;
353 }
354 }
355 return -ENOSPC;
356}
357
358/**
359 * irq_matrix_free - Free allocated interrupt in the matrix
360 * @m: Matrix pointer
361 * @cpu: Which CPU map needs be updated
362 * @bit: The bit to remove
363 * @managed: If true, the interrupt is managed and not accounted
364 * as available.
365 */
366void irq_matrix_free(struct irq_matrix *m, unsigned int cpu,
367 unsigned int bit, bool managed)
368{
369 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
370
371 if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
372 return;
373
374 clear_bit(bit, cm->alloc_map);
375 cm->allocated--;
376
377 if (cm->online)
378 m->total_allocated--;
379
380 if (!managed) {
381 cm->available++;
382 if (cm->online)
383 m->global_available++;
384 }
385 trace_irq_matrix_free(bit, cpu, m, cm);
386}
387
388/**
389 * irq_matrix_available - Get the number of globally available irqs
390 * @m: Pointer to the matrix to query
391 * @cpudown: If true, the local CPU is about to go down, adjust
392 * the number of available irqs accordingly
393 */
394unsigned int irq_matrix_available(struct irq_matrix *m, bool cpudown)
395{
396 struct cpumap *cm = this_cpu_ptr(m->maps);
397
398 if (!cpudown)
399 return m->global_available;
400 return m->global_available - cm->available;
401}
402
403/**
404 * irq_matrix_reserved - Get the number of globally reserved irqs
405 * @m: Pointer to the matrix to query
406 */
407unsigned int irq_matrix_reserved(struct irq_matrix *m)
408{
409 return m->global_reserved;
410}
411
412/**
413 * irq_matrix_allocated - Get the number of allocated irqs on the local cpu
414 * @m: Pointer to the matrix to search
415 *
416 * This returns number of allocated irqs
417 */
418unsigned int irq_matrix_allocated(struct irq_matrix *m)
419{
420 struct cpumap *cm = this_cpu_ptr(m->maps);
421
422 return cm->allocated;
423}
424
425#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
426/**
427 * irq_matrix_debug_show - Show detailed allocation information
428 * @sf: Pointer to the seq_file to print to
429 * @m: Pointer to the matrix allocator
430 * @ind: Indentation for the print format
431 *
432 * Note, this is a lockless snapshot.
433 */
434void irq_matrix_debug_show(struct seq_file *sf, struct irq_matrix *m, int ind)
435{
436 unsigned int nsys = bitmap_weight(m->system_map, m->matrix_bits);
437 int cpu;
438
439 seq_printf(sf, "Online bitmaps: %6u\n", m->online_maps);
440 seq_printf(sf, "Global available: %6u\n", m->global_available);
441 seq_printf(sf, "Global reserved: %6u\n", m->global_reserved);
442 seq_printf(sf, "Total allocated: %6u\n", m->total_allocated);
443 seq_printf(sf, "System: %u: %*pbl\n", nsys, m->matrix_bits,
444 m->system_map);
445 seq_printf(sf, "%*s| CPU | avl | man | act | vectors\n", ind, " ");
446 cpus_read_lock();
447 for_each_online_cpu(cpu) {
448 struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
449
450 seq_printf(sf, "%*s %4d %4u %4u %4u %*pbl\n", ind, " ",
451 cpu, cm->available, cm->managed, cm->allocated,
452 m->matrix_bits, cm->alloc_map);
453 }
454 cpus_read_unlock();
455}
456#endif