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1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2017 Thomas Gleixner <tglx@linutronix.de>
4 #include <linux/spinlock.h>
5 #include <linux/seq_file.h>
6 #include <linux/bitmap.h>
7 #include <linux/percpu.h>
11 #define IRQ_MATRIX_SIZE (BITS_TO_LONGS(IRQ_MATRIX_BITS))
14 unsigned int available
;
15 unsigned int allocated
;
17 unsigned int managed_allocated
;
20 unsigned long alloc_map
[IRQ_MATRIX_SIZE
];
21 unsigned long managed_map
[IRQ_MATRIX_SIZE
];
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
];
39 #define CREATE_TRACE_POINTS
40 #include <trace/events/irq_matrix.h>
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
49 __init
struct irq_matrix
*irq_alloc_matrix(unsigned int matrix_bits
,
50 unsigned int alloc_start
,
51 unsigned int alloc_end
)
55 if (matrix_bits
> IRQ_MATRIX_BITS
)
58 m
= kzalloc(sizeof(*m
), GFP_KERNEL
);
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
);
75 * irq_matrix_online - Bring the local CPU matrix online
78 void irq_matrix_online(struct irq_matrix
*m
)
80 struct cpumap
*cm
= this_cpu_ptr(m
->maps
);
84 if (!cm
->initialized
) {
85 cm
->available
= m
->alloc_size
;
86 cm
->available
-= cm
->managed
+ m
->systembits_inalloc
;
87 cm
->initialized
= true;
89 m
->global_available
+= cm
->available
;
92 trace_irq_matrix_online(m
);
96 * irq_matrix_offline - Bring the local CPU matrix offline
99 void irq_matrix_offline(struct irq_matrix
*m
)
101 struct cpumap
*cm
= this_cpu_ptr(m
->maps
);
103 /* Update the global available size */
104 m
->global_available
-= cm
->available
;
107 trace_irq_matrix_offline(m
);
110 static unsigned int matrix_alloc_area(struct irq_matrix
*m
, struct cpumap
*cm
,
111 unsigned int num
, bool managed
)
113 unsigned int area
, start
= m
->alloc_start
;
114 unsigned int end
= m
->alloc_end
;
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);
122 bitmap_set(cm
->managed_map
, area
, num
);
124 bitmap_set(cm
->alloc_map
, area
, num
);
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
)
132 unsigned int cpu
, best_cpu
, maxavl
= 0;
137 for_each_cpu(cpu
, msk
) {
138 cm
= per_cpu_ptr(m
->maps
, cpu
);
140 if (!cm
->online
|| cm
->available
<= maxavl
)
144 maxavl
= cm
->available
;
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
)
153 unsigned int cpu
, best_cpu
, allocated
= UINT_MAX
;
158 for_each_cpu(cpu
, msk
) {
159 cm
= per_cpu_ptr(m
->maps
, cpu
);
161 if (!cm
->online
|| cm
->managed_allocated
> allocated
)
165 allocated
= cm
->managed_allocated
;
171 * irq_matrix_assign_system - Assign system wide entry in the matrix
173 * @bit: Which bit to reserve
174 * @replace: Replace an already allocated vector with a system
175 * vector at the same bit position.
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.
181 void irq_matrix_assign_system(struct irq_matrix
*m
, unsigned int bit
,
184 struct cpumap
*cm
= this_cpu_ptr(m
->maps
);
186 BUG_ON(bit
> m
->matrix_bits
);
187 BUG_ON(m
->online_maps
> 1 || (m
->online_maps
&& !replace
));
189 set_bit(bit
, m
->system_map
);
191 BUG_ON(!test_and_clear_bit(bit
, cm
->alloc_map
));
193 m
->total_allocated
--;
195 if (bit
>= m
->alloc_start
&& bit
< m
->alloc_end
)
196 m
->systembits_inalloc
++;
198 trace_irq_matrix_assign_system(bit
, m
);
202 * irq_matrix_reserve_managed - Reserve a managed interrupt in a CPU map
204 * @msk: On which CPUs the bits should be reserved.
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
210 int irq_matrix_reserve_managed(struct irq_matrix
*m
, const struct cpumask
*msk
)
212 unsigned int cpu
, failed_cpu
;
214 for_each_cpu(cpu
, msk
) {
215 struct cpumap
*cm
= per_cpu_ptr(m
->maps
, cpu
);
218 bit
= matrix_alloc_area(m
, cm
, 1, true);
219 if (bit
>= m
->alloc_end
)
224 m
->global_available
--;
226 trace_irq_matrix_reserve_managed(bit
, cpu
, m
, cm
);
231 for_each_cpu(cpu
, msk
) {
232 if (cpu
== failed_cpu
)
234 irq_matrix_remove_managed(m
, cpumask_of(cpu
));
240 * irq_matrix_remove_managed - Remove managed interrupts in a CPU map
242 * @msk: On which CPUs the bits should be removed
244 * Can be called for offline CPUs
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.
251 void irq_matrix_remove_managed(struct irq_matrix
*m
, const struct cpumask
*msk
)
255 for_each_cpu(cpu
, msk
) {
256 struct cpumap
*cm
= per_cpu_ptr(m
->maps
, cpu
);
257 unsigned int bit
, end
= m
->alloc_end
;
259 if (WARN_ON_ONCE(!cm
->managed
))
262 /* Get managed bit which are not allocated */
263 bitmap_andnot(m
->scratch_map
, cm
->managed_map
, cm
->alloc_map
, end
);
265 bit
= find_first_bit(m
->scratch_map
, end
);
266 if (WARN_ON_ONCE(bit
>= end
))
269 clear_bit(bit
, cm
->managed_map
);
274 m
->global_available
++;
276 trace_irq_matrix_remove_managed(bit
, cpu
, m
, cm
);
281 * irq_matrix_alloc_managed - Allocate a managed interrupt in a CPU map
283 * @cpu: On which CPU the interrupt should be allocated
285 int irq_matrix_alloc_managed(struct irq_matrix
*m
, const struct cpumask
*msk
,
286 unsigned int *mapped_cpu
)
288 unsigned int bit
, cpu
, end
= m
->alloc_end
;
291 if (cpumask_empty(msk
))
294 cpu
= matrix_find_best_cpu_managed(m
, msk
);
298 cm
= per_cpu_ptr(m
->maps
, cpu
);
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
);
305 set_bit(bit
, cm
->alloc_map
);
307 cm
->managed_allocated
++;
308 m
->total_allocated
++;
310 trace_irq_matrix_alloc_managed(bit
, cpu
, m
, cm
);
315 * irq_matrix_assign - Assign a preallocated interrupt in the local CPU map
317 * @bit: Which bit to mark
319 * This should only be used to mark preallocated vectors
321 void irq_matrix_assign(struct irq_matrix
*m
, unsigned int bit
)
323 struct cpumap
*cm
= this_cpu_ptr(m
->maps
);
325 if (WARN_ON_ONCE(bit
< m
->alloc_start
|| bit
>= m
->alloc_end
))
327 if (WARN_ON_ONCE(test_and_set_bit(bit
, cm
->alloc_map
)))
330 m
->total_allocated
++;
332 m
->global_available
--;
333 trace_irq_matrix_assign(bit
, smp_processor_id(), m
, cm
);
337 * irq_matrix_reserve - Reserve interrupts
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.
345 void irq_matrix_reserve(struct irq_matrix
*m
)
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");
351 m
->global_reserved
++;
352 trace_irq_matrix_reserve(m
);
356 * irq_matrix_remove_reserved - Remove interrupt reservation
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
364 void irq_matrix_remove_reserved(struct irq_matrix
*m
)
366 m
->global_reserved
--;
367 trace_irq_matrix_remove_reserved(m
);
371 * irq_matrix_alloc - Allocate a regular interrupt in a CPU map
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
377 int irq_matrix_alloc(struct irq_matrix
*m
, const struct cpumask
*msk
,
378 bool reserved
, unsigned int *mapped_cpu
)
380 unsigned int cpu
, bit
;
383 cpu
= matrix_find_best_cpu(m
, msk
);
387 cm
= per_cpu_ptr(m
->maps
, cpu
);
388 bit
= matrix_alloc_area(m
, cm
, 1, false);
389 if (bit
>= m
->alloc_end
)
393 m
->total_allocated
++;
394 m
->global_available
--;
396 m
->global_reserved
--;
398 trace_irq_matrix_alloc(bit
, cpu
, m
, cm
);
404 * irq_matrix_free - Free allocated interrupt in the matrix
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
411 void irq_matrix_free(struct irq_matrix
*m
, unsigned int cpu
,
412 unsigned int bit
, bool managed
)
414 struct cpumap
*cm
= per_cpu_ptr(m
->maps
, cpu
);
416 if (WARN_ON_ONCE(bit
< m
->alloc_start
|| bit
>= m
->alloc_end
))
419 clear_bit(bit
, cm
->alloc_map
);
422 cm
->managed_allocated
--;
425 m
->total_allocated
--;
430 m
->global_available
++;
432 trace_irq_matrix_free(bit
, cpu
, m
, cm
);
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
441 unsigned int irq_matrix_available(struct irq_matrix
*m
, bool cpudown
)
443 struct cpumap
*cm
= this_cpu_ptr(m
->maps
);
446 return m
->global_available
;
447 return m
->global_available
- cm
->available
;
451 * irq_matrix_reserved - Get the number of globally reserved irqs
452 * @m: Pointer to the matrix to query
454 unsigned int irq_matrix_reserved(struct irq_matrix
*m
)
456 return m
->global_reserved
;
460 * irq_matrix_allocated - Get the number of allocated irqs on the local cpu
461 * @m: Pointer to the matrix to search
463 * This returns number of allocated irqs
465 unsigned int irq_matrix_allocated(struct irq_matrix
*m
)
467 struct cpumap
*cm
= this_cpu_ptr(m
->maps
);
469 return cm
->allocated
;
472 #ifdef CONFIG_GENERIC_IRQ_DEBUGFS
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
479 * Note, this is a lockless snapshot.
481 void irq_matrix_debug_show(struct seq_file
*sf
, struct irq_matrix
*m
, int ind
)
483 unsigned int nsys
= bitmap_weight(m
->system_map
, m
->matrix_bits
);
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
,
492 seq_printf(sf
, "%*s| CPU | avl | man | mac | act | vectors\n", ind
, " ");
494 for_each_online_cpu(cpu
) {
495 struct cpumap
*cm
= per_cpu_ptr(m
->maps
, cpu
);
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
,
500 m
->matrix_bits
, cm
->alloc_map
);