// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2017 Thomas Gleixner <[email protected]>
#include <linux/spinlock.h>
#include <linux/seq_file.h>
#include <linux/bitmap.h>
#include <linux/percpu.h>
#include <linux/cpu.h>
#include <linux/irq.h>
struct cpumap {
unsigned int available;
unsigned int allocated;
unsigned int managed;
unsigned int managed_allocated;
bool initialized;
bool online;
unsigned long *managed_map;
unsigned long alloc_map[];
};
struct irq_matrix {
unsigned int matrix_bits;
unsigned int alloc_start;
unsigned int alloc_end;
unsigned int alloc_size;
unsigned int global_available;
unsigned int global_reserved;
unsigned int systembits_inalloc;
unsigned int total_allocated;
unsigned int online_maps;
struct cpumap __percpu *maps;
unsigned long *system_map;
unsigned long scratch_map[];
};
#define CREATE_TRACE_POINTS
#include <trace/events/irq_matrix.h>
/**
* irq_alloc_matrix - Allocate a irq_matrix structure and initialize it
* @matrix_bits: Number of matrix bits must be <= IRQ_MATRIX_BITS
* @alloc_start: From which bit the allocation search starts
* @alloc_end: At which bit the allocation search ends, i.e first
* invalid bit
*/
__init struct irq_matrix *irq_alloc_matrix(unsigned int matrix_bits,
unsigned int alloc_start,
unsigned int alloc_end)
{
unsigned int cpu, matrix_size = BITS_TO_LONGS(matrix_bits);
struct irq_matrix *m;
m = kzalloc(struct_size(m, scratch_map, matrix_size * 2), GFP_KERNEL);
if (!m)
return NULL;
m->system_map = &m->scratch_map[matrix_size];
m->matrix_bits = matrix_bits;
m->alloc_start = alloc_start;
m->alloc_end = alloc_end;
m->alloc_size = alloc_end - alloc_start;
m->maps = __alloc_percpu(struct_size(m->maps, alloc_map, matrix_size * 2),
__alignof__(*m->maps));
if (!m->maps) {
kfree(m);
return NULL;
}
for_each_possible_cpu(cpu) {
struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
cm->managed_map = &cm->alloc_map[matrix_size];
}
return m;
}
/**
* irq_matrix_online - Bring the local CPU matrix online
* @m: Matrix pointer
*/
void irq_matrix_online(struct irq_matrix *m)
{
struct cpumap *cm = this_cpu_ptr(m->maps);
BUG_ON(cm->online);
if (!cm->initialized) {
cm->available = m->alloc_size;
cm->available -= cm->managed + m->systembits_inalloc;
cm->initialized = true;
}
m->global_available += cm->available;
cm->online = true;
m->online_maps++;
trace_irq_matrix_online(m);
}
/**
* irq_matrix_offline - Bring the local CPU matrix offline
* @m: Matrix pointer
*/
void irq_matrix_offline(struct irq_matrix *m)
{
struct cpumap *cm = this_cpu_ptr(m->maps);
/* Update the global available size */
m->global_available -= cm->available;
cm->online = false;
m->online_maps--;
trace_irq_matrix_offline(m);
}
static unsigned int matrix_alloc_area(struct irq_matrix *m, struct cpumap *cm,
unsigned int num, bool managed)
{
unsigned int area, start = m->alloc_start;
unsigned int end = m->alloc_end;
bitmap_or(m->scratch_map, cm->managed_map, m->system_map, end);
bitmap_or(m->scratch_map, m->scratch_map, cm->alloc_map, end);
area = bitmap_find_next_zero_area(m->scratch_map, end, start, num, 0);
if (area >= end)
return area;
if (managed)
bitmap_set(cm->managed_map, area, num);
else
bitmap_set(cm->alloc_map, area, num);
return area;
}
/* Find the best CPU which has the lowest vector allocation count */
static unsigned int matrix_find_best_cpu(struct irq_matrix *m,
const struct cpumask *msk)
{
unsigned int cpu, best_cpu, maxavl = 0;
struct cpumap *cm;
best_cpu = UINT_MAX;
for_each_cpu(cpu, msk) {
cm = per_cpu_ptr(m->maps, cpu);
if (!cm->online || cm->available <= maxavl)
continue;
best_cpu = cpu;
maxavl = cm->available;
}
return best_cpu;
}
/* Find the best CPU which has the lowest number of managed IRQs allocated */
static unsigned int matrix_find_best_cpu_managed(struct irq_matrix *m,
const struct cpumask *msk)
{
unsigned int cpu, best_cpu, allocated = UINT_MAX;
struct cpumap *cm;
best_cpu = UINT_MAX;
for_each_cpu(cpu, msk) {
cm = per_cpu_ptr(m->maps, cpu);
if (!cm->online || cm->managed_allocated > allocated)
continue;
best_cpu = cpu;
allocated = cm->managed_allocated;
}
return best_cpu;
}
/**
* irq_matrix_assign_system - Assign system wide entry in the matrix
* @m: Matrix pointer
* @bit: Which bit to reserve
* @replace: Replace an already allocated vector with a system
* vector at the same bit position.
*
* The BUG_ON()s below are on purpose. If this goes wrong in the
* early boot process, then the chance to survive is about zero.
* If this happens when the system is life, it's not much better.
*/
void irq_matrix_assign_system(struct irq_matrix *m, unsigned int bit,
bool replace)
{
struct cpumap *cm = this_cpu_ptr(m->maps);
BUG_ON(bit > m->matrix_bits);
BUG_ON(m->online_maps > 1 || (m->online_maps && !replace));
set_bit(bit, m->system_map);
if (replace) {
BUG_ON(!test_and_clear_bit(bit, cm->alloc_map));
cm->allocated--;
m->total_allocated--;
}
if (bit >= m->alloc_start && bit < m->alloc_end)
m->systembits_inalloc++;
trace_irq_matrix_assign_system(bit, m);
}
/**
* irq_matrix_reserve_managed - Reserve a managed interrupt in a CPU map
* @m: Matrix pointer
* @msk: On which CPUs the bits should be reserved.
*
* Can be called for offline CPUs. Note, this will only reserve one bit
* on all CPUs in @msk, but it's not guaranteed that the bits are at the
* same offset on all CPUs
*/
int irq_matrix_reserve_managed(struct irq_matrix *m, const struct cpumask *msk)
{
unsigned int cpu, failed_cpu;
for_each_cpu(cpu, msk) {
struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
unsigned int bit;
bit = matrix_alloc_area(m, cm, 1, true);
if (bit >= m->alloc_end)
goto cleanup;
cm->managed++;
if (cm->online) {
cm->available--;
m->global_available--;
}
trace_irq_matrix_reserve_managed(bit, cpu, m, cm);
}
return 0;
cleanup:
failed_cpu = cpu;
for_each_cpu(cpu, msk) {
if (cpu == failed_cpu)
break;
irq_matrix_remove_managed(m, cpumask_of(cpu));
}
return -ENOSPC;
}
/**
* irq_matrix_remove_managed - Remove managed interrupts in a CPU map
* @m: Matrix pointer
* @msk: On which CPUs the bits should be removed
*
* Can be called for offline CPUs
*
* This removes not allocated managed interrupts from the map. It does
* not matter which one because the managed interrupts free their
* allocation when they shut down. If not, the accounting is screwed,
* but all what can be done at this point is warn about it.
*/
void irq_matrix_remove_managed(struct irq_matrix *m, const struct cpumask *msk)
{
unsigned int cpu;
for_each_cpu(cpu, msk) {
struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
unsigned int bit, end = m->alloc_end;
if (WARN_ON_ONCE(!cm->managed))
continue;
/* Get managed bit which are not allocated */
bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
bit = find_first_bit(m->scratch_map, end);
if (WARN_ON_ONCE(bit >= end))
continue;
clear_bit(bit, cm->managed_map);
cm->managed--;
if (cm->online) {
cm->available++;
m->global_available++;
}
trace_irq_matrix_remove_managed(bit, cpu, m, cm);
}
}
/**
* irq_matrix_alloc_managed - Allocate a managed interrupt in a CPU map
* @m: Matrix pointer
* @msk: Which CPUs to search in
* @mapped_cpu: Pointer to store the CPU for which the irq was allocated
*/
int irq_matrix_alloc_managed(struct irq_matrix *m, const struct cpumask *msk,
unsigned int *mapped_cpu)
{
unsigned int bit, cpu, end;
struct cpumap *cm;
if (cpumask_empty(msk))
return -EINVAL;
cpu = matrix_find_best_cpu_managed(m, msk);
if (cpu == UINT_MAX)
return -ENOSPC;
cm = per_cpu_ptr(m->maps, cpu);
end = m->alloc_end;
/* Get managed bit which are not allocated */
bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
bit = find_first_bit(m->scratch_map, end);
if (bit >= end)
return -ENOSPC;
set_bit(bit, cm->alloc_map);
cm->allocated++;
cm->managed_allocated++;
m->total_allocated++;
*mapped_cpu = cpu;
trace_irq_matrix_alloc_managed(bit, cpu, m, cm);
return bit;
}
/**
* irq_matrix_assign - Assign a preallocated interrupt in the local CPU map
* @m: Matrix pointer
* @bit: Which bit to mark
*
* This should only be used to mark preallocated vectors
*/
void irq_matrix_assign(struct irq_matrix *m, unsigned int bit)
{
struct cpumap *cm = this_cpu_ptr(m->maps);
if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
return;
if (WARN_ON_ONCE(test_and_set_bit(bit, cm->alloc_map)))
return;
cm->allocated++;
m->total_allocated++;
cm->available--;
m->global_available--;
trace_irq_matrix_assign(bit, smp_processor_id(), m, cm);
}
/**
* irq_matrix_reserve - Reserve interrupts
* @m: Matrix pointer
*
* This is merely a book keeping call. It increments the number of globally
* reserved interrupt bits w/o actually allocating them. This allows to
* setup interrupt descriptors w/o assigning low level resources to it.
* The actual allocation happens when the interrupt gets activated.
*/
void irq_matrix_reserve(struct irq_matrix *m)
{
if (m->global_reserved == m->global_available)
pr_warn("Interrupt reservation exceeds available resources\n");
m->global_reserved++;
trace_irq_matrix_reserve(m);
}
/**
* irq_matrix_remove_reserved - Remove interrupt reservation
* @m: Matrix pointer
*
* This is merely a book keeping call. It decrements the number of globally
* reserved interrupt bits. This is used to undo irq_matrix_reserve() when the
* interrupt was never in use and a real vector allocated, which undid the
* reservation.
*/
void irq_matrix_remove_reserved(struct irq_matrix *m)
{
m->global_reserved--;
trace_irq_matrix_remove_reserved(m);
}
/**
* irq_matrix_alloc - Allocate a regular interrupt in a CPU map
* @m: Matrix pointer
* @msk: Which CPUs to search in
* @reserved: Allocate previously reserved interrupts
* @mapped_cpu: Pointer to store the CPU for which the irq was allocated
*/
int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
bool reserved, unsigned int *mapped_cpu)
{
unsigned int cpu, bit;
struct cpumap *cm;
/*
* Not required in theory, but matrix_find_best_cpu() uses
* for_each_cpu() which ignores the cpumask on UP .
*/
if (cpumask_empty(msk))
return -EINVAL;
cpu = matrix_find_best_cpu(m, msk);
if (cpu == UINT_MAX)
return -ENOSPC;
cm = per_cpu_ptr(m->maps, cpu);
bit = matrix_alloc_area(m, cm, 1, false);
if (bit >= m->alloc_end)
return -ENOSPC;
cm->allocated++;
cm->available--;
m->total_allocated++;
m->global_available--;
if (reserved)
m->global_reserved--;
*mapped_cpu = cpu;
trace_irq_matrix_alloc(bit, cpu, m, cm);
return bit;
}
/**
* irq_matrix_free - Free allocated interrupt in the matrix
* @m: Matrix pointer
* @cpu: Which CPU map needs be updated
* @bit: The bit to remove
* @managed: If true, the interrupt is managed and not accounted
* as available.
*/
void irq_matrix_free(struct irq_matrix *m, unsigned int cpu,
unsigned int bit, bool managed)
{
struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
return;
if (WARN_ON_ONCE(!test_and_clear_bit(bit, cm->alloc_map)))
return;
cm->allocated--;
if(managed)
cm->managed_allocated--;
if (cm->online)
m->total_allocated--;
if (!managed) {
cm->available++;
if (cm->online)
m->global_available++;
}
trace_irq_matrix_free(bit, cpu, m, cm);
}
/**
* irq_matrix_available - Get the number of globally available irqs
* @m: Pointer to the matrix to query
* @cpudown: If true, the local CPU is about to go down, adjust
* the number of available irqs accordingly
*/
unsigned int irq_matrix_available(struct irq_matrix *m, bool cpudown)
{
struct cpumap *cm = this_cpu_ptr(m->maps);
if (!cpudown)
return m->global_available;
return m->global_available - cm->available;
}
/**
* irq_matrix_reserved - Get the number of globally reserved irqs
* @m: Pointer to the matrix to query
*/
unsigned int irq_matrix_reserved(struct irq_matrix *m)
{
return m->global_reserved;
}
/**
* irq_matrix_allocated - Get the number of allocated non-managed irqs on the local CPU
* @m: Pointer to the matrix to search
*
* This returns number of allocated non-managed interrupts.
*/
unsigned int irq_matrix_allocated(struct irq_matrix *m)
{
struct cpumap *cm = this_cpu_ptr(m->maps);
return cm->allocated - cm->managed_allocated;
}
#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
/**
* irq_matrix_debug_show - Show detailed allocation information
* @sf: Pointer to the seq_file to print to
* @m: Pointer to the matrix allocator
* @ind: Indentation for the print format
*
* Note, this is a lockless snapshot.
*/
void irq_matrix_debug_show(struct seq_file *sf, struct irq_matrix *m, int ind)
{
unsigned int nsys = bitmap_weight(m->system_map, m->matrix_bits);
int cpu;
seq_printf(sf, "Online bitmaps: %6u\n", m->online_maps);
seq_printf(sf, "Global available: %6u\n", m->global_available);
seq_printf(sf, "Global reserved: %6u\n", m->global_reserved);
seq_printf(sf, "Total allocated: %6u\n", m->total_allocated);
seq_printf(sf, "System: %u: %*pbl\n", nsys, m->matrix_bits,
m->system_map);
seq_printf(sf, "%*s| CPU | avl | man | mac | act | vectors\n", ind, " ");
cpus_read_lock();
for_each_online_cpu(cpu) {
struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
seq_printf(sf, "%*s %4d %4u %4u %4u %4u %*pbl\n", ind, " ",
cpu, cm->available, cm->managed,
cm->managed_allocated, cm->allocated,
m->matrix_bits, cm->alloc_map);
}
cpus_read_unlock();
}
#endif
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