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/*
* Copyright (C) 2017 Thomas Gleixner <tglx@linutronix.de>
*
* SPDX-License-Identifier: GPL-2.0
*/
#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>
#define IRQ_MATRIX_SIZE (BITS_TO_LONGS(IRQ_MATRIX_BITS) * sizeof(unsigned long))
struct cpumap {
unsigned int available;
unsigned int allocated;
unsigned int managed;
bool online;
unsigned long alloc_map[IRQ_MATRIX_SIZE];
unsigned long managed_map[IRQ_MATRIX_SIZE];
};
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 scratch_map[IRQ_MATRIX_SIZE];
unsigned long system_map[IRQ_MATRIX_SIZE];
};
#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)
{
struct irq_matrix *m;
if (matrix_bits > IRQ_MATRIX_BITS)
return NULL;
m = kzalloc(sizeof(*m), GFP_KERNEL);
if (!m)
return NULL;
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(*m->maps);
if (!m->maps) {
kfree(m);
return NULL;
}
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);
bitmap_zero(cm->alloc_map, m->matrix_bits);
cm->available = m->alloc_size - (cm->managed + m->systembits_inalloc);
cm->allocated = 0;
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;
}
/**
* 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
* @cpu: On which CPU the interrupt should be allocated
*/
int irq_matrix_alloc_managed(struct irq_matrix *m, unsigned int cpu)
{
struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
unsigned int bit, 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++;
m->total_allocated++;
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);
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