Release 4.15 kernel/irq/ipi.c
/*
* linux/kernel/irq/ipi.c
*
* Copyright (C) 2015 Imagination Technologies Ltd
* Author: Qais Yousef <qais.yousef@imgtec.com>
*
* This file contains driver APIs to the IPI subsystem.
*/
#define pr_fmt(fmt) "genirq/ipi: " fmt
#include <linux/irqdomain.h>
#include <linux/irq.h>
/**
* irq_reserve_ipi() - Setup an IPI to destination cpumask
* @domain: IPI domain
* @dest: cpumask of cpus which can receive the IPI
*
* Allocate a virq that can be used to send IPI to any CPU in dest mask.
*
* On success it'll return linux irq number and error code on failure
*/
int irq_reserve_ipi(struct irq_domain *domain,
const struct cpumask *dest)
{
unsigned int nr_irqs, offset;
struct irq_data *data;
int virq, i;
if (!domain ||!irq_domain_is_ipi(domain)) {
pr_warn("Reservation on a non IPI domain\n");
return -EINVAL;
}
if (!cpumask_subset(dest, cpu_possible_mask)) {
pr_warn("Reservation is not in possible_cpu_mask\n");
return -EINVAL;
}
nr_irqs = cpumask_weight(dest);
if (!nr_irqs) {
pr_warn("Reservation for empty destination mask\n");
return -EINVAL;
}
if (irq_domain_is_ipi_single(domain)) {
/*
* If the underlying implementation uses a single HW irq on
* all cpus then we only need a single Linux irq number for
* it. We have no restrictions vs. the destination mask. The
* underlying implementation can deal with holes nicely.
*/
nr_irqs = 1;
offset = 0;
} else {
unsigned int next;
/*
* The IPI requires a seperate HW irq on each CPU. We require
* that the destination mask is consecutive. If an
* implementation needs to support holes, it can reserve
* several IPI ranges.
*/
offset = cpumask_first(dest);
/*
* Find a hole and if found look for another set bit after the
* hole. For now we don't support this scenario.
*/
next = cpumask_next_zero(offset, dest);
if (next < nr_cpu_ids)
next = cpumask_next(next, dest);
if (next < nr_cpu_ids) {
pr_warn("Destination mask has holes\n");
return -EINVAL;
}
}
virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE, NULL);
if (virq <= 0) {
pr_warn("Can't reserve IPI, failed to alloc descs\n");
return -ENOMEM;
}
virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
(void *) dest, true, NULL);
if (virq <= 0) {
pr_warn("Can't reserve IPI, failed to alloc hw irqs\n");
goto free_descs;
}
for (i = 0; i < nr_irqs; i++) {
data = irq_get_irq_data(virq + i);
cpumask_copy(data->common->affinity, dest);
data->common->ipi_offset = offset;
irq_set_status_flags(virq + i, IRQ_NO_BALANCING);
}
return virq;
free_descs:
irq_free_descs(virq, nr_irqs);
return -EBUSY;
}
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/**
* irq_destroy_ipi() - unreserve an IPI that was previously allocated
* @irq: linux irq number to be destroyed
* @dest: cpumask of cpus which should have the IPI removed
*
* The IPIs allocated with irq_reserve_ipi() are retuerned to the system
* destroying all virqs associated with them.
*
* Return 0 on success or error code on failure.
*/
int irq_destroy_ipi(unsigned int irq, const struct cpumask *dest)
{
struct irq_data *data = irq_get_irq_data(irq);
struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL;
struct irq_domain *domain;
unsigned int nr_irqs;
if (!irq || !data || !ipimask)
return -EINVAL;
domain = data->domain;
if (WARN_ON(domain == NULL))
return -EINVAL;
if (!irq_domain_is_ipi(domain)) {
pr_warn("Trying to destroy a non IPI domain!\n");
return -EINVAL;
}
if (WARN_ON(!cpumask_subset(dest, ipimask)))
/*
* Must be destroying a subset of CPUs to which this IPI
* was set up to target
*/
return -EINVAL;
if (irq_domain_is_ipi_per_cpu(domain)) {
irq = irq + cpumask_first(dest) - data->common->ipi_offset;
nr_irqs = cpumask_weight(dest);
} else {
nr_irqs = 1;
}
irq_domain_free_irqs(irq, nr_irqs);
return 0;
}
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/**
* ipi_get_hwirq - Get the hwirq associated with an IPI to a cpu
* @irq: linux irq number
* @cpu: the target cpu
*
* When dealing with coprocessors IPI, we need to inform the coprocessor of
* the hwirq it needs to use to receive and send IPIs.
*
* Returns hwirq value on success and INVALID_HWIRQ on failure.
*/
irq_hw_number_t ipi_get_hwirq(unsigned int irq, unsigned int cpu)
{
struct irq_data *data = irq_get_irq_data(irq);
struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL;
if (!data || !ipimask || cpu >= nr_cpu_ids)
return INVALID_HWIRQ;
if (!cpumask_test_cpu(cpu, ipimask))
return INVALID_HWIRQ;
/*
* Get the real hardware irq number if the underlying implementation
* uses a seperate irq per cpu. If the underlying implementation uses
* a single hardware irq for all cpus then the IPI send mechanism
* needs to take care of the cpu destinations.
*/
if (irq_domain_is_ipi_per_cpu(data->domain))
data = irq_get_irq_data(irq + cpu - data->common->ipi_offset);
return data ? irqd_to_hwirq(data) : INVALID_HWIRQ;
}
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EXPORT_SYMBOL_GPL(ipi_get_hwirq);
static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data,
const struct cpumask *dest, unsigned int cpu)
{
struct cpumask *ipimask = irq_data_get_affinity_mask(data);
if (!chip || !ipimask)
return -EINVAL;
if (!chip->ipi_send_single && !chip->ipi_send_mask)
return -EINVAL;
if (cpu >= nr_cpu_ids)
return -EINVAL;
if (dest) {
if (!cpumask_subset(dest, ipimask))
return -EINVAL;
} else {
if (!cpumask_test_cpu(cpu, ipimask))
return -EINVAL;
}
return 0;
}
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/**
* __ipi_send_single - send an IPI to a target Linux SMP CPU
* @desc: pointer to irq_desc of the IRQ
* @cpu: destination CPU, must in the destination mask passed to
* irq_reserve_ipi()
*
* This function is for architecture or core code to speed up IPI sending. Not
* usable from driver code.
*
* Returns zero on success and negative error number on failure.
*/
int __ipi_send_single(struct irq_desc *desc, unsigned int cpu)
{
struct irq_data *data = irq_desc_get_irq_data(desc);
struct irq_chip *chip = irq_data_get_irq_chip(data);
#ifdef DEBUG
/*
* Minimise the overhead by omitting the checks for Linux SMP IPIs.
* Since the callers should be arch or core code which is generally
* trusted, only check for errors when debugging.
*/
if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu)))
return -EINVAL;
#endif
if (!chip->ipi_send_single) {
chip->ipi_send_mask(data, cpumask_of(cpu));
return 0;
}
/* FIXME: Store this information in irqdata flags */
if (irq_domain_is_ipi_per_cpu(data->domain) &&
cpu != data->common->ipi_offset) {
/* use the correct data for that cpu */
unsigned irq = data->irq + cpu - data->common->ipi_offset;
data = irq_get_irq_data(irq);
}
chip->ipi_send_single(data, cpu);
return 0;
}
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/**
* ipi_send_mask - send an IPI to target Linux SMP CPU(s)
* @desc: pointer to irq_desc of the IRQ
* @dest: dest CPU(s), must be a subset of the mask passed to
* irq_reserve_ipi()
*
* This function is for architecture or core code to speed up IPI sending. Not
* usable from driver code.
*
* Returns zero on success and negative error number on failure.
*/
int __ipi_send_mask(struct irq_desc *desc, const struct cpumask *dest)
{
struct irq_data *data = irq_desc_get_irq_data(desc);
struct irq_chip *chip = irq_data_get_irq_chip(data);
unsigned int cpu;
#ifdef DEBUG
/*
* Minimise the overhead by omitting the checks for Linux SMP IPIs.
* Since the callers should be arch or core code which is generally
* trusted, only check for errors when debugging.
*/
if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0)))
return -EINVAL;
#endif
if (chip->ipi_send_mask) {
chip->ipi_send_mask(data, dest);
return 0;
}
if (irq_domain_is_ipi_per_cpu(data->domain)) {
unsigned int base = data->irq;
for_each_cpu(cpu, dest) {
unsigned irq = base + cpu - data->common->ipi_offset;
data = irq_get_irq_data(irq);
chip->ipi_send_single(data, cpu);
}
} else {
for_each_cpu(cpu, dest)
chip->ipi_send_single(data, cpu);
}
return 0;
}
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/**
* ipi_send_single - Send an IPI to a single CPU
* @virq: linux irq number from irq_reserve_ipi()
* @cpu: destination CPU, must in the destination mask passed to
* irq_reserve_ipi()
*
* Returns zero on success and negative error number on failure.
*/
int ipi_send_single(unsigned int virq, unsigned int cpu)
{
struct irq_desc *desc = irq_to_desc(virq);
struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL;
struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL;
if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu)))
return -EINVAL;
return __ipi_send_single(desc, cpu);
}
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EXPORT_SYMBOL_GPL(ipi_send_single);
/**
* ipi_send_mask - Send an IPI to target CPU(s)
* @virq: linux irq number from irq_reserve_ipi()
* @dest: dest CPU(s), must be a subset of the mask passed to
* irq_reserve_ipi()
*
* Returns zero on success and negative error number on failure.
*/
int ipi_send_mask(unsigned int virq, const struct cpumask *dest)
{
struct irq_desc *desc = irq_to_desc(virq);
struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL;
struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL;
if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0)))
return -EINVAL;
return __ipi_send_mask(desc, dest);
}
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EXPORT_SYMBOL_GPL(ipi_send_mask);
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