linux/kernel/irq/ipi.c
Matt Redfearn 4589f450fb genirq: Dont allow affinity mask to be updated on IPIs
The IPI domain re-purposes the IRQ affinity to signify the mask of CPUs
that this IPI will deliver to. This must not be modified before the IPI
is destroyed again, so set the IRQ_NO_BALANCING flag to prevent the
affinity being overwritten by setup_affinity().

Without this, if an IPI is reserved for a single target CPU, then
allocated using __setup_irq(), the affinity is overwritten with
cpu_online_mask. When ipi_destroy() is subsequently called on a
multi-cpu system, it will attempt to free cpumask_weight() IRQs
that were never allocated, and crash.

Fixes: d17bf24e69 ("genirq: Add a new generic IPI reservation code to irq core")
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: jason@lakedaemon.net
Cc: marc.zyngier@arm.com
Cc: ralf@linux-mips.org
Cc: Qais Yousef <qsyousef@gmail.com>
Cc: lisa.parratt@imgtec.com
Link: http://lkml.kernel.org/r/1461229712-13057-1-git-send-email-matt.redfearn@imgtec.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-04-21 12:05:15 +02:00

328 lines
8.7 KiB
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 0 on failure
*/
unsigned 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 0;
}
if (!cpumask_subset(dest, cpu_possible_mask)) {
pr_warn("Reservation is not in possible_cpu_mask\n");
return 0;
}
nr_irqs = cpumask_weight(dest);
if (!nr_irqs) {
pr_warn("Reservation for empty destination mask\n");
return 0;
}
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 0;
}
}
virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE);
if (virq <= 0) {
pr_warn("Can't reserve IPI, failed to alloc descs\n");
return 0;
}
virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
(void *) dest, true);
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 0;
}
/**
* irq_destroy_ipi() - unreserve an IPI that was previously allocated
* @irq: linux irq number to be destroyed
*
* Return the IPIs allocated with irq_reserve_ipi() to the system destroying
* all virqs associated with them.
*/
void irq_destroy_ipi(unsigned int irq)
{
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;
domain = data->domain;
if (WARN_ON(domain == NULL))
return;
if (!irq_domain_is_ipi(domain)) {
pr_warn("Trying to destroy a non IPI domain!\n");
return;
}
if (irq_domain_is_ipi_per_cpu(domain))
nr_irqs = cpumask_weight(ipimask);
else
nr_irqs = 1;
irq_domain_free_irqs(irq, nr_irqs);
}
/**
* 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;
}
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;
}
/**
* __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;
}
/**
* 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;
}
/**
* 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);
}
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);
}
EXPORT_SYMBOL_GPL(ipi_send_mask);