mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-28 07:04:00 +08:00
83e3fa6f01
Builds of the MIPS platform ip32_defconfig fails as of commit0195c00244("Merge tag 'split-asm_system_h ...") because MIPS xchg() macro uses BUILD_BUG_ON and it was moved in commitb81947c646("Disintegrate asm/system.h for MIPS"). The root cause is that the system.h split wasn't tested on a baseline with commit6c03438ede("kernel.h: doesn't explicitly use bug.h, so don't include it.") Since this file uses BUG code in several other places besides the xchg call, simply make the inclusion explicit. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
145 lines
3.1 KiB
C
145 lines
3.1 KiB
C
/*
|
|
* Copyright (C) 2010 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
|
|
*
|
|
* Provides a framework for enqueueing and running callbacks from hardirq
|
|
* context. The enqueueing is NMI-safe.
|
|
*/
|
|
|
|
#include <linux/bug.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/export.h>
|
|
#include <linux/irq_work.h>
|
|
#include <linux/percpu.h>
|
|
#include <linux/hardirq.h>
|
|
#include <asm/processor.h>
|
|
|
|
/*
|
|
* An entry can be in one of four states:
|
|
*
|
|
* free NULL, 0 -> {claimed} : free to be used
|
|
* claimed NULL, 3 -> {pending} : claimed to be enqueued
|
|
* pending next, 3 -> {busy} : queued, pending callback
|
|
* busy NULL, 2 -> {free, claimed} : callback in progress, can be claimed
|
|
*/
|
|
|
|
#define IRQ_WORK_PENDING 1UL
|
|
#define IRQ_WORK_BUSY 2UL
|
|
#define IRQ_WORK_FLAGS 3UL
|
|
|
|
static DEFINE_PER_CPU(struct llist_head, irq_work_list);
|
|
|
|
/*
|
|
* Claim the entry so that no one else will poke at it.
|
|
*/
|
|
static bool irq_work_claim(struct irq_work *work)
|
|
{
|
|
unsigned long flags, nflags;
|
|
|
|
for (;;) {
|
|
flags = work->flags;
|
|
if (flags & IRQ_WORK_PENDING)
|
|
return false;
|
|
nflags = flags | IRQ_WORK_FLAGS;
|
|
if (cmpxchg(&work->flags, flags, nflags) == flags)
|
|
break;
|
|
cpu_relax();
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void __weak arch_irq_work_raise(void)
|
|
{
|
|
/*
|
|
* Lame architectures will get the timer tick callback
|
|
*/
|
|
}
|
|
|
|
/*
|
|
* Queue the entry and raise the IPI if needed.
|
|
*/
|
|
static void __irq_work_queue(struct irq_work *work)
|
|
{
|
|
bool empty;
|
|
|
|
preempt_disable();
|
|
|
|
empty = llist_add(&work->llnode, &__get_cpu_var(irq_work_list));
|
|
/* The list was empty, raise self-interrupt to start processing. */
|
|
if (empty)
|
|
arch_irq_work_raise();
|
|
|
|
preempt_enable();
|
|
}
|
|
|
|
/*
|
|
* Enqueue the irq_work @entry, returns true on success, failure when the
|
|
* @entry was already enqueued by someone else.
|
|
*
|
|
* Can be re-enqueued while the callback is still in progress.
|
|
*/
|
|
bool irq_work_queue(struct irq_work *work)
|
|
{
|
|
if (!irq_work_claim(work)) {
|
|
/*
|
|
* Already enqueued, can't do!
|
|
*/
|
|
return false;
|
|
}
|
|
|
|
__irq_work_queue(work);
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(irq_work_queue);
|
|
|
|
/*
|
|
* Run the irq_work entries on this cpu. Requires to be ran from hardirq
|
|
* context with local IRQs disabled.
|
|
*/
|
|
void irq_work_run(void)
|
|
{
|
|
struct irq_work *work;
|
|
struct llist_head *this_list;
|
|
struct llist_node *llnode;
|
|
|
|
this_list = &__get_cpu_var(irq_work_list);
|
|
if (llist_empty(this_list))
|
|
return;
|
|
|
|
BUG_ON(!in_irq());
|
|
BUG_ON(!irqs_disabled());
|
|
|
|
llnode = llist_del_all(this_list);
|
|
while (llnode != NULL) {
|
|
work = llist_entry(llnode, struct irq_work, llnode);
|
|
|
|
llnode = llist_next(llnode);
|
|
|
|
/*
|
|
* Clear the PENDING bit, after this point the @work
|
|
* can be re-used.
|
|
*/
|
|
work->flags = IRQ_WORK_BUSY;
|
|
work->func(work);
|
|
/*
|
|
* Clear the BUSY bit and return to the free state if
|
|
* no-one else claimed it meanwhile.
|
|
*/
|
|
(void)cmpxchg(&work->flags, IRQ_WORK_BUSY, 0);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(irq_work_run);
|
|
|
|
/*
|
|
* Synchronize against the irq_work @entry, ensures the entry is not
|
|
* currently in use.
|
|
*/
|
|
void irq_work_sync(struct irq_work *work)
|
|
{
|
|
WARN_ON_ONCE(irqs_disabled());
|
|
|
|
while (work->flags & IRQ_WORK_BUSY)
|
|
cpu_relax();
|
|
}
|
|
EXPORT_SYMBOL_GPL(irq_work_sync);
|