The branch main has been updated by andrew:
URL:
https://cgit.FreeBSD.org/src/commit/?id=0863dc10354ff458a3ddf8ef3b47044d7a615154
commit 0863dc10354ff458a3ddf8ef3b47044d7a615154
Author: Andrew Turner <and...@freebsd.org>
AuthorDate: 2025-01-13 05:35:27 +0000
Commit: Andrew Turner <and...@freebsd.org>
CommitDate: 2025-01-24 15:08:09 +0000
ithread: Allow some ithreads to sleep
Some ithreads need to hold a sleep mutex, e.g. when calling ACPI
methods. Allow ithreads to be marked as sleepable when this is known
to be safe.
Reviewed by: markj, jhb
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D48283
---
share/man/man9/intr_event.9 | 10 +++++++++-
sys/kern/kern_intr.c | 18 +++++++++++++-----
sys/sys/bus.h | 1 +
sys/sys/interrupt.h | 1 +
4 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/share/man/man9/intr_event.9 b/share/man/man9/intr_event.9
index d1964ce289a5..ba8faf877e6a 100644
--- a/share/man/man9/intr_event.9
+++ b/share/man/man9/intr_event.9
@@ -27,7 +27,7 @@
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
-.Dd October 30, 2022
+.Dd January 24, 2025
.Dt INTR_EVENT 9
.Os
.Sh NAME
@@ -295,6 +295,14 @@ from the handler's source triggers.
Presently, the
.Dv INTR_ENTROPY
flag is not valid for software interrupt handlers.
+The
+.Dv INTR_SLEEPABLE
+flag specifies that the interrupt ithread may sleep.
+Presently, the
+.Dv INTR_SLEEPABLE
+flag requires the
+.Dv INTR_EXCL
+flag to be set.
.Ss Handler Callbacks
Each
.Vt struct intr_event
diff --git a/sys/kern/kern_intr.c b/sys/kern/kern_intr.c
index ad0cc135167e..4ef37ac829b3 100644
--- a/sys/kern/kern_intr.c
+++ b/sys/kern/kern_intr.c
@@ -610,6 +610,12 @@ intr_event_add_handler(struct intr_event *ie, const char
*name,
if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
return (EINVAL);
+ if ((flags & INTR_SLEEPABLE) != 0 && (flags & INTR_EXCL) == 0) {
+ printf("%s: INTR_SLEEPABLE requires INTR_EXCL to be set\n",
+ __func__);
+ return (EINVAL);
+ }
+
/* Allocate and populate an interrupt handler structure. */
ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
ih->ih_filter = filter;
@@ -627,16 +633,18 @@ intr_event_add_handler(struct intr_event *ie, const char
*name,
if (flags & INTR_TYPE_NET)
ih->ih_flags |= IH_NET;
- /* We can only have one exclusive handler in a event. */
+ /* We can only have one exclusive or sleepable handler in a event. */
mtx_lock(&ie->ie_lock);
if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
- if ((flags & INTR_EXCL) ||
+ if ((flags & (INTR_EXCL | INTR_SLEEPABLE)) ||
(CK_SLIST_FIRST(&ie->ie_handlers)->ih_flags &
IH_EXCLUSIVE)) {
mtx_unlock(&ie->ie_lock);
free(ih, M_ITHREAD);
return (EINVAL);
}
}
+ if (flags & INTR_SLEEPABLE)
+ ie->ie_flags |= IE_SLEEPABLE;
/* Create a thread if we need one. */
while (ie->ie_thread == NULL && handler != NULL) {
@@ -1190,11 +1198,11 @@ static void
ithread_execute_handlers(struct proc *p, struct intr_event *ie)
{
- /* Interrupt handlers should not sleep. */
- if (!(ie->ie_flags & IE_SOFT))
+ /* Only specifically marked sleepable interrupt handlers can sleep. */
+ if (!(ie->ie_flags & (IE_SOFT | IE_SLEEPABLE)))
THREAD_NO_SLEEPING();
intr_event_execute_handlers(p, ie);
- if (!(ie->ie_flags & IE_SOFT))
+ if (!(ie->ie_flags & (IE_SOFT | IE_SLEEPABLE)))
THREAD_SLEEPING_OK();
/*
diff --git a/sys/sys/bus.h b/sys/sys/bus.h
index 8b32e10f1285..84df9e6956d3 100644
--- a/sys/sys/bus.h
+++ b/sys/sys/bus.h
@@ -277,6 +277,7 @@ enum intr_type {
INTR_EXCL = 256, /* exclusive interrupt */
INTR_MPSAFE = 512, /* this interrupt is SMP safe */
INTR_ENTROPY = 1024, /* this interrupt provides entropy */
+ INTR_SLEEPABLE = 2048, /* this interrupt handler can sleep */
INTR_MD1 = 4096, /* flag reserved for MD use */
INTR_MD2 = 8192, /* flag reserved for MD use */
INTR_MD3 = 16384, /* flag reserved for MD use */
diff --git a/sys/sys/interrupt.h b/sys/sys/interrupt.h
index 899d65e386e0..2e84faa78e38 100644
--- a/sys/sys/interrupt.h
+++ b/sys/sys/interrupt.h
@@ -129,6 +129,7 @@ struct intr_event {
/* Interrupt event flags kept in ie_flags. */
#define IE_SOFT 0x000001 /* Software interrupt. */
+#define IE_SLEEPABLE 0x000002 /* Sleepable ithread */
#define IE_ADDING_THREAD 0x000004 /* Currently building an
ithread. */
/* Flags to pass to swi_sched. */
