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authorJohannes Berg <johannes.berg@intel.com>2020-12-13 22:18:18 +0100
committerRichard Weinberger <richard@nod.at>2020-12-13 22:42:06 +0100
commit11385539c024b6071dce538123a2043a8f52c9a1 (patch)
treef56c3d16a32fcf7566c4b6ed4c71f20857a968f2 /arch/um
parentcae20ba0a16cdb2c6d218ea3519bb0942f287b69 (diff)
downloadlinux-11385539c024b6071dce538123a2043a8f52c9a1.tar.bz2
um: time-travel: Correct time event IRQ delivery
Lockdep (on 5.10-rc) points out that we're delivering IRQs while IRQs are not even enabled, which clearly shouldn't happen. Defer the time event IRQ delivery until they actually are enabled. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/include/shared/common-offsets.h3
-rw-r--r--arch/um/include/shared/os.h3
-rw-r--r--arch/um/kernel/time.c38
-rw-r--r--arch/um/os-Linux/signal.c3
4 files changed, 47 insertions, 0 deletions
diff --git a/arch/um/include/shared/common-offsets.h b/arch/um/include/shared/common-offsets.h
index 4e99fe05576a..16a51a8c800f 100644
--- a/arch/um/include/shared/common-offsets.h
+++ b/arch/um/include/shared/common-offsets.h
@@ -40,3 +40,6 @@ DEFINE(UML_CONFIG_UML_X86, CONFIG_UML_X86);
#ifdef CONFIG_64BIT
DEFINE(UML_CONFIG_64BIT, CONFIG_64BIT);
#endif
+#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
+DEFINE(UML_CONFIG_UML_TIME_TRAVEL_SUPPORT, CONFIG_UML_TIME_TRAVEL_SUPPORT);
+#endif
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index bc25c960f7e0..13d86f94cf0f 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -342,4 +342,7 @@ extern void unblock_signals_trace(void);
extern void um_trace_signals_on(void);
extern void um_trace_signals_off(void);
+/* time-travel */
+extern void deliver_time_travel_irqs(void);
+
#endif
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index e48282308126..f4db89b5b5a6 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -31,6 +31,7 @@ static bool time_travel_start_set;
static unsigned long long time_travel_start;
static unsigned long long time_travel_time;
static LIST_HEAD(time_travel_events);
+static LIST_HEAD(time_travel_irqs);
static unsigned long long time_travel_timer_interval;
static unsigned long long time_travel_next_event;
static struct time_travel_event time_travel_timer_event;
@@ -324,6 +325,35 @@ void time_travel_periodic_timer(struct time_travel_event *e)
deliver_alarm();
}
+void deliver_time_travel_irqs(void)
+{
+ struct time_travel_event *e;
+ unsigned long flags;
+
+ /*
+ * Don't do anything for most cases. Note that because here we have
+ * to disable IRQs (and re-enable later) we'll actually recurse at
+ * the end of the function, so this is strictly necessary.
+ */
+ if (likely(list_empty(&time_travel_irqs)))
+ return;
+
+ local_irq_save(flags);
+ irq_enter();
+ while ((e = list_first_entry_or_null(&time_travel_irqs,
+ struct time_travel_event,
+ list))) {
+ WARN(e->time != time_travel_time,
+ "time moved from %lld to %lld before IRQ delivery\n",
+ time_travel_time, e->time);
+ list_del(&e->list);
+ e->pending = false;
+ e->fn(e);
+ }
+ irq_exit();
+ local_irq_restore(flags);
+}
+
static void time_travel_deliver_event(struct time_travel_event *e)
{
if (e == &time_travel_timer_event) {
@@ -332,6 +362,14 @@ static void time_travel_deliver_event(struct time_travel_event *e)
* by itself, so must handle it specially here
*/
e->fn(e);
+ } else if (irqs_disabled()) {
+ list_add_tail(&e->list, &time_travel_irqs);
+ /*
+ * set pending again, it was set to false when the
+ * event was deleted from the original list, but
+ * now it's still pending until we deliver the IRQ.
+ */
+ e->pending = true;
} else {
unsigned long flags;
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 510e956b4320..96f511d1aabe 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -271,6 +271,9 @@ void unblock_signals(void)
return;
signals_enabled = 1;
+#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
+ deliver_time_travel_irqs();
+#endif
/*
* We loop because the IRQ handler returns with interrupts off. So,