Driver authors seem to get the ordering of irq_set_chained_handler()
and irq_set_handler_data() wrong - ordering the former before the
latter. This opens a race window where, if there is an interrupt
pending, the handler will be called between these two calls,
potentially resulting in an oops.
Provide a single interface to set both of these together, especially
as that's commonly what is required.
Signed-off-by: Russell King <rmk+ker...@arm.linux.org.uk>
---
It probably makes sense to convert everything over to this new
registration function, and kill all users of irq_set_chained_handler()
to prevent this problem recurring. Thoughts?
include/linux/irq.h | 9 +++++++++
kernel/irq/chip.c | 45 ++++++++++++++++++++++++++++++++++-----------
2 files changed, 43 insertions(+), 11 deletions(-)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 62c6901cab55..4942cbc379bb 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -517,6 +517,15 @@ irq_set_chained_handler(unsigned int irq,
irq_flow_handler_t handle)
__irq_set_handler(irq, handle, 1, NULL);
}
+/*
+ * Set a highlevel chained flow handler and its data for a given IRQ.
+ * (a chained handler is automatically enabled and set to
+ * IRQ_NOREQUEST, IRQ_NOPROBE, and IRQ_NOTHREAD)
+ */
+void
+irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
+ void *data);
+
void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set);
static inline void irq_set_status_flags(unsigned int irq, unsigned long set)
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index eb9a4ea394ab..92bed9010bc6 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -719,15 +719,9 @@ void handle_percpu_devid_irq(unsigned int irq, struct
irq_desc *desc)
}
void
-__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
- const char *name)
+__irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,
+ int is_chained, const char *name)
{
- unsigned long flags;
- struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
-
- if (!desc)
- return;
-
if (!handle) {
handle = handle_bad_irq;
} else {
@@ -749,13 +743,13 @@ __irq_set_handler(unsigned int irq, irq_flow_handler_t
handle, int is_chained,
* right away.
*/
if (WARN_ON(is_chained))
- goto out;
+ return;
/* Try the parent */
irq_data = irq_data->parent_data;
}
#endif
if (WARN_ON(!irq_data || irq_data->chip == &no_irq_chip))
- goto out;
+ return;
}
/* Uninstall? */
@@ -774,12 +768,41 @@ __irq_set_handler(unsigned int irq, irq_flow_handler_t
handle, int is_chained,
irq_settings_set_nothread(desc);
irq_startup(desc, true);
}
-out:
+}
+
+void
+__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
+ const char *name)
+{
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
+
+ if (!desc)
+ return;
+
+ __irq_do_set_handler(desc, handle, is_chained, name);
irq_put_desc_busunlock(desc, flags);
}
EXPORT_SYMBOL_GPL(__irq_set_handler);
void
+irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
+ void *data)
+{
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
+
+ if (!desc)
+ return;
+
+ __irq_do_set_handler(desc, handle, 1, NULL);
+ desc->irq_data.handler_data = data;
+
+ irq_put_desc_busunlock(desc, flags);
+}
+EXPORT_SYMBOL_GPL(irq_set_chained_handler_and_data);
+
+void
irq_set_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
irq_flow_handler_t handle, const char *name)
{
--
2.1.0
--
To unsubscribe from this list: send the line "unsubscribe linux-tegra" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
