| From 1033be58992f818dc564196ded2bcc3f360bc297 Mon Sep 17 00:00:00 2001 |
| From: Bartosz Golaszewski <bgolaszewski@baylibre.com> |
| Date: Fri, 4 Jan 2019 11:24:20 +0100 |
| Subject: gpiolib: fix line event timestamps for nested irqs |
| |
| From: Bartosz Golaszewski <bgolaszewski@baylibre.com> |
| |
| commit 1033be58992f818dc564196ded2bcc3f360bc297 upstream. |
| |
| Nested interrupts run inside the calling thread's context and the top |
| half handler is never called which means that we never read the |
| timestamp. |
| |
| This issue came up when trying to read line events from a gpiochip |
| using regmap_irq_chip for interrupts. |
| |
| Fix it by reading the timestamp from the irq thread function if it's |
| still 0 by the time the second handler is called. |
| |
| Fixes: d58f2bf261fd ("gpio: Timestamp events in hardirq handler") |
| Cc: stable@vger.kernel.org |
| Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/gpio/gpiolib.c | 9 ++++++++- |
| 1 file changed, 8 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/gpio/gpiolib.c |
| +++ b/drivers/gpio/gpiolib.c |
| @@ -828,7 +828,14 @@ static irqreturn_t lineevent_irq_thread( |
| /* Do not leak kernel stack to userspace */ |
| memset(&ge, 0, sizeof(ge)); |
| |
| - ge.timestamp = le->timestamp; |
| + /* |
| + * We may be running from a nested threaded interrupt in which case |
| + * we didn't get the timestamp from lineevent_irq_handler(). |
| + */ |
| + if (!le->timestamp) |
| + ge.timestamp = ktime_get_real_ns(); |
| + else |
| + ge.timestamp = le->timestamp; |
| |
| if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE |
| && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { |
