* [PATCH 1/2] rtc: tps6586x: fix possible race condition
@ 2018-05-17 20:48 Alexandre Belloni
2018-05-17 20:48 ` [PATCH 2/2] rtc: tps6586x: let the core handle rtc range Alexandre Belloni
0 siblings, 1 reply; 2+ messages in thread
From: Alexandre Belloni @ 2018-05-17 20:48 UTC (permalink / raw)
To: linux-rtc; +Cc: linux-kernel, Alexandre Belloni
The probe function is not allowed to fail after the RTC is registered
because the following may happen:
CPU0: CPU1:
sys_load_module()
do_init_module()
do_one_initcall()
cmos_do_probe()
rtc_device_register()
__register_chrdev()
cdev->owner = struct module*
open("/dev/rtc0")
rtc_device_unregister()
module_put()
free_module()
module_free(mod->module_core)
/* struct module *module is now
freed */
chrdev_open()
spin_lock(cdev_lock)
cdev_get()
try_module_get()
module_is_live()
/* dereferences already
freed struct module* */
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
drivers/rtc/rtc-tps6586x.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/rtc/rtc-tps6586x.c b/drivers/rtc/rtc-tps6586x.c
index 46a19adf9a96..9b741143f131 100644
--- a/drivers/rtc/rtc-tps6586x.c
+++ b/drivers/rtc/rtc-tps6586x.c
@@ -276,14 +276,15 @@ static int tps6586x_rtc_probe(struct platform_device *pdev)
device_init_wakeup(&pdev->dev, 1);
platform_set_drvdata(pdev, rtc);
- rtc->rtc = devm_rtc_device_register(&pdev->dev, dev_name(&pdev->dev),
- &tps6586x_rtc_ops, THIS_MODULE);
+ rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc->rtc)) {
ret = PTR_ERR(rtc->rtc);
- dev_err(&pdev->dev, "RTC device register: ret %d\n", ret);
+ dev_err(&pdev->dev, "RTC allocate device: ret %d\n", ret);
goto fail_rtc_register;
}
+ rtc->rtc->ops = &tps6586x_rtc_ops;
+
ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
tps6586x_rtc_irq,
IRQF_ONESHOT,
@@ -294,6 +295,13 @@ static int tps6586x_rtc_probe(struct platform_device *pdev)
goto fail_rtc_register;
}
disable_irq(rtc->irq);
+
+ ret = rtc_register_device(rtc->rtc);
+ if (ret) {
+ dev_err(&pdev->dev, "RTC device register: ret %d\n", ret);
+ goto fail_rtc_register;
+ }
+
return 0;
fail_rtc_register:
--
2.17.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH 2/2] rtc: tps6586x: let the core handle rtc range
2018-05-17 20:48 [PATCH 1/2] rtc: tps6586x: fix possible race condition Alexandre Belloni
@ 2018-05-17 20:48 ` Alexandre Belloni
0 siblings, 0 replies; 2+ messages in thread
From: Alexandre Belloni @ 2018-05-17 20:48 UTC (permalink / raw)
To: linux-rtc; +Cc: linux-kernel, Alexandre Belloni
Let the core handle offsetting and windowing the RTC range.
The RTC has a 40-bit counter counting at 1024 Hz. So its maximum value is
2^(40-10) - 1. Also, let the core handle the offset instead of coding it in
the callbacks. Keep the default epoch at the beginning of 2009 (this will
fail in 2043).
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
drivers/rtc/rtc-tps6586x.c | 27 +++++----------------------
1 file changed, 5 insertions(+), 22 deletions(-)
diff --git a/drivers/rtc/rtc-tps6586x.c b/drivers/rtc/rtc-tps6586x.c
index 9b741143f131..d6434e514a52 100644
--- a/drivers/rtc/rtc-tps6586x.c
+++ b/drivers/rtc/rtc-tps6586x.c
@@ -58,7 +58,6 @@ struct tps6586x_rtc {
struct rtc_device *rtc;
int irq;
bool irq_en;
- time64_t epoch_start;
};
static inline struct device *to_tps6586x_dev(struct device *dev)
@@ -68,7 +67,6 @@ static inline struct device *to_tps6586x_dev(struct device *dev)
static int tps6586x_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
- struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
struct device *tps_dev = to_tps6586x_dev(dev);
unsigned long long ticks = 0;
time64_t seconds;
@@ -88,14 +86,13 @@ static int tps6586x_rtc_read_time(struct device *dev, struct rtc_time *tm)
}
seconds = ticks >> 10;
- seconds += rtc->epoch_start;
- rtc_time_to_tm(seconds, tm);
+ rtc_time64_to_tm(seconds, tm);
+
return 0;
}
static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
- struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
struct device *tps_dev = to_tps6586x_dev(dev);
unsigned long long ticks;
time64_t seconds;
@@ -103,11 +100,6 @@ static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
int ret;
seconds = rtc_tm_to_time64(tm);
- if (seconds < rtc->epoch_start) {
- dev_err(dev, "requested time unsupported\n");
- return -EINVAL;
- }
- seconds -= rtc->epoch_start;
ticks = (unsigned long long)seconds << 10;
buff[0] = (ticks >> 32) & 0xff;
@@ -155,7 +147,6 @@ static int tps6586x_rtc_alarm_irq_enable(struct device *dev,
static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
- struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
struct device *tps_dev = to_tps6586x_dev(dev);
time64_t seconds;
unsigned long ticks;
@@ -168,18 +159,12 @@ static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
seconds = rtc_tm_to_time64(&alrm->time);
- if (alrm->enabled && (seconds < rtc->epoch_start)) {
- dev_err(dev, "can't set alarm to requested time\n");
- return -EINVAL;
- }
-
ret = tps6586x_rtc_alarm_irq_enable(dev, alrm->enabled);
if (ret < 0) {
dev_err(dev, "can't set alarm irq, err %d\n", ret);
return ret;
}
- seconds -= rtc->epoch_start;
ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD,
sizeof(rbuff), rbuff);
if (ret < 0) {
@@ -210,7 +195,6 @@ static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
- struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
struct device *tps_dev = to_tps6586x_dev(dev);
unsigned long ticks;
time64_t seconds;
@@ -225,7 +209,6 @@ static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
ticks = (buff[0] << 16) | (buff[1] << 8) | buff[2];
seconds = ticks >> 10;
- seconds += rtc->epoch_start;
rtc_time64_to_tm(seconds, &alrm->time);
return 0;
@@ -260,9 +243,6 @@ static int tps6586x_rtc_probe(struct platform_device *pdev)
rtc->dev = &pdev->dev;
rtc->irq = platform_get_irq(pdev, 0);
- /* Set epoch start as 00:00:00:01:01:2009 */
- rtc->epoch_start = mktime64(2009, 1, 1, 0, 0, 0);
-
/* 1 kHz tick mode, enable tick counting */
ret = tps6586x_update(tps_dev, RTC_CTRL,
RTC_ENABLE | OSC_SRC_SEL |
@@ -284,6 +264,9 @@ static int tps6586x_rtc_probe(struct platform_device *pdev)
}
rtc->rtc->ops = &tps6586x_rtc_ops;
+ rtc->rtc->range_max = (1ULL << 30) - 1; /* 30-bit seconds */
+ rtc->rtc->start_secs = mktime64(2009, 1, 1, 0, 0, 0);
+ rtc->rtc->set_start_time = true;
ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
tps6586x_rtc_irq,
--
2.17.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
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