| From foo@baz Mon Apr 9 17:09:24 CEST 2018 |
| From: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> |
| Date: Fri, 19 May 2017 15:35:09 +0530 |
| Subject: rtc: opal: Handle disabled TPO in opal_get_tpo_time() |
| |
| From: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> |
| |
| |
| [ Upstream commit 6dc1cf6f932bb0ea4d8f5e913a0a401ecacd2f03 ] |
| |
| On PowerNV platform when Timed-Power-On(TPO) is disabled, read of |
| stored TPO yields value with all date components set to '0' inside |
| opal_get_tpo_time(). The function opal_to_tm() then converts it to an |
| offset from year 1900 yielding alarm-time == "1900-00-01 |
| 00:00:00". This causes problems with __rtc_read_alarm() that |
| expecting an offset from "1970-00-01 00:00:00" and returned alarm-time |
| results in a -ve value for time64_t. Which ultimately results in this |
| error reported in kernel logs with a seemingly garbage value: |
| |
| "rtc rtc0: invalid alarm value: -2-1--1041528741 |
| 2005511117:71582844:32" |
| |
| We fix this by explicitly handling the case of all alarm date-time |
| components being '0' inside opal_get_tpo_time() and returning -ENOENT |
| in such a case. This signals generic rtc that no alarm is set and it |
| bails out from the alarm initialization flow without reporting the |
| above error. |
| |
| Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> |
| Reported-by: Steve Best <sbest@redhat.com> |
| Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/rtc/rtc-opal.c | 10 ++++++++++ |
| 1 file changed, 10 insertions(+) |
| |
| --- a/drivers/rtc/rtc-opal.c |
| +++ b/drivers/rtc/rtc-opal.c |
| @@ -150,6 +150,16 @@ static int opal_get_tpo_time(struct devi |
| |
| y_m_d = be32_to_cpu(__y_m_d); |
| h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32); |
| + |
| + /* check if no alarm is set */ |
| + if (y_m_d == 0 && h_m_s_ms == 0) { |
| + pr_debug("No alarm is set\n"); |
| + rc = -ENOENT; |
| + goto exit; |
| + } else { |
| + pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms); |
| + } |
| + |
| opal_to_tm(y_m_d, h_m_s_ms, &alarm->time); |
| |
| exit: |
