4.4-stable review patch. If anyone has any objections, please let me know.
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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: