Messages in this thread Patch in this message |  | | From | Andrew Kim <> | Subject | [PATCH 1/1] rtc: add century field data boundary | Date | Tue, 4 Oct 2016 11:06:03 -0700 |
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According to ACPI specification, the century field data should be ranged 0-63. so if it's over this range, it could cause system RTC settings error including alarmwakeup settings. So it's required to have this boundary for safe RTC init settings.
Signed-off-by: Andrew Kim <andrew.kim@intel.com> --- arch/x86/kernel/rtc.c | 7 +++++-- drivers/rtc/rtc-mc146818-lib.c | 7 +++++-- include/linux/mc146818rtc.h | 2 ++ 3 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index 79c6311c..feac180 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -84,8 +84,11 @@ void mach_get_cmos_time(struct timespec *now) #ifdef CONFIG_ACPI if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID && - acpi_gbl_FADT.century) - century = CMOS_READ(acpi_gbl_FADT.century); + acpi_gbl_FADT.century) { + if ((century = CMOS_READ(acpi_gbl_FADT.century)) > + RTC_CENTURY_LIMIT) + century = 0; + } #endif status = CMOS_READ(RTC_CONTROL); diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index 2f1772a..1d83c2c 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -61,8 +61,11 @@ unsigned int mc146818_get_time(struct rtc_time *time) #endif #ifdef CONFIG_ACPI if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID && - acpi_gbl_FADT.century) - century = CMOS_READ(acpi_gbl_FADT.century); + acpi_gbl_FADT.century) { + if ((century = CMOS_READ(acpi_gbl_FADT.century)) > + RTC_CENTURY_LIMIT) + century = 0; + } #endif ctrl = CMOS_READ(RTC_CONTROL); spin_unlock_irqrestore(&rtc_lock, flags); diff --git a/include/linux/mc146818rtc.h b/include/linux/mc146818rtc.h index a585b4b..199065a 100644 --- a/include/linux/mc146818rtc.h +++ b/include/linux/mc146818rtc.h @@ -122,6 +122,8 @@ struct cmos_rtc_board_info { #define RTC_IO_EXTENT_USED RTC_IO_EXTENT #endif /* ARCH_RTC_LOCATION */ +#define RTC_CENTURY_LIMIT 0x3F + unsigned int mc146818_get_time(struct rtc_time *time); int mc146818_set_time(struct rtc_time *time); -- 1.9.1
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