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| author | Finn Thain <fthain@telegraphics.com.au> | 2018-04-23 03:02:57 +0200 |
|---|---|---|
| committer | Geert Uytterhoeven <geert@linux-m68k.org> | 2018-05-22 10:31:50 +0200 |
| commit | b65769fc013edb7c2e5fdcd91ea6124ad76168f5 (patch) | |
| tree | b6ad02cfbf7a81d1a4f339d0873fabb71b8b549e /arch/m68k/kernel | |
| parent | m68k: Fix style, spelling, and grammar in siginfo_build_tests() (diff) | |
| download | linux-b65769fc013edb7c2e5fdcd91ea6124ad76168f5.tar.xz linux-b65769fc013edb7c2e5fdcd91ea6124ad76168f5.zip | |
m68k: Fix off-by-one calendar month
This fixes a bug in read_persistent_clock() which causes the system
clock to lag the Real Time Clock by one month. The problem was noticed
on a Mac, but theoretically it must also affect Atari, BVME6000 and Q40.
The tm_mon value in the struct rtc_time passed to mach_hwclk() is
zero-based, and atari_mste_hwclk(), atari_tt_hwclk(), bvme6000_hwclk(),
mac_hwclk() and q40_hwclk() all make this adjustment. Unfortunately,
dn_dummy_hwclk(), mvme147_hwclk(), mvme16x_hwclk(), sun3_hwclk() and
sun3x_hwclk() fail to decrement tm_mon. Also m68328_hwclk() assumes
a one-based tm_mon.
Bring these platforms into line and fix read_persistent_clock() so it
works correctly on all m68k platforms.
The datasheets for the RTC devices found on the affected platforms
all confirm that the year is stored as a value in the range 0-99 and
the month is stored as a value in the range 1-12. Please refer to the
datasheets for MC146818 (Apollo), DS1643 (MVME), ICM7170 (Sun 3)
and M48T02 (Sun 3x).
Reported-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Diffstat (limited to 'arch/m68k/kernel')
| -rw-r--r-- | arch/m68k/kernel/time.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/m68k/kernel/time.c b/arch/m68k/kernel/time.c index 97dd4e26f234..6b4389a6e8ea 100644 --- a/arch/m68k/kernel/time.c +++ b/arch/m68k/kernel/time.c @@ -74,17 +74,17 @@ static irqreturn_t timer_interrupt(int irq, void *dummy) void read_persistent_clock(struct timespec *ts) { struct rtc_time time; + ts->tv_sec = 0; ts->tv_nsec = 0; - if (mach_hwclk) { - mach_hwclk(0, &time); + if (!mach_hwclk) + return; + + mach_hwclk(0, &time); - if ((time.tm_year += 1900) < 1970) - time.tm_year += 100; - ts->tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday, - time.tm_hour, time.tm_min, time.tm_sec); - } + ts->tv_sec = mktime(time.tm_year + 1900, time.tm_mon + 1, time.tm_mday, + time.tm_hour, time.tm_min, time.tm_sec); } #if defined(CONFIG_ARCH_USES_GETTIMEOFFSET) && IS_ENABLED(CONFIG_RTC_DRV_GENERIC) |