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ACPICA: Fix an off-by-one error in acpi_get_timer_duration().

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ACPICA commit b4fd33f3c2af014aeec978d46392d286fd7f52b3

Delta calculation has an off-by-one error when there is a rollover.
For example, when start_ticks is 0x00FFFFFF and end_ticks is 0x00000000
(for 24-bit timer), delta_ticks should be 1 (one) but it was 0 (zero).

Link: https://github.com/acpica/acpica/commit/b4fd33f3
Signed-off-by: Jung-uk Kim <jkim@free_BSD.org>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Jung-uk Kim 2017-11-17 15:40:14 -08:00 committed by Rafael J. Wysocki
parent 4fbd8d194f
commit 8f275615a6
1 changed files with 14 additions and 15 deletions
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29
drivers/acpi/acpica/hwtimer.c
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@ -150,10 +150,10 @@ ACPI_EXPORT_SYMBOL(acpi_get_timer)
*
******************************************************************************/
acpi_status
acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 *time_elapsed)
{
acpi_status status;
u32 delta_ticks;
u64 delta_ticks;
u64 quotient;
ACPI_FUNCTION_TRACE(acpi_get_timer_duration);
@ -168,30 +168,29 @@ acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
return_ACPI_STATUS(AE_SUPPORT);
}
if (start_ticks == end_ticks) {
*time_elapsed = 0;
return_ACPI_STATUS(AE_OK);
}
/*
* Compute Tick Delta:
* Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
*/
if (start_ticks < end_ticks) {
delta_ticks = end_ticks - start_ticks;
} else if (start_ticks > end_ticks) {
delta_ticks = end_ticks;
if (start_ticks > end_ticks) {
if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
/* 24-bit Timer */
delta_ticks =
(((0x00FFFFFF - start_ticks) +
end_ticks) & 0x00FFFFFF);
delta_ticks |= (u64)1 << 24;
} else {
/* 32-bit Timer */
delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks;
delta_ticks |= (u64)1 << 32;
}
} else { /* start_ticks == end_ticks */
*time_elapsed = 0;
return_ACPI_STATUS(AE_OK);
}
delta_ticks -= start_ticks;
/*
* Compute Duration (Requires a 64-bit multiply and divide):
@ -199,10 +198,10 @@ acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
* time_elapsed (microseconds) =
* (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
*/
status = acpi_ut_short_divide(((u64)delta_ticks) * ACPI_USEC_PER_SEC,
status = acpi_ut_short_divide(delta_ticks * ACPI_USEC_PER_SEC,
ACPI_PM_TIMER_FREQUENCY, &quotient, NULL);
*time_elapsed = (u32) quotient;
*time_elapsed = (u32)quotient;
return_ACPI_STATUS(status);
}