Commit 5b8843fc authored by Jacky Bai's avatar Jacky Bai Committed by Daniel Lezcano
Browse files

clocksource/drivers/imx-tpm: Fix return -ETIME when delta exceeds INT_MAX 



In tpm_set_next_event(delta), return -ETIME by wrong cast to int when delta
is larger than INT_MAX.

For example:

tpm_set_next_event(delta = 0xffff_fffe)
{
        ...
        next = tpm_read_counter(); // assume next is 0x10
        next += delta; // next will 0xffff_fffe + 0x10 = 0x1_0000_000e
        now = tpm_read_counter();  // now is 0x10
        ...

        return (int)(next - now) <= 0 ? -ETIME : 0;
                     ^^^^^^^^^^
                     0x1_0000_000e - 0x10 = 0xffff_fffe, which is -2 when
                     cast to int. So return -ETIME.
}

To fix this, introduce a 'prev' variable and check if 'now - prev' is
larger than delta.

Cc: stable@vger.kernel.org
Fixes: 059ab7b8 ("clocksource/drivers/imx-tpm: Add imx tpm timer support")
Signed-off-by: default avatarJacky Bai <ping.bai@nxp.com>
Reviewed-by: default avatarPeng Fan <peng.fan@nxp.com>
Reviewed-by: default avatarYe Li <ye.li@nxp.com>
Reviewed-by: default avatarJason Liu <jason.hui.liu@nxp.com>
Signed-off-by: default avatarFrank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240725193355.1436005-1-Frank.Li@nxp.com


Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
parent 471ef0b5

drivers/clocksource/timer-imx-tpm.c

+4 −4
Original line number Diff line number Diff line
@@ -83,10 +83,10 @@ static u64 notrace tpm_read_sched_clock(void) 
static int tpm_set_next_event(unsigned long delta,

				struct clock_event_device *evt)

{

	unsigned long next, now;

	unsigned long next, prev, now;



	next = tpm_read_counter();

	next += delta;

	prev = tpm_read_counter();

	next = prev + delta;

	writel(next, timer_base + TPM_C0V);

	now = tpm_read_counter();
@@ -96,7 +96,7 @@ static int tpm_set_next_event(unsigned long delta, 
	 * of writing CNT registers which may cause the min_delta event got

	 * missed, so we need add a ETIME check here in case it happened.

	 */

	return (int)(next - now) <= 0 ? -ETIME : 0;

	return (now - prev) >= delta ? -ETIME : 0;

}



static int tpm_set_state_oneshot(struct clock_event_device *evt)