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

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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: 059ab7b82e ("clocksource/drivers/imx-tpm: Add imx tpm timer support")
Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Jason Liu <jason.hui.liu@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240725193355.1436005-1-Frank.Li@nxp.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Jacky Bai 2024-07-25 15:33:54 -04:00 committed by Daniel Lezcano
parent 471ef0b5a8
commit 5b8843fcd4
1 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/clocksource/timer-imx-tpm.c
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@ -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)