From eabdd0252a2c3f8fb03b83781019243d47737e80 Mon Sep 17 00:00:00 2001 From: Yidi Lin Date: Thu, 2 Nov 2023 14:17:02 +0800 Subject: libpayload/libc/time: Fix possible overflow in multiplication The value from raw_read_cntfrq_el0() could be large enough to cause overflow when multiplied by USECS_PER_SEC. To prevent this, both USECS_PER_SEC and hz can be reduced by dividing them by their GCD. This patch also modifies the return type of `timer_hz()` from `uint64_t` to `uint32_t`, assuming that in practice the timestamp counter should never be that fast. BUG=b:307790895 TEST=boot to kernel and check the timestamps from `cbmem` Change-Id: Ia55532490651fcf47128b83a8554751f050bcc89 Signed-off-by: Yidi Lin Reviewed-on: https://review.coreboot.org/c/coreboot/+/78888 Reviewed-by: Julius Werner Reviewed-by: Yu-Ping Wu Tested-by: build bot (Jenkins) --- payloads/libpayload/drivers/timer/generic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'payloads/libpayload/drivers/timer/generic.c') diff --git a/payloads/libpayload/drivers/timer/generic.c b/payloads/libpayload/drivers/timer/generic.c index ef9eda54ad..bd5674be8c 100644 --- a/payloads/libpayload/drivers/timer/generic.c +++ b/payloads/libpayload/drivers/timer/generic.c @@ -33,7 +33,7 @@ #include #include -uint64_t timer_hz(void) +uint32_t timer_hz(void) { /* libc/time.c currently requires all timers to be at least 1MHz. */ assert(CONFIG_LP_TIMER_GENERIC_HZ >= 1000000); -- cgit v1.2.3