diff options
| -rw-r--r-- | src/arch/arm64/arch_timer.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/src/arch/arm64/arch_timer.c b/src/arch/arm64/arch_timer.c index 089afee385..3eb5656a15 100644 --- a/src/arch/arm64/arch_timer.c +++ b/src/arch/arm64/arch_timer.c @@ -1,12 +1,29 @@ /* SPDX-License-Identifier: GPL-2.0-only */ -#include <timer.h> #include <arch/lib_helpers.h> +#include <commonlib/bsd/gcd.h> +#include <timer.h> void timer_monotonic_get(struct mono_time *mt) { uint64_t tvalue = raw_read_cntpct_el0(); - uint32_t tfreq = raw_read_cntfrq_el0(); - long usecs = (tvalue * 1000000) / tfreq; + static uint32_t tfreq, mult; + uint32_t div; + + /* + * 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 tfreq can be reduced by dividing them by + * their GCD. + */ + if (tfreq == 0) { + tfreq = raw_read_cntfrq_el0(); + mult = USECS_PER_SEC; + div = gcd32(tfreq, mult); + tfreq /= div; + mult /= div; + } + + long usecs = (tvalue * mult) / tfreq; mono_time_set_usecs(mt, usecs); } |