The corner-case codepath was adjusting nexttick such that overflow
wouldn't occur when timer_mod() scaled the value back up. Remove a use
of GTIMER_SCALE and avoid unnecessary operations by calling
timer_mod_ns() directly.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 target/arm/helper.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index a089fb5a6909..65c4441a3896 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -2446,9 +2446,10 @@ static void gt_recalc_timer(ARMCPU *cpu, int timeridx)
          * timer expires we will reset the timer for any remaining period.
          */
         if (nexttick > INT64_MAX / GTIMER_SCALE) {
-            nexttick = INT64_MAX / GTIMER_SCALE;
+            timer_mod_ns(cpu->gt_timer[timeridx], INT64_MAX);
+        } else {
+            timer_mod(cpu->gt_timer[timeridx], nexttick);
         }
-        timer_mod(cpu->gt_timer[timeridx], nexttick);
         trace_arm_gt_recalc(timeridx, irqstate, nexttick);
     } else {
         /* Timer disabled: ISTATUS and timer output always clear */
-- 
2.20.1

On 28/11/2019 06:45, Andrew Jeffery wrote:
> The corner-case codepath was adjusting nexttick such that overflow
> wouldn't occur when timer_mod() scaled the value back up. Remove a use
> of GTIMER_SCALE and avoid unnecessary operations by calling
> timer_mod_ns() directly.
> 
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>

Reviewed-by: Cédric Le Goater <clg@kaod.org>


> ---
>  target/arm/helper.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index a089fb5a6909..65c4441a3896 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -2446,9 +2446,10 @@ static void gt_recalc_timer(ARMCPU *cpu, int timeridx)
>           * timer expires we will reset the timer for any remaining period.
>           */
>          if (nexttick > INT64_MAX / GTIMER_SCALE) {
> -            nexttick = INT64_MAX / GTIMER_SCALE;
> +            timer_mod_ns(cpu->gt_timer[timeridx], INT64_MAX);
> +        } else {
> +            timer_mod(cpu->gt_timer[timeridx], nexttick);
>          }
> -        timer_mod(cpu->gt_timer[timeridx], nexttick);
>          trace_arm_gt_recalc(timeridx, irqstate, nexttick);
>      } else {
>          /* Timer disabled: ISTATUS and timer output always clear */
>