Re: [PATCH v14 13/15] arm64/delay: enable testing smp_cond_load_relaxed_timeout()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Conditionally exporting `__delay_cycles` and `arch_timer_evtstrm_available` only for KUnit prevents standard kernel modules from using generic atomic timeout APIs on arm64.
--

--- Patch [13]: [PATCH v14 13/15] arm64/delay: enable testing smp_cond_load_relaxed_timeout() ---
commit 66ad403e3794b9907fdbe044468423d2877131a1
Author: Ankur Arora <ankur.a.arora@oracle.com>

arm64/delay: enable testing smp_cond_load_relaxed_timeout()

This commit exports __delay_cycles() and arch_timer_evtstrm_available()
using EXPORT_SYMBOL_IF_KUNIT() to allow testing barrier timeout functions
as a module.

> diff --git a/arch/arm64/lib/delay.c b/arch/arm64/lib/delay.c
> index c660a7ea26dd6..dfb102ce30098 100644
> --- a/arch/arm64/lib/delay.c
> +++ b/arch/arm64/lib/delay.c
[ ... ]
> @@ -30,6 +31,7 @@ u64 notrace __delay_cycles(void)
>  	guard(preempt_notrace)();
>  	return __arch_counter_get_cntvct_stable();
>  }
> +EXPORT_SYMBOL_IF_KUNIT(__delay_cycles);

[Severity: Medium]
Will this cause linking errors for standard kernel modules that use generic
atomic timeout APIs when CONFIG_KUNIT is disabled?

If a module uses macros like smp_cond_load_relaxed_timeout(), they expand
inline into the compilation unit, which relies on __delay_cycles().
Restricting this export to KUnit could prevent non-test modules from
building on arm64.

>  
>  void __delay(unsigned long cycles)
>  {
[ ... ]
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 90aeff44a2764..1de63e1a2cd2f 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
[ ... ]
> @@ -896,6 +897,7 @@ bool arch_timer_evtstrm_available(void)
>  	 */
>  	return cpumask_test_cpu(raw_smp_processor_id(), &evtstrm_available);
>  }
> +EXPORT_SYMBOL_IF_KUNIT(arch_timer_evtstrm_available);

[Severity: Medium]
Could this also cause modpost failures for standard modules?

Like __delay_cycles(), arch_timer_evtstrm_available() may be called by the
inline expansion of generic barrier macros. Exporting it only for KUnit
restricts these generic APIs from being used in standard modules.

>  
>  static struct arch_timer_kvm_info arch_timer_kvm_info;
>

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260714073041.40250-1-ankur.a.arora@oracle.com?part=13