Re: [PATCH] rtc: class: Make the time32 hctosys limit configurable

[sashiko-bot@kernel.org]

> On 32-bit systems with RTC_HCTOSYS enabled, rtc_hctosys() rejects
> RTC dates whose seconds value exceeds INT_MAX, even when userspace
> uses a 64-bit time_t. This leaves system time uninitialized by the RTC.
> 
> Commit b3a5ac42ab18 ("rtc: hctosys: Ensure system time doesn't overflow
> time_t") introduced this limit to protect time32 userspace from future
> RTC dates that can break boot. The same limit prevents systems with
> time64 userspace from initializing the clock from valid post-2038 dates.
> 
> Add RTC_HCTOSYS_TIME32_LIMIT for 32-bit kernels, defaulting to y to
> preserve the existing safeguard. Allow integrators to disable it once
> their entire userspace, including init, supports post-2038 dates.
> Warn on rejection with the RTC date and option name so users can
> identify the cause and find the setting.
> 
> Keep the option independent of COMPAT_32BIT_TIME. Userspace with a
> 64-bit time_t may still need legacy syscalls for operations that do
> not represent post-2038 dates.
> 
> Fixes: b3a5ac42ab18 ("rtc: hctosys: Ensure system time doesn't overflow time_t")
> Link: https://lore.kernel.org/all/20220908115337.1604277-1-arnd@kernel.org/
> Assisted-by: LLM
> Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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