On 23/09/19 06:57, Jianyong Wu (Arm Technology China) wrote: >> On 19/09/19 11:46, Jianyong Wu (Arm Technology China) wrote: >>>> On 18/09/19 11:57, Jianyong Wu (Arm Technology China) wrote: >>>>> Paolo Bonzini wrote: >>>>>> This is not Y2038-safe. Please use ktime_get_real_ts64 instead, >>>>>> and split the 64-bit seconds value between val[0] and val[1]. >>> >>> Val[] should be long not u32 I think, so in arm64 I can avoid that >>> Y2038_safe, but also need rewrite for arm32. >> >> I don't think there's anything inherently wrong with u32 val[], and as you >> notice it lets you reuse code between arm and arm64. It's up to you and >> Marc to decide. >> > To compatible 32-bit, Integrates second value and nanosecond value as a nanosecond value then split it into val[0] and val[1] and split cycle value into val[2] and val[3], > In this way, time will overflow at Y2262. > WDYT? So if I understand correctly you'd multiply by 10^9 (or better shift by 30) the nanoseconds. That works, but why not provide 5 output registers? Alternatively, take an address as input and write there. Finally, on x86 we added an argument for the CLOCK_* that is being read (currently only CLOCK_REALTIME, but having room for extensibility in the API is always nice). Paolo
