vsyscall

https://alittleresearcher.blogspot.com/2017/04/linux-vdso-and-vsyscall-history.html　中详细描述了vsyscall的由来。

vsyscall固定地址：0xffffffffff600000，有三个函数

0xffffffffff600000，0xffffffffff600000+400,0xffffffffff600000+800

vsyscall int gettimeofday(struct timeval *tv, struct timezone *tz);

vsyscall + 400 time函数定义：time_t time(time_t *tloc)

vsyscall + 800 getcpu函数定义:

int getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache);

https://alittleresearcher.blogspot.com/2017/04/linux-vdso-and-vsyscall-history.html