[Linux] vdso 32bit vs 64bit

不实践还真是不知道，vdso，在32位和64位之间还有差别。

https://github.com/mzhan017/dump-vdso

32bit的vdso提供的接口函数：

mzhan017@:/mnt/d/dump-vdso$ ./dump-vdso-32 -s
Name                                     Address      Offset
----                                     -------      ------
__kernel_vsyscall                        0xf7fa1560 0x00000560
__vdso_gettimeofday                      0xf7fa1790 0x00000790
__vdso_clock_getres                      0xf7fa2520 0x00001520
__vdso_clock_gettime64                   0xf7fa2030 0x00001030
__kernel_sigreturn                       0xf7fa1580 0x00000580
__vdso_time                              0xf7fa1b40 0x00000b40
__kernel_rt_sigreturn                    0xf7fa1590 0x00000590
__vdso_clock_gettime                     0xf7fa1b80 0x00000b80
__vdso_getcpu                            0xf7fa25b0 0x000015b0

64bit提供的

mzhan017@:/mnt/d/dump-vdso$ ./dump-vdso -s
Name                                     Address            Offset
----                                     -------            ------
clock_gettime                            0x00007fffc1f8fa70 0x00000a70
__vdso_gettimeofday                      0x00007fffc1f8f7b0 0x000007b0
clock_getres                             0x00007fffc1f8fdd0 0x00000dd0
__vdso_clock_getres                      0x00007fffc1f8fdd0 0x00000dd0
gettimeofday                             0x00007fffc1f8f7b0 0x000007b0
__vdso_time                              0x00007fffc1f8fa40 0x00000a40
__vdso_sgx_enter_enclave                 0x00007fffc1f8fe70 0x00000e70
time                                     0x00007fffc1f8fa40 0x00000a40
__vdso_clock_gettime                     0x00007fffc1f8fa70 0x00000a70
__vdso_getcpu                            0x00007fffc1f8fe40 0x00000e40
getcpu                                   0x00007fffc1f8fe40 0x00000e40

差异介绍：

https://zhuanlan.zhihu.com/p/436454953