Alexandre Julliard (@julliard) commented about dlls/ntdll/unix/loader.c:
#elif defined(__linux__) && (defined(__i386__) || defined(__arm__))
+/* In Win32, KUSER_SHARED_DATA is at a fixed address (0x7ffe0000), so it needs
- to be mapped there in every virtual process space by wine.
- It is used to map kernel address space pages to user space, so that it is
- user-space readable without any syscall overhead. It is very comparable
- to Linux's vDSO.
Actually it's very different from vDSO.