mmap to fixed adr

[Volker Poplawski]

Hi,

is there a VA range in userspace which is always safe for mmap() with 
fixed adr? (x86_64 mostly)

I.e. a VA range where mmap() or ld will never map memory.

I know I can try particular fixed adr with mmap() and check if the 
mapping succeeds. However this is not what I want. I want mmap() to stay 
clear of certain ranges and map memory there myself.

Regards
.....Volker