[ITA] _autorebase
Corinna Vinschen
corinna-cygwin@cygwin.com
Mon Dec 15 17:57:00 GMT 2014
On Dec 15 18:20, Achim Gratz wrote:
> Corinna Vinschen writes:
> > The change is required. The base address 0x4:00000000 is a convention
> > which has been introduced to get reliable memory layout on x86_64. All
> > of Cygwin's memory allocations, be it thread stack, executable and DLL
> > base addresses, heap address, or mmap's with NULL addresses, are chosen
> > so as not to collide with memory allocations chosen by the OS. The OS
> > utilizes the lower 2GB 32 bit address space and the upper 0xff0:00000000
> > address space pretty much exclusively, and leaves everything in between
> > for the application. Thus we developed the following convention, which
> > should be followed by every tool in the distro:
> >
> > 0x000:00000000 - 0x000:7fffffff Reserved for OS
> > 0x000:80000000 - 0x000:ffffffff POSIX threads
> > 0x001:00000000 - 0x001:7fffffff Process image
> > 0x001:80000000 - 0x001:ffffffff Cygwin DLL w/ all shared data
> > 0x002:00000000 - 0x003:ffffffff 8 Gigs for rebased DLLs
> > 0x004:00000000 - 0x005:ffffffff 8 Gigs for non-rebased DLLs
> > 0x006:00000000 - 0x6ff:ffffffff Heap bottom-up, mmaps top-down
> > 0x700:00000000 - 0x7ff:ffffffff Reserved for OS
> >
> > This was discussed and documented multiple times during the development
> > of the 64 bit version. Please let's stick to that.
>
> I've missed it at the time or didn't remember any of it. In any case
> it's implemented exactly like that in rebaselst anyway.
>
> >> I'll have to see if I can dig out my notes from that time, but I think
> >> it was both the ASLR and the TSAware flag that were creating problems
> >> with some libraries
> >
> > TS aware? To the contrary. Don't remove it!
>
> We're not talking about executables here, see my other reply.
Sorry, missed that.
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Maintainer cygwin AT cygwin DOT com
Red Hat
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