emulators/linux-wine: Help in porting to FreeBSD

[Divacky Roman]

On Fri, Mar 09, 2007 at 05:46:04PM -0500, Jung-uk Kim wrote:
> On Friday 09 March 2007 03:51 pm, Scot Hetzel wrote:
> > On 3/9/07, Tijl Coosemans <tijl at ulyssis.org> wrote:
> > > This is a problem with the FreeBSD mmap.
> > >
> > > * The wine executable is loaded at 0x7bf00000.
> > > * It reserves 0x00000000-0x60000000 and 0x80000000-(stack).
> > > * Then a couple dlls are dlopen'ed (ntdll,kernel32,...).
> > > * This fails because the freebsd mmap, when called without
> > > MAP_FIXED and NULL for the addr argument, looks for free space
> > > after the executable + maximum possible data segment (to preserve
> > > space for brk(2) style allocations). The default maximum data
> > > segment size is 512MiB, so mmap is looking for free space well
> > > beyond 0x80000000 which isn't there.
> > >
> > > In current you could work around this by setting
> > > kern.maxdsiz="8M" or so in /boot/loader.conf, but that probably
> > > causes problems for programs that use brk(2). A better solutions
> > > would be to create a wrapper program that reduces the data
> > > segment size with setrlimit(2) and then runs wine with execv(3).
> >
> > Thanks for the hint, I didn't find kern.maxdsiz in the sysctl tree,
> > but I did find 2 other maxdsiz settings.
> >
> > hp010# sysctl -a | grep maxdsiz
> > compat.ia32.maxdsiz: 536870912
> > compat.linux32.maxdsiz: 536870912
> >
> > hp010# /compat/linux/usr/bin/wineprefixcreate
> > wine: failed to initialize: /usr/lib/wine/ntdll.dll.so: failed to
> > map segment from shared object: Cannot allocate memory
> >
> > hp010# /compat/linux/usr/bin/wine --version
> > wine: failed to initialize: /usr/lib/wine/ntdll.dll.so: failed to
> > map segment from shared object: Cannot allocate memory
> >
> > Changing only compat.linux32.maxdsiz to 8M,  allowed
> > wineprefixcreate to run without giving the above error, but instead
> > resulted in a core dump.
> 
> ---- CUT!!! ---
> 
> Segmentation.  Wine seems to (ab)use set_thread_area() (to set up 
> special GDT entry), %fs, and %gs to emulate Windows kernel.  I am 
> sorry to tell you this but there is no way that we can get that fixed 
> unless we give up performance, i.e., for every context switch, we 
> have to save and restore three segment registers, their corresponding 
> base addresses and GDT entries.  I have implemented set_thread_area() 
> for amd64 but that is just not enough to support Wine.

yes... linux supports 3 GDT entries for TLS we support just 1. And I dont
think we will ever be willing to pay the performance price for the ability
to run just 1 (one!!!) program more...

but as there is native fbsd version of wine I think we'd better spend our
time on fixing/improving the native version

my two cents

roman