On Wed, Nov 21, 2001 at 10:28:46AM -0500, Chuck Cranor wrote:
> In article <20011121142154.A2062@krishna>,
> Bang Jun-Young <bjy@mogua.org> wrote:
> >would be enough. Also, the comment is wrong:
> >
> >-		 * not fixed: make sure we skip over the largest possible heap.
> >
> >0x400000 doesn't belong to the heap. I guess he didn't consider the
> >address range below vm_taddr. 
> 
> that's certainly true and something that is worth better understanding.
> "start" used to live down around 0x1000 or so on most systems.   now
> it seems to have moved to around 0x08048110 or so (at least on my i386
> systems).
> 
> i think this is due to things like this appearing in the ELF ld scripts:
>   . = 0x08048000 + SIZEOF_HEADERS;
> 
> 
> i would like to know where this magic 0x08048000 number comes from
> and what the ~128MB of address space before "start" is supposed to be 
> used for now.  does anyone know?

I saw the number in SysV ABI manual, but did never know why it's
chosen.

> on the one hand, it seems clear to me that what Wine is doing is 
> bad form.   on the other hand, irrespective of Wine, it isn't clear
> to me that UVM should make efforts protect that leading 128MB as 
> part of the text/data area like it currently does.   but i'm not 
> sure --- i don't even know why the 128MB gap was put there.

The patch addresses that, but unfortunately...

Jun-Young

-- 
Bang Jun-Young <bjy@mogua.org>