pci changes

[Alan Cox]

> 2) The current fix duplicated machine independent code (expand_stack
>    and find_vma), modified them, and placed them into the machine
>    dependent code. The problem with that is that whenever changes are
>    made to expand_stack and/or find_vma, we have to notice that and
>    port the fixes, since whoever makes the changes is not likely to
>    notice our special versions. I was hoping that we could get some
>    support for stacks that grow up in the machine independent code
>    so that they are visible.

Duplicating them is right for the 2.4 path, fixing the generic code is
probably right post 2.4

> 3) I hope that we will have some control of the stack location in the
>    machine dependent code. I would like to be able to place the stack
>    near the top of memory, and have the location based on the stack
>    size limit (rlim[RLIMIT_STACK].rlim_max).

Yep

> 4) The top of memory for user space is currently 0xc0000000, but I hope
>    to change that to 0xffffe000 in the next month or two.

Just frob the numbers, that isnt a big issue.

> 5) To make it clear "why" the code is different, I was hoping that
>    any #ifdef's in the machine independent code for stack grows up
>    changes would be something like #ifdef STACK_GROWS_UP, rather than
>    #ifdef parisc. Then STACK_GROWS_UP would be set for parisc. This

That is what Linus said when I asked him hppa v STACK_GROWS_UP v duplicating
all the code

> I would appreciate it if you would keep us informed regarding discussions
> between you and Linus regarding this issue.

I will do