Re: Fixed addresses for various architectures

From: Eli Carter (eli.carter@inet.com)
Date: Fri Sep 15 2000 - 09:54:48 EST


Russell King wrote:
> Eli Carter writes:
> > I have a Gnome Dia document in which I've tried to lay out the fixed
> > memory locations for arm-linux and the mapping of
> > ioremap<->virt<->phys<->bus. It's not perfect, but if you want a copy,
> > email me.
>
> Note that all of this is dependent on many things: machine type, binary
> type etc.

I do realize it is machine type dependant... I am not familiar with the
binary type dependancies--can someone point me to
information/explaination about that?

The virtual memory mapping looks like it is (or maybe can be?)
generalized in terms of kernel constants (#defines). My knowledge is
based on your arm-linux, let me know if things are different for other
archs or if I just got something plain wrong...

0 to TASK_SIZE is user process memory space (with the 0 page accesses
trapped or something...)
PAGE_OFFSET is the start of physical memory, with memory_start to
memory_end being what's left after the kernel takes what it wants.
VMALLOC_START to VMALLOC_END is the memory space reserved for ioremapped
addresses
(On the ARM, that still leaves a blank above e0000000... what's up
there?)

These #defines seem to appear in most/all architectures, just with
different values. What of the above is bogus? Where can I get a more
accurate and complete understanding of this?

C-ya,

Eli
--------------------. "To the systems programmer, users and applications
Eli Carter | serve only to provide a test load."
eli.carter@inet.com `---------------------------------- (random fortune)
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