[LV-kern-commit] CVS: kernel-2.4/Documentation/vax process.txt,NONE,1.1

[Dave A. <ai...@us...>]

Update of /cvsroot/linux-vax/kernel-2.4/Documentation/vax
In directory usw-pr-cvs1:/tmp/cvs-serv28761

Added Files:
	process.txt 
Log Message:
DA: info on process memory in VAX/Linux


--- NEW FILE ---
Process Memory Space on the VAX
===============================
DA June 2001

The VAX has no sparse page tables.
The VAX supports two sets of memory space for a process, the P0 and P1 spaces, which are described by page tables held in the system space pointed to by the CPU register p0br, p0lr, p1br, p1lr.

The P0 space goes from 0 -> 0x40000000
    P1 space goes from 0x40000000 -> 0x80000000

We currently allocate 48MB of memory per process, similiar to the NetBSD schemx.

NetBSD allocate as follows, 

8MB TEXT   - P0
24MB DATA  - P0
8MB MMAP   - P0 
8MB STACK  - P1

We go with similiar 40MB in P0 space and 8MB in P1 space. 

TASK_UNMAPPED_BASE is pointed to 32MB into the P0 space so as to work on similiar principles to NetBSD.