[GSoC] Defining Memory for MMU page tables at CSB337

[Joel Sherrill]

Does it have to be placed in the linker script?

Can you dynamically allocate it as the properly needed size?
________________________________________
From: rtems-devel-bounces at rtems.org [rtems-devel-bounces at rtems.org] On Behalf Of Hesham Moustafa [heshamelmatary at gmail.com]
Sent: Saturday, August 04, 2012 7:52 AM
To: rtems-devel at rtems.org
Subject: [GSoC] Defining Memory for MMU page tables at CSB337

Hi,

I want to define memory for page tables at CSB337 BSP.

The following is quoted from lincmds.csb337

MEMORY {
SDRAM_MMU : ORIGIN = 0x20100000, LENGTH = 16k
SDRAM : ORIGIN = 0x20104000, LENGTH = 15M - 16k
SRAM : ORIGIN = 0x00200000, LENGTH = 16k
NIRVANA : ORIGIN = 0, LENGTH = 0
}

That only allocate page table for level 1 page table which is 16 k ( each entry represents 1M page of memory). I'd like to add level 2 page tables to represent 4k pages. A level-2 page table consists of 256 entry and consumes 1K of memory and its base address is installed at level-1 page table entry.

The question is what's the proper size of level-2 page tables to reserve from memory and what should be its base address (ORIGIN) to be written at that linker script ?

Thanks,
Hesham