atom feed2 messages in org.freebsd.freebsd-ppclink address
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Aditya GodboleJul 25, 2006 11:38 am 
Peter GrehanJul 25, 2006 4:12 pm 
Subject:link address
From:Peter Grehan (gre@freebsd.org)
Date:Jul 25, 2006 4:12:09 pm
List:org.freebsd.freebsd-ppc

Hi Aditya,

I'm a bit confused about the link address of the kernel in freebsd-ppc. The linker script says its 0x00100000. However on the i386 it seems to be 3GB (KERNBASE). Does the machine independant code not assume anything about the location of the kernel in virtual memory?

That's right.

On FreeBSD/ppc, kernel text/data/bss is mapped 1:1 mainly for simplicity - the loader's job is a lot easier, and it allows the early part of the kernel to run with the MMU disabled if so required.

The load address is somewhat arbirtrary but it can't be zero since that's where vectors live, and boot loader variables are often stored below 0x100000.

later,

Peter.