The linux kernel runs in VIRTUAL memory space starting at 0xC000_0000. It needs to be loaded in PHYSICAL space where there is RAM for it to run out of. When it starts up, it relocates itself to location 0x0000_0000, and then turns on the MMU which it uses to map the physical RAM that it is running out of to virtual memory location 0xC000_0000.
The previous paragraph is extremely simplified. I strongly suggest you read some kernel and booting HOWTOs and/or buy some books that cover details of the kernel. One good starting place is Denx' DULG manual http://www.denx.de/twiki/bin/view/DULG/Manual (the title is "Linux for PowerPC Embedded Systems HOWTO", but much/most of it is generic to all the CPUs). It may be helpful in future questions to identify the CPU (and possibly the board) you are using. gvb > -----Original Message----- > From: owner-linuxppc-embedded at lists.linuxppc.org > [mailto:owner-linuxppc-embedded at lists.linuxppc.org]On Behalf > Of Thamarai > Selvan > Sent: Friday, March 05, 2004 1:34 AM > To: Stephen Williams > Cc: linuxppc-embedded at lists.linuxppc.org > Subject: Re: How Can The Starting Address Of An Image In ELF File > BeChanged > > > > hi > > iam still not clear with it > can u guide me 2 some document/link on it or brief it little bit more > why it is linked to that address ? > if it is linked it should be configurable > bcuz iam using vision ice to download my image. > Thanks for your immediate reply > > with regards > Thamarai Selvan.G > > [ "Stephen Williams" <612dlag102 at sneakemail.com> writes: ] > > Thamarai Selvan Thamarai.Selvan-at-lntinfotech.com |PPC Linux > Embedded| wrote: > > > > I created the elf file of the kernel using "make vmlinux", when i > > checked the created system.map i found the the kernel image starting > > from 0xc0000000. Can any tell where this address is defined or > > configured? and how can this be changed to 0x0000000 is it possible? > > The linux cernel is linked to 0xc0000000, and the entry is really up > there. In fact, the kernel is loaded starting at 0x0, and > there is code > at the beginning that turns on address translation so that it > appears at > the right place. > > In other words, there is nothing for you to change. > ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
