elfboot

Xavier Pegenaute xpegenaute at telepolis.es
Tue Jul 8 03:24:01 CEST 2003


Hi,


On Tue, 2003-07-08 at 02:03, Eric W. Biederman wrote:
> > 1) We want start an ELF binary (not payload) that is in DoC (p.e.) after
> > LinuxBios. Then we execute elfboot() that look inside the ROM for the
> > next code starting with a valid ELF header, build the segments, copy the
> > segments and give the control to the program.
> > 
> > No problem in this case, i think.
> 
> Sounds like standard use.
> 
> > 2) We want start a Linux Kernel that is recorded (neither payload) after
> > LinuxBios binary in DoC (p.e.), then we execute linuxbiosmain() and in
> > the end of this function we make a long jump to 0x90000.
> 
> Linuxbiosmain() is deprecated code and it always jumps to 0x100000 1MB.
> Anything is not done.  And everyone is encouraged not to use linuxbiosmain
> for new deployments.
> 
> > Here, i don't see what function in linuxbiosmain() copy the code of
> > Kernel to DRAM.Any one know it ?
> 
> It is the gunzip part.  But please don't use that.

The problem, is that, if i follow the instructions of
freebios/HOWTO/SiS630, the linux kernel binary generated doesn't has
elfheader.

Then if i want to use the standard use, i have apply some external
utility to generate an elf file (mkelfImage) and put in config file
"fileoption USE_ELF_BOOT=1". Is it right ?

Another think, i thought that the Linux Kernel alone has the code to
decompress himself (in the same way that we can put Kernel in a floppy
disk and it decompress alone. (dd if=kernel of=/dev/fd0))

Thanks.
Xavi.






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