mrbrown wrote:
Linux runs strictly under the resident RTE library, so it does not access or use the native kernel - because the native kernel isn't even in RAM once the RTE takes over. You can easily write native programs like the Linux kernel that are RTE-only (I have written several), but then no one without the Linux Kit would be able to use your programs. That's why I wrote reload1.
I wasn't very clear where I was coming from, so I will explain a little more :)
I am finally going to begin my porting project of a RTOS to the PS2linux.
I will start first with porting it to the EE, and later I will port it to the IOP.
My goal is to completely replace the existing Sony RTOS way of doing things
and provide a different platform for development. Not necessarily because
I think anyone will use it (though I hope people will) but because it is
interesting for me to do.
Now, I am actually not an expert kernel hacker, embedded expert, or anything
like that, but I like to set high goals and work on challenging projects
in order to become more expert. :)
So having said that, the reason why I am interested in using the PS2Linux
boot method, or reload, or other methods, is to have a variety of ways of
booting a completely new kernel.
THe RTE I don't consider much of a barrier. If I can use the PS2Linux
boot menu to load something else, and have it install its own interupt
and exception handler routines at 0x0,0x80,0x100,0x180, and 0x200, then
the RTE is effectively out of the picture. In fact, since the RTE appears
to install at 0x1000, and nothing else is used up to that point except
interrupt some interrupt routines up to about 0x220, there is nearly
the entire first 1MB of KSEG address space for me to install something
to take over without trampling over anything else until I am ready to
throw the "switch".
The thing I don't know yet is where does the PS2Linux kernel boot
loader install the kernel, does it go to a fixed address or does it do it
based on the elf header ? Elf headers and relocations are areas where
I lack experience, so this is why I am asking questions like "why can't
we just load things directly from the PS2Linux boot loader screen" instead
of going through "reload1". I am sure there are reasons, its just not yet
intuitive to me.