On Thu, Oct 18, 2001 at 07:58:58PM -0500, Gerald Champagne wrote:
> I'm planning to work with a very minimal boot loader, and I'd like
> to hard-code a jump to kernel_entry in my boot loader. I got tired
> of having kernel_entry moving around, so I just moved it to the top
> of head.S, just afte the ".fill 0x280". That places kernel_entry at
> the same place every time. It's always at LOADADDR+0x280.
Dont do this - Its easy to decode the elf stuff:
Basically this is the code needed to relocate the elf chunks
and return the entry point. I might have corrupted it a bit due to stripping
unneeded bits but you will get the point. This code even clears bss
chunk which the kernel will do itself again.
Elf32_Ehdr *fhdr = fb;
Elf32_Shdr *shdr;
int i;
if (fhdr->e_machine != EM_MIPS) {
printf("No Mips ELF\n");
return(0);
}
fhdr=(void *) KSEG1ADDR(fb);
shdr=fb + fhdr->e_shoff;
for(i=0;i<fhdr->e_shnum;i++,shdr++) {
if (shdr->sh_size <= 0)
continue;
if (shdr->sh_type == SHT_PROGBITS) {
memcpy((void *) KSEG1ADDR(shdr->sh_addr),
KSEG1ADDR(fb + shdr->sh_offset),
shdr->sh_size);
} else if (shdr->sh_type == SHT_NOBITS) {
memset((void *) KSEG1ADDR(shdr->sh_addr), 0x0, shdr->sh_size);
}
}
return((void *) fhdr->e_entry);
--
Florian Lohoff flo@rfc822.org +49-5201-669912
Nine nineth on september the 9th Welcome to the new billenium
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