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ELF physical address. Need a refresh.

Posted: Sun Jul 05, 2015 2:15 am
by JulienDarc
Hello,

I just need a slight remainder. I read again the ELF wiki page http://wiki.osdev.org/ELF#File_Structure.

Can someone tell me when I need to take care of the physical address provided by the elf header sections on modern Unix systems ?
I guess even DMA is not concerned, since you allocate it at runtime, and make use of the physical allocator.

Is it something to remain compatible with systems that don't have virtual memory / didn't enable it yet (boot, real mode...) ?


Thanks

Julien

Re: ELF physical address. Need a refresh.

Posted: Sun Jul 05, 2015 2:41 am
by jnc100
The specifications are relatively clear:
ELF Standard wrote:p_paddr: On systems for which physical addressing is relevant, this member is reserved for the segment’s physical address. Because System V ignores physical addressing for application programs, this member has unspecified contents for executable files and shared objects.
Regards,
John.

Re: ELF physical address. Need a refresh.

Posted: Sun Jul 05, 2015 2:51 am
by JulienDarc
Thanks jnc,

I massively sucked on this one.

:lol:

Bye