Re: BSD_SYMTAB ELF notes

[John Nemeth <jnemeth%cue.bc.ca@localhost>]

On Aug 8, 11:51am, =?UTF-8?B?Um9nZXIgUGF1IE1vbm7DqQ==?= wrote:
} On 07/08/14 23:48, Ryan O'Neill wrote:
} > Hello. After reading through some of the libelf-loader.c and 
} > libelf-dominfo.c code, it appears that Xen expects BSD guest
} > kernels to have an ELF .note auxillary entry of type
} > XEN_ELFNOTE_BSD_SYMTAB that gets parsed in so that Xen knows to
} > allocate room for the kernels symbol table.
} 
} This is only used by PV(H) guests, this note is simply a boolean that
} tells Xen whether to load the symtab and strtab or not. Linux for
} example doesn't load the symtab and strtab, because it has no
} in-kernel debugger and doesn't use the full symbol table.
} 
} > I do not see this Note (Or any note segment/section) in my freebsd
} > guest kernel image (readelf -n). Can someone explain to me if this
} > Note is still used? If so, then in what case?
} 
} You will see this note if you compile a i386 XEN kernel, or if you
} compile a GENERIC amd64 kernel from -current.

     No, I don't.  I only see the IDENT note giving the kernel
version.  However, this might explain something.  One project I
worked on was trying to make modules work with Xen domU kernels.
I managed to make them work for very simple modules, but got stymied
with complex modules due to missing symbols.  This could potentially
be the cause.  The question now is, how does one go about adding
these notes?  Even if you don't know how to add the note, do you
know the details of the note?

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