@David VomLehn:

This is four days overdue, but here's a big document on the 32-bit MIPS ABI:
http://math-atlas.sourceforge.net/devel/assembly/mipsabi32.pdf

I haven't read it all, but it seems to cover everything you would ever
need, including the relocation types.

Regards,
Marshall

On Mon, Aug 3, 2009 at 8:19 PM, David VomLehn [off-list ref] wrote:

On Mon, Aug 03, 2009 at 10:20:30AM +0100, Ralf Baechle wrote:

quoted

On Thu, Jul 30, 2009 at 11:49:23AM -0700, David VomLehn wrote:

quoted

To: GCC Help Mailing List <redacted>,
    Linux MIPS Mailing List [off-list ref]
Subject: Relocation problem with MIPS kernel modules
Content-Type: text/plain; charset=us-ascii

I have a MIPS loadable kernel module that, when I try to insmod it, causes the
kernel to emit the message:

    module xyz: dangerous relocation

...

quoted

quoted

According to the MIPS ABI, for what it's worth, "Each relocation type of
R_MIPS_HI16 must have an associated R_MIPS_LO16 entry immediately following
it in the list of relocations." So, what's actually getting generated by
gcc and linker differs from the closest thing we have to an ABI of record for
MIPS processors.

The GNU tools as an extension over the MIPS ABI allows an arbitrary number of
R_MIPS_HI16 relocations to be followed by a R_MIPS_LO16 symbol.  All
relocations of this sequence must use the same symbol, of course.  This is
a very old extension; I think it predates the Linux/MIPS port.

Perhaps a foolish question, but is this documented anywhere? I know there is a
a document over at http://gcc.gnu.org/gcc-3.4/mips-abi.html addressing some
other MIPS ABI changes, but I didn't see this one. Obviously, we could put
documentation on the linux-mips Wiki, with pointers to other documents, but
I'm not sure this is the right place. I'm also concerned there could be other
ABI changes/extensions that need to be included.

quoted

  Ralf

David