Hi, and welcome!
Recently I've been wanting to play around with my old 68k mac's again and decided I wanted to try and put Debian on my old LC630. Unfortunately on opening up my 630 I seem to possibly have one of the defective 68LC040's (XC68LC040RC33B 02E23G QEUE9439A Malaysia) so I was wanting to at least do a test boot to see if mine might not be defective. The only information I'm finding on doing this is quite ancient (http://www.mac.linux-m68k.org/docs/gettingstarted.php) and I was wondering if someone had information on testing this with one of the more modern kernels, rather than the really old etch kernel.
Someone else will have to speak to the state of the FPU emulation in the latest versions of the kernel, but unforunately your mask is not new enough to be able to reliably handle FPU traps. With NetBSD, at least, you'd just see a lot of userland programs dumping core now and then because the FPU isn't used in the kernel.
If I do happen to have one of the defective batch what would my options be, short of buying a full 68040? Some of the pages I was reading sound like it's potentially do able but no one has done it, and other's say there is no way. That said a lot of the information I'm seeing is quite a few years or even a decade out of date.
You can do a full softfloat userland on NetBSD with such chips. That should also be possible with GNU/Linux, but the question of who'd build it and whether it's worthwhile is another matter, particularly since they can be found for $20 USD or less.
John -- I am become Death, the destroyer of worlds.