Let me see when I last treated this... but I thought it was much more recently than that.
On August 17, 2015 1:01:43 AM PDT, Ingo Molnar <mi...@kernel.org> wrote: > >(Sorry about the late reply, wasn't around on the weekend.) > >* Linus Torvalds <torva...@linux-foundation.org> wrote: > >> Now that said, I doubt anybody cares. Since we don't support the >original 80386, >> the only way to ever trigger FP emulation is by having a 486SX or >possibly a >> couple of even rarer clone chips. [...] > >Yeah. So when I re-wrote the FPU code I tried to test math-emu by >booting with >'no387': it turned out that ever since the XSAVE code got merged >upstream, >math-emu oopsed reliably during bootup with a NULL reference, because >it wasn't >updated to the dynamic allocation logic in: > > 61c4628b5386 ("x86, fpu: split FPU state from task struct - v5") > >That was 6 years ago, so anything v2.6.26 and later probably has 100% >non-working >math-emu. > >So when I re-introduced static allocations math-emu started working >again, to a >limited degree: on a modern distro, trying to boot /bin/bash I got a >prompt, but >various programs would segfault. I did not investigate it any deeper, I >suppose >the FPU emulation does not go far enough for modern user-space, or >maybe it has >more bugs. > >So in reality nobody has cared about x86 math-emu in the last 6 years >and we can >probably remove it for good. I kept it for nostalgic reasons, but I >guess using >v2.4 kernels ought to be enough for those with nostalgia? > >> [...] So it's not like the fact that the code is completely wrong and >crap >> actually *matters*, but I still refuse to pull stuff that seems to be >so >> completely screwed up. > >That's true, my bad for merging it! > >Any objections against removing all of math-emu in v4.3? This would >simplify the >FPU code in various places beyond math-emu/. > >Thanks, > > Ingo -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/