It came down to me not initializing the mxcsr correctly at boot. The default power-on value masks every SIMD floating-point exception. I am preparing a patch that correctly initializes the MXCSR in the x86_default_fpu struct so that the register gets set correctly during per-cpu init.
On Saturday, February 27, 2016 at 8:33:28 AM UTC-8, rminnich wrote: > > well I knew barret and mike would fix it, and being a lame duck hacker, > well ... > > ron > > On Sat, Feb 27, 2016 at 7:10 AM Dan Cross <[email protected] <javascript:>> > wrote: > >> Thanks, Obama! Er, I mean Ron.... >> >> On Sat, Feb 27, 2016 at 12:40 AM, ron minnich <[email protected] >> <javascript:>> wrote: >> >>> And that's my fault ... I told michael it would be nice to get the >>> kernel bits in and leave user space for next. >>> >>> oopsie! >>> >>> ron >>> >>> On Fri, Feb 26, 2016 at 9:37 PM barret rhoden <[email protected] >>> <javascript:>> wrote: >>> >>>> On 2016-02-26 at 17:21 Barret Rhoden wrote: >>>> > lock_test is trapping with a SIMD floating point error (trap 19) >>>> > around here: >>>> > >>>> > 40589d: f2 0f 51 c0 sqrtsd %xmm0,%xmm0 >>>> > >>>> > Maybe whatever exception that is thrown used to be masked, but isn't >>>> > anymore? Does the new XSAVE stuff treat MXCSR differently? >>>> >>>> Oh. It's likely that the problem is that userspace is still using the >>>> old fp save and restore. >>>> >>>> Barret >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Akaros" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected] <javascript:>. >>>> To post to this group, send email to [email protected] >>>> <javascript:>. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Akaros" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected] <javascript:>. >>> To post to this group, send email to [email protected] >>> <javascript:>. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Akaros" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To post to this group, send email to [email protected] >> <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "Akaros" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. For more options, visit https://groups.google.com/d/optout.
