re: port-sparc/55573: sparc testbed logs many "coprocessor instruction" messages

[matthew green <mrg%eterna.com.au@localhost>]

Martin Husemann writes:
> The following reply was made to PR port-sparc/55573; it has been noted by GNATS.
> 
> From: Martin Husemann <martin%duskware.de@localhost>
> To: gnats-bugs%netbsd.org@localhost
> Cc: 
> Subject: Re: port-sparc/55573: sparc testbed logs many "coprocessor
>  instruction" messages
> Date: Fri, 14 Aug 2020 10:30:23 +0200
> 
>  On Fri, Aug 14, 2020 at 08:15:01AM +0000, Andreas Gustafsson wrote:
>  >   [  15.0167285] coprocessor instruction
>  
>  This is a FPU instruction with FPU disabled (trap T_CPDISABLED),
>  sending a SIGILL to the process.
>  
>  Wild guess: the in-kernel FPU changes modified the FPU disable method
>  so we now get this instead of T_FPDISABLED (which would cause us to do
>  proper FPU fixup).

i think you're confused.  i had to look up sparc copro,
thinking similar:

#define T_FPDISABLED    0x04    /* (5) fp instr while fp disabled */
#define T_CPDISABLED    0x24    /* (5) coprocessor instr while disabled */

are different.  the latter happens for stuff that access
the "%cN" registers, but i can't find code that does that
in openssl...

search for "cp_disabled" in the v8 manual for details.


.mrg.