On 4/28/2014 1:56 PM, Gedare Bloom wrote: > On Mon, Apr 28, 2014 at 2:47 PM, Joel Sherrill > <joel.sherr...@oarcorp.com> wrote: >> Hi >> >> This is going to be interesting. MIPS TLS is broken because >> we don't have a trap handler for this. From GCC: >> >> ;; Thread-Local Storage >> >> ;; The TLS base pointer is accessed via "rdhwr $3, $29". No current >> ;; MIPS architecture defines this register, and no current >> ;; implementation provides it; instead, any OS which supports TLS is >> ;; expected to trap and emulate this instruction. rdhwr is part of the >> ;; MIPS 32r2 specification, but we use it on any architecture because >> ;; we expect it to be emulated. Use .set to force the assembler to >> ;; accept it. >> ;; >> ;; We do not use a constraint to force the destination to be $3 >> ;; because $3 can appear explicitly as a function return value. >> ;; If we leave the use of $3 implicit in the constraints until >> ;; reload, we may end up making a $3 return value live across >> ;; the instruction, leading to a spill failure when reloading it. >> >> This code from NetBSD appears to be the core part of the >> handler. >> >> http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/arch/mips/mips/locore_mips3.S?only_with_tag=MAIN >> > Do you mean > http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/arch/mips/mips/mips_emul.c?rev=1.26&content-type=text/x-cvsweb-markup&only_with_tag=MAIN > near case OP_RDHWR > Yeah.
And at one point I thought we had code similar to that because the R3000 like the MongooseV needed help to be IEEE FP compliant. And we used the NetBSD instruction trap emulator to help. >> If someone can adapt this, then the MIPS will have working >> TLS. >> >> Thanks. >> >> -- >> Joel Sherrill, Ph.D. Director of Research & Development >> joel.sherr...@oarcorp.com On-Line Applications Research >> Ask me about RTEMS: a free RTOS Huntsville AL 35805 >> Support Available (256) 722-9985 >> >> _______________________________________________ >> rtems-devel mailing list >> rtems-devel@rtems.org >> http://www.rtems.org/mailman/listinfo/rtems-devel -- Joel Sherrill, Ph.D. Director of Research & Development joel.sherr...@oarcorp.com On-Line Applications Research Ask me about RTEMS: a free RTOS Huntsville AL 35805 Support Available (256) 722-9985 _______________________________________________ rtems-devel mailing list rtems-devel@rtems.org http://www.rtems.org/mailman/listinfo/rtems-devel
