I found the issue and fixed it. The return value wasn't being put into the Rax register in src/arch/x86/isa/decoder/two_byte_opcodes.isa
0x4: BasicOperate::gem5Op({{ uint64_t ret; bool recognized = PseudoInst::pseudoInst<X86PseudoInstABI>( xc->tcBase(), IMMEDIATE, ret); if (!recognized) fault = std::make_shared<InvalidOpcode>(); Rax = ret; //<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<Added This }}, IsNonSpeculative); This code was simplified with the new abi stuff and the Rax = ret; must have been lost in the shuffle. I could push the fix to develop, or should I just make an issue on Jira? Best, Dan On Mon, Nov 9, 2020 at 2:50 PM Daniel Gerzhoy <daniel.gerz...@gmail.com> wrote: > Let me further say that I know that the magic instructions are being > called. I am just getting bogus return values. > > On Mon, Nov 9, 2020 at 2:18 PM Daniel Gerzhoy <daniel.gerz...@gmail.com> > wrote: > >> Hi Matt, >> >> Thanks for this, it's very helpful. However after following the >> instructions (I had to extrapolate a little because of the directory >> structure changes you mentioned) I get the same result: Nill returns from >> the magic instructions. >> Actually It isn't nill, but a constant no matter what. If I compile my >> program with -O0 its nill, if with -O2 its: 4198192, which is suspicious. >> >> To clarify, are these updated instructions specifically meant to fix >> this issue I am running into? Or just general instructions to build m5op.o >> >> Here are the specific changes I made according to the link you provided, >> the supplemental instructions, and extrapolating based on the directory >> structure change. >> >> 1. In SConsopts I commented both: >> >> --- a/util/m5/src/abi/x86/SConsopts >> +++ b/util/m5/src/abi/x86/SConsopts >> @@ -27,8 +27,8 @@ Import('*') >> >> env['ABI'] = 'x86' >> get_abi_opt('CROSS_COMPILE', '') >> -env.Append(CXXFLAGS='-DM5OP_ADDR=0xFFFF0000') >> -env.Append(CCFLAGS='-DM5OP_ADDR=0xFFFF0000') >> +#env.Append(CXXFLAGS='-DM5OP_ADDR=0xFFFF0000') >> +#env.Append(CCFLAGS='-DM5OP_ADDR=0xFFFF0000') >> >> env['CALL_TYPE']['inst'].impl('m5op.S', 'verify_inst.cc') >> env['CALL_TYPE']['addr'].impl('m5op_addr.S', default=True) >> >> 2. In SConstruct I added: >> >> --- a/util/m5/SConstruct >> +++ b/util/m5/SConstruct >> @@ -44,7 +44,9 @@ def abspath(d): >> >> # Universal settings. >> main.Append(CXXFLAGS=[ '-O2' ]) >> +main.Append(CXXFLAGS=[ '-std=c++11' ]) >> main.Append(CCFLAGS=[ '-O2' ]) >> main.Append(CPPPATH=[ common_include ]) >> >> The compilation process compiles m5op.S with gcc though, so c++11 doesn't >> have any effect on it. Not sure if that matters. >> >> 3. Finally I linked both m5_mmap.o and m5op.o as per the instructions but >> I am a little wary of m5_mmap >> >> What does m5_mmap actually do if I don't have M5OP_ADDR defined. It looks >> like nothing? Do I need to link it? >> >> *Is there something inside the program I need to do before calling magic >> instructions that has to do with m5_mmap?* >> >> Thanks for your help, >> >> Dan >> >> On Mon, Nov 9, 2020 at 12:12 PM Matt Sinclair <mattdsincl...@gmail.com> >> wrote: >> >>> Hi Dan, >>> >>> In recent weeks, Gabe (if I recall correctly) updated how the m5ops are >>> created. I had created a homework assignment for my course about it: >>> https://pages.cs.wisc.edu/~sinclair/courses/cs752/fall2020/handouts/hw3.html >>> (see #2), but this is now already out of date as the location of some files >>> changed. The updated instructions are: >>> >>> 1. Update $GEM5_ROOT/util/m5/SConstruct, add a new line between the >>> current lines 46 and 47: >>> >>> main.Append(CXXFLAGS=[ '-O2' ]) >>> *+main.Append(CXXFLAGS=[ '-std=c++11' ])* >>> >>> main.Append(CCFLAGS=[ '-O2' ]) >>> >>> 2. Now run the same command you ran in step 2 of the above link: >>> >>> scons build/x86/out/m5 >>> >>> 3. This will create the same two .o files in step 2 of the above link, >>> in the same places (although the location of m5op.o may have changed to >>> include/gem5 util/m5/build/x86/abi/x86/ according to some of the >>> students in my course). >>> Matt >>> >>> On Mon, Nov 9, 2020 at 9:25 AM Daniel Gerzhoy via gem5-users < >>> gem5-users@gem5.org> wrote: >>> >>>> Hey all, >>>> >>>> I've recently updated to using the dev branch for my GCN3 simulations. >>>> I've noticed that I am now getting return values of 0 for every magic >>>> instruction (m5_rpns for instance). >>>> >>>> Is there a special way I need to be compiling/linking m5ops.S to get >>>> the return values to show up correctly? Or might this be a bug? >>>> >>>> Thanks, >>>> >>>> Dan >>>> _______________________________________________ >>>> gem5-users mailing list -- gem5-users@gem5.org >>>> To unsubscribe send an email to gem5-users-le...@gem5.org >>>> %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s >>> >>>
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