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2013-01-12x86: Changes to decoder, corrects 9376Nilay Vaish
The changes made by the changeset 9376 were not quite correct. The patch made changes to the code which resulted in decoder not getting initialized correctly when the state was restored from a checkpoint. This patch adds a startup function to each ISA object. For x86, this function sets the required state in the decoder. For other ISAs, the function is empty right now.
2013-01-07cpu: Fix broken thread context handoverAndreas Sandberg
The thread context handover code used to break when multiple handovers were performed during the same quiesce period. Previously, the thread contexts would assign the TC pointer in the old quiesce event to the new TC. This obviously broke in cases where multiple switches were performed within the same quiesce period, in which case the TC pointer in the quiesce event would point to an old CPU. The new implementation deschedules pending quiesce events in the old TC and schedules a new quiesce event in the new TC. The code has been refactored to remove most of the code duplication.
2013-01-07cpu: Unify SimpleCPU and O3 CPU serialization codeAndreas Sandberg
The O3 CPU used to copy its thread context to a SimpleThread in order to do serialization. This was a bit of a hack involving two static SimpleThread instances and a magic constructor that was only used by the O3 CPU. This patch moves the ThreadContext serialization code into two global procedures that, in addition to the normal serialization parameters, take a ThreadContext reference as a parameter. This allows us to reuse the serialization code in all ThreadContext implementations.
2013-01-07cpu: Implement a flat register interface in thread contextsAndreas Sandberg
Some architectures map registers differently depending on their mode of operations. There is currently no architecture independent way of accessing all registers. This patch introduces a flat register interface to the ThreadContext class. This interface is useful, for example, when serializing or copying thread contexts.
2013-01-07arch: Make the ISA class inherit from SimObjectAndreas Sandberg
The ISA class on stores the contents of ID registers on many architectures. In order to make reset values of such registers configurable, we make the class inherit from SimObject, which allows us to use the normal generated parameter headers. This patch introduces a Python helper method, BaseCPU.createThreads(), which creates a set of ISAs for each of the threads in an SMT system. Although it is currently only needed when creating multi-threaded CPUs, it should always be called before instantiating the system as this is an obvious place to configure ID registers identifying a thread/CPU.
2012-08-28Clock: Add a Cycles wrapper class and use where applicableAndreas Hansson
This patch addresses the comments and feedback on the preceding patch that reworks the clocks and now more clearly shows where cycles (relative cycle counts) are used to express time. Instead of bumping the existing patch I chose to make this a separate patch, merely to try and focus the discussion around a smaller set of changes. The two patches will be pushed together though. This changes done as part of this patch are mostly following directly from the introduction of the wrapper class, and change enough code to make things compile and run again. There are definitely more places where int/uint/Tick is still used to represent cycles, and it will take some time to chase them all down. Similarly, a lot of parameters should be changed from Param.Tick and Param.Unsigned to Param.Cycles. In addition, the use of curTick is questionable as there should not be an absolute cycle. Potential solutions can be built on top of this patch. There is a similar situation in the o3 CPU where lastRunningCycle is currently counting in Cycles, and is still an absolute time. More discussion to be had in other words. An additional change that would be appropriate in the future is to perform a similar wrapping of Tick and probably also introduce a Ticks class along with suitable operators for all these classes.
2012-05-25Decode: Make the Decoder class defined per ISA.Gabe Black
--HG-- rename : src/cpu/decode.cc => src/arch/generic/decoder.cc rename : src/cpu/decode.hh => src/arch/generic/decoder.hh
2012-03-19gcc: Clean-up of non-C++0x compliant code, first stepsAndreas Hansson
This patch cleans up a number of minor issues aiming to get closer to compliance with the C++0x standard as interpreted by gcc and clang (compile with std=c++0x and -pedantic-errors). In particular, the patch cleans up enums where the last item was succeded by a comma, namespaces closed by a curcly brace followed by a semi-colon, and the use of the GNU-extension typeof (replaced by templated functions). It does not address variable-length arrays, zero-size arrays, anonymous structs, range expressions in switch statements, and the use of long long. The generated CPU code also has a large number of issues that remain to be fixed, mainly related to overflows in implicit constant conversion (due to shifts).
2012-03-09CheckerCPU: Make CheckerCPU runtime selectable instead of compile selectableGeoffrey Blake
Enables the CheckerCPU to be selected at runtime with the --checker option from the configs/example/fs.py and configs/example/se.py configuration files. Also merges with the SE/FS changes.
2012-02-24MEM: Make port proxies use references rather than pointersAndreas Hansson
This patch is adding a clearer design intent to all objects that would not be complete without a port proxy by making the proxies members rathen than dynamically allocated. In essence, if NULL would not be a valid value for the proxy, then we avoid using a pointer to make this clear. The same approach is used for the methods using these proxies, such as loadSections, that now use references rather than pointers to better reflect the fact that NULL would not be an acceptable value (in fact the code would break and that is how this patch started out). Overall the concept of "using a reference to express unconditional composition where a NULL pointer is never valid" could be done on a much broader scale throughout the code base, but for now it is only done in the locations affected by the proxies.
2012-02-10SE/FS: Record the system pointer all the time for the simple CPU.Gabe Black
This pointer was only being stored in code that came from SE mode. The system pointer is always meaningful and available, so it should always be stored.
2012-01-31Merge with head, hopefully the last time for this batch.Gabe Black
2012-01-31Thread: Use inherited baseCpu rather than cpu in SimpleThreadAndreas Hansson
This patch is a trivial simplification, removing the cpu pointer from SimpleThread and relying on the baseCpu pointer in ThreadState. The patch does not add or change any functionality, it merely cleans up the code.
2012-01-31CheckerCPU: Re-factor CheckerCPU to be compatible with current gem5Geoffrey Blake
Brings the CheckerCPU back to life to allow FS and SE checking of the O3CPU. These changes have only been tested with the ARM ISA. Other ISAs potentially require modification.
2012-01-30Merge with main repository.Gabe Black
2012-01-30MEM: Clean-up of Functional/Virtual/TranslatingPort remnantsAndreas Hansson
This patch cleans up forward declarations and a member-function prototype that still referred to the old FunctionalPort, VirtualPort and TranslatingPort. There is no change in functionality.
2012-01-28Merge with the main repo.Gabe Black
--HG-- rename : src/mem/vport.hh => src/mem/fs_translating_port_proxy.hh rename : src/mem/translating_port.cc => src/mem/se_translating_port_proxy.cc rename : src/mem/translating_port.hh => src/mem/se_translating_port_proxy.hh
2012-01-17MEM: Add port proxies instead of non-structural portsAndreas Hansson
Port proxies are used to replace non-structural ports, and thus enable all ports in the system to correspond to a structural entity. This has the advantage of accessing memory through the normal memory subsystem and thus allowing any constellation of distributed memories, address maps, etc. Most accesses are done through the "system port" that is used for loading binaries, debugging etc. For the entities that belong to the CPU, e.g. threads and thread contexts, they wrap the CPU data port in a port proxy. The following replacements are made: FunctionalPort > PortProxy TranslatingPort > SETranslatingPortProxy VirtualPort > FSTranslatingPortProxy --HG-- rename : src/mem/vport.cc => src/mem/fs_translating_port_proxy.cc rename : src/mem/vport.hh => src/mem/fs_translating_port_proxy.hh rename : src/mem/translating_port.cc => src/mem/se_translating_port_proxy.cc rename : src/mem/translating_port.hh => src/mem/se_translating_port_proxy.hh
2011-11-18SE/FS: Get rid of includes of config/full_system.hh.Gabe Black
2011-11-18SE/FS: Get rid of FULL_SYSTEM in the CPU directory.Gabe Black
2011-10-31SE/FS: Make the functions available from the TC consistent between SE and FS.Gabe Black
2011-10-16SE/FS: Build/expose vport in SE mode.Gabe Black
2011-10-16CPU: Make physPort and getPhysPort available in SE mode.Gabe Black
2011-09-09Decode: Pull instruction decoding out of the StaticInst class into its own.Gabe Black
This change pulls the instruction decoding machinery (including caches) out of the StaticInst class and puts it into its own class. This has a few intrinsic benefits. First, the StaticInst code, which has gotten to be quite large, gets simpler. Second, the code that handles decode caching is now separated out into its own component and can be looked at in isolation, making it easier to understand. I took the opportunity to restructure the code a bit which will hopefully also help. Beyond that, this change also lays some ground work for each ISA to have its own, potentially stateful decode object. We'd be able to include less contextualizing information in the ExtMachInst objects since that context would be applied at the decoder. Also, the decoder could "know" ahead of time that all the instructions it's going to see are going to be, for instance, 64 bit mode, and it will have one less thing to check when it decodes them. Because the decode caching mechanism has been separated out, it's now possible to have multiple caches which correspond to different types of decoding context. Having one cache for each element of the cross product of different configurations may become prohibitive, so it may be desirable to clear out the cache when relatively static state changes and not to have one for each setting. Because the decode function is no longer universally accessible as a static member of the StaticInst class, a new function was added to the ThreadContexts that returns the applicable decode object.
2011-06-19simple-thread: give a name() function for debugging w/the SimpleThread objectKorey Sewell
2011-04-15trace: reimplement the DTRACE function so it doesn't use a vectorNathan Binkert
At the same time, rename the trace flags to debug flags since they have broader usage than simply tracing. This means that --trace-flags is now --debug-flags and --trace-help is now --debug-help
2011-04-15includes: sort all includesNathan Binkert
2010-10-31ISA,CPU,etc: Create an ISA defined PC type that abstracts out ISA behaviors.Gabe Black
This change is a low level and pervasive reorganization of how PCs are managed in M5. Back when Alpha was the only ISA, there were only 2 PCs to worry about, the PC and the NPC, and the lsb of the PC signaled whether or not you were in PAL mode. As other ISAs were added, we had to add an NNPC, micro PC and next micropc, x86 and ARM introduced variable length instruction sets, and ARM started to keep track of mode bits in the PC. Each CPU model handled PCs in its own custom way that needed to be updated individually to handle the new dimensions of variability, or, in the case of ARMs mode-bit-in-the-pc hack, the complexity could be hidden in the ISA at the ISA implementation's expense. Areas like the branch predictor hadn't been updated to handle branch delay slots or micropcs, and it turns out that had introduced a significant (10s of percent) performance bug in SPARC and to a lesser extend MIPS. Rather than perpetuate the problem by reworking O3 again to handle the PC features needed by x86, this change was introduced to rework PC handling in a more modular, transparent, and hopefully efficient way. PC type: Rather than having the superset of all possible elements of PC state declared in each of the CPU models, each ISA defines its own PCState type which has exactly the elements it needs. A cross product of canned PCState classes are defined in the new "generic" ISA directory for ISAs with/without delay slots and microcode. These are either typedef-ed or subclassed by each ISA. To read or write this structure through a *Context, you use the new pcState() accessor which reads or writes depending on whether it has an argument. If you just want the address of the current or next instruction or the current micro PC, you can get those through read-only accessors on either the PCState type or the *Contexts. These are instAddr(), nextInstAddr(), and microPC(). Note the move away from readPC. That name is ambiguous since it's not clear whether or not it should be the actual address to fetch from, or if it should have extra bits in it like the PAL mode bit. Each class is free to define its own functions to get at whatever values it needs however it needs to to be used in ISA specific code. Eventually Alpha's PAL mode bit could be moved out of the PC and into a separate field like ARM. These types can be reset to a particular pc (where npc = pc + sizeof(MachInst), nnpc = npc + sizeof(MachInst), upc = 0, nupc = 1 as appropriate), printed, serialized, and compared. There is a branching() function which encapsulates code in the CPU models that checked if an instruction branched or not. Exactly what that means in the context of branch delay slots which can skip an instruction when not taken is ambiguous, and ideally this function and its uses can be eliminated. PCStates also generally know how to advance themselves in various ways depending on if they point at an instruction, a microop, or the last microop of a macroop. More on that later. Ideally, accessing all the PCs at once when setting them will improve performance of M5 even though more data needs to be moved around. This is because often all the PCs need to be manipulated together, and by getting them all at once you avoid multiple function calls. Also, the PCs of a particular thread will have spatial locality in the cache. Previously they were grouped by element in arrays which spread out accesses. Advancing the PC: The PCs were previously managed entirely by the CPU which had to know about PC semantics, try to figure out which dimension to increment the PC in, what to set NPC/NNPC, etc. These decisions are best left to the ISA in conjunction with the PC type itself. Because most of the information about how to increment the PC (mainly what type of instruction it refers to) is contained in the instruction object, a new advancePC virtual function was added to the StaticInst class. Subclasses provide an implementation that moves around the right element of the PC with a minimal amount of decision making. In ISAs like Alpha, the instructions always simply assign NPC to PC without having to worry about micropcs, nnpcs, etc. The added cost of a virtual function call should be outweighed by not having to figure out as much about what to do with the PCs and mucking around with the extra elements. One drawback of making the StaticInsts advance the PC is that you have to actually have one to advance the PC. This would, superficially, seem to require decoding an instruction before fetch could advance. This is, as far as I can tell, realistic. fetch would advance through memory addresses, not PCs, perhaps predicting new memory addresses using existing ones. More sophisticated decisions about control flow would be made later on, after the instruction was decoded, and handed back to fetch. If branching needs to happen, some amount of decoding needs to happen to see that it's a branch, what the target is, etc. This could get a little more complicated if that gets done by the predecoder, but I'm choosing to ignore that for now. Variable length instructions: To handle variable length instructions in x86 and ARM, the predecoder now takes in the current PC by reference to the getExtMachInst function. It can modify the PC however it needs to (by setting NPC to be the PC + instruction length, for instance). This could be improved since the CPU doesn't know if the PC was modified and always has to write it back. ISA parser: To support the new API, all PC related operand types were removed from the parser and replaced with a PCState type. There are two warts on this implementation. First, as with all the other operand types, the PCState still has to have a valid operand type even though it doesn't use it. Second, using syntax like PCS.npc(target) doesn't work for two reasons, this looks like the syntax for operand type overriding, and the parser can't figure out if you're reading or writing. Instructions that use the PCS operand (which I've consistently called it) need to first read it into a local variable, manipulate it, and then write it back out. Return address stack: The return address stack needed a little extra help because, in the presence of branch delay slots, it has to merge together elements of the return PC and the call PC. To handle that, a buildRetPC utility function was added. There are basically only two versions in all the ISAs, but it didn't seem short enough to put into the generic ISA directory. Also, the branch predictor code in O3 and InOrder were adjusted so that they always store the PC of the actual call instruction in the RAS, not the next PC. If the call instruction is a microop, the next PC refers to the next microop in the same macroop which is probably not desirable. The buildRetPC function advances the PC intelligently to the next macroop (in an ISA specific way) so that that case works. Change in stats: There were no change in stats except in MIPS and SPARC in the O3 model. MIPS runs in about 9% fewer ticks. SPARC runs with 30%-50% fewer ticks, which could likely be improved further by setting call/return instruction flags and taking advantage of the RAS. TODO: Add != operators to the PCState classes, defined trivially to be !(a==b). Smooth out places where PCs are split apart, passed around, and put back together later. I think this might happen in SPARC's fault code. Add ISA specific constructors that allow setting PC elements without calling a bunch of accessors. Try to eliminate the need for the branching() function. Factor out Alpha's PAL mode pc bit into a separate flag field, and eliminate places where it's blindly masked out or tested in the PC.
2010-09-13Faults: Pass the StaticInst involved, if any, to a Fault's invoke method.Gabe Black
Also move the "Fault" reference counted pointer type into a separate file, sim/fault.hh. It would be better to name this less similarly to sim/faults.hh to reduce confusion, but fault.hh matches the name of the type. We could change Fault to FaultPtr to match other pointer types, and then changing the name of the file would make more sense.
2010-08-23CPU: Print out flatten-out register index as with IntRegs/FloatRegs traceflagMin Kyu Jeong
2010-08-23ARM/O3: store the result of the predicate evaluation in DynInst or Threadstate.Min Kyu Jeong
THis allows the CPU to handle predicated-false instructions accordingly. This particular patch makes loads that are predicated-false to be sent straight to the commit stage directly, not waiting for return of the data that was never requested since it was predicated-false.
2010-06-02ARM: Implement ARM CPU interruptsAli Saidi
2010-06-02Simple CPU: Make the FloatRegs trace flag do something.Gabe Black
2009-09-23arch: nuke arch/isa_specific.hh and move stuff to generated config/the_isa.hhNathan Binkert
2009-07-29Simple CPU: Make the simple CPU handle the IntRegs trace flag.Gabe Black
2009-07-08Get rid of the unused get(Data|Inst)Asid and (inst|data)Asid functions.Gabe Black
2009-07-08Registers: Add a registers.hh file as an ISA switched header.Gabe Black
This file is for register indices, Num* constants, and register types. copyRegs and copyMiscRegs were moved to utility.hh and utility.cc. --HG-- rename : src/arch/alpha/regfile.hh => src/arch/alpha/registers.hh rename : src/arch/arm/regfile.hh => src/arch/arm/registers.hh rename : src/arch/mips/regfile.hh => src/arch/mips/registers.hh rename : src/arch/sparc/regfile.hh => src/arch/sparc/registers.hh rename : src/arch/x86/regfile.hh => src/arch/x86/registers.hh
2009-07-08Registers: Eliminate the ISA defined RegFile class.Gabe Black
2009-07-08Registers: Move the PCs out of the ISAs and into the CPUs.Gabe Black
2009-07-08ARM, Simple CPU: Fix an index and add assert checks.Gabe Black
2009-07-08Registers: Eliminate the ISA defined integer register file.Gabe Black
2009-07-08Registers: Eliminate the ISA defined floating point register file.Gabe Black
2009-07-08Registers: Get rid of the float register width parameter.Gabe Black
2009-07-08Registers: Add an ISA object which replaces the MiscRegFile.Gabe Black
This object encapsulates (or will eventually) the identity and characteristics of the ISA in the CPU.
2009-05-26types: add a type for thread IDs and try to use it everywhereNathan Binkert
2009-05-17includes: sort includes againNathan Binkert
2009-05-17types: Move stuff for global types into src/base/types.hhNathan Binkert
--HG-- rename : src/sim/host.hh => src/base/types.hh
2009-04-15Get rid of the Unallocated thread context state.Steve Reinhardt
Basically merge it in with Halted. Also had to get rid of a few other functions that called ThreadContext::deallocate(), including: - InOrderCPU's setThreadRescheduleCondition. - ThreadContext::exit(). This function was there to avoid terminating simulation when one thread out of a multi-thread workload exits, but we need to find a better (non-cpu-centric) way.
2009-04-08tlb: Don't separate the TLB classes into an instruction TLB and a data TLBGabe Black
2009-02-27Processes: Make getting and setting system call arguments part of a process ↵Gabe Black
object.