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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.
2012-01-29Implement Ali's review feedback.Gabe Black
Try to decrease indentation, and remove some redundant FullSystem checks.
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
2011-10-30SE/FS: Make getProcessPtr available in both modes, and get rid of FULL_SYSTEMs.Gabe Black
2010-11-11SPARC: Clean up some historical style issues.Gabe Black
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.
2010-10-15GetArgument: Rework getArgument so that X86_FS compiles again.Gabe Black
When no size is specified for an argument, push the decision about what size to use into the ISA by passing a size of -1.
2010-10-01Debug: Implement getArgument() and function skipping for ARM.Ali Saidi
In the process make add skipFuction() to handle isa specific function skipping instead of ifdefs and other ugliness. For almost all ABIs, 64 bit arguments can only start in even registers. Size is now passed to getArgument() so that 32 bit systems can make decisions about register selection for 64 bit arguments. The number argument is now passed by reference because getArgument() will need to change it based on the size of the argument and the current argument number. For ARM, if the argument number is odd and a 64-bit register is requested the number must first be incremented to because all 64 bit arguments are passed in an even argument register. Then the number will be incremented again to access both halves of the argument.
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.
2009-07-10SPARC: Set up a lookup table for integer register flattening.Gabe Black
Using a look up table changed the run time of the SPARC_FS solaris boot regression from: real 14m45.951s user 13m57.528s sys 0m3.452s to: real 12m19.777s user 12m2.685s sys 0m2.420s
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
2009-02-27Processes: Make getting and setting system call arguments part of a process ↵Gabe Black
object.
2008-07-01Remove delVirtPort() and make getVirtPort() only return cached version.Ali Saidi
2008-07-01Change everything to use the cached virtPort rather than created their own ↵Ali Saidi
each time. This appears to work, but I don't want to commit it until it gets tested a lot more. I haven't deleted the functionality in this patch that will come later, but one question is how to enforce encourage objects that call getVirtPort() to not cache the virtual port since if the CPU changes out from under them it will be worse than useless. Perhaps a null function like delVirtPort() is still useful in that case.
2007-08-01Arguments: Get rid of duplicate code for the Arguments class in each ↵Ali Saidi
architecture. Move the argument files to src/sim and add a utility.cc file with a function getArguments() that returns the given argument in the architecture specific fashion. getArguments() was getArg() is the architecture specific Argument class and has had all magic numbers replaced with meaningful constants. Also add a function to the Argument class for testing if an argument is NULL. --HG-- rename : src/arch/alpha/arguments.cc => src/sim/arguments.cc rename : src/arch/alpha/arguments.hh => src/sim/arguments.hh extra : convert_revision : 8b93667bafaa03b52aadb64d669adfe835266b8e