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2017-05-18base: Refactor the GDB code.Gabe Black
The new version modularizes the implementation of the various commands, gets rid of dynamic allocation of the register cache, fixes some small style problems, and uses exceptions to simplify error handling internal to the GDB stub. Change-Id: Iff3548373ce4adfb99106a810f5713b769df89b2 Reviewed-on: https://gem5-review.googlesource.com/3280 Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Boris Shingarov <shingarov@gmail.com> Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2016-11-09style: [patch 1/22] use /r/3648/ to reorganize includesBrandon Potter
2015-12-18arm: remote GDB: rationalize structure of register offsetsBoris Shingarov
Currently, the wire format of register values in g- and G-packets is modelled using a union of uint8/16/32/64 arrays. The offset positions of each register are expressed as a "register count" scaled according to the width of the register in question. This results in counter- intuitive and error-prone "register count arithmetic", and some formats would even be altogether unrepresentable in such model, e.g. a 64-bit register following a 32-bit one would have a fractional index in the regs64 array. Another difficulty is that the array is allocated before the actual architecture of the workload is known (and therefore before the correct size for the array can be calculated). With this patch I propose a simpler mechanism for expressing the register set structure. In the new code, GdbRegCache is an abstract class; its subclasses contain straightforward structs reflecting the register representation. The determination whether to use e.g. the AArch32 vs. AArch64 register set (or SPARCv8 vs SPARCv9, etc.) is made by polymorphically dispatching getregs() to the concrete subclass. The subclass is not instantiated until it is needed for actual g-/G-packet processing, when the mode is already known. This patch is not meant to be merged in on its own, because it changes the contract between src/base/remote_gdb.* and src/arch/*/remote_gdb.*, so as it stands right now, it would break the other architectures. In this patch only the base and the ARM code are provided for review; once we agree on the structure, I will provide src/arch/*/remote_gdb.* for the other architectures; those patches could then be merged in together. Review Request: http://reviews.gem5.org/r/3207/ Pushed by Joel Hestness <jthestness@gmail.com>
2014-12-05misc: Generalize GDB single stepping.Gabe Black
The new single stepping implementation for x86 doesn't rely on any ISA specific properties or functionality. This change pulls out the per ISA implementation of those functions and promotes the X86 implementation to the base class. One drawback of that implementation is that the CPU might stop on an instruction twice if it's affected by both breakpoints and single stepping. While that might be a little surprising, it's harmless and would only happen under somewhat unlikely circumstances.
2014-12-05misc: Make the GDB register cache accessible in various sized chunks.Gabe Black
Not all ISAs have 64 bit sized registers, so it's not always very convenient to access the GDB register cache in 64 bit sized chunks. This change makes it accessible in 8, 16, 32, or 64 bit chunks. The MIPS and ARM implementations were working around that limitation by bundling and unbundling 32 bit values into 64 bit values. That code has been removed.
2012-09-10NetBSD: Build on NetBSDPalle Lyckegaard
Minor patch against so building on NetBSD is possible.
2012-02-11SPARC: Make PSTATE and HPSTATE a BitUnion.Gabe Black
This gets rid of cryptic bits of code with lots of bit manipulation, and makes some comments redundant.
2011-11-18SE/FS: Get rid of includes of config/full_system.hh.Gabe Black
2011-10-30SE/FS: Make getProcessPtr available in both modes, and get rid of FULL_SYSTEMs.Gabe Black
2011-06-02copyright: clean up copyright blocksNathan Binkert
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
2010-11-11SPARC: 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.
2010-09-13Faults: 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.
2008-09-27arch: TheISA shouldn't really ever be used in the arch directory.Nathan Binkert
We should always refer to the specific ISA in that arch directory. This is especially necessary if we're ever going to make it to the point where we actually have heterogeneous systems.
2008-09-10style: Remove non-leading tabs everywhere they shouldn't be. Developers ↵Ali Saidi
should configure their editors to not insert tabs
2007-10-02SPARC,Remote GDB: Flesh out the acc function for SE mode.Gabe Black
--HG-- extra : convert_revision : eada066ab64701b5c53e7351dfffbdc0e0d4f344
2007-03-07*MiscReg->*MiscRegNoEffect, *MiscRegWithEffect->*MiscRegAli Saidi
--HG-- extra : convert_revision : f799b65f1b2a6bf43605e6870b0f39b473dc492b
2007-02-18implement vtophys and 32bit gdb supportAli Saidi
src/arch/alpha/vtophys.cc: src/arch/alpha/vtophys.hh: src/arch/sparc/arguments.hh: move Copy* to vport since it's generic for all the ISAs src/arch/sparc/isa_traits.hh: the Solaris kernel sets up a virtual-> real mapping for all memory starting at SegKPMBase src/arch/sparc/pagetable.hh: add a class for getting bits out of the TteTag src/arch/sparc/remote_gdb.cc: add 32bit support kinda.... If its 32 bit src/arch/sparc/remote_gdb.hh: Add 32bit register offsets too. src/arch/sparc/tlb.cc: cleanup generation of tsb pointers src/arch/sparc/tlb.hh: add function to return tsb pointers for an address make lookup public so vtophys can use it src/arch/sparc/vtophys.cc: src/arch/sparc/vtophys.hh: write vtophys for sparc src/base/bitfield.hh: return a mask of bits first->last src/mem/vport.cc: src/mem/vport.hh: move Copy* here since it's ISA generic --HG-- extra : convert_revision : c42c331e396c0d51a2789029d8e232fe66995d0f
2007-02-15fixup remote gdb support for sparc fsAli Saidi
--HG-- extra : convert_revision : 5edf0ad492fe438d66bcf0ae469ef841cd71e157
2007-01-30Make clearSingleStep in SPARC a warning, and rephrase the panic for ↵Gabe Black
setSingleStep --HG-- extra : convert_revision : fde27a1faa6c03a24a4321a153dfa89a438f9a32
2006-11-08Changed the getReg and setReg functions so that they work like netbsd. ↵Gabe Black
Apparently, gdb expects to do single stepping on its own, so those functions panic for SPARC. acc still needs to be implemented. --HG-- extra : convert_revision : c6e98e37b8ab3d6f8d6b3cd2c961faa65b08a179
2006-11-07Broke remote_gdb into a base class and architecture specific derived classes.Gabe Black
--HG-- extra : convert_revision : 8c528fab56a95b8245ad0f2572d62bb556ce0dde
2006-11-06Remote GDB support has been changed to use inheritance. Alpha should work, ↵Gabe Black
but isn't tested. Other architectures will not. --HG-- extra : convert_revision : fc7e1e73e2f3b1a4ab9905a1eb98c5f07c6c8707