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2017-12-21arch-arm: Hyp routed undef fault need to change its syndromeGiacomo Travaglini
If undefined instruction has to be routed to EL2, the HSR register must change the HSR.EC and HSR.ISS accordingly, which means not using the EL1 exception syndrome, but the unknown reason one (EC=0, ISS=0) Change-Id: I1540c713ab545bf307c1dad3ae305de4178443f4 Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/6621 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2017-12-19arch-arm: Change casting type from reinterpret to staticGiacomo Travaglini
Cosmetic fix: prefer static_cast rather than reinterpret_cast in hierarchy. Change-Id: Ic0e5a4df9b18072a6df5ee316f674241074c349a Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/6761 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2017-11-22arch-arm: Add support for the brk instructionAndreas Sandberg
Add support for software breakpoints as signalled by the aarch64 brk instruction. This introduces a new SoftwareBreakpoint fault. Change-Id: I93646c3298e09d7f7b0983108ba8937c7331297a Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com> Reviewed-on: https://gem5-review.googlesource.com/5721 Reviewed-by: Giacomo Gabrielli <Giacomo.Gabrielli@arm.com>
2017-11-15arch-arm: Removing FlushPipe fault, using SquashAfterGiacomo Travaglini
This Patch is removing the FlushPipe ArmFault, which was used for flushing the pipeline in favour of the general IsSquashAfter StaticInstr flag. Using a fault was preventing tracers from tracing barriers like ISB and from adding them to the instruction count Change-Id: I176e9254eca904694f2f611eb486c55e50ec61ff Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com> Reviewed-on: https://gem5-review.googlesource.com/5361 Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2015-07-20syscall_emul: [patch 13/22] add system call retry capabilityBrandon Potter
This changeset adds functionality that allows system calls to retry without affecting thread context state such as the program counter or register values for the associated thread context (when system calls return with a retry fault). This functionality is needed to solve problems with blocking system calls in multi-process or multi-threaded simulations where information is passed between processes/threads. Blocking system calls can cause deadlock because the simulator itself is single threaded. There is only a single thread servicing the event queue which can cause deadlock if the thread hits a blocking system call instruction. To illustrate the problem, consider two processes using the producer/consumer sharing model. The processes can use file descriptors and the read and write calls to pass information to one another. If the consumer calls the blocking read system call before the producer has produced anything, the call will block the event queue (while executing the system call instruction) and deadlock the simulation. The solution implemented in this changeset is to recognize that the system calls will block and then generate a special retry fault. The fault will be sent back up through the function call chain until it is exposed to the cpu model's pipeline where the fault becomes visible. The fault will trigger the cpu model to replay the instruction at a future tick where the call has a chance to succeed without actually going into a blocking state. In subsequent patches, we recognize that a syscall will block by calling a non-blocking poll (from inside the system call implementation) and checking for events. When events show up during the poll, it signifies that the call would not have blocked and the syscall is allowed to proceed (calling an underlying host system call if necessary). If no events are returned from the poll, we generate the fault and try the instruction for the thread context at a distant tick. Note that retrying every tick is not efficient. As an aside, the simulator has some multi-threading support for the event queue, but it is not used by default and needs work. Even if the event queue was completely multi-threaded, meaning that there is a hardware thread on the host servicing a single simulator thread contexts with a 1:1 mapping between them, it's still possible to run into deadlock due to the event queue barriers on quantum boundaries. The solution of replaying at a later tick is the simplest solution and solves the problem generally.
2016-11-09style: [patch 1/22] use /r/3648/ to reorganize includesBrandon Potter
2016-08-02arm: correctly assign faulting IPA's to HPFAR_EL2Dylan Johnson
This patch corrects IPA reporting if the translation faults in a stage 2 lookup. Change-Id: I0b914527f8a9f98a5e980a131cf9d03e5584b4e9
2016-08-02arm: Fix secure state checking in various placesDylan Johnson
Faults that could potentially be routed to the hypervisor checked whether or not they were in a secure state without checking if security was enabled or not. This caused faults not to be routed correctly. This patch causes secure state checking to first ask if security is enabled. Change-Id: I179e9b181b27f552734c9bab2b18d05ac579a119
2016-08-02arm: Add check to fault routing for hypervisor/virtualizationDylan Johnson
This patch adds the option for faults to be routed to the hypervisor using the pre-existing routeToHyp() functions that are present in each fault type. Change-Id: I9735512c094457636b9870456a5be5432288e004
2016-08-02arm: Add AArch64 hypervisor call instruction 'hvc'Dylan Johnson
This patch adds the AArch64 instruction hvc which raises an exception from EL1 into EL2. The host OS uses this instruction to world switch into the guest. Change-Id: I930ee43f4f0abd4b35a68eb2a72e44e3ea6570be
2016-08-02arm: enable EL2 supportCurtis Dunham
Change-Id: I59fa4fae98c33d9e5c2185382e1411911d27d341
2016-05-27arm: Use the target EL state when determining fault formatAndreas Sandberg
We currently check the current state instead of the state of the target EL when determining how we report a fault. This breaks interprocessing since EL0 in aarch32 would report its fault status using the aarch32 registers even if EL1 is in aarch64. Fix this to report the fault using the format of the target EL. Change-Id: Ic080267ac210783d1e01c722a4ddaa687dce280e Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Mitch Hayenga <mitch.hayenga@arm.com>
2015-09-30isa,cpu: Add support for FS SMT InterruptsMitch Hayenga
Adds per-thread interrupt controllers and thread/context logic so that interrupts properly get routed in SMT systems.
2014-09-27arch: Use const StaticInstPtr references where possibleAndreas Hansson
This patch optimises the passing of StaticInstPtr by avoiding copying the reference-counting pointer. This avoids first incrementing and then decrementing the reference-counting pointer.
2014-09-12style: Fix line continuation, especially in debug messagesAndrew Bardsley
This patch closes a number of space gaps in debug messages caused by the incorrect use of line continuation within strings. (There's also one consistency change to a similar, but correct, use of line continuation)
2014-04-29arm: use condition code registers for ARM ISACurtis Dunham
Analogous to ee049bf (for x86). Requires a bump of the checkpoint version and corresponding upgrader code to move the condition code register values to the new register file.
2014-01-24arm: Add support for ARMv8 (AArch64 & AArch32)ARM gem5 Developers
Note: AArch64 and AArch32 interworking is not supported. If you use an AArch64 kernel you are restricted to AArch64 user-mode binaries. This will be addressed in a later patch. Note: Virtualization is only supported in AArch32 mode. This will also be fixed in a later patch. Contributors: Giacomo Gabrielli (TrustZone, LPAE, system-level AArch64, AArch64 NEON, validation) Thomas Grocutt (AArch32 Virtualization, AArch64 FP, validation) Mbou Eyole (AArch64 NEON, validation) Ali Saidi (AArch64 Linux support, code integration, validation) Edmund Grimley-Evans (AArch64 FP) William Wang (AArch64 Linux support) Rene De Jong (AArch64 Linux support, performance opt.) Matt Horsnell (AArch64 MP, validation) Matt Evans (device models, code integration, validation) Chris Adeniyi-Jones (AArch64 syscall-emulation) Prakash Ramrakhyani (validation) Dam Sunwoo (validation) Chander Sudanthi (validation) Stephan Diestelhorst (validation) Andreas Hansson (code integration, performance opt.) Eric Van Hensbergen (performance opt.) Gabe Black
2013-02-19scons: Add warning for missing field initializersAndreas Hansson
This patch adds a warning for missing field initializers for both gcc and clang, and addresses the warnings that were generated.
2012-01-29Implement Ali's review feedback.Gabe Black
Try to decrease indentation, and remove some redundant FullSystem checks.
2011-11-02SE/FS: Get rid of FULL_SYSTEM in the ARM ISA.Gabe Black
2011-09-13LSQ: Only trigger a memory violation with a load/load if the value changes.Ali Saidi
Only create a memory ordering violation when the value could have changed between two subsequent loads, instead of just when loads go out-of-order to the same address. While not very common in the case of Alpha, with an architecture with a hardware table walker this can happen reasonably frequently beacuse a translation will miss and start a table walk and before the CPU re-schedules the faulting instruction another one will pass it to the same address (or cache block depending on the dendency checking). This patch has been tested with a couple of self-checking hand crafted programs to stress ordering between two cores. The performance improvement on SPEC benchmarks can be substantial (2-10%).
2011-08-19Fix bugs due to interaction between SEV instructions and O3 pipelineGeoffrey Blake
SEV instructions were originally implemented to cause asynchronous squashes via the generateTCSquash() function in the O3 pipeline when updating the SEV_MAILBOX miscReg. This caused race conditions between CPUs in an MP system that would lead to a pipeline either going inactive indefinitely or not being able to commit squashed instructions. Fixed SEV instructions to behave like interrupts and cause synchronous sqaushes inside the pipeline, eliminating the race conditions. Also fixed up the semantics of the WFE instruction to behave as documented in the ARMv7 ISA description to not sleep if SEV_MAILBOX=1 or unmasked interrupts are pending.
2011-05-23O3: Fix issue with interrupts/faults occuring in the middle of a macro-opGeoffrey Blake
This patch fixes two problems with the O3 cpu model. The first is an issue with an instruction fetch causing a fault on the next address while the current macro-op is being issued. This happens when the micro-ops exceed the fetch bandwdith and then on the next cycle the fetch stage attempts to issue a request to the next line while it still has micro-ops to issue if the next line faults a fault is attached to a micro-op in the currently executing macro-op rather than a "nop" from the next instruction block. This leads to an instruction incorrectly faulting when on fetch when it had no reason to fault. A similar problem occurs with interrupts. When an interrupt occurs the fetch stage nominally stops issuing instructions immediately. This is incorrect in the case of a macro-op as the current location might not be interruptable.
2011-05-13ARM: Further break up condition code into NZ, C, V bits.Ali Saidi
Break up the condition code bits into NZ, C, V registers. These are individually written and this removes some incorrect dependencies between instructions.
2011-05-13ARM: Remove the saturating (Q) condition code from the renamed register.Ali Saidi
Move the saturating bit (which is also saturating) from the renamed register that holds the flags to the CPSR miscreg and adds a allows setting it in a similar way to the FP saturating registers. This removes a dependency in instructions that don't write, but need to preserve the Q bit.
2011-05-13ARM: Break up condition codes into normal flags, saturation, and simd.Ali Saidi
This change splits out the condcodes from being one monolithic register into three blocks that are updated independently. This allows CPUs to not have to do RMW operations on the flags registers for instructions that don't write all flags.
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
2011-04-04ARM: Cleanup implementation of ITSTATE and put important code in PCState.Ali Saidi
Consolidate all code to handle ITSTATE in the PCState object rather than touching a variety of structures/objects.
2011-04-04ARM: Fix table walk going on while ASID changes errorAli Saidi
2011-02-23ARM: Set ITSTATE correctly after FlushPipeAli Saidi
2011-02-23ARM: Delete OABI syscall handling.Ali Saidi
We only support EABI binaries, so there is no reason to support OABI syscalls. The loader detects OABI calls and fatal() so there is no reason to even check here.
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.
2010-10-01ARM: Clean up use of TBit and JBit.Ali Saidi
Rather tha constantly using ULL(1) << PcXBitShift define those directly. Additionally, add some helper functions to further clean up the code.
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.
2010-08-25ARM: Adding a bogus fault that does nothing.Min Kyu Jeong
This fault can used to flush the pipe, not including the faulting instruction. The particular case I needed this was for a self-modifying code. It needed to drain the store queue and force the following instruction to refetch from icache. DCCMVAC cp15 mcr instruction is modified to raise this fault.
2010-08-25ARM: Implement CPACR register and return Undefined Instruction when FP ↵Gabe Black
access is disabled.
2010-08-23ARM: Add system for ARM/Linux and bootstrappingAli Saidi
2010-06-02ARM: Get rid of the binary dumping function in utility.hh.Gabe Black
2010-06-02ARM: Make sure the upc is zeroed when vectoring to a fault.Gabe Black
2010-06-02ARM: Implement ARM CPU interruptsAli Saidi
2010-06-02ARM: Implement and update the DFSR and IFSR registers on faults.Gabe Black
2010-06-02ARM: Set CPSR.E to SCTLR.EE on faults.Gabe Black
2010-06-02ARM: Zero the micropc when vectoring to a fault.Gabe Black
2010-06-02ARM: Trigger system calls from the SupervisorCall invoke method.Gabe Black
This simplifies the decoder slightly, and makes the system call mechanism very slightly more realistic.
2010-06-02ARM: Rework how unrecognized/unimplemented instructions are handled.Gabe Black
Instead of panic immediately when these instructions are executed, an UndefinedInstruction fault is returned. In FS mode (not currently implemented), this is the fault that should, to my knowledge, be triggered in these situations and should be handled using the normal architected mechanisms. In SE mode, the fault causes a panic when it's invoked that gives the same information as the instruction did. When/if support for speculative execution of ARM is supported, this will allow a mispeculated and unrecognized and/or unimplemented instruction from causing a panic. Only once the instruction is going to be committed will the fault be invoked, triggering the panic.
2010-06-02ARM: Track the current ISA mode using the PC.Gabe Black
2009-11-10ARM: Implement fault classes.Gabe Black
Implement some fault classes using the curriously recurring template pattern, similar to SPARCs.
2009-07-08Registers: Eliminate the ISA defined RegFile class.Gabe Black
2009-04-05arm: add ARM support to M5Stephen Hines