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2019-09-18arch-arm: Fix Data Abort ISS when caused by Atomic operationGiacomo Travaglini
Data Aborts caused by an atomic instruction have a special rule for their syndrome: From a ISS point of view they count as read if a read to that address would generate a fault; they count as writes otherwise (ISS.WnR bit) This patch is implementing this in the TLB. For permission faults we need to explicitly check if a read would trigger a fault (e.g. checking for the AP bits) since permissions can allow read-only accesses. For other MMU exceptions (like translation faults) we are confident the nature of the access doesn't affect the genration of a fault. This means that if the access is atomic, we treat it as a read from an ISS.WnR point of view. Change-Id: Ia524aa6ae07f81513cdc26c516b5fd9b01a931c3 Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20981 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>
2019-09-18arch-arm: PSTATE.PAN affecting EL2 only when HCR_EL2.E2H=1Giacomo Travaglini
Change-Id: I6df0cdcbadca17f30d3de3bed887f75c739b00f0 Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20979 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>
2019-08-20arch-arm: Replace occ of opModeToEL(currOpMode/cpsr) with currELGiacomo Travaglini
Change-Id: I739a9be03ea5caa63540c62fd110eee86a058c4c Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20252 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>
2019-08-05arch-arm: Implement ARMv8.1-PAN, Privileged access neverGiacomo Travaglini
ARMv8.1-PAN adds a new bit to PSTATE. When the value of this PAN state bit is 1, any privileged data access from EL1 or EL2 to a virtual memory address that is accessible at EL0 generates a Permission fault. This feature is mandatory in ARMv8.1 implementations. This feature is supported in AArch64 and AArch32 states. The ID_AA64MMFR1_EL1.PAN, ID_MMFR3_EL1.PAN, and ID_MMFR3.PAN fields identify the support for ARMv8.1-PAN. Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Change-Id: I94a76311711739dd2394c72944d88ba9321fd159 Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19729 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>
2019-07-17arch-arm: Use ExceptionLevel type in TlbEntryGiacomo Travaglini
Replacing uint8_t with ExceptionLevel type in the arm TlbEntry. The variable is representing the translation regime it is targeting. Change-Id: Ifcd6e86c5d73f752e8476a2b7fda9ea74a0c7a3b Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19488 Reviewed-by: Ciro Santilli <ciro.santilli@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>
2019-06-26arch, arm: Update miscRegs in getTEAnouk Van Laer
Normally, a translation will start via translateTiming/functional which will check if the miscRegs have been updated and if so, will update the TLB state accordingly. However, in a 2 stage system, if there is a hit in stage 1, the resulting IPA will be sent to the S2-TLB for translation via a getTE() function call (via the stage2_lookup object). This will cause the state of the S2-TLB to be out of sync. Change-Id: I117e4032fc76d7d31f4f999887b5573a7e5811e6 Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/14995 Tested-by: kokoro <noreply+kokoro@google.com> Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
2019-05-14arch-arm: Do not check MustBeOne flag for TLB requests from the prefetcherJavier Bueno
Allow TLB requests generated from prefetchers to override the MustBeOne arch flag. This allows the prefetchers to issue requests without having to know architecutre-specific flags. Change-Id: Id83e0c93f3d1a614da11c4f344ab4dc594423672 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18768 Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Maintainer: Andreas Sandberg <andreas.sandberg@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>
2019-04-26arch-arm: updateMiscReg not setting isHyp in aarch64Giacomo Travaglini
The isHyp flag should be set for a TLB::NormalTran when in EL2. This was happening in aarch32 only, where the CPSR mode is checked, while aarch64 was only using it for explicit EL2 translations, like for AT instructions. Change-Id: I54605811e9dde75b5cf8868190b0f4c2a8d46570 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/c/public/gem5/+/18394 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>
2019-04-25arch-arm: Remove un-needed hyp flag in TLBI operationsGiacomo Travaglini
The hyp flag was probably a legacy pre-v8 flag distinguishing invalidation targeting PL2 translation regime (hyp mode). Since the introduction of target_el parameter, hyp boolean is not needed anymore. The patch works by setting the hyp flag in the flush* methods in the TLB automatically by checking if target_el == EL2. Change-Id: I798009e09ff24a383dea871e348188bae2685e8e Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Jan-Peter Larsson <jan-peter.larsson@arm.com> Reviewed-by: Anouk Van Laer <anouk.vanlaer@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18389 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com> Tested-by: kokoro <noreply+kokoro@google.com>
2019-03-21dev-arm: ambiguous use of getPort()Andrea Mondelli
The recent introduction of getPort() creates a conflict with the existing method used in arm MMU. This patch rename the old getPort() in getDMAPort() according to the returned value (DmaPort class type) Change-Id: Ief3d83650fd6b08490522341631244be06e380ce Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17469 Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Jason Lowe-Power <jason@lowepower.com> Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2019-03-19arch, cpu, dev, gpu, mem, sim, python: start using getPort.Gabe Black
Replace the getMasterPort, getSlavePort, and getEthPort functions with getPort, and remove extraneous mechanisms that are no longer necessary. Change-Id: Iab7e3c02d2f3a0cf33e7e824e18c28646b5bc318 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17040 Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2019-03-01mem-cache: alias to mem::getMasterPort in TLB classAndrea Mondelli
TLB:getMasterPort is used to obtain the PageWalkMasterPort if present and hides the BaseTLB::getMasterPort(). The TLB::getMasterPort() is renamed according to the expected behavior. Change-Id: If4f61189094a706d59805cd10f4f814e5830eda8 Reviewed-on: https://gem5-review.googlesource.com/c/16648 Reviewed-by: Jason Lowe-Power <jason@lowepower.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2018-11-28cpu,arch-arm: Initialise data membersRekai Gonzalez-Alberquilla
The value that is not initialized has a bogus value that manifests when using some debug-flags what makes the usage of tracediff a bit more challenging. In addition, while debugging with other techniques, it introduces the problem of understanding if the value of a field is 'intended' or just an effect of the lack of initialisation. Change-Id: Ied88caa77479c6f1d5166d80d1a1a057503cb106 Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/13125 Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com> Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
2018-11-05arch, arm: Effect of AT instructions on descriptor handlingAnouk Van Laer
Some address translation instructions will stop translation after the 1st stage and intercept the IPA, even in the presence of stage 2 (eg AT S1E1). However, in the case of a TLB miss, the table descriptors still need to be translated from IPA to PA to avoid fetching the wrong addresses. This commit splits whether IPA->PA translation is required for the VA and/or for the table descriptors. Change-Id: Ie53cdc00585f116150256f1d833460931b3bfb7d Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/13781 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2018-06-14arch-arm: Add Illegal Execution flag to PCStateGiacomo Travaglini
This patch moves the detection of the Illegal Execution flag (PSTATE.IL) from the tlb translation stage (fetch) to the decoding stage. This is done by adding the illegalExecution field to the PCState. Change-Id: I9c1c4e9c6bd5ded905c1d56b3034e4e9322582fa Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/10813 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2018-06-11misc: Using smart pointers for memory RequestsGiacomo Travaglini
This patch is changing the underlying type for RequestPtr from Request* to shared_ptr<Request>. Having memory requests being managed by smart pointers will simplify the code; it will also prevent memory leakage and dangling pointers. Change-Id: I7749af38a11ac8eb4d53d8df1252951e0890fde3 Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/10996 Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com> Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
2018-06-06arch-arm: Respect EL from translation typeAndreas Sandberg
There are cases where instructions request translations in the context of a lower EL. This is currently not respected in the TLB and the page table walker. Fix that. Change-Id: Icd59657a1ecfd8bd75a001bb1a4e41a6f4808a36 Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-on: https://gem5-review.googlesource.com/10506 Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
2018-02-16arch-arm: Fix syntax error in TLB::getResultTeChuan Zhu
The patch fixes one syntax error in TLB::getResultTe Change-Id: I31a72a52d5c03f43929a69ca1be61d9c20e76f5b Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/7983 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2018-02-07arch-arm: Check cache maintenance insts for permission faultsNikos Nikoleris
In AArch32, data cache maintenance instructions that operate by VA do not generate permission faults. In AArch64, a data cache invalidate instruction can generate a permission fault when there are no write permissions to the specified VA. Data cache clean and data cache clean and invalidate instructions do not generate permission faults. Checks for external aborts are also bypassed for data cache maintenance instructions. Change-Id: Iea5bc665e4cf66d528e36b671535b66637c4b224 Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/7827 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2018-02-07arch-arm: Change function name for banked miscregsGiacomo Travaglini
This commit changes the function's name used for retrieving the index of a security banked register given the flatten index. This will avoid confusion with flattenRegId, which has a different purpose. Change-Id: I470ffb55916cb7fc9f78e071a7f2e609c1829f1a Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com> Reviewed-on: https://gem5-review.googlesource.com/7982 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
2017-12-22arch,cpu: "virtualize" the TLB interface.Gabe Black
CPUs have historically instantiated the architecture specific version of the TLBs to avoid a virtual function call, making them a little bit more dependent on what the current ISA is. Some simple performance measurement, the x86 twolf regression on the atomic CPU, shows that there isn't actually any performance benefit, and if anything the simulator goes slightly faster (although still within margin of error) when the TLB functions are virtual. This change switches everything outside of the architectures themselves to use the generic BaseTLB type, and then inside the ISA for them to cast that to their architecture specific type to call into architecture specific interfaces. The ARM TLB needed the most adjustment since it was using non-standard translation function signatures. Specifically, they all took an extra "type" parameter which defaulted to normal, and translateTiming returned a Fault. translateTiming actually doesn't need to return a Fault because everywhere that consumed it just stored it into a structure which it then deleted(?), and the fault is stored in the Translation object when the translation is done. A little more work is needed to fully obviate the arch/tlb.hh header, so the TheISA::TLB type is still visible outside of the ISAs. Specifically, the TlbEntry type is used in the generic PageTable which lives in src/mem. Change-Id: I51b68ee74411f9af778317eff222f9349d2ed575 Reviewed-on: https://gem5-review.googlesource.com/6921 Maintainer: Gabe Black <gabeblack@google.com> Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
2017-12-05arm: Add CMO support for Non-Cacheable memoryNikos Nikoleris
Cache Maintainance operations to the point of coherence are treated as normal cahceable requests and clean and/or invalidate the caches of all PEs. Change-Id: Ia4a749c2318fe29c8601848b034b8315c4186c8a Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/5056 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
2017-05-09arm: Add support for memory-mapped m5opsAndreas Sandberg
Add support for a memory mapped m5op interface. When enabled, the TLB intercepts accesses in the 64KiB region designated by the ArmTLB.m5ops_base parameter. An access to this range maps to a specific m5op call. The upper 8 bits of the offset into the range denote the m5op function to call and the lower 8 bits denote the subfunction. Change-Id: I55fd8ac1afef4c3cc423b973870c9fe600a843a2 Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com> Reviewed-on: https://gem5-review.googlesource.com/2964
2017-02-21arm: Blame the right instruction address on a Prefetch AbortNikos Nikoleris
CPU models (e.g., O3CPU) issue instruction fetches for the whole cache block rather than a specific instruction. Consequently the TLB lookups translate the cache block virtual address. When the TLB lookup fails, however, the Prefetch Abort must be raised for the PC of the instruction that caused the fault rather than for the address of the block. This change fixes the way we instantiate the PrefetchAbort faults to use the PC of the request rather the address of the instruction fetch request. Change-Id: I8e45549da1c3be55ad204a060029c95ce822a851 Reviewed-by: Curtis Dunham <curtis.dunham@arm.com> Reviewed-by: Rekai Gonzalez Alberquilla <rekai.gonzalezalberquilla@arm.com> Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
2016-11-09style: [patch 1/22] use /r/3648/ to reorganize includesBrandon Potter
2016-08-15cpu, arch: fix the type used for the request flagsNikos Nikoleris
Change-Id: I183b9942929c873c3272ce6d1abd4ebc472c7132 Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
2016-08-02arm: Add TLBI instruction for stage 2 IPA'sDylan Johnson
This patch adds support for stage 2 TLBI instructions such as TLBI IPAS2E1_Xt. Change-Id: I0cd5e8055b0c1003e03439aa5183252f50ea0a88
2016-08-02arm: Fix stage 2 determination in table walkerDylan Johnson
We recompute if we are doing a stage 2 walk inside of the table walker but we have already figured it out in the tlb. Pass the information in to the walk instead of recomputing it. Change-Id: I39637ce99309b2ddbc30344d45ac9ebf6a203401
2016-08-02arm: Fix EL perceived at TLB for address translation instructionsDylan Johnson
During address translation instructions (such as AT S1E1R_Xt) the exception level can be different than the current exception level. This patch fixes how the TLB determines what EL to use during these instructions. Change-Id: Ia9ce229404de9e284bc1f7479fd2c580efd55f8f
2016-08-02arm: add stage2 translation supportDylan Johnson
Change-Id: I8f7c09c7ec3a97149ebebf4b21471b244e6cecc1
2016-07-11arm: Don't consult the TLB test iface for functional translationsAndreas Sandberg
Don't consult the TLB test interface for PA's returned by functional translations by the AT instruction. We implement this by chaning the ISA code to synthesize 0-length functional reads for the TLB lookup. The TLB then bypasses the final PA check in the tester if the size is zero. Change-Id: I2487b7f829cea88c37e229e9fc7a4543aced961b Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
2016-06-06sim: Call regStats of base-class as wellStephan Diestelhorst
We want to extend the stats of objects hierarchically and thus it is necessary to register the statistics of the base-class(es), as well. For now, these are empty, but generic stats will be added there. Patch originally provided by Akash Bagdia at ARM Ltd.
2016-06-02arm: refactor page table format determinationCurtis Dunham
In particular, when EL0 is in AArch32 but EL1 is AArch64, AArch64 memory translation must be used. This is essential for typical AArch64/32 interworking use cases.
2016-05-31arm: Correctly check translation mode (aarch64/aarch32)Andreas Sandberg
According to the ARM ARM (see AArch32.TranslateAddress in the pseudocode library), the TLB should be operating in aarch64 mode if the EL0 is aarch32 and EL1 is aarch64. This is currently not the case in gem5, which breaks 64/32 interprocessing. Update the check to match the reference manual. Change-Id: I6f1444d57c0e2eb5f8880f513f33a9197b7cb2ce Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Mitch Hayenga <mitch.hayenga@arm.com> Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
2016-05-26arm: Fix incorrect TLB permission check in aarch32Andreas Sandberg
The TLB currently assumes that the pxn bit in an LPAE page descriptor disables execution from unprivileged mode. However, according to the architecture manual, this bit should disable execution from privileged modes. Update the TLB implementation to reflect this behavior. Change-Id: I7f1bb232d7a94a93fd601a9230223195ac952947 Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
2016-03-21arm: Refactor the TLB test interfaceAndreas Sandberg
Refactor the TLB and page table walker test interface to use a dynamic registration mechanism. Instead of patching a couple of empty methods to wire up a TLB tester, this change allows such testers to register themselves using the setTestInterface() method.
2016-02-06style: fix missing spaces in control statementsSteve Reinhardt
Result of running 'hg m5style --skip-all --fix-control -a'.
2015-09-30arm: Change TLB Software CachingMitch Hayenga
In ARM, certain variables are only updated when a necessary change is detected. Having 2 SMT threads share a TLB resulted in these not being updated as required. This patch adds a thread context identifer to assist in the invalidation of these variables.
2015-08-21arm, mem: Remove unused CLEAR_LL request flagAndreas Hansson
Cleaning up dead code. The CLREX stores zero directly to MISCREG_LOCKFLAG and so the request flag is no longer needed. The corresponding functionality in the cache tags is also removed.
2015-07-07sim: Refactor the serialization base classAndreas Sandberg
Objects that are can be serialized are supposed to inherit from the Serializable class. This class is meant to provide a unified API for such objects. However, so far it has mainly been used by SimObjects due to some fundamental design limitations. This changeset redesigns to the serialization interface to make it more generic and hide the underlying checkpoint storage. Specifically: * Add a set of APIs to serialize into a subsection of the current object. Previously, objects that needed this functionality would use ad-hoc solutions using nameOut() and section name generation. In the new world, an object that implements the interface has the methods serializeSection() and unserializeSection() that serialize into a named /subsection/ of the current object. Calling serialize() serializes an object into the current section. * Move the name() method from Serializable to SimObject as it is no longer needed for serialization. The fully qualified section name is generated by the main serialization code on the fly as objects serialize sub-objects. * Add a scoped ScopedCheckpointSection helper class. Some objects need to serialize data structures, that are not deriving from Serializable, into subsections. Previously, this was done using nameOut() and manual section name generation. To simplify this, this changeset introduces a ScopedCheckpointSection() helper class. When this class is instantiated, it adds a new /subsection/ and subsequent serialization calls during the lifetime of this helper class happen inside this section (or a subsection in case of nested sections). * The serialize() call is now const which prevents accidental state manipulation during serialization. Objects that rely on modifying state can use the serializeOld() call instead. The default implementation simply calls serialize(). Note: The old-style calls need to be explicitly called using the serializeOld()/serializeSectionOld() style APIs. These are used by default when serializing SimObjects. * Both the input and output checkpoints now use their own named types. This hides underlying checkpoint implementation from objects that need checkpointing and makes it easier to change the underlying checkpoint storage code.
2015-06-21arm: Cleanup arch headers to remove dma_device.hh dependencyAndreas Sandberg
Break the dependency on dma_device.hh by forward-declaring DmaPort in the relevant header.
2015-05-26arm: Make address translation faster with better cachingNathanael Premillieu
This patch adds better caching of the sys regs for AArch64, thus avoiding unnecessary calls to tc->readMiscReg(MISCREG_CPSR) in the non-faulting case.
2015-05-05arm: Relax ordering for some uncacheable accessesAndreas Sandberg
We currently assume that all uncacheable memory accesses are strictly ordered. Instead of always enforcing strict ordering, we now only enforce it if the required memory type is device memory or strongly ordered memory.
2015-05-05mem, cpu: Add a separate flag for strictly ordered memoryAndreas Sandberg
The Request::UNCACHEABLE flag currently has two different functions. The first, and obvious, function is to prevent the memory system from caching data in the request. The second function is to prevent reordering and speculation in CPU models. This changeset gives the order/speculation requirement a separate flag (Request::STRICT_ORDER). This flag prevents CPU models from doing the following optimizations: * Speculation: CPU models are not allowed to issue speculative loads. * Write combining: CPU models and caches are not allowed to merge writes to the same cache line. Note: The memory system may still reorder accesses unless the UNCACHEABLE flag is set. It is therefore expected that the STRICT_ORDER flag is combined with the UNCACHEABLE flag to prevent this behavior.
2015-05-05arm: Remove unnecessary boot uncachabilityAndreas Hansson
With the recent patches addressing how we deal with uncacheable accesses there is no longer need for the work arounds put in place to enforce certain sections of memory to be uncacheable during boot.
2015-03-02arm: Share a port for the two table walker objectsAndreas Hansson
This patch changes how the MMU and table walkers are created such that a single port is used to connect the MMU and the TLBs to the memory system. Previously two ports were needed as there are two table walker objects (stage one and stage two), and they both had a port. Now the port itself is moved to the Stage2MMU, and each TableWalker is simply using the port from the parent. By using the same port we also remove the need for having an additional crossbar joining the two ports before the walker cache or the L2. This simplifies the creation of the CPU cache topology in BaseCPU.py considerably. Moreover, for naming and symmetry reasons, the TLB walker port is connected through the stage-one table walker thus making the naming identical to x86. Along the same line, we use the stage-one table walker to generate the master id that is used by all TLB-related requests.
2014-12-23arm: Raise an alignment fault if a PC has illegal alignmentAndreas Sandberg
We currently don't handle unaligned PCs correctly. There is one check for unaligned PCs in the TLB when running in aarch64 mode, but this check does not cover cases where the CPU does not do a TLB lookup when decoding an instruction (e.g., a branch stays within the same cache line). Additionally, the Decoder class sometimes throws an assertion for unaligned PCs which breaks speculation. This changeset introduces a decoder fault bit field in the ExtMachInst structure. This field can be used to signal a decoder failure. If set, the decoder generates an internal gem5fault instruction instead of a normal instruction. This instruction in turns either panics (fault type PANIC), returns an PCAlignmentFault (fault type UNALIGNED, aarch64) or PrefetchAbort (fault type UNALIGNED, aarch32). The patch causes minor changes to the realview64 regressions, and a stats bump will follow.
2014-11-14arm: Fixes based on UBSan and static analysisAndreas Hansson
Another churn to clean up undefined behaviour, mostly ARM, but some parts also touching the generic part of the code base. Most of the fixes are simply ensuring that proper intialisation. One of the more subtle changes is the return type of the sign-extension, which is changed to uint64_t. This is to avoid shifting negative values (undefined behaviour) in the ISA code.
2014-10-29arm: Fix multi-system AArch64 boot w/caches.Ali Saidi
Automatically extract cpu release address from DTB file. Check SCTLR_EL1 to verify all caches are enabled.
2014-10-16arch: Use shared_ptr for all FaultsAndreas Hansson
This patch takes quite a large step in transitioning from the ad-hoc RefCountingPtr to the c++11 shared_ptr by adopting its use for all Faults. There are no changes in behaviour, and the code modifications are mostly just replacing "new" with "make_shared".