cpu-o3: Fix too strict assert condition in writeback()

The assert() in the LSQ writeback() only allowed ReExec faults.
However, a SplitRequest which completed the translation in
PartialFault state (i.e. any but the very first cacheline
translation failed) may end up here. The assert() condition is
extended accordingly.

The patch also removes the superfluous/unused Complete/Squashed
states from the LSQ request. (The completion of the request is
recorded in the flags still.)

Change-Id: Ie575f4d3b4d5295585828ad8c7d3f4c7c1fe15d0
Signed-off-by: Gabor Dozsa <gabor.dozsa@arm.com>
Reviewed-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19174
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

cpu: Add first-/non-faulting load support to Minor and O3

Some architectures allow masking faults of memory load instructions in
some specific circumstances (e.g. first-faulting and non-faulting
loads in Arm SVE). This patch adds support for such loads in the Minor
and O3 CPU models.

Change-Id: I264a81a078f049127779aa834e89f0e693ba0bea
Signed-off-by: Gabor Dozsa <gabor.dozsa@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19178
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

cpu,mem: Add support for partial loads/stores and wide mem. accesses

This changeset adds support for partial (or masked) loads/stores, i.e.
loads/stores that can disable accesses to individual bytes within the
target address range. In addition, this changeset extends the code to
crack memory accesses across most CPU models (TimingSimpleCPU still
TBD), so that arbitrarily wide memory accesses are supported. These
changes are required for supporting ISAs with wide vectors.

Additional authors:
- Gabor Dozsa <gabor.dozsa@arm.com>
- Tiago Muck <tiago.muck@arm.com>

Change-Id: Ibad33541c258ad72925c0b1d5abc3e5e8bf92d92
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/13518
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

cpu: Add a memory access predicate

This changeset introduces a new predicate to guard memory accesses.
The most immediate use for this is to allow proper handling of
predicated-false vector contiguous loads and predicated-false
micro-ops of vector gather loads (added in separate changesets).

Change-Id: Ice6894fe150faec2f2f7ab796a00c99ac843810a
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17991
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bradley Wang <radwang@ucdavis.edu>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

misc: Removed inconsistency in O3* debug msgs

Added consistency in the DEBUG message form, to allow a better parsing.
Fixed sn/tid type parameter.
Removed some annoying newlines

Change-Id: I4761c49fc12b874a7d8b46779475b606865cad4b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17248
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

misc: Segmentation Fault during O3PipeView execution

During the O3PipeView execution, a potential invalid iterator is used to
Update the instruction storeTick field.

If the store_idx iterator is the first() of the StoreQueue, the
corresponding instruction is removed from the queue, leaving the iterator
invalid and not usable in the TRACING_ON block.

This patch uses the store_inst variable to access (and update) the
instruction tick, instead of the (potential) invalid one.

Change-Id: I671052ef282b9048e5239da8629b89e8afa86bf0
Reviewed-on: https://gem5-review.googlesource.com/c/16322
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

cpu-o3: Add cache read ports limit to LSQ

This change introduces cache read ports to limit the number of
per-cycle loads. Previously only the number of per-cycle stores
could be limited.

Change-Id: I39bbd984056c5a696725ee2db462a55b2079e2d4
Signed-off-by: Gabor Dozsa <gabor.dozsa@arm.com>
Reviewed-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13517
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

cpu: support atomic memory request type with AtomicOpFunctor

This patch enables all 4 CPU models (AtomicSimpleCPU, TimingSimpleCPU,
MinorCPU and DerivO3CPU) to issue atomic memory (AMO) requests to memory
system.

Atomic memory instruction is treated as a special store instruction in
all CPU models.

In simple CPUs, an AMO request with an associated AtomicOpFunctor is
simply sent to L1 dcache.

In MinorCPU, an AMO request bypasses store buffer and waits for any
conflicting store request(s) currently in the store buffer to retire
before the AMO request is sent to the cache. AMO requests are not buffered
in the store buffer, so their effects appear immediately in the cache.

In DerivO3CPU, an AMO request is inserted in the store buffer so that it
is delivered to the cache only after all previous stores are issued to
the cache. Data forwarding between between an outstanding AMO in the
store buffer and a subsequent load is not allowed since the AMO request
does not hold valid data until it's executed in the cache.

This implementation assumes that a target ISA implementation must insert
enough memory fences as micro-ops around an atomic instruction to
enforce a correct order of memory instructions with respect to its
memory consistency model. Without extra memory fences, this implementation
can allow AMOs and other memory instructions that do not conflict
(i.e., not target the same address) to reorder.

This implementation also assumes that atomic instructions execute within
a cache line boundary since the cache for now is not able to execute an
operation on two different cache lines in one single step. Therefore,
ISAs like x86 that require multi-cache-line atomic instructions need to
either use a pair of locking load and unlocking store or change the
cache implementation to guarantee the atomicity of an atomic
instruction.

Change-Id: Ib8a7c81868ac05b98d73afc7d16eb88486f8cf9a
Reviewed-on: https://gem5-review.googlesource.com/c/8188
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

cpu-o3: O3 LSQ Generalisation

This patch does a large modification of the LSQ in the O3 model. The
main goal of the patch is to remove the 'an operation can be served with
one or two memory requests' assumption that is present in the LSQ
and the instruction with the req, reqLow, reqHigh triplet, and
generalising it to operations that can be addressed with one request,
and operations that require many requests, embodied in the
SingleDataRequest and the SplitDataRequest.

This modification has been done mimicking the minor model to an extent,
shifting the responsibilities of dealing with VtoP translation and
tracking the status and resources from the DynInst to the LSQ via the
LSQRequest. The LSQRequest models the information concerning the
operation, handles the creation of fragments for translation and request
as well as assembling/splitting the data accordingly.

With this modifications, the implementation of vector ISAs, particularly
on the memory side, become more rich, as the new model permits a
dissociation of the ISA characteristics as vector length, from the
microarchitectural characteristics that govern how contiguous loads are
executing, allowing exploration of different LSQ to DL1 bus widths to
understand the tradeoffs in complexity and performance.

Part of the complexities introduced stem from the fact that gem5 keeps a
large amount of metadata regarding, in particular, memory operations,
thus, when an instruction is squashed while some operation as TLB lookup
or cache access is ongoing, when the relevant structure communicates to
the LSQ that the operation is over, it tries to access some pieces of
data that should have died when the instruction is squashed, leading to
asserts, panics, or memory corruption. To ensure the correct behaviour,
the LSQRequest rely on assesing who is their owner, and self-destroying
if they detect their owner is done with the request, and there will be
no subsequent action. For example, in the case of an instruction
squashed whal the TLB is doing a walk to serve the translation, when the
translation is served by the TLB, the LSQRequest detects that the
instruction was squashed, and as the translation is done, no one else
expect to access its information, and therefore, it self-destructs.
Having destroyed the LSQRequest earlier, would lead to wrong behaviour
as the TLB walk may access some fields of it.

Additional authors:
- Gabor Dozsa <gabor.dozsa@arm.com>

Change-Id: I9578a1a3f6b899c390cdd886856a24db68ff7d0c
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13516
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>

cpu-o3: Fix bug in LSQUnit(uint32_t, uint32_t) ctor

Change 9af1214 added a new ctor to the LSQUnit, however
there is a typo/bug because it sizes the SQEntries
member variable to lqEntries + 1, as opposed to
sqEntries + 1. This change corrects the issue by
using sqEntries.

Change-Id: I19dfaa5c0e335bd7b84343a92034147d7c5d914e
Reviewed-on: https://gem5-review.googlesource.com/c/15015
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

cpu: Change raw pointers to STL Containers

This patch changes two members from being raw pointers to being STL
containers. The reason behind, other than cleanlyness and arguable OO
best practices is that containers have more intronspections capabilities
than naked pointers do, as the size is known.

Using STL containers adds little overhead and eases the automation of
process during debugging (gdb).

Change-Id: I4d9d3eedafa8b5e50ac512ea93b458a4200229f2
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13126
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

cpu: Fix the usage of const DynInstPtr

Summary: Usage of const DynInstPtr& when possible and introduction of
move operators to RefCountingPtr.

In many places, scoped references to dynamic instructions do a copy of
the DynInstPtr when a reference would do. This is detrimental to
performance. On top of that, in case there is a need for reference
tracking for debugging, the redundant copies make the process much more
painful than it already is.

Also, from the theoretical point of view, a function/method that
defines a convenience name to access an instruction should not be
considered an owner of the data, i.e., doing a copy and not a reference
is not justified.

On a related topic, C++11 introduces move semantics, and those are
useful when, for example, there is a class modelling a HW structure that
contains a list, and has a getHeadOfList function, to prevent doing a
copy to an internal variable -> update pointer, remove from the list ->
update pointer, return value making a copy to the assined variable ->
update pointer, destroy the returned value -> update pointer.

Change-Id: I3bb46c20ef23b6873b469fd22befb251ac44d2f6
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13105
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

misc: Using smart pointers for memory Requests

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>

misc: Substitute pointer to Request with aliased RequestPtr

Every usage of Request* in the code has been replaced with the
RequestPtr alias. This is a preparing patch for when RequestPtr will be
the typdefed to a smart pointer to Request rather then a raw pointer to
Request.

Change-Id: I73cbaf2d96ea9313a590cdc731a25662950cd51a
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/10995
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>

cpu-o3: Check predication before the SQ size for a debug print

The size of the store entry in the LSQ is used to indicate a fault in
the execution of the store. At the same time, a store that is
predicated false will also have 0 size in the corresponding store
queue entry. This changeset ensures that we check if the store was
predicated false before checking the size field. This way we avoid
printing stores as faulting when they are only predicated false.

Change-Id: Ie07982197bd73d7b44d26a3257d54ecb103a952a
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/4821
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

cpu-o3: Avoid early checker verification for store conditionals

The O3CPU allows stores to commit before they are completed and as
soon as they enter the store queue. This is the reason why stores are
verified by the the checker CPU, separately, once they complete
and after they are sent to the memory.

Store conditionals, on the other hand, have an additional writeback
stage in the pipeline as they return their result to a register,
similarly to loads. This is the reason why they do not commit
before they receive a response from the memory. This allows store
conditionals to be verified by the checker CPU as soon as they
commit in the same way as all other non-store insturctions.

At the same time, the presense of a checker CPU should not require
changes to way we handle instructions. This change removes explicit
calls to:
* incorrectly set the extra data of the request to 0 (a subsequent
call to completeAcc already does this without making any ISA
assumptions about the return value of the failed store conditional)
* complete failing store conditionals

Change-Id: If21d70b21caa55b35e9fdcc50f254c590465d3c3
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/4820
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

cpu: Clarify meaning of cachePorts variable in lsq_unit.hh of O3

cachePorts currently constrains the number of store packets written to the
D-Cache each cycle), but loads currently affect this variable. This leads
to unexpected congestion (e.g., setting cachePorts to a realistic 1 will
in fact allow a store to WB only if no loads have accessed the D-Cache
this cycle). In the absence of arbitration, this patch decouples how many
loads can be done per cycle from how many stores can be done per cycle.

Signed-off-by: Jason Lowe-Power <jason@lowepower.com>

mem, cpu: Add assertions to snoop invalidation logic

This patch adds assertions that enforce that only invalidating snoops
will ever reach into the logic that tracks in-order load completion and
also invalidation of LL/SC (and MONITOR / MWAIT) monitors. Also adds
some comments to MSHR::replaceUpgrades().

cpu: Fix LLSC atomic CPU wakeup

Writes to locked memory addresses (LLSC) did not wake up the locking
CPU. This can lead to deadlocks on multi-core runs. In AtomicSimpleCPU,
recvAtomicSnoop was checking if the incoming packet was an invalidation
(isInvalidate) and only then handled a locked snoop. But, writes are
seen instead of invalidates when running without caches (fast-forward
configurations). As as simple fix, now handleLockedSnoop is also called
even if the incoming snoop packet are from writes.

cpu: fix unitialized variable which may cause assertion failure

The assert in lsq_unit_impl.hh line 963 needs pktPending to be initialized to
NULL (I got the assertion failure several times without the fix).

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

cpu, o3: consider split requests for LSQ checksnoop operations

This patch enables instructions in LSQ to track two physical addresses for
corresponding two split requests. Later, the information is used in
checksnoop() to search for/invalidate the corresponding LD instructions.

The current implementation has kept track of only the physical address that is
referenced by the first split request. Thus, for checksnoop(), the line
accessed by the second request has not been considered, causing potential
correctness issues.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

mem, cpu: Add a separate flag for strictly ordered memory

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.

cpu, o3: Ignored invalidate causing same-address load reordering

In case the memory subsystem sends a combined response with invalidate
(e.g. ReadRespWithInvalidate), we cannot ignore the invalidate part
of the response.

If we were to ignore the invalidate part, under certain circumstances
this effectively leads to reordering of loads to the same address
which is not permitted under any memory consistency model implemented
in gem5.

Consider the case where a later load's address is computed before an
earlier load in program order, and is therefore sent to the memory
subsystem first. At some point the earlier load's address is computed
and in doing so correctly marks the later load as a
possibleLoadViolation. In the meantime some other node writes and
sends invalidations to all other nodes. The invalidation races with
the later load's ReadResp, and arrives before ReadResp and is
deferred. Upon receipt of the ReadResp, the response is changed to
ReadRespWithInvalidate, and sent to the CPU. If we ignore the
invalidate part of the packet, we let the later load read the old
value of the address. Eventually the earlier load's ReadResp arrives,
but with new data. As there was no invalidate snoop (sunk into the
ReadRespWithInvalidate), and if we did not process the invalidate of
the ReadRespWithInvalidate, we obtain a load reordering.

A similar scenario can be constructed where the earlier load's address
is computed after ReadRespWithInvalidate arrives for the younger
load. In this case hitExternalSnoop needs to be set to true on the
ReadRespWithInvalidate, so that upon knowing the address of the
earlier load, checkViolations will cause the later load to be
squashed.

Finally we must account for the case where both loads are sent to the
memory subsystem (reordered), a snoop invalidate arrives and correctly
sets the later loads fault to ReExec. However, before the CPU
processes the fault, the later load's ReadResp arrives and the
writeback discards the outstanding fault. We must add a check to
ensure that we do not skip any unprocessed faults.

cpu: Move packet deallocation to recvTimingResp in the O3 CPU

Move the packet deallocations in the O3 CPU so that the completeDataAccess
deals only with the LSQ specific parts and the generic recvTimingResp frees the
packet in all other cases.

arch: Use shared_ptr for all Faults

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".

base: Clean up redundant string functions and use C++11

This patch does a bit of housekeeping on the string helper functions
and relies on the C++11 standard library where possible. It also does
away with our custom string hash as an implementation is already part
of the standard library.

mem: Refactor assignment of Packet types

Put the packet type swizzling (that is currently done in a lot of places)
into a refineCommand() member function.

cpu: Fix cache blocked load behavior in o3 cpu

This patch fixes the load blocked/replay mechanism in the o3 cpu. Rather than
flushing the entire pipeline, this patch replays loads once the cache becomes
unblocked.

Additionally, deferred memory instructions (loads which had conflicting stores),
when replayed would not respect the number of functional units (only respected
issue width). This patch also corrects that.

Improvements over 20% have been observed on a microbenchmark designed to
exercise this behavior.

cpu: Change writeback modeling for outstanding instructions

As highlighed on the mailing list gem5's writeback modeling can impact
performance. This patch removes the limitation on maximum outstanding issued
instructions, however the number that can writeback in a single cycle is still
respected in instToCommit().

o3: split load & store queue full cases in rename

Check for free entries in Load Queue and Store Queue separately to
avoid cases when load cannot be renamed due to full Store Queue and
vice versa.

This work was done while Binh was an intern at AMD Research.

style: eliminate equality tests with true and false

Using '== true' in a boolean expression is totally redundant,
and using '== false' is pretty verbose (and arguably less
readable in most cases) compared to '!'.

It's somewhat of a pet peeve, perhaps, but I had some time
waiting for some tests to run and decided to clean these up.

Unfortunately, SLICC appears not to have the '!' operator,
so I had to leave the '== false' tests in the SLICC code.

cpu: Fix case where o3 lsq could print out uninitialized data

In the O3 LSQ, data read/written is printed out in DPRINTFs. However,
the data field is treated as a character string with a null terminated.
However the data field is not encoded this way. This patch removes
that possibility by removing the data part of the print.

cpu: o3: lsq: Fix TSO implementation
This patch fixes violation of TSO in the O3CPU, as all loads must be
ordered with all other loads. In the LQ, if a snoop is observed, all
subsequent loads need to be squashed if the system is TSO.

Prior to this patch, the following case could be violated:

P0 | P1 ;
MOV [x],mail=/usr/spool/mail/nilay | MOV EAX,[y] ;
MOV [y],mail=/usr/spool/mail/nilay | MOV EBX,[x] ;

exists (1:EAX=1 /\ 1:EBX=0) [is a violation]

The problem was found using litmus [http://diy.inria.fr].

Committed by: Nilay Vaish <nilay@cs.wisc.edu

cpu: Add support for instructions that zero cache lines.

cpu: Add CPU support for generatig wake up events when LLSC adresses are snooped.

This patch add support for generating wake-up events in the CPU when an address
that is currently in the exclusive state is hit by a snoop. This mechanism is required
for ARMv8 multi-processor support.

base: add support for probe points and common probes

The probe patch is motivated by the desire to move analytical and trace code
away from functional code. This is achieved by the probe interface which is
essentially a glorified observer model.

What this means to users:
* add a probe point and a "notify" call at the source of an "event"
* add an isolated module, that is being used to carry out *your* analysis (e.g. generate a trace)
* register that module as a probe listener
Note: an example is given for reference in src/cpu/o3/simple_trace.[hh|cc] and src/cpu/SimpleTrace.py

What is happening under the hood:
* every SimObject maintains has a ProbeManager.
* during initialization (src/python/m5/simulate.py) first regProbePoints and
the regProbeListeners is called on each SimObject. this hooks up the probe
point notify calls with the listeners.

FAQs:
Why did you develop probe points:
* to remove trace, stats gathering, analytical code out of the functional code.
* the belief that probes could be generically useful.

What is a probe point:
* a probe point is used to notify upon a given event (e.g. cpu commits an instruction)

What is a probe listener:
* a class that handles whatever the user wishes to do when they are notified
about an event.

What can be passed on notify:
* probe points are templates, and so the user can generate probes that pass any
type of argument (by const reference) to a listener.

What relationships can be generated (1:1, 1:N, N:M etc):
* there isn't a restriction. You can hook probe points and listeners up in a
1:1, 1:N, N:M relationship. They become useful when a number of modules
listen to the same probe points. The idea being that you can add a small
number of probes into the source code and develop a larger number of useful
analysis modules that use information passed by the probes.

Can you give examples:
* adding a probe point to the cpu's commit method allows you to build a trace
module (outputting assembler), you could re-use this to gather instruction
distribution (arithmetic, load/store, conditional, control flow) stats.

Why is the probe interface currently restricted to passing a const reference:
* the desire, initially at least, is to allow an interface to observe
functionality, but not to change functionality.
* of course this can be subverted by const-casting.

What is the performance impact of adding probes:
* when nothing is actively listening to the probes they should have a
relatively minor impact. Profiling has suggested even with a large number of
probes (60) the impact of them (when not active) is very minimal (<1%).

mem: track per-request latencies and access depths in the cache hierarchy

Add some values and methods to the request object to track the translation
and access latency for a request and which level of the cache hierarchy responded
to the request.

cpu: add consistent guarding to *_impl.hh files.

cpu: Put in assertions to check for maximum supported LQ/SQ size

LSQSenderState represents the LQ/SQ index using uint8_t, which supports up to
256 entries (including the sentinel entry). Sending packets to memory with a
higher index than 255 truncates the index, such that the response matches the
wrong entry. For instance, this can result in a deadlock if a store completion
does not clear the head entry.

mem: Set the cache line size on a system level

This patch removes the notion of a peer block size and instead sets
the cache line size on the system level.

Previously the size was set per cache, and communicated through the
interconnect. There were plenty checks to ensure that everyone had the
same size specified, and these checks are now removed. Another benefit
that is not yet harnessed is that the cache line size is now known at
construction time, rather than after the port binding. Hence, the
block size can be locally stored and does not have to be queried every
time it is used.

A follow-on patch updates the configuration scripts accordingly.

o3: fix tick used for renaming and issue with range selection

Fixes the tick used from rename:
- previously this gathered the tick on leaving rename which was always 1 less
than the dispatch. This conflated the decode ticks when back pressure built
in the pipeline.
- now picks up tick on entry.

Added --store_completions flag:
- will additionally display the store completion tail in the viewer.
- this highlights periods when large numbers of stores are outstanding (>16 LSQ
blocking)

Allows selection by tick range (previously this caused an infinite loop)

cpu: Rewrite O3 draining to avoid stopping in microcode

Previously, the O3 CPU could stop in the middle of a microcode
sequence. This patch makes sure that the pipeline stops when it has
committed a normal instruction or exited from a microcode
sequence. Additionally, it makes sure that the pipeline has no
instructions in flight when it is drained, which should make draining
more robust.

Draining is controlled in the commit stage, which checks if the next
PC after a committed instruction is in microcode. If this isn't the
case, it requests a squash of all instructions after that the
instruction that just committed and immediately signals a drain stall
to the fetch stage. The CPU then continues to execute until the
pipeline and all associated buffers are empty.

cpu: Fix O3 LSQ debug dumping constness and formatting

o3: Fix issue with LLSC ordering and speculation

This patch unlocks the cpu-local monitor when the CPU sees a snoop to a locked
address. Previously we relied on the cache to handle the locking for us, however
some users on the gem5 mailing list reported a case where the cpu speculatively
executes a ll operation after a pending sc operation in the pipeline and that
makes the cache monitor valid. This should handle that case by invaliding the
local monitor.

o3 cpu: remove some unused buggy functions in the lsq
Committed by: Nilay Vaish <nilay@cs.wisc.edu>

Packet: Remove NACKs from packet and its use in endpoints

This patch removes the NACK frrom the packet as there is no longer any
module in the system that issues them (the bridge was the only one and
the previous patch removes that).

The handling of NACKs was mostly avoided throughout the code base, by
using e.g. panic or assert false, but in a few locations the NACKs
were actually dealt with (although NACKs never occured in any of the
regressions). Most notably, the DMA port will now never receive a NACK
and the backoff time is thus never changed. As a consequence, the
entire backoff mechanism (similar to a PCI bus) is now removed and the
DMA port entirely relies on the bus performing the arbitration and
issuing a retry when appropriate. This is more in line with e.g. PCIe.

Surprisingly, this patch has no impact on any of the regressions. As
mentioned in the patch that removes the NACK from the bridge, a
follow-up patch should change the request and response buffer size for
at least one regression to also verify that the system behaves as
expected when the bridge fills up.

O3: Clean up the O3 structures and try to pack them a bit better.

DynInst is extremely large the hope is that this re-organization will put the
most used members close to each other.

MEM: Separate requests and responses for timing accesses

This patch moves send/recvTiming and send/recvTimingSnoop from the
Port base class to the MasterPort and SlavePort, and also splits them
into separate member functions for requests and responses:
send/recvTimingReq, send/recvTimingResp, and send/recvTimingSnoopReq,
send/recvTimingSnoopResp. A master port sends requests and receives
responses, and also receives snoop requests and sends snoop
responses. A slave port has the reciprocal behaviour as it receives
requests and sends responses, and sends snoop requests and receives
snoop responses.

For all MemObjects that have only master ports or slave ports (but not
both), e.g. a CPU, or a PIO device, this patch merely adds more
clarity to what kind of access is taking place. For example, a CPU
port used to call sendTiming, and will now call
sendTimingReq. Similarly, a response previously came back through
recvTiming, which is now recvTimingResp. For the modules that have
both master and slave ports, e.g. the bus, the behaviour was
previously relying on branches based on pkt->isRequest(), and this is
now replaced with a direct call to the apprioriate member function
depending on the type of access. Please note that send/recvRetry is
still shared by all the timing accessors and remains in the Port base
class for now (to maintain the current bus functionality and avoid
changing the statistics of all regressions).

The packet queue is split into a MasterPort and SlavePort version to
facilitate the use of the new timing accessors. All uses of the
PacketQueue are updated accordingly.

With this patch, the type of packet (request or response) is now well
defined for each type of access, and asserts on pkt->isRequest() and
pkt->isResponse() are now moved to the appropriate send member
functions. It is also worth noting that sendTimingSnoopReq no longer
returns a boolean, as the semantics do not alow snoop requests to be
rejected or stalled. All these assumptions are now excplicitly part of
the port interface itself.

MEM: Remove the Broadcast destination from the packet

This patch simplifies the packet by removing the broadcast flag and
instead more firmly relying on (and enforcing) the semantics of
transactions in the classic memory system, i.e. request packets are
routed from a master to a slave based on the address, and when they
are created they have neither a valid source, nor destination. On
their way to the slave, the request packet is updated with a source
field for all modules that multiplex packets from multiple master
(e.g. a bus). When a request packet is turned into a response packet
(at the final slave), it moves the potentially populated source field
to the destination field, and the response packet is routed through
any multiplexing components back to the master based on the
destination field.

Modules that connect multiplexing components, such as caches and
bridges store any existing source and destination field in the sender
state as a stack (just as before).

The packet constructor is simplified in that there is no longer a need
to pass the Packet::Broadcast as the destination (this was always the
case for the classic memory system). In the case of Ruby, rather than
using the parameter to the constructor we now rely on setDest, as
there is already another three-argument constructor in the packet
class.

In many places where the packet information was printed as part of
DPRINTFs, request packets would be printed with a numeric "dest" that
would always be -1 (Broadcast) and that field is now removed from the
printing.

MEM: Introduce the master/slave port sub-classes in C++

This patch introduces the notion of a master and slave port in the C++
code, thus bringing the previous classification from the Python
classes into the corresponding simulation objects and memory objects.

The patch enables us to classify behaviours into the two bins and add
assumptions and enfore compliance, also simplifying the two
interfaces. As a starting point, isSnooping is confined to a master
port, and getAddrRanges to slave ports. More of these specilisations
are to come in later patches.

The getPort function is not getMasterPort and getSlavePort, and
returns a port reference rather than a pointer as NULL would never be
a valid return value. The default implementation of these two
functions is placed in MemObject, and calls fatal.

The one drawback with this specific patch is that it requires some
code duplication, e.g. QueuedPort becomes QueuedMasterPort and
QueuedSlavePort, and BusPort becomes BusMasterPort and BusSlavePort
(avoiding multiple inheritance). With the later introduction of the
port interfaces, moving the functionality outside the port itself, a
lot of the duplicated code will disappear again.

CheckerCPU: Make CheckerCPU runtime selectable instead of compile selectable

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.

CheckerCPU: Re-factor CheckerCPU to be compatible with current gem5

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.

O3 CPU LSQ: Implement TSO
This patch makes O3's LSQ maintain total order between stores. Essentially
only the store at the head of the store buffer is allowed to be in flight.
Only after that store completes, the next store is issued to the memory
system. By default, the x86 architecture will have TSO.

O3: Tidy up some DPRINTFs in the LSQ.

Faults: Replace calls to genMachineCheckFault with M5PanicFault.

LSQ: Moved a couple of lines to enable O3 + Ruby
This patch makes O3 CPU work along with the Ruby memory model. Ruby
overwrites the senderState pointer with another pointer. The pointer
is restored only when Ruby gets done with the packet. LSQ makes use of
senderState just after sendTiming() returns. But the dynamic_cast returns
a NULL pointer since Ruby's senderState pointer is from a different class.
Storing the senderState pointer before calling sendTiming() does away with
the problem.

event: minor cleanup
Initialize flags via the Event constructor instead of calling
setFlags() in the body of the derived class's constructor. I
forget exactly why, but this made life easier when implementing
multi-queue support.

Also rename Event::getFlags() to isFlagSet() to better match
common usage, and get rid of some unused Event methods.

LSQ: Only trigger a memory violation with a load/load if the value changes.

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%).

O3: Implement memory mapped IPRs for O3.

O3: Fix a small corner case with the lsq hazard detection logic.

stats: one more name violation

trace: reimplement the DTRACE function so it doesn't use a vector
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

includes: sort all includes

O3: Tighten memory order violation checking to 16 bytes.

The comment in the code suggests that the checking granularity should be 16
bytes, however in reality the shift by 8 is 256 bytes which seems much
larger than required.

O3: Fix unaligned stores when cache blocked

Without this change the a store can be issued to the cache multiple times.
If this case occurs when the l1 cache is out of mshrs (and thus blocked)
the processor will never make forward progress because each cycle it will
send a single request using the recently freed mshr and not completing the
multipart store. This will continue forever.

O3: Enhance data address translation by supporting hardware page table walkers.

Some ISAs (like ARM) relies on hardware page table walkers. For those ISAs,
when a TLB miss occurs, initiateTranslation() can return with NoFault but with
the translation unfinished.

Instructions experiencing a delayed translation due to a hardware page table
walk are deferred until the translation completes and kept into the IQ. In
order to keep track of them, the IQ has been augmented with a queue of the
outstanding delayed memory instructions. When their translation completes,
instructions are re-executed (only their initiateAccess() was already
executed; their DTB translation is now skipped). The IEW stage has been
modified to support such a 2-pass execution.

O3: Fix corner cases where multiple squashes/fetch redirects overwrite timebuf.

ARM: Add support for moving predicated false dest operands from sources.

Replace curTick global variable with accessor functions.
This step makes it easy to replace the accessor functions
(which still access a global variable) with ones that access
per-thread curTick values.

O3: Support SWAP and predicated loads/store in ARM.

ISA,CPU,etc: Create an ISA defined PC type that abstracts out ISA behaviors.



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.

O3: Skipping mem-order violation check for uncachable loads.
Uncachable load is not executed until it reaches the head of the ROB,
hence cannot cause one.

CPU: Make Exec trace to print predication result (if false) for memory instructions

O3: Handle loads when the destination is the PC.
For loads that PC is the destination, check if the load
was mispredicted again when the value being loaded returns from memory

ARM/O3: store the result of the predicate evaluation in DynInst or Threadstate.
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.

O3PCU: Split loads and stores that cross cache line boundaries.

When each load or store is sent to the LSQ, we check whether it will cross a
cache line boundary and, if so, split it in two. This creates two TLB
translations and two memory requests. Care has to be taken if the first
packet of a split load is sent but the second blocks the cache. Similarly,
for a store, if the first packet cannot be sent, we must store the second
one somewhere to retry later.

This modifies the LSQSenderState class to record both packets in a split
load or store.

Finally, a new const variable, HasUnalignedMemAcc, is added to each ISA
to indicate whether unaligned memory accesses are allowed. This is used
throughout the changed code so that compiler can optimise away code dealing
with split requests for ISAs that don't need them.

arch: nuke arch/isa_specific.hh and move stuff to generated config/the_isa.hh

types: add a type for thread IDs and try to use it everywhere

Mem: Change isLlsc to isLLSC.

Memory: Rename LOCKED for load locked store conditional to LLSC.

eventq: convert all usage of events to use the new API.
For now, there is still a single global event queue, but this is
necessary for making the steps towards a parallelized m5.

params: Convert the CPU objects to use the auto generated param structs.
A whole bunch of stuff has been converted to use the new params stuff, but
the CPU wasn't one of them. While we're at it, make some things a bit
more stylish. Most of the work was done by Gabe, I just cleaned stuff up
a bit more at the end.

Make the Event::description() a const function

Merge with head

Mem: Make errors in the memory system be responses, not requests. Fixes cache handling of error responses.

o3: Fix for retry ID bug.
It should be cleared prior to the call to recvRetry.
Add extra DPRINTF statement for clearer debugging output.

Fix WriteReq/StoreCondReq setting in O3.

Make CPU models use new LoadLockedReq/StoreCondReq commands.

Event descriptions should not end in "event"
(they function as adjectives not nouns)

Get rid of Packet result field. Error responses are
now encoded in cmd field.

Remove extra delete that was causing segfault.

Get the "hard" SPARC instructions working in o3. I don't like that the IsStoreConditional flag needs to be set for them because they aren't store conditional instructions, and I should fix the format code which is not handling the opt_flags correctly.

Merge zizzer.eecs.umich.edu:/bk/newmem
into ahchoo.blinky.homelinux.org:/home/gblack/m5/newmem-o3-spec

Pass ISA-specific O3 CPU as a constructor parameter instead of using setCPU functions.

src/cpu/o3/alpha/cpu_impl.hh:
Pass ISA-specific O3 CPU to FullO3CPU as a constructor parameter instead of using setCPU functions.

Made the "data" field of store queue entries into a character array. It's sized to match an IntReg which was what it used to be, but we might want to make it something architecture independent. All data is now endian converted before entering the store queue entries which simplifies store to load forwarding in "trans endian" simulations, and makes twin memory ops work.

src/cpu/o3/lsq_unit.hh:
src/cpu/o3/lsq_unit_impl.hh:
fixed twin memory operations.

Fix a memory leak. Hopefully this fixes the longer running benchmarks.

Remove/comment out DPRINTFs that were causing a segfault.

The removed ones were unnecessary. The commented out ones could be useful in the future, should this problem get fixed. See flyspray task #243.

src/cpu/o3/commit_impl.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue_impl.hh:
src/cpu/o3/lsq_impl.hh:
src/cpu/o3/lsq_unit_impl.hh:
src/cpu/o3/rename_impl.hh:
src/cpu/o3/rob_impl.hh:
Remove/comment out DPRINTFs that were causing a segfault.

Merge ktlim@zizzer:/bk/newmem
into zamp.eecs.umich.edu:/z/ktlim2/clean/tmp/clean2

src/cpu/base_dyn_inst.hh:
Hand merge. Line is no longer needed because it's handled in the ISA.

Two fixes:
1. Requests are handled more properly now. They assume the memory system takes control of the request upon sending out an access.
2. load-load ordering is maintained.

src/cpu/base_dyn_inst.hh:
Update how requests are handled. The BaseDynInst should not be able to hold a pointer to the request because the request becomes owned by the memory system once it is sent out.

Also include some functions to allow certain status bits to be cleared.
src/cpu/base_dyn_inst_impl.hh:
Update how requests are handled. The BaseDynInst should not be able to hold a pointer to the request because the request becomes owned by the memory system once it is sent out.
src/cpu/o3/fetch_impl.hh:
General correctness fixes. retryPkt is not necessarily always set, so handle it properly. Also consider the cache unblocked only when recvRetry is called.
src/cpu/o3/lsq_unit.hh:
Handle requests a little more correctly. Now that the requests aren't pointed to by the DynInst, be sure to delete the request if it's not being used by the memory system.

Also be sure to not store-load forward from an uncacheable store.
src/cpu/o3/lsq_unit_impl.hh:
Check to make sure load-load ordering was maintained.

Also handle requests a little more correctly.

Make memory commands dense again to avoid cache stat table explosion.
Created MemCmd class to wrap enum and provide handy methods to
check attributes, convert to string/int, etc.

Make sure endian conversion is done on the memory data when it's just set to an existing buffer.

Merge zizzer:/bk/newmem/
into zower.eecs.umich.edu:/eecshome/m5/newmem

Added in endianness conversion on memory accesses as the data goes out. This will break the checker!

Fix up in case a req hasn't yet been generated for this instruction (if there was a fault prior to translation).

Merge ktlim@zizzer:/bk/newmem
into zamp.eecs.umich.edu:/z/ktlim2/clean/o3-merge/newmem

Initialize pointer to NULL.

src/cpu/o3/lsq_unit_impl.hh:
Be sure to initialize pointer to NULL.

Merge ktlim@zizzer:/bk/newmem
into zamp.eecs.umich.edu:/z/ktlim2/clean/o3-merge/newmem

Use PacketPtr everywhere

Add in support for LL/SC in the O3 CPU. Needs to be fully tested.

src/cpu/base_dyn_inst.hh:
Extend BaseDynInst a little bit so it can be use as a TC as well (specifically for ll/sc code).
src/cpu/base_dyn_inst_impl.hh:
Add variable to track if the result of the instruction should be recorded.
src/cpu/o3/alpha/cpu_impl.hh:
Clear lock flag upon hwrei.
src/cpu/o3/lsq_unit.hh:
Use ISA specified handling of locked reads.
src/cpu/o3/lsq_unit_impl.hh:
Use ISA specified handling of locked writes.

Merge ktlim@zizzer:/bk/newmem
into zamp.eecs.umich.edu:/z/ktlim2/clean/o3-merge/newmem

src/cpu/memtest/memtest.cc:
src/cpu/memtest/memtest.hh:
src/cpu/simple/timing.hh:
tests/configs/o3-timing-mp.py:
Hand merge.

Updates to O3 CPU. It should now work in FS mode, although sampling still has a bug.

src/cpu/o3/commit_impl.hh:
Fixes for compile and sampling.
src/cpu/o3/cpu.cc:
Deallocate and activate threads properly. Also hopefully fix being able to use caches while switching over.
src/cpu/o3/cpu.hh:
Fixes for deallocating and activating threads.
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/lsq_unit.hh:
Handle getting back a BadAddress result from the access.
src/cpu/o3/iew_impl.hh:
More debug output.
src/cpu/o3/lsq_unit_impl.hh:
Fixup store conditional handling (still a bit of a hack, but works now).

Also handle getting back a BadAddress result from the access.
src/cpu/o3/thread_context_impl.hh:
Deallocate context now records if the context should be fully removed.

Replace tests of LOCKED/UNCACHEABLE flags with isLocked()/isUncacheable().

Updates to fix merge issues and bring almost everything up to working speed. Ozone CPU remains untested, but everything else compiles and runs.

src/arch/alpha/isa_traits.hh:
This got changed to the wrong version by accident.
src/cpu/base.cc:
Fix up progress event to not schedule itself if the interval is set to 0.
src/cpu/base.hh:
Fix up the CPU Progress Event to not print itself if it's set to 0. Also remove stats_reset_inst (something I added to m5 but isn't necessary here).
src/cpu/base_dyn_inst.hh:
src/cpu/checker/cpu.hh:
Remove float variable of instResult; it's always held within the double part now.
src/cpu/checker/cpu_impl.hh:
Use thread and not cpuXC.
src/cpu/o3/alpha/cpu_builder.cc:
src/cpu/o3/checker_builder.cc:
src/cpu/ozone/checker_builder.cc:
src/cpu/ozone/cpu_builder.cc:
src/python/m5/objects/BaseCPU.py:
Remove stats_reset_inst.
src/cpu/o3/commit_impl.hh:
src/cpu/ozone/lw_back_end_impl.hh:
Get TC, not XCProxy.
src/cpu/o3/cpu.cc:
Switch out updates from the version of m5 I have. Also remove serialize code that got added twice.
src/cpu/o3/iew_impl.hh:
src/cpu/o3/lsq_impl.hh:
src/cpu/thread_state.hh:
Remove code that was added twice.
src/cpu/o3/lsq_unit.hh:
Add back in stats that got lost in the merge.
src/cpu/o3/lsq_unit_impl.hh:
Use proper method to get flags. Also wake CPU if we're coming back from a cache miss.
src/cpu/o3/thread_context_impl.hh:
src/cpu/o3/thread_state.hh:
Support profiling.
src/cpu/ozone/cpu.hh:
Update to use proper typename.
src/cpu/ozone/cpu_impl.hh:
src/cpu/ozone/dyn_inst_impl.hh:
Updates for newmem.
src/cpu/ozone/lw_lsq_impl.hh:
Get flags correctly.
src/cpu/ozone/thread_state.hh:
Reorder constructor initialization, use tc.
src/sim/pseudo_inst.cc:
Allow for loading of symbol file. Be sure to use ThreadContext and not ExecContext.

Merge ktlim@zamp:./local/clean/o3-merge/m5
into zamp.eecs.umich.edu:/z/ktlim2/clean/o3-merge/newmem

configs/boot/micro_memlat.rcS:
configs/boot/micro_tlblat.rcS:
src/arch/alpha/ev5.cc:
src/arch/alpha/isa/decoder.isa:
src/arch/alpha/isa_traits.hh:
src/cpu/base.cc:
src/cpu/base.hh:
src/cpu/base_dyn_inst.hh:
src/cpu/checker/cpu.hh:
src/cpu/checker/cpu_impl.hh:
src/cpu/o3/alpha/cpu_impl.hh:
src/cpu/o3/alpha/params.hh:
src/cpu/o3/checker_builder.cc:
src/cpu/o3/commit_impl.hh:
src/cpu/o3/cpu.cc:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue.hh:
src/cpu/o3/lsq.hh:
src/cpu/o3/lsq_impl.hh:
src/cpu/o3/lsq_unit.hh:
src/cpu/o3/lsq_unit_impl.hh:
src/cpu/o3/regfile.hh:
src/cpu/o3/rename_impl.hh:
src/cpu/o3/thread_state.hh:
src/cpu/ozone/checker_builder.cc:
src/cpu/ozone/cpu.hh:
src/cpu/ozone/cpu_impl.hh:
src/cpu/ozone/front_end.hh:
src/cpu/ozone/front_end_impl.hh:
src/cpu/ozone/lw_back_end.hh:
src/cpu/ozone/lw_back_end_impl.hh:
src/cpu/ozone/lw_lsq.hh:
src/cpu/ozone/lw_lsq_impl.hh:
src/cpu/ozone/thread_state.hh:
src/cpu/simple/base.cc:
src/cpu/simple_thread.cc:
src/cpu/simple_thread.hh:
src/cpu/thread_state.hh:
src/dev/ide_disk.cc:
src/python/m5/objects/O3CPU.py:
src/python/m5/objects/Root.py:
src/python/m5/objects/System.py:
src/sim/pseudo_inst.cc:
src/sim/pseudo_inst.hh:
src/sim/system.hh:
util/m5/m5.c:
Hand merge.

Fixes for Kevins O3 model to work with the blocking caches.

src/cpu/o3/fetch_impl.hh:
Fix ordering so dereference works
src/cpu/o3/lsq_impl.hh:
Check to make sure we didn't squash already
src/cpu/o3/lsq_unit.hh:
Fix for counting squashed retrys in the WB count
src/cpu/o3/lsq_unit_impl.hh:
Make sure to set retryID for stores, and clear it appropriately

O3CPU fixes.

src/cpu/o3/lsq_unit.hh:
LSQ needs to decrement the WB counter if the load is going to be replayed.
src/cpu/o3/lsq_unit_impl.hh:
LSQ needs to decrement the WB counter if the load is squashed.

Move Dcache port creation from LSQUnit to LSQ in order to support Ron's recent changes, and using the O3CPU in SMT mode.

src/cpu/o3/lsq.hh:
Update to have LSQ work with only one dcache port for all LSQ Units. LSQ has the dcache port, and the LSQ Units must tell the LSQ if the cache has become blocked.
src/cpu/o3/lsq_impl.hh:
Updates to have the LSQ work with only one dcache port for all LSQUnits.
src/cpu/o3/lsq_unit.hh:
src/cpu/o3/lsq_unit_impl.hh:
Update for LSQ to create dcache port instead of LSQUnits. Now LSQUnits are given the dcache port from the LSQ, and also must check the LSQ if the cache is blocked prior to accessing the cache.

Support Ron's changes for hooking up ports.

src/cpu/checker/cpu.hh:
Now that BaseCPU is a MemObject, the checker must define this function.
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/lsq.hh:
src/cpu/o3/lsq_unit.hh:
Implement getPort function so the connector can connect the ports properly.
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/lsq_unit_impl.hh:
The connector handles connecting the ports now.
src/python/m5/objects/O3CPU.py:
Add ports to the parameters.

Add some different parameters. The main change is that the writeback count is now limited so that it doesn't overflow the buffer.

src/cpu/o3/alpha_cpu_builder.cc:
src/cpu/o3/alpha_params.hh:
Add in dispatchWidth, wbWidth, wbDepth parameters. wbDepth is the number of cycles of wbWidth instructions that can be buffered.
src/cpu/o3/iew.hh:
Include separate parameter for dispatch width.
Also limit the number of outstanding writebacks so the writeback buffer isn't overflowed. The IQ must make sure with the IEW stage that it can issue instructions prior to issuing.
src/cpu/o3/iew_impl.hh:
Include separate parameter for dispatch width.
Also limit the number of outstanding writebacks so the writeback buffer isn't overflowed.
src/cpu/o3/inst_queue_impl.hh:
IQ needs to check with the IEW to make sure it can issue instructions, and increments the IEW wb counter each time there is an outstanding instruction that will writeback.
src/cpu/o3/lsq_unit_impl.hh:
Be sure to decrement the writeback counter if there's a squashed load that returned.
src/python/m5/objects/AlphaO3CPU.py:
Change the parameters to include dispatch width, writeback width, and writeback depth.

Misc fixes.

src/cpu/o3/alpha_dyn_inst_impl.hh:
Consolidate these calls into one.
src/cpu/o3/commit_impl.hh:
Include checker only if it's being used.
src/cpu/o3/fetch_impl.hh:
Do not deallocate request if it's a squashed response that was received.
src/cpu/o3/lsq_unit.hh:
Add in comment.
src/cpu/o3/lsq_unit_impl.hh:
Only include checker if it's being used.

Two updates that got combined into one ChangeSet accidentally. They're both pretty simple so they shouldn't cause any trouble.

First: Rename FullCPU and its variants in the o3 directory to O3CPU to differentiate from the old model, and also to specify it's an out of order model.

Second: Include build options for selecting the Checker to be used. These options make sure if the Checker is being used there is a CPU that supports it also being compiled.

SConstruct:
Add in option USE_CHECKER to allow for not compiling in checker code. The checker is enabled through this option instead of through the CPU_MODELS list. However it's still necessary to treat the Checker like a CPU model, so it is appended onto the CPU_MODELS list if enabled.
configs/test/test.py:
Name change for DetailedCPU to DetailedO3CPU. Also include option for max tick.
src/base/traceflags.py:
Add in O3CPU trace flag.
src/cpu/SConscript:
Rename AlphaFullCPU to AlphaO3CPU.

Only include checker sources if they're necessary. Also add a list of CPUs that support the Checker, and only allow the Checker to be compiled in if one of those CPUs are also being included.
src/cpu/base_dyn_inst.cc:
src/cpu/base_dyn_inst.hh:
Rename typedef to ImplCPU instead of FullCPU, to differentiate from the old FullCPU.
src/cpu/cpu_models.py:
src/cpu/o3/alpha_cpu.cc:
src/cpu/o3/alpha_cpu.hh:
src/cpu/o3/alpha_cpu_builder.cc:
src/cpu/o3/alpha_cpu_impl.hh:
Rename AlphaFullCPU to AlphaO3CPU to differentiate from old FullCPU model.
src/cpu/o3/alpha_dyn_inst.hh:
src/cpu/o3/alpha_dyn_inst_impl.hh:
src/cpu/o3/alpha_impl.hh:
src/cpu/o3/alpha_params.hh:
src/cpu/o3/commit.hh:
src/cpu/o3/cpu.hh:
src/cpu/o3/decode.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue.hh:
src/cpu/o3/lsq.hh:
src/cpu/o3/lsq_impl.hh:
src/cpu/o3/lsq_unit.hh:
src/cpu/o3/regfile.hh:
src/cpu/o3/rename.hh:
src/cpu/o3/rename_impl.hh:
src/cpu/o3/rob.hh:
src/cpu/o3/rob_impl.hh:
src/cpu/o3/thread_state.hh:
src/python/m5/objects/AlphaO3CPU.py:
Rename FullCPU to O3CPU to differentiate from old FullCPU model.
src/cpu/o3/commit_impl.hh:
src/cpu/o3/cpu.cc:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/lsq_unit_impl.hh:
Rename FullCPU to O3CPU to differentiate from old FullCPU model.
Also #ifdef the checker code so it doesn't need to be included if it's not selected.

Checker updates.

src/cpu/checker/cpu.cc:
src/cpu/checker/cpu.hh:
Updates for checker. Output more informative messages on error. Rename some functions. Add in option to warn (and not exit) on load results being incorrect.
src/cpu/checker/cpu_builder.cc:
src/cpu/checker/o3_cpu_builder.cc:
Add in parameter to warn (and not exit) on load result errors.
src/cpu/o3/commit_impl.hh:
src/cpu/o3/lsq_unit_impl.hh:
Renamed checker functin.

Minor code cleanup of BaseDynInst.

src/cpu/base_dyn_inst.cc:
src/cpu/base_dyn_inst.hh:
Minor code cleanup by putting several bools into a bitset instead.
src/cpu/o3/commit_impl.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue_impl.hh:
src/cpu/o3/lsq_unit.hh:
src/cpu/o3/lsq_unit_impl.hh:
src/cpu/o3/rename_impl.hh:
src/cpu/o3/rob_impl.hh:
Changed around some things in BaseDynInst.

Minor updates for stats.

src/cpu/o3/commit_impl.hh:
src/cpu/o3/fetch.hh:
Update stats comments.
src/cpu/o3/fetch_impl.hh:
Differentiate stats.
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue.hh:
src/cpu/o3/inst_queue_impl.hh:
Update for stats.
src/cpu/o3/lsq.hh:
LSQ now has stats.
src/cpu/o3/lsq_impl.hh:
Register stats of all LSQ units.
src/cpu/o3/lsq_unit.hh:
src/cpu/o3/lsq_unit_impl.hh:
Add in stats.

Compile fix.

Two minor fixes.

src/cpu/o3/lsq_unit_impl.hh:
Missed this name change.
src/cpu/thread_state.cc:
Fix for stats.

Removing of old code and adding in new comments.

src/cpu/base_dyn_inst.cc:
Clean up old functions, comments.
src/cpu/o3/alpha_cpu_builder.cc:
src/cpu/o3/alpha_params.hh:
src/cpu/o3/cpu.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/lsq.hh:
src/cpu/o3/lsq_impl.hh:
src/cpu/o3/rename_impl.hh:
src/cpu/ozone/lsq_unit.hh:
src/cpu/ozone/lsq_unit_impl.hh:
Remove old commented code.
src/cpu/o3/fetch.hh:
Remove old commented code, add in comments.
src/cpu/o3/inst_queue_impl.hh:
Move comment to better place.
src/cpu/o3/lsq_unit.hh:
Remove old commented code, add in new comments.
src/cpu/o3/lsq_unit_impl.hh:
Remove old commented code, rename variable.

Fixes for some outstanding issues in the LSQ. It should now be able to retry. It should also be able to handle LL/SC (through hacks) for the UP case.

src/cpu/o3/lsq_unit.hh:
Handle being able to retry (untested but hopefully very close to working).

Handle lock flag for LL/SC hack. Hopefully the memory system will add in LL/SC soon.

Better output message.
src/cpu/o3/lsq_unit_impl.hh:
Handle being able to retry (untested but should be very close to working).

Make SC's work (hopefully) while the memory system doesn't have a LL/SC implementation.

Tell checker that an instruction is completed prior once it does the access to memory. As long as the checker does not access memory to verify the store's data (currently impossible in the O3 model), this will work fine.

src/cpu/o3/lsq_unit_impl.hh:
Tell checker that an instruction is completed prior once it does the access to memory.

Update copyright.

Fix checker to work in newmem in SE mode.

src/cpu/o3/fetch_impl.hh:
Give the checker a pointer to the icachePort.
src/cpu/o3/lsq_unit_impl.hh:
Give the checker a pointer to the dcachePort.
src/mem/request.hh:
Allow checking for the scResult being valid prior to accessing it.

Fixes to get new CPU model working for simple test case. The CPU does not yet support retrying accesses.

src/cpu/base_dyn_inst.cc:
Delete the allocated data in destructor.
src/cpu/base_dyn_inst.hh:
Only copy the addresses if the translation succeeded.
src/cpu/o3/alpha_cpu.hh:
Return actual translating port.
Don't panic on setNextNPC() as it's always called, regardless of the architecture, when the process initializes.
src/cpu/o3/alpha_cpu_impl.hh:
Pass in memobject to the thread state in SE mode.
src/cpu/o3/commit_impl.hh:
Initialize all variables.
src/cpu/o3/decode_impl.hh:
Handle early resolution of branches properly.
src/cpu/o3/fetch.hh:
Switch structure back to requests.
src/cpu/o3/fetch_impl.hh:
Initialize all variables, create/delete requests properly.
src/cpu/o3/lsq_unit.hh:
Include sender state along with the packet. Also include a more generic writeback event that's only used for stores forwarding data to loads.
src/cpu/o3/lsq_unit_impl.hh:
Redo writeback code to support the response path of the memory system.
src/cpu/o3/mem_dep_unit.cc:
src/cpu/o3/mem_dep_unit_impl.hh:
Wrap variables in #ifdefs.
src/cpu/o3/store_set.cc:
Include to get panic() function.
src/cpu/o3/thread_state.hh:
Create with MemObject as well.
src/cpu/thread_state.hh:
Have a translating port in the thread state object.
src/python/m5/objects/AlphaFullCPU.py:
Mem parameter no longer needed.

Merge ktlim@zamp:/z/ktlim2/clean/m5-o3
into zamp.eecs.umich.edu:/z/ktlim2/clean/newmem-merge

src/cpu/checker/o3_cpu_builder.cc:
src/cpu/o3/alpha_cpu.hh:
src/cpu/o3/alpha_cpu_impl.hh:
src/cpu/o3/alpha_dyn_inst_impl.hh:
src/cpu/o3/bpred_unit.cc:
src/cpu/o3/commit.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/lsq_unit.hh:
src/cpu/o3/lsq_unit_impl.hh:
src/cpu/o3/thread_state.hh:
Hand merge.

Fixes to get compiling to work. This is mainly fixing up some includes; changing functions within the XCs; changing MemReqPtrs to Requests or Packets where appropriate.

Currently the O3 and Ozone CPUs do not work in the new memory system; I still need to fix up the ports to work and handle responses properly. This check-in is so that the merge between m5 and newmem is no longer outstanding.

src/SConscript:
Need to include FU Pool for new CPU model. I'll try to figure out a cleaner way to handle this in the future.
src/base/traceflags.py:
Include new traces flags, fix up merge mess up.
src/cpu/SConscript:
Include the base_dyn_inst.cc as one of othe sources.
Don't compile the Ozone CPU for now.
src/cpu/base.cc:
Remove an extra } from the merge.
src/cpu/base_dyn_inst.cc:
Fixes to make compiling work. Don't instantiate the OzoneCPU for now.
src/cpu/base_dyn_inst.hh:
src/cpu/o3/2bit_local_pred.cc:
src/cpu/o3/alpha_cpu_builder.cc:
src/cpu/o3/alpha_cpu_impl.hh:
src/cpu/o3/alpha_dyn_inst.hh:
src/cpu/o3/alpha_params.hh:
src/cpu/o3/bpred_unit.cc:
src/cpu/o3/btb.hh:
src/cpu/o3/commit.hh:
src/cpu/o3/commit_impl.hh:
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/free_list.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue.hh:
src/cpu/o3/inst_queue_impl.hh:
src/cpu/o3/regfile.hh:
src/cpu/o3/sat_counter.hh:
src/cpu/op_class.hh:
src/cpu/ozone/cpu.hh:
src/cpu/checker/cpu.cc:
src/cpu/checker/cpu.hh:
src/cpu/checker/exec_context.hh:
src/cpu/checker/o3_cpu_builder.cc:
src/cpu/ozone/cpu_impl.hh:
src/mem/request.hh:
src/cpu/o3/fu_pool.hh:
src/cpu/o3/lsq.hh:
src/cpu/o3/lsq_unit.hh:
src/cpu/o3/lsq_unit_impl.hh:
src/cpu/o3/thread_state.hh:
src/cpu/ozone/back_end.hh:
src/cpu/ozone/dyn_inst.cc:
src/cpu/ozone/dyn_inst.hh:
src/cpu/ozone/front_end.hh:
src/cpu/ozone/inorder_back_end.hh:
src/cpu/ozone/lw_back_end.hh:
src/cpu/ozone/lw_lsq.hh:
src/cpu/ozone/ozone_impl.hh:
src/cpu/ozone/thread_state.hh:
Fixes to get compiling to work.
src/cpu/o3/alpha_cpu.hh:
Fixes to get compiling to work.
Float reg accessors have changed, as well as MemReqPtrs to RequestPtrs.
src/cpu/o3/alpha_dyn_inst_impl.hh:
Fixes to get compiling to work.
Pass in the packet to the completeAcc function.
Fix up syscall function.