cpu: Move O3's data port into the LSQ.

That's where it's used, and putting it there avoids having to pass
around the port using the top level getDataPort function.

Change-Id: I0dea25d0c5f4bb3f58a6574a8f2b2d242784caf2
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20238
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>

cpu-o3: Add support for pinned writes

This patch adds support for pinning registers for a certain number of
consecutive writes. This is only relevant for timing CPU models
(functional-only models are unaffected), and it is primarily needed to
provide a realistic execution model for micro-coded operations whose
microops can write to non-overlapping portions of a destination
register, e.g. vector gather loads. In those cases, this mechanism
can disable renaming for a sequence of consecutive writes, thus making
the resulting execution more efficient: allocating a new physical
register for each microop would introduce a read-modify-write chain of
dependencies, while with these modifications the microops can write
back in parallel.

Please note that this new feature is only leveraged by O3CPU for the
time being.

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

Change-Id: I07eb5fdbd1fa0b748c9bdc1174d9f330fda34f81
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/13520
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.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>

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: fixed how O3 CPU executes an exit system call

When a thread executed an exit syscall in SE mode, the thread context
was removed immediately in the same cycle, which left inflight squash
operations and trap event incomplete. The problem happened when a new
thread was assigned to the CPU later. The new thread started with some
incomplete transactions of the previous thread (e.g., squashing). This
problem could cause incorrect execution flow for the new thread (i.e.,
pc was not reset properly at the exit point), deadlock (i.e., some
stage-to-stage signals were not reset) and incorrect rename map between
logical and physical registers.

This patch adds a new state called 'Halting' to the thread context and
defers removing thread context from a CPU until a trap event initiated
by an exit syscall execution is processed. This patch also makes sure
that the removal of a thread context happens after all inflight
transactions of the to-be-removed thread in the pipeline complete.

Change-Id: If7ef1462fb8864e22b45371ee7ae67e2a5ad38b8
Reviewed-on: https://gem5-review.googlesource.com/c/8184
Reviewed-by: Giacomo Gabrielli <giacomo.gabrielli@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,arch-arm: Initialise data members

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>

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>

cpu-o3: Don't add non-speculative mem barriers to the IQ twice

There are cases where the IEW adds a non-speculative instruction to
the IQ twice. This can happen if an instruction is flagged as
IsMemBarrier and IsNonSpeculative. Avoid adding non-speculative
instructions in the IEW to the IQ by checking if it has been added
already.

Change-Id: Ifcff676a451b57b2406ce00ed8dae19ed399515f
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Javier Setoain <javier.setoain@arm.com>
Reviewed-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/8374
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

cpu: Simplify the rename interface and use RegId

With the hierarchical RegId there are a lot of functions that are
redundant now.

The idea behind the simplification is that instead of having the regId,
telling which kind of register read/write/rename/lookup/etc. and then
the function panic_if'ing if the regId is not of the appropriate type,
we provide an interface that decides what kind of register to read
depending on the register type of the given regId.

Change-Id: I7d52e9e21fc01205ae365d86921a4ceb67a57178
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
[ Fix RISCV build issues ]
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2702

cpu: Physical register structural + flat indexing

Mimic the changes done on the architectural register indexes on the
physical register indexes. This is specific to the O3 model. The
structure, called PhysRegId, contains a register class, a register
index and a flat register index. The flat register index is kept
because it is useful in some cases where the type of register is not
important (dependency graph and scoreboard for example). Instead
of directly using the structure, most of the code is working with
a const PhysRegId* (typedef to PhysRegIdPtr). The actual PhysRegId
objects are stored in the regFile.

Change-Id: Ic879a3cc608aa2f34e2168280faac1846de77667
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2701
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

cpu: Fix the O3 CPU Drain

The drain did not wait until stages were ready again. Therefore, as a
result of messages in the TimeBuffer being drain, the state after the
drain was not consistent and asserts fired in some places when the
draining happened after a stage got blocked, but before the notification
arrived to the previous stages.

Change-Id: Ib50b3b40b7f745b62c1eba2931dec76860824c71
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

probe: Add probe in Fetch, IEW, Rename and Commit

This patch adds probe points in Fetch, IEW, Rename and Commit stages as follows.

A probe point is added in the Fetch stage for probing when a fetch request is
sent. Notify is fired on the probe point when a request is sent succesfully in
the first attempt as well as on a retry attempt.

Probe points are added in the IEW stage when an instruction begins to execute
and when execution is complete. This points can be used for monitoring the
execution time of an instruction.

Probe points are added in the Rename stage to probe renaming of source and
destination registers and when there is squashing. These probe points can be
used to track register dependencies and remove when there is squashing.

A probe point for squashing is added in Commit to probe squashed instructions.

o3: drop unused statistic wbPenalized and wbPenalizedRate

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: Remove unused code in iew, add assert instead.

cpu: Add drain check functionality to IEW

IEW did not check the instQueue and memDepUnit to ensure
they were drained. This caused issues when drainSanityCheck()
did check those structures after asserting IEW was drained.

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: Fix o3 front-end pipeline interlock behavior

The o3 pipeline interlock/stall logic is incorrect. o3 unnecessicarily stalled
fetch and decode due to later stages in the pipeline. In general, a stage
should usually only consider if it is stalled by the adjacent, downstream stage.
Forcing stalls due to later stages creates and results in bubbles in the
pipeline. Additionally, o3 stalled the entire frontend (fetch, decode, rename)
on a branch mispredict while the ROB is being serially walked to update the
RAT (robSquashing). Only should have stalled at rename.

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: make dispatch LSQ full check more selective

Dispatch should not check LSQ size/LSQ stall for non load/store
instructions.

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

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: Add O3 CPU width checks

O3CPU has a compile-time maximum width set in o3/impl.hh, but checking
the configuration against this limit was not implemented anywhere
except for fetch. Configuring a wider pipe than the limit can silently
cause various issues during the simulation. This patch adds the proper
checking in the constructor of the various pipeline stages.

o3: Fix occupancy checks for SMT
A number of calls to isEmpty() and numFreeEntries()
should be thread-specific.

In cpu.cc, the fact that tid is /*commented*/ out is a bug. Say the rob
has instructions from thread 0 (isEmpty() returns false), and none from
thread 1. If we are trying to squash all of thread 1, then
readTailInst(thread 1) will be called because rob->isEmpty() returns
false. The result is end_it is not in the list and the while
statement loops indefinitely back over the cpu's instList.

In iew_impl.hh, all threads are told they have the entire remaining IQ, when
each thread actually has a certain allocation. The result is extra stalls at
the iew dispatch stage which the rename stage usually takes care of.

In commit_impl.hh, rob->readHeadInst(thread 1) can be called if the rob only
contains instructions from thread 0. This returns a dummyInst (which may work
since we are trying to squash all instructions, but hardly seems like the right
way to do it).

In rob_impl.hh this fix skips the rest of the function more frequently and is
more efficient.

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

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%).

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

cpu: Change IEW DPRINTF to use IEW debug flag

IEW DPRINTF uses Decode debug flag, which appears to be a copying error. This
patch changes this to the IEW Debug flag.

cpu: Consider instructions waiting for FU completion in draining

This patch changes the IEW drain check to include the FU pool as there
can be instructions that are "stored" in FU completion events and thus
not covered by the existing checks. With this patch, we simply include
a check to see if all the FUs are considered non-busy in the next
tick.

Without this patch, the pc-switcheroo-full regression fails after
minor changes to the cache timing (aligning to clock edge).

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: Initialize the O3 pipeline from startup()

The entire O3 pipeline used to be initialized from init(), which is
called before initState() or unserialize(). This causes the pipeline
to be initialized from an incorrect thread context. This doesn't
currently lead to correctness problems as instructions fetched from
the incorrect start PC will be squashed a few cycles after
initialization.

This patch will affect the regressions since the O3 CPU now issues its
first instruction fetch to the correct PC instead of 0x0.

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.

O3/Ozone: Eliminate dead code counting software prefetch insts

Eliminates dead code in the O3 and Ozone CPU models that counted
software prefetch instructions separately for the ALPHA ISA only.

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.

CPU: Round-two unifying instr/data CPU ports across models

This patch continues the unification of how the different CPU models
create and share their instruction and data ports. Most importantly,
it forces every CPU to have an instruction and a data port, and gives
these ports explicit getters in the BaseCPU (getDataPort and
getInstPort). The patch helps in simplifying the code, make
assumptions more explicit, andfurther ease future patches related to
the CPU ports.

The biggest changes are in the in-order model (that was not modified
in the previous unification patch), which now moves the ports from the
CacheUnit to the CPU. It also distinguishes the instruction fetch and
load-store unit from the rest of the resources, and avoids the use of
indices and casting in favour of keeping track of these two units
explicitly (since they are always there anyways). The atomic, timing
and O3 model simply return references to their already existing ports.

clang: Enable compiling gem5 using clang 2.9 and 3.0

This patch adds the necessary flags to the SConstruct and SConscript
files for compiling using clang 2.9 and later (on Ubuntu et al and OSX
XCode 4.2), and also cleans up a bunch of compiler warnings found by
clang. Most of the warnings are related to hidden virtual functions,
comparisons with unsigneds >= 0, and if-statements with empty
bodies. A number of mismatches between struct and class are also
fixed. clang 2.8 is not working as it has problems with class names
that occur in multiple namespaces (e.g. Statistics in
kernel_stats.hh).

clang has a bug (http://llvm.org/bugs/show_bug.cgi?id=7247) which
causes confusion between the container std::set and the function
Packet::set, and this is currently addressed by not including the
entire namespace std, but rather selecting e.g. "using std::vector" in
the appropriate places.

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.

DPRINTF: Improve some dprintf messages.

O3: Squash the violator and younger instructions instead not all insts.

Change the way instructions are squashed on memory ordering violations
to squash the violator and younger instructions, not all instructions
that are younger than the instruction they violated (no reason to throw
away valid work).

O3: Create a pipeline activity viewer for the O3 CPU model.

Implemented a pipeline activity viewer as a python script (util/o3-pipeview.py)
and modified O3 code base to support an extra trace flag (O3PipeView) for
generating traces to be used as inputs by the tool.

O3: Fix issue w/wbOutstading being decremented multiple times on blocked cache.

If a split load fails on a blocked cache wbOutstanding can be decremented
twice if the first part of the split load succeeds and the second part fails.
Condition the decrementing on not having completed the first part of the load.

O3: Fix an issue with a load & branch instruction and mem dep squashing

Instructions that load an address and are control instructions can
execute down the wrong path if they were predicted correctly and then
instructions following them are squashed. If an instruction is a
memory and control op use the predicted address for the next PC instead
of just advancing the PC. Without this change NPC is used for the next
instruction, but predPC is used to verify that the branch was successful
so the wrong path is silently executed.

stats: rename stats so they can be used as python expressions

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: fix up code after sorting

includes: sort all includes

O3: Cleanup the commitInfo comm struct.

Get rid of unused members and use base types rather than derrived values
where possible to limit amount of state.

O3: When a prefetch causes a fault, don't record it in the inst

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.

mcpat: Adds McPAT performance counters

Updated patches from Rick Strong's set that modify performance counters for
McPAT

O3: Don't test misprediction on load instructions until executed.

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

O3: Fix mispredicts from non control instructions.
The squash inside the fetch unit should not attempt to remove them from the
branch predictor as non-control instructions are not pushed into the predictor.

O3: Fixes the way prefetches are handled inside the iew unit.

This patch prevents the prefetch being added to the instCommit queue twice.

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

O3: Fixes fetch deadlock when the interrupt clears before CPU handles it.

When this condition occurs the cpu should restart the fetch stage to fetch from
the original execution path. Fault handling in the commit stage is cleaned up a
little bit so the control flow is simplier. Finally, if an instruction is being
used to carry a fault it isn't executed, so the fault propagates appropriately.

Move sched_list.hh and timebuf.hh from src/base to src/cpu.
These files really aren't general enough to belong in src/base.
This patch doesn't reorder include lines, leaving them unsorted
in many cases, but Nate's magic script will fix that up shortly.

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.

ARM: mark msr/mrs instructions as SerializeBefore/After
Since miscellaneous registers bypass wakeup logic, force serialization
to resolve data dependencies through them
* * *
ARM: adding non-speculative/serialize flags for instructions change CPSR

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

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

o3-delay-slot-bpred: fix decode stage handling of uncdtl. branches.\n decode stage was not setting the predicted PC correctly or passing that information back to fetch correctly

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.

O3: Remove unneeded variable.

Add support for microcode and pull out the special branch delay slot handling. Branch delay slots need to be squash on a mispredict as well because the nnpc they saw was incorrect.

Remove most of the special handling for delay slots since they have to be squashed anyway on a mispredict. This is because the NNPC value they saw when executing was incorrect.

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.

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.

Handle status bits a little better, as well as non-speculative instructions.

src/cpu/o3/iew_impl.hh:
Allow for slightly more flexible handling of non-speculative instructions. They can be other classes now, such as loads or stores.

Also be sure to clear the state associated with squashes that are not used. i.e. if a squash due to a memory ordering violation happens on the same cycle as an older branch squashing, clear the state associated with the memory ordering violation.

Lastly don't consider uncached loads to officially be "at commit" until IEW receives the signal back from commit about the load.
src/cpu/o3/inst_queue_impl.hh:
Don't consider non-speculative instructions to be "at commit" until the IQ has received a signal from commit about the instruction. This prevents non-speculative instructions from being issued too early.
src/cpu/o3/mem_dep_unit_impl.hh:
Clear instruction's ability to issue if it's replayed.

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

Fixes to get non-delay slot ISAs (Alpha) working again, and pulling some debug output out of ifdefs.

Fix a place where the wrong width parameter was used, and set the nextNPC correctly on memory squashes.

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

src/arch/isa_parser.py:
src/arch/sparc/isa/formats/mem/basicmem.isa:
src/arch/sparc/isa/formats/mem/blockmem.isa:
src/arch/sparc/isa/formats/mem/util.isa:
src/arch/sparc/miscregfile.cc:
src/arch/sparc/miscregfile.hh:
src/cpu/o3/iew_impl.hh:
Hand Merge

Remove some #if FULL_SYSTEMs so MP stuff works even in SE mode.

don't use (*activeThreads).begin(), use activeThreads->blah().
Also don't call (*activeThreads).end() over and over. Just
call activeThreads->end() once and save the result.
Make sure we always check that there are elements in the list
before we grab the first one.

Made branch delay slots get squashed, and passed back an NPC and NNPC to start fetching from.

Change how optional delay slot instructions are detected and squashed.

Allow for multiple redirects to happen on a single cycle (only the one for the oldest instruction is passed on to commit).

This fixes a minor bug when multiple FU completions come back out of order (due to the order in which the FUs are freed up), and the oldest redirect isn't recorded properly. The eon benchmark should run now.

src/cpu/o3/iew_impl.hh:
Allow for multiple redirects to happen on a single cycle (only the one for the oldest instruction is passed on to commit).

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.

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.

add ISA_HAS_DELAY_SLOT directive instead of "#if THE_ISA == ALPHA_ISA" throughout CPU models

src/arch/alpha/isa_traits.hh:
src/arch/mips/isa_traits.hh:
src/arch/sparc/isa_traits.hh:
define 'ISA_HAS_DELAY_SLOT'
src/cpu/base_dyn_inst.hh:
src/cpu/o3/bpred_unit_impl.hh:
src/cpu/o3/commit_impl.hh:
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.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/rename_impl.hh:
src/cpu/simple/base.cc:
use ISA_HAS_DELAY_SLOT instead of THE_ISA == ALPHA_ISA

Cleaned up include files and got rid of many using directives in header files.

This changeset gets the MIPS ISA pretty much working in the O3CPU. It builds, runs, and gets very very close to completing the hello world
succesfully but there are some minor quirks to iron out. Who would've known a DELAY SLOT introduces that much complexity?! arrgh!

Anyways, a lot of this stuff had to do with my project at MIPS and me needing to know how I was going to get this working for the MIPS
ISA. So I figured I would try to touch it up and throw it in here (I hate to introduce non-completely working components... )

src/arch/alpha/isa/mem.isa:
spacing
src/arch/mips/faults.cc:
src/arch/mips/faults.hh:
Gabe really authored this
src/arch/mips/isa/decoder.isa:
add StoreConditional Flag to instruction
src/arch/mips/isa/formats/basic.isa:
Steven really did this file
src/arch/mips/isa/formats/branch.isa:
fix bug for uncond/cond control
src/arch/mips/isa/formats/mem.isa:
Adjust O3CPU memory access to use new memory model interface.
src/arch/mips/isa/formats/util.isa:
update LoadStoreBase template
src/arch/mips/isa_traits.cc:
update SERIALIZE partially
src/arch/mips/process.cc:
src/arch/mips/process.hh:
no need for this for NOW. ASID/Virtual addressing handles it
src/arch/mips/regfile/misc_regfile.hh:
add in clear() function and comments for future usage of special misc. regs
src/cpu/base_dyn_inst.hh:
add in nextNPC variable and supporting functions.

add isCondDelaySlot function

Update predTaken and mispredicted functions
src/cpu/base_dyn_inst_impl.hh:
init nextNPC
src/cpu/o3/SConscript:
add MIPS files to compile
src/cpu/o3/alpha/thread_context.hh:
no need for my name on this file
src/cpu/o3/bpred_unit_impl.hh:
Update RAS appropriately for MIPS
src/cpu/o3/comm.hh:
add some extra communication variables to aid in handling the
delay slots
src/cpu/o3/commit.hh:
minor name fix for nextNPC functions.
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/rename_impl.hh:
Fix necessary variables and functions for squashes with delay slots
src/cpu/o3/cpu.cc:
Update function interface ...

adjust removeInstsNotInROB function to recognize delay slots insts
src/cpu/o3/cpu.hh:
update removeInstsNotInROB
src/cpu/o3/decode.hh:
declare necessary variables for handling delay slot
src/cpu/o3/dyn_inst.hh:
Add in MipsDynInst
src/cpu/o3/fetch.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/rename.hh:
declare necessary variables and adjust functions for handling delay slot
src/cpu/o3/inst_queue.hh:
src/cpu/simple/base.cc:
no need for my name here
src/cpu/o3/isa_specific.hh:
add in MIPS files
src/cpu/o3/scoreboard.hh:
dont include alpha specific isa traits!
src/cpu/o3/thread_context.hh:
no need for my name here, i just rearranged where the file goes
src/cpu/static_inst.hh:
add isCondDelaySlot function
src/cpu/o3/mips/cpu.cc:
src/cpu/o3/mips/cpu.hh:
src/cpu/o3/mips/cpu_builder.cc:
src/cpu/o3/mips/cpu_impl.hh:
src/cpu/o3/mips/dyn_inst.cc:
src/cpu/o3/mips/dyn_inst.hh:
src/cpu/o3/mips/dyn_inst_impl.hh:
src/cpu/o3/mips/impl.hh:
src/cpu/o3/mips/params.hh:
src/cpu/o3/mips/thread_context.cc:
src/cpu/o3/mips/thread_context.hh:
MIPS file for O3CPU...mirrors ALPHA definition

Add parameters for backwards and forwards sizes for time buffers.

src/base/timebuf.hh:
Add a function to return the size of the time buffer.

Fix the O3CPU to support the multi-pass method for checking if the system has fully drained.

src/cpu/o3/commit.hh:
src/cpu/o3/commit_impl.hh:
src/cpu/o3/decode.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/rename.hh:
src/cpu/o3/rename_impl.hh:
Return a value so that the CPU can instantly return from draining if the pipeline is already drained.
src/cpu/o3/cpu.cc:
Use values returned from pipeline stages so that the CPU can instantly return from draining if the pipeline is already drained.

Support for draining, and the new method of switching out. Now switching out happens after the pipeline has been drained, deferring the three way handshake to the normal drain mechanism. The calls of switchOut() and takeOverFrom() both take action immediately.

src/cpu/o3/commit.hh:
src/cpu/o3/commit_impl.hh:
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/decode.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/rename.hh:
src/cpu/o3/rename_impl.hh:
Support for draining, new method of switching out.

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.

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.

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.

Clean up/shift some code around.

src/cpu/base_dyn_inst.cc:
Clean up some code and update.
src/cpu/base_dyn_inst.hh:
Clean up some code and update with more descriptive function names.
src/cpu/o3/alpha_cpu_builder.cc:
src/cpu/o3/alpha_params.hh:
src/cpu/o3/commit.hh:
Remove unused parameters.
src/cpu/o3/commit_impl.hh:
Remove unused parameters, also set squashCounter directly to the counted number of squashes.
src/cpu/o3/fetch_impl.hh:
Update for function name changes.
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
Remove unused parameter, move some code into a function.

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.

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.

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

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.

Updated Authors from bk prs info

Merge ktlim@zizzer:/bk/m5
into zamp.eecs.umich.edu:/z/ktlim2/clean/newmem

SConstruct:
src/SConscript:
src/arch/SConscript:
src/arch/alpha/faults.cc:
src/arch/alpha/tlb.cc:
src/base/traceflags.py:
src/cpu/SConscript:
src/cpu/base.cc:
src/cpu/base.hh:
src/cpu/base_dyn_inst.cc:
src/cpu/cpu_exec_context.cc:
src/cpu/cpu_exec_context.hh:
src/cpu/exec_context.hh:
src/cpu/o3/alpha_cpu.hh:
src/cpu/o3/alpha_cpu_impl.hh:
src/cpu/o3/alpha_dyn_inst.hh:
src/cpu/o3/cpu.cc:
src/cpu/o3/cpu.hh:
src/cpu/o3/regfile.hh:
src/cpu/ozone/cpu.hh:
src/cpu/simple/base.cc:
src/cpu/base_dyn_inst.hh:
src/cpu/o3/2bit_local_pred.cc:
src/cpu/o3/2bit_local_pred.hh:
src/cpu/o3/alpha_cpu.cc:
src/cpu/o3/alpha_cpu_builder.cc:
src/cpu/o3/alpha_dyn_inst.cc:
src/cpu/o3/alpha_dyn_inst_impl.hh:
src/cpu/o3/alpha_impl.hh:
src/cpu/o3/alpha_params.hh:
src/cpu/o3/bpred_unit.cc:
src/cpu/o3/bpred_unit.hh:
src/cpu/o3/bpred_unit_impl.hh:
src/cpu/o3/btb.cc:
src/cpu/o3/btb.hh:
src/cpu/o3/comm.hh:
src/cpu/o3/commit.cc:
src/cpu/o3/commit.hh:
src/cpu/o3/commit_impl.hh:
src/cpu/o3/cpu_policy.hh:
src/cpu/o3/decode.cc:
src/cpu/o3/decode.hh:
src/cpu/o3/decode_impl.hh:
src/cpu/o3/fetch.cc:
src/cpu/o3/fetch.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/o3/free_list.cc:
src/cpu/o3/free_list.hh:
src/cpu/o3/iew.cc:
src/cpu/o3/iew.hh:
src/cpu/o3/iew_impl.hh:
src/cpu/o3/inst_queue.cc:
src/cpu/o3/inst_queue.hh:
src/cpu/o3/inst_queue_impl.hh:
src/cpu/o3/mem_dep_unit.cc:
src/cpu/o3/mem_dep_unit.hh:
src/cpu/o3/mem_dep_unit_impl.hh:
src/cpu/o3/ras.cc:
src/cpu/o3/ras.hh:
src/cpu/o3/rename.cc:
src/cpu/o3/rename.hh:
src/cpu/o3/rename_impl.hh:
src/cpu/o3/rename_map.cc:
src/cpu/o3/rename_map.hh:
src/cpu/o3/rob.cc:
src/cpu/o3/rob.hh:
src/cpu/o3/rob_impl.hh:
src/cpu/o3/sat_counter.cc:
src/cpu/o3/sat_counter.hh:
src/cpu/o3/store_set.cc:
src/cpu/o3/store_set.hh:
src/cpu/o3/tournament_pred.cc:
src/cpu/o3/tournament_pred.hh:
Hand merges.

New directory structure:
- simulator source now in 'src' subdirectory
- imported files from 'ext' repository
- support building in arbitrary places, including
outside of the source tree. See comment at top
of SConstruct file for more details.
Regression tests are temporarily disabled; that
syetem needs more extensive revisions.

SConstruct:
Update for new directory structure.
Modify to support build trees that are not subdirectories
of the source tree. See comment at top of file for
more details.
Regression tests are temporarily disabled.
src/arch/SConscript:
src/arch/isa_parser.py:
src/python/SConscript:
Update for new directory structure.