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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>
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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>
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This is now handled within the ISA description.
Change-Id: Ie409bb46d102e59d4eb41408d9196fe235626d32
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18434
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
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This mechanism is specific to Alpha and doesn't belong sprinkled around
the CPU's generic mechanisms.
Change-Id: I87904d1a08df2b03eb770205e2c4b94db25201a1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18432
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
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Then cast to the ISA specific type when necessary. This removes
(mostly) an ISA specific aspect to some of the interfaces. The ISA
specific version of the kernel stats still needs to be constructed and
stored in a few places which means that kernel_stats.hh still needs to
be a switching arch header, for instance.
In the future, I'd like to make the kernel its own object like the
Process objects in SE mode, and then it would be able to instantiate
and maintain its own stats.
Change-Id: I8309d49019124f6bea1482aaea5b5b34e8c97433
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18429
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
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These are implemented by MIPS internally now.
Change-Id: If7465e1666e51e1314968efb56a5a814e62ee2d1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18436
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>
Tested-by: kokoro <noreply+kokoro@google.com>
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MemObject doesn't provide anything beyond its base ClockedObject any
more, so this change removes it from most inheritance hierarchies.
Occasionally MemObject is replaced with SimObject when I was fairly
confident that the extra functionality of ClockedObject wasn't needed.
Change-Id: Ic014ab61e56402e62548e8c831eb16e26523fdce
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18289
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>
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Change-Id: I53f34b2d9db6e4d2e03dde42a970764bb2a5e701
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17730
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
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A probe is added to notify the address of each retired instruction.
Change-Id: Iefc1b09d74b3aa0aa5773b17ba637bf51f5a59c9
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17632
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
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The importer in Python 3 doesn't like the way we import SimObjects
from the global namespace. Convert the existing SimObject declarations
to import from m5.objects. As a side-effect, this makes these files
consistent with configuration files.
Change-Id: I11153502b430822130722839e1fa767b82a027aa
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15981
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
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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>
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Most architectures weren't using the CCReg type, and in x86 and arm
it was already a uint64_t.
Change-Id: I0b3d5e690e6b31db6f2627f449c89bde0f6750a6
Reviewed-on: https://gem5-review.googlesource.com/c/14515
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
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Now that there's no plain FloatReg, there's no reason to distinguish
FloatRegBits with a special suffix since it's the only way to read or
write FP registers.
Change-Id: I3a60168c1d4302aed55223ea8e37b421f21efded
Reviewed-on: https://gem5-review.googlesource.com/c/14460
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
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Latest-gen. vector/SIMD extensions, including the Arm Scalable Vector
Extension (SVE), introduce the notion of a predicate register file.
This changeset adds this feature across architectures and CPU models.
Change-Id: Iebcadbad89c0a582ff8b1b70de353305db603946
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13715
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
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This patch is:
* Adding a missing VecElemClass entry
* Fixing assertion in rename map which was checking the number of free
vector registers rather than free vector element registers
* Fixing assertion in read/setVecElemOperand APIs.
* Using the right register index in SimpleThread
* Using VecElem instead of VecReg on O3 readArchVecElem
Change-Id: I265320dcbe35eb47075991301dfc99333c5190c4
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15598
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
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These values are all basic integers (specifically uint64_t now), and
so passing them by const & is actually less efficient since there's a
extra level of indirection and an extra value, and the same sized value
(a 64 bit pointer vs. a 64 bit int) is being passed around.
Change-Id: Ie9956b8dc4c225068ab1afaba233ec2b42b76da3
Reviewed-on: https://gem5-review.googlesource.com/c/13626
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
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These types are IntReg, FloatReg, FloatRegBits, and MiscReg. There are
some remaining types, specifically the vector registers and the CCReg.
I'm less familiar with these new types of registers, and so will look
at getting rid of them at some later time.
Change-Id: Ide8f76b15c531286f61427330053b44074b8ac9b
Reviewed-on: https://gem5-review.googlesource.com/c/13624
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
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Use the binary accessors instead.
Change-Id: Iff1877e92c79df02b3d13635391a8c2f025776a2
Reviewed-on: https://gem5-review.googlesource.com/c/14457
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
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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>
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Change-Id: If8ec5f5f49e99d4989658273723b943dd8df84c6
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/13144
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
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The AtomicSimpleCPU used to be able to access memory directly to speed
up simulation if no caches are used. This is fine as long as no
switching between CPU models is required. In order to switch to a new
CPU model that requires caches, we currently need to checkpoint the
system and restore it into a new configuration. The new
'atomic_noncaching' memory mode provides a solution that avoids this
issue since caches are bypassed in this mode. This changeset removes
the old fastmem option from the AtomicSimpleCPU and introduces a new
CPU, NonCachingSimpleCPU, which derives from the AtomicSimpleCPU.
The NonCachingSimpleCPU uses the same mechanism as the AtomicSimpleCPU
used to use when accessing memory in when fastmem was enabled.
This changeset also introduces a new switcheroo test that tests
switching between a NonCachingSimpleCPU and a TimingSimpleCPU with
caches.
Change-Id: If01893f9b37528b14f530c11ce6f53c097582c21
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/12419
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
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In TimingSimpleCPU model, when a CPU is suspended by a syscall (e.g.,
futex(FUTEX_WAIT)), the CPU waits for another CPU to wake it up
(e.g., FUTEX_WAKE operation). While staying Idle, the suspended CPU
should not try to fetch next instructions after the syscall.
This patch added a status check before a CPU schedule a fetch event
after a fault is handled.
Change-Id: I0cc953135686c9b35afe94942aa1d0b245ec60a2
Reviewed-on: https://gem5-review.googlesource.com/8181
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
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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>
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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>
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In the atomic model a dynamic_pointer_cast is performed at every tick to
check if the fault is a SyscallRetryFault. This was happening even when
there was no generated fault.
Change-Id: I7f4afeffffdf4f988230e05286602d8d9a919c6c
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/10101
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
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Starting with version 3, scons imposes using the print function instead
of the print statement in code it processes. To get things building
again, this change moves all python code within gem5 to use the
function version. Another change by another author separately made this
same change to the site_tools and site_init.py files.
Change-Id: I2de7dc3b1be756baad6f60574c47c8b7e80ea3b0
Reviewed-on: https://gem5-review.googlesource.com/8761
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>
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Get rid of some remnants of a system which was intended to separate
address computation into its own instruction object.
Change-Id: I23f9ffd70fcb89a8ea5bbb934507fb00da9a0b7f
Reviewed-on: https://gem5-review.googlesource.com/7122
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>
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CPUs have historically instantiated the architecture specific version
of the TLBs to avoid a virtual function call, making them a little bit
more dependent on what the current ISA is. Some simple performance
measurement, the x86 twolf regression on the atomic CPU, shows that
there isn't actually any performance benefit, and if anything the
simulator goes slightly faster (although still within margin of error)
when the TLB functions are virtual.
This change switches everything outside of the architectures themselves
to use the generic BaseTLB type, and then inside the ISA for them to
cast that to their architecture specific type to call into architecture
specific interfaces.
The ARM TLB needed the most adjustment since it was using non-standard
translation function signatures. Specifically, they all took an extra
"type" parameter which defaulted to normal, and translateTiming
returned a Fault. translateTiming actually doesn't need to return a
Fault because everywhere that consumed it just stored it into a
structure which it then deleted(?), and the fault is stored in the
Translation object when the translation is done.
A little more work is needed to fully obviate the arch/tlb.hh header,
so the TheISA::TLB type is still visible outside of the ISAs.
Specifically, the TlbEntry type is used in the generic PageTable which
lives in src/mem.
Change-Id: I51b68ee74411f9af778317eff222f9349d2ed575
Reviewed-on: https://gem5-review.googlesource.com/6921
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
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Replace them with std::array<>s.
Change-Id: I76624c87a1cd9b21c386a96147a18de92b8a8a34
Reviewed-on: https://gem5-review.googlesource.com/6602
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
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Print faulting instruction for unmapped address panic in faults.cc
and print extra info about corresponding fetched PC in base.cc.
Change-Id: Id9e15d3e88df2ad6b809fb3cf9f6ae97e9e97e0f
Reviewed-on: https://gem5-review.googlesource.com/6461
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
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Cache maintenance operations go through the write channel of the
cpu. This changes makes sure that the cpu does not try to fill in the
packet with data.
Change-Id: Ic83205bb1cda7967636d88f15adcb475eb38d158
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/5055
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
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These files aren't a collection of miscellaneous stuff, they're the
definition of the Logger interface, and a few utility macros for
calling into that interface (panic, warn, etc.).
Change-Id: I84267ac3f45896a83c0ef027f8f19c5e9a5667d1
Reviewed-on: https://gem5-review.googlesource.com/6226
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>
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Move the code responsible for performing the actual probe point notify
into BaseCPU. Use BaseCPU activateContext and suspendContext to keep
track of sleep cycles. Create a probe point (ppActiveCycles) that does
not count cycles where the processor was asleep. Rename ppCycles
to ppAllCycles to reflect its nature.
Change-Id: I1907ddd07d0ff9f2ef22cc9f61f5f46c630c9d66
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/5762
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
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If the CPU has been clock gated for a sufficient amount of time
(configurable via pwrGatingLatency), the CPU will go into the OFF
power state. This does not model hardware, just behaviour.
Change-Id: Ib3681d1ffa6ad25eba60f47b4020325f63472d43
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/3969
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
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Change-Id: If765c6100d67556f157e4e61aa33c2b7eeb8d2f0
Signed-off-by: Sean Wilson <spwilson2@wisc.edu>
Reviewed-on: https://gem5-review.googlesource.com/3923
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
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Reiley's update :) of the isa parser definitions. My addition of the
vector element operand concept for the ISA parser. Nathanael's modification
creating a hierarchy between vector registers and its constituencies to the
isa parser.
Some fixes/updates on top to consider instructions as vectors instead of
floating when they use the VectorRF. Some counters added to all the
models to keep faithful counts.
Change-Id: Id8f162a525240dfd7ba884c5a4d9fa69f4050101
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2706
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
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This patch adds some more functionality to the cpu model and the arch to
interface with the vector register file.
This change consists mainly of augmenting ThreadContexts and ExecContexts
with calls to get/set full vectors, underlying microarchitectural elements
or lanes. Those are meant to interface with the vector register file. All
classes that implement this interface also get an appropriate implementation.
This requires implementing the vector register file for the different
models using the VecRegContainer class.
This change set also updates the Result abstraction to contemplate the
possibility of having a vector as result.
The changes also affect how the remote_gdb connection works.
There are some (nasty) side effects, such as the need to define dummy
numPhysVecRegs parameter values for architectures that do not implement
vector extensions.
Nathanael Premillieu's work with an increasing number of fixes and
improvements of mine.
Change-Id: Iee65f4e8b03abfe1e94e6940a51b68d0977fd5bb
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
[ Fix RISCV build issues and CC reg free list initialisation ]
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2705
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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
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Replace the unified register mapping with a structure associating
a class and an index. It is now much easier to know which class of
register the index is referring to. Also, when adding a new class
there is no need to modify existing ones.
Change-Id: I55b3ac80763702aa2cd3ed2cbff0a75ef7620373
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/2700
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Change-Id: Idd5992463bcf9154f823b82461070d1f1842cea3
Signed-off-by: Sean Wilson <spwilson2@wisc.edu>
Reviewed-on: https://gem5-review.googlesource.com/3746
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
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This changeset adds functionality that allows system calls to retry without
affecting thread context state such as the program counter or register values
for the associated thread context (when system calls return with a retry
fault).
This functionality is needed to solve problems with blocking system calls
in multi-process or multi-threaded simulations where information is passed
between processes/threads. Blocking system calls can cause deadlock because
the simulator itself is single threaded. There is only a single thread
servicing the event queue which can cause deadlock if the thread hits a
blocking system call instruction.
To illustrate the problem, consider two processes using the producer/consumer
sharing model. The processes can use file descriptors and the read and write
calls to pass information to one another. If the consumer calls the blocking
read system call before the producer has produced anything, the call will
block the event queue (while executing the system call instruction) and
deadlock the simulation.
The solution implemented in this changeset is to recognize that the system
calls will block and then generate a special retry fault. The fault will
be sent back up through the function call chain until it is exposed to the
cpu model's pipeline where the fault becomes visible. The fault will trigger
the cpu model to replay the instruction at a future tick where the call has
a chance to succeed without actually going into a blocking state.
In subsequent patches, we recognize that a syscall will block by calling a
non-blocking poll (from inside the system call implementation) and checking
for events. When events show up during the poll, it signifies that the call
would not have blocked and the syscall is allowed to proceed (calling an
underlying host system call if necessary). If no events are returned from the
poll, we generate the fault and try the instruction for the thread context
at a distant tick. Note that retrying every tick is not efficient.
As an aside, the simulator has some multi-threading support for the event
queue, but it is not used by default and needs work. Even if the event queue
was completely multi-threaded, meaning that there is a hardware thread on
the host servicing a single simulator thread contexts with a 1:1 mapping
between them, it's still possible to run into deadlock due to the event queue
barriers on quantum boundaries. The solution of replaying at a later tick
is the simplest solution and solves the problem generally.
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Change-Id: I183b9942929c873c3272ce6d1abd4ebc472c7132
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
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Add functionality to the BaseCPU that will put the entire CPU
into a low-power idle state whenever all threads in it are idle.
Change-Id: I984d1656eb0a4863c87ceacd773d2d10de5cfd2b
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In general, the ThreadID parameter is unnecessary in the memory system
as the ContextID is what is used for the purposes of locks/wakeups.
Since we allocate sequential ContextIDs for each thread on MT-enabled
CPUs, ThreadID is unnecessary as the CPUs can identify the requesting
thread through sideband info (SenderState / LSQ entries) or ContextID
offset from the base ContextID for a cpu.
This is a re-spin of 20264eb after the revert (bd1c6789) and includes
some fixes of that commit.
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The following patches had unexpected interactions with the current
upstream code and have been reverted for now:
e07fd01651f3: power: Add support for power models
831c7f2f9e39: power: Low-power idle power state for idle CPUs
4f749e00b667: power: Add power states to ClockedObject
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
--HG--
extra : amend_source : 0b6fb073c6bbc24be533ec431eb51fbf1b269508
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In general, the ThreadID parameter is unnecessary in the memory system
as the ContextID is what is used for the purposes of locks/wakeups.
Since we allocate sequential ContextIDs for each thread on MT-enabled
CPUs, ThreadID is unnecessary as the CPUs can identify the requesting
thread through sideband info (SenderState / LSQ entries) or ContextID
offset from the base ContextID for a cpu.
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Add functionality to the BaseCPU that will put the entire CPU into a low-power
idle state whenever all threads in it are idle.
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This changeset adds support for changing the simulator output
directory. This can be useful when the simulation goes through several
stages (e.g., a warming phase, a simulation phase, and a verification
phase) since it allows the output from each stage to be located in a
different directory. Relocation is done by calling core.setOutputDir()
from Python or simout.setOutputDirectory() from C++.
This change affects several parts of the design of the gem5's output
subsystem. First, files returned by an OutputDirectory instance (e.g.,
simout) are of the type OutputStream instead of a std::ostream. This
allows us to do some more book keeping and control re-opening of files
when the output directory is changed. Second, new subdirectories are
OutputDirectory instances, which should be used to create files in
that sub-directory.
Signed-off-by: Andreas Sandberg <andreas@sandberg.pp.se>
[sascha.bischoff@arm.com: Rebased patches onto a newer gem5 version]
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
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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.
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