The config option HAVE_CAPSTONE is added in the previous [1] and
the Kconfig options should be sync with it.
[1] https://github.com/gem5/gem5/pull/494
Change-Id: Id83718bc825f53d87d37d6ac930b96371209bdb3
The CL updates the Kconfig:
1. Replace the USE_NULL_ISA with BUILD_ISA
2. The USE_XXX_ISAs are depends on BUILD_ISA
3. If the BUILD_ISA is set, at least one of USE_XXX_ISAs must be set
4. Refactor the USE_KVM option
Change-Id: I2a600dea9fb671263b0191c46c5790ebbe91a7b8
These are not yet consumed by anything, but convert all the settings
from SCons variables to Kconfig variables.
If you have existing SConsopts files which need to be converted, you
should take a look at KCONFIG.md to learn about how kconfig is used in
gem5. You should decide if any variables need to be available to C++ or
kconfig itself, and whether those are options which should be detected
automatically, or should be up to the user. Options which should be
measured automatically should still be in SConsopts files, while user
facing options should be added to new or existing Kconfig files.
Generally, make sure you're storing c++/kconfig visible options in
env['CONF'][...]. Also remove references to sticky_vars since persistent
options should now be handled with kconfig, and export_vars since
everything in env['CONF'] is now exported automatically.
Switch SCons/gem5 to use Kconfig for configuration, except EXTRAS which
is still a sticky SCons variable. This is necessary because EXTRAS also
controls what config options exist. If it came from Kconfig itself, then
there would be a circular dependency. This dependency could
theoretically be handled by reparsing the Kconfig when EXTRAS
directories were added or removed, but that would be complicated, and
isn't supported by kconfiglib. It wouldn't be worth the significant
effort it would take to add it, just to use Kconfig more purely.
Change-Id: I29ab1940b2d7b0e6635a490452d05befe5b4a2c9
This reverts gem5#133, the temporary work-around for gem5#131, allowing
both SLC and GLC atomic requests to be made in the GPU tester.
The underlying issues behind gem5#131 have been resolved by gem5#367 and
gem5#397.
Major refactoring of the branch predictor unit.
- Clearer control flow of the main branch predictor
- Remove `uncondBranch` and `btbUpdate` functions in favor
of a common `historyUpdate` function. There is now only
one lookup function for conditional branches and the new
`historyUpdate` for speculative history update.
- Added a new *target provider* class.
- More expressive statistics depending on the different branch
types.
- Cleanup the branch history management
Major refactoring of the branch predictor unit.
- Clearer control flow of the main branch predictor
- Remove `uncondBranch` and `btbUpdate` functions in favour of a
common `historyUpdate` function. There is now only one lookup
function for conditional branches and the new `historyUpdate` for
speculative history update.
- Added a new *target provider* class.
- More expressive statistics depending on the different branch types.
- Cleanup the branch history management
Change-Id: I21fa555b5663e4abad7c836fc1d41a9c8b205263
Signed-off-by: David Schall <david.schall@ed.ac.uk>
Capstone is an open source disassembler [1] already used by
other projects (like QEMU).
gem5 is already capable of disassembling instructions. Every StaticInst
is supposed to define a generateDisassembly method which returns the
instruction mnemonic (opcode + operand list) as a string.
This "distributed" implementation of a disassembler relies
on the developer to properly populate the metadata fields
of the base instruction class.
The growing complexity of the ISA code and the massive reuse
of base classes beyond their intended use has led to a
disassembling logic which contains several bugs.
By allowing a tracer to rely on a third party disassembler, we fill the
intruction trace with a more trustworthy instruction stream.
This will make any trace parsing tool to work better and it will
also allow us to spot/fix our own bugs by comparing instruction
traces with native vs custom disassembler
[1]: http://www.capstone-engine.org/
Change-Id: I3c4db5072c03d2731265d0398d3863c101dcb180
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
The return address stack (RAS) is restructured to be a separate SimObject.
This enables disabling the RAS and better separation of the functionality.
Furthermore, easier statistics and debugging.
Change-Id: I8aacf7d4c8e308165d0e7e15bc5a5d0df77f8192
Signed-off-by: David Schall <david.schall@ed.ac.uk>
This only applies to pseudo instructions with their own encoding (m5
ops)... In other
words memory mapped m5 operations are not supported. This make sense as
they should
rather be treated as device accesses... Though it is something to take
into consideration
when relying on the flag
While it's plausible to define the cache_line_size as a 32-bit unsigned
int, the use of cache_line_size is way out of its original scope.
cache_line_size has been used to produce an address mask, which masking
out the offset bits from an address. For example, [1], [2], [3], and
[4]. However, since the cache_line_size is an "unsigned int", the type
of the value is not guaranteed to be 64-bit long. Subsequently, the bit
twiddling hacks in [1], [2], [3], and [4] produce 32-bit mask, i.e.,
0x00000000FFFFFFC0.
This behavior at least caused a problem in LLSC in RISC-V [5], where the
load reservation (LR) relies on the mask to produce the cache block
address. Two distinct 64-bit addresses can be mapped to the same cache
block using the above mask.
This patch explicitly defines cache_line_size as a 64-bit unsigned int
so the cache block mask can be produced correctly for 64-bit addresses.
[1]
3bdcfd6f7a/src/cpu/simple/atomic.hh (L147)
[2]
3bdcfd6f7a/src/cpu/simple/timing.hh (L224)
[3]
3bdcfd6f7a/src/cpu/o3/lsq_unit.cc (L241)
[4]
3bdcfd6f7a/src/cpu/minor/lsq.cc (L1425)
[5]
3bdcfd6f7a/src/arch/riscv/isa.cc (L787)
Being able to recognise pseudo ops from the static instruction
pointer is actually quite useful in several circumstances
Change-Id: Ib39badf9aabba15ab3ebe7a8e9717583412731e4
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Simplify indirect predictor interface. Several of the existing
functions where merged together into four clear once. Those
four are similar to the main direction predictor interface.
'lookup', 'update', 'squash' and 'commit'. This makes the
interface much more clear, allows better functionality isolation
and makes it simpler to develop new predictor models.
A new parameter is added to allow additional buffer space for
speculative path history.
Change-Id: I6d6b43965b2986ef959953a64c428e50bc68d38e
Signed-off-by: David Schall <david.schall@ed.ac.uk>
- A new abstract BTB class is created to enable different BTB
implementations. The new BTB class gets its own parameter
and stats.
- An enum is added to differentiate branch instruction types.
This enum is used to enhance statistics and BPU management.
- The existing BTB is moved into `simple_btb` as default.
- An additional function is added to store the static instruction in
the BTB. This function is used for the decoupled front-end.
- Update configs to match new BTB parameters.
Change-Id: I99b29a19a1b57e59ea2b188ed7d62a8b79426529
Signed-off-by: David Schall <david.schall@ed.ac.uk>
This introduces the changes necessary for clang-15 and clang-16 to run
within gem5, and adds them to the compiler tests.
This also updates the dockerfiles for ubuntu 22.04 to include the steps
necessary to compile clang-15 and clang-16.
Add the instruction size of a static instruction. x86 and arm decoders
add now the instruction size to the macro instruction. However, microops
are still handled by the fetch stage which is not nice.
Furthermore, we add a set method to the PC state. It allows setting a PC
state to acertain address.
Both methods are required for the decoupled front-end.
Change-Id: I311fe3f637e867c42dee7781f5373ea2e69e2072
Adds the instruction size to all static instruction. x86, arm
and RISC-V decoders add the instruction size to every decoded
macro instruction. As microops should reflect the size of the
their parent macroop the set method is overwritten to pass the
size to all microops.
Furthermore, we add a set method to the PC state. It allows
setting a PC state to a certain address.
Both methods are required for the decoupled front-end.
Change-Id: I311fe3f637e867c42dee7781f5373ea2e69e2072
Signed-off-by: David Schall <david.schall@ed.ac.uk>
This introduces the changes necessary for clang-15 and clang-16
to run within gem5, and adds them to the compiler tests.
Change-Id: If809eae1bd8c366b4d62476891feff0625bdf210
As discussed here, [1], O3CPU counts getWritableRegOperand() as a
reg read, while SimpleCPU variants count getWriableRegOperand()
as a reg write.
This patch fixes this inconsistency. Here, I assume that if
getWritableRegOperand() is used, setReg() will not be used again
to write to the destination register.
[1] https://github.com/gem5/gem5/pull/341
Change-Id: If00049eb598f6722285e9e09419aef98ceed759f
Signed-off-by: Hoa Nguyen <hn@hnpl.org>
While it makes sense to define the cache_line_size as a 32-bit unsigned int,
the use of cache_line_size is way out of its original scope.
cache_line_size has been used to produce an address mask, which masking out
the offset bits from an address. For example, [1], [2], [3], and [4].
However, since the cache_line_size is an "unsigned int", the type of the
value is not guaranteed to be 64-bit long. Subsequently, the
bit twiddling hacks in [1], [2], [3], and [4] produce 32-bit mask,
i.e., 0x00000000FFFFFFC0.
This behavior at least caused a problem in LLSC in RISC-V [5], where the
load reservation (LR) relies on the mask to produce the cache block address.
Two distinct 64-bit addresses can be mapped to the same cache block using
the above mask.
This patch explicitly defines cache_line_size as a 64-bit unsigned int so
the cache block mask can be produced correctly for 64-bit addresses.
[1] 3bdcfd6f7a/src/cpu/simple/atomic.hh (L147)
[2] 3bdcfd6f7a/src/cpu/simple/timing.hh (L224)
[3] 3bdcfd6f7a/src/cpu/o3/lsq_unit.cc (L241)
[4] 3bdcfd6f7a/src/cpu/minor/lsq.cc (L1425)
[5] 3bdcfd6f7a/src/arch/riscv/isa.cc (L787)
Change-Id: I29abc7aaab266a37326846bbf7a82219071c4ffe
Signed-off-by: Hoa Nguyen <hn@hnpl.org>
Now that the TraceCPU is no longer a BaseCPU we disable CPU switching
functionality. AFAICS from the code, it seems like using m5.switchCpus
was never really working.
The takeOverFrom was described as being used when checkpointing
(which is not really the case). Moreover the icache/dcache
event loops were not checking if the CPU was switched out
so the trace was always been consumed regardless of the BaseCPU
state.
Note: IMHO the only case where you might want to switch between
an execution-driven CPU to the TraceCPU is when you want to
warm your caches before the ROI.
All other cases don't really make sense as with the TraceCPU
there is no architectural state being maintained/updated.
Change-Id: I0611359d2b833e1bc0762be72642df24a7c92b1e
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
This is fixing a recently reported issue [1] where it is
not possible to use the TraceCPU to replay elastic traces
It requires some architectural data structures (like ArchMMU,
ArchDecoder...) which are no longer defined in the BaseCPU class at
compilation time. Which Arch version should be used for a class
(TraceCPU) that is supposed to be ISA agnostic ? Does it really make
sense to define them for the TraceCPU? Those classes are not used anyway
during trace replay and their sole purpose would just be to comply to
the BaseCPU interface.
As there is no elegant way to make things work, this patch stops
treating the TraceCPU as a BaseCPU.
While it philosophically makes sense to treat the TraceCPU as a common
CPU (it sort of replays pre-executed instructions), a case can be made
for considering it more like a traffic generator.
[1]: https://github.com/gem5/gem5/issues/301
Change-Id: I7438169e8cc7fb6272731efb336ed2cf271c0844
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
In the RISC-V system, we need to VecClassReg to run RISC-V vector
instruction, and VecElemReg is not applicable because the element
length of vector can be resizable via vset*vl* instruction.
The change will seperate the reg_index for VecReg and VecElemReg to
ensure that have the space for VecReg when VecElemReg is not
applicable.
Change-Id: I99a82dec273baeee31df89a0ee0f5e87f3ff187c
In an SMT CPU, upon a squash, the mis-predicted(squashing) instructions
can still be executing at IEW and own phys registers. If these registers
are added back to the rename freelist on this Tick, the registers may be
renamed to be used by other SMT thread(s). This causes register
ownership hazards, which may eventually freeze the CPU. This problem
seems to date back to 2014
(https://www.mail-archive.com/gem5-users@gem5.org/msg10180.html).
This patch delays the freelist update to avoid the hazard.
I tested that this patch does not cause any performance impact for my
set of benchmarks on default non-SMT O3CPU.
In an SMT CPU, upon a squash, the phys regs used by
mispredicted instructions can still be owned by executing
instructions in IEW. If the regs are added back to freelist
on this tick, the reg may be renamed to be used by another
SMT thread. This causes reg ownership hazard, which may
eventually freeze the CPU.
This patch delays the freelist update to avoid the hazard.
Change-Id: I993b3c7d357269f01146db61fc8a7b83a989ea45
In "src/cpu/testers/gpu_ruby_test" a random number generator was used.
This was using the CPP "<random>" library. This patch changes it to the
gem5 random class (that declared in "base/random.hh").
In addition to this, undeterministic behavior has been removed. Via
"protocol_tester.cc" the RNG is either seeded with a seed specified by
the user, or goes with the gem5 default seed. This ensures reproducable
runs. Prior to this patch the RNG was seeded with `time(NULL)`. This
made finding faults difficult.
Change-Id: Ia8e9f7b87e91323f828e0b7f6c3906c0c5793b2c
This fixes#131 by reverting to the old behavior of performing all
atomics at the system level. To do this the SLC bit needs to be set for
all atomic requests.
Change-Id: I63f4e449be1b02c933832d09700237f8c8026f4c
In https://gem5-review.googlesource.com/c/public/gem5/+/52047 inst.pc
was changed from an object to a pointer. It is possible that this
pointer is null (e.g., if there is an interrupt and there is a bubble).
Make sure to check that it's not null before printing.
I believe that other places this pointer is dereferenced without an
explicit null check are safe, but I'm not certain.
Change-Id: Idbe246cfdb62d4d75416d41b451fb3c076233bbc
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
* cpu-kvm: Add a variable signifying whether we are using perf
Change-Id: Iaa081e364f85c863f781723b5524d267724ed0e4
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
* cpu-kvm: Making it clear the functionalities are specific to KVM
Change-Id: I982426f294d90655227dc15337bf73c42a260ded
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
* cpu-kvm: Make perf optional
Change-Id: I8973c2a96575383976cea7ca3fda478f83e95c3f
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
* configs: Add an example config of using KVM without perf
Change-Id: Ic69fa7dac4f1a2c8fe23712b0fa77b5b22c5f2df
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
* Apply suggestions from code review
Co-authored-by: Jason Lowe-Power <jason@lowepower.com>
* misc: Add an example to the panic
Change-Id: Ic1fdfb955e5d8b9ad1d4f0a2bf30fa8050deba70
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
* misc: Add warning of not using perf when using KVM CPU
Change-Id: I96c0832fb48c63a79773665ca6228da778ef0497
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
* misc: Fix stuff
Change-Id: Ib407ae7407955b695f0e0f2718324f41bb0d768f
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
* misc: style fix
Change-Id: I7275942e43f46140fdd52c975f76abb3c81b8b0a
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
---------
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Co-authored-by: Jason Lowe-Power <jason@lowepower.com>
* gpu-compute: Remove use of 'std::random_shuffle'
This was deprecated in C++14 and removed in C++17. This has been
replaced with std::random. This has been implemented to ensure
reproducible results despite (pseudo)random behavior.
Change-Id: Idd52bc997547c7f8c1be88f6130adff8a37b4116
* dev-amdgpu: Add missing 'overrides'
This causes warnings/errors in some compilers.
Change-Id: I36a3548943c030d2578c2f581c8985c12eaeb0ae
* dev: Fix Linux specific includes to be portable
This allows for compilation in non-linux systems (e.g., Mac OS).
Change-Id: Ib6c9406baf42db8caaad335ebc670c1905584ea2
* tests: Add 'VEGA_X86' build target to compiler-tests.sh
Change-Id: Icbf1d60a096b1791a4718a7edf17466f854b6ae5
* tests: Add 'GCN3_X86' build target to compiler-tests.sh
Change-Id: Ie7c9c20bb090f8688e48c8619667312196a7c123
This removes ccRegfileReads, ccRegfileWrites, fpRegfileReads,
fpRegfileWrites, intRegfileReads, intRegfileWrites, miscRegfileReads,
miscRegfileWrites, vecPredRegfileReads, vecPredRegfileWrites,
vecRegfileReads, and vecRegfileWrites are removed from cpu.hh and
cpu.cc in O3CPU. The corresponding stats in BaseCPU::ExecuteCPUStats
are used instead. Changed the getReg, getWritableReg, and setReg
functions in the O3 CPU object to take the thread ID as a parameter.
This is because the stats in base are stored in vectors that are
indexed by the thread ID.
The stats moved from SimpleCPU are dcacheStallCycles,
icacheStallCycles, numCCRegReads, numCCRegWrites, numFpAluAccesses,
numFpRegReads, numFpRegWrites, numIntAluAccesses, numIntRegReads,
numIntRegWrites, numMemRefs, numMiscRegReads, numMiscRegWrites,
numVecAluAccesses, numVecPredRegReads, numVecPredRegWrites,
numVecRegReads, numVecRegWrites.
The stat moved from MinorCPU is numDiscardedOps.
Change-Id: I843af63b3db639858083bdea708de961f23b3048
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/69107
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
