The way these were set up, there would be a conflict between SimObject
files with the same name set up for different ISAs.
This change creates a single file which tries to determine how many ISAs
are enabled, and if there is exactly one, it creates a backwards
compatible alias for the ISA specific CPU types.
Change-Id: Iab358c2880d49222e814a98354c81d0f306fe1fc
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52493
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
The TARGET_ISA variable would let you select one ISA from a list of
possible ISAs. That has now been replaced with USE_ARM_ISA, USE_X86_ISA,
etc, variables which are boolean on or off. That will allow any number
of ISAs to be enabled or disabled individually. Enabling something other
than exactly one of these will probably prevent you from getting a
working gem5 binary, but those problems are being addressed in other,
parallel change series.
I decided to use the USE_ prefix since it was consistent with most other
on/off variables we have in gem5. One noteable exception is the
BUILD_GPU setting which, you could convincingly argue, is a better
prefix than USE_. Another option would be to use CONFIG_, in
anticipation of using a kconfig style config mechanism in gem5.
It seemed premature to start using a CONFIG_ prefix here, and if we
decide to switch to some other prefix like BUILD_, it should be a
purposeful choice and not something somebody just starts using.
Change-Id: I90fef2835aa4712782e6c1313fbf564d0ed45538
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52491
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
This makes what are configuration and what are internal SCons variables
explicit and separate, and makes it unnecessary to call out what
variables to export to C++.
These variables will also be plumbed into and out of kconfiglib in later
changes.
Change-Id: Iaf5e098d7404af06285c421dbdf8ef4171b3f001
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56892
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Rather than constantly overwriting the "zero" register to return its
value to zero, just ignore writes to it.
We assume here that the "zero" register is a standard RegVal type
register (ie not bigger than 64 bits) and is accessed as such.
Change-Id: I06029b78103019c668647569c6037ca64a4d9c76
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/49709
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The BaseCPU type had been specializing itself based on the value of
TARGET_ISA, which is not compatible with building more than one ISA at a
time.
This change refactors the CPU models so that the BaseCPU is more
general, and the ISA specific components are added to the CPU when the
CPU types are fully specialized. For instance, The AtomicSimpleCPU has a
version called X86AtomicSimpleCPU which installs the X86 specific
aspects of the CPU.
This specialization is done in three ways.
1. The mmu parameter is assigned an instance of the architecture
specific MMU type. This provides a reasonable default, but also avoids
having having to use the ISA specific type when the parameter is
created.
2. The ISA specific types are made available as class attributes, and
the utility functions (including __init__!) in the BaseCPU class can
refer to them to get the types they need to set up the CPU at run time.
Because SimObjects have strange, unhelpful semantics as far as assigning
to their attributes, these types need to be set up in a non-SimObject
class, which is then brought in as a base of the actual SimObject type.
Because the metaclass of this other type is just "type", things work
like you would expect. The SimObject doesn't do any special processing
of base classes if they aren't also SimObjects, so these attributes
survive and are accessible using normal lookup in the BaseCPU class.
3. There are some methods like addCheckerCPU and properties like
needsTSO which have ISA specific values or behaviors. These are set in
the ISA specific subclass, where they are inherently specific to an ISA
and don't need to check TARGET_ISA.
Also, the DummyChecker which was set up for the BaseSimpleCPU which
doesn't actually do anything in either C++ or python was not carried
forward. The CPU type still exists, but it isn't installed in the
simple CPUs.
To provide backward compatibility, each ISA implements a .py file which
matches the original .py for a CPU, and the original is renamed with a
Base prefix. The ISA specific version creates an alias with the old CPU
name which maps to the ISA specific type. This way, old scripts which
refer to, for example, AtomicSimpleCPU, will get the X86AtomicSimpleCPU
if the x86 version was compiled in, the ArmAtomicSimpleCPU on arm, etc.
Unfortunately, because of how tags on PySource and by extension SimObjects
are implemented right now, if you set the tags on two SimObjects or
PySources which have the same module path, the later will overwrite the
former whether or not they both would be included. There are some
changes in review which would revamp this and make it work like you
would expect, without this central bookkeeping which has the conflict.
Since I can't use that here, I fell back to checking TARGET_ISA to
decide whether to tell SCons about those files at all.
In the long term, this mechanism should be revamped so that these
compatibility types are only available if there is exactly one ISA
compiled into gem5. After the configs have been updated and no longer
assume they can use AtomicSimpleCPU in all cases, then these types can
be deleted.
Also, because ISAs can now either provide subclasses for a CPU or not,
the CPU_MODELS variable has been removed, meaning the non-ISA
specialized versions of those CPU models will always be included in
gem5, except when building the NULL ISA.
In the future, a more granular config mechanism will hopefully be
implemented for *all* of gem5 and not just the CPUs, and these can be
conditional again in case you only need certain models, and want to
reduce build time or binary size by excluding the others.
Change-Id: I02fc3f645c551678ede46268bbea9f66c3f6c74b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52490
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Currently, an access to an invalid address will cause GEM5 to exit with
a `!pkt.isError()` assertion failure. I was seeing this assertion while
running a baremetal RISC-V binary that faulted before the trap vector
had been configured and therefore tried to jump to address zero. With
this change we now print the invalid address and the type of access
(ifetch/load/store/amo) which makes debugging such a problem much easier.
For example, my faulting program now prints the following:
`panic: Instruction fetch ([0:0x4]) failed: BadAddressError [0:3] IF`
I also saw this assertion with a program that was dereferencing a NULL
pointer, which now prints a more helpful message:
`panic: Data fetch ([0x10:0x11]) failed: BadAddressError [10:10]`
Change-Id: Id983b74bf4688711f47308c6c7c15f49662ac495
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55203
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This was originally intended to make it more efficient to get the
microPC without making a copy of the entire PCState object to return.
Now that the PCState is returned through a pointer without a copy and
the microPC can be accessed with an inline accessor, we don't need to
create a special accessor for it.
Change-Id: I1d354dfca6be5d954e147f23dc9d27917b379bf2
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52061
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabe.black@gmail.com>
This virtual method can trivially be shared among different CPUs, making
it unnecessary to cast from a BaseCPU pointer to some more specific CPU
class. The existing similar functions which implement this functionality
are only trivially different, and can be merged into overloads of this
common method.
Noteably this method is not implemented for the MinorCPU which uses the
SimpleThread class, typedef-ed to be MinorThread. If the previous
version of this method had been called on that CPU, it would have
crashed the simulator since a dynamic_cast would have failed. This
doesn't provide an implementation for the MinorCPU, but it also doesn't
make the problem worse, and provides a way to actually implement it some
day.
Change-Id: I23399ea6bbbbabd87e6c8bf7a66d48902745d2cf
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52084
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Turn the functions within it into virtual methods on the ISA classes.
Eliminate the implementation in MIPS, which was just copy pasted from
Alpha long ago. Fix some minor style issues in ARM. Remove templating.
Switch from using an "XC" type parameter to using the ThreadContext *
installed in all ISA classes.
The ARM version of these functions actually depend on the ExecContext
delaying writes to MiscRegs to work correctly. More insiduously than
that, they also depend on the conicidental ThreadContext like
availability of certain functions like contextId and getCpuPtr which
come from the class which happened to implement the type passed into XC.
To accomodate that, those functions need both a real ThreadContext, and
another object which is either an ExecContext or a ThreadContext
depending on how the method is called.
Jira Issue: https://gem5.atlassian.net/browse/GEM5-1053
Change-Id: I68f95f7283f831776ba76bc5481bfffd18211bc4
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/50087
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The CpuModel class looks like it was originally intended to hold a lot
more information that it does now, which is just the name of a CPU, and
whether it should be enabled by default. All the built in configs in
build_opts already explicitly list a set of CPUs, and CPUs should not,
generally speaking, be enabled by default, since they almost always need
to be specifically supported by an ISA. This is mutual, since usually
ISAs definitions are not quite correct or complete, and this is often
exposed by plugging them into different, and/or more complex CPU models
which stress those short comings.
This change drops the idea of a "default" CPU, and since the only thing
being tracked at this point is a list of CPUs, it turns CpuModel() into
a simple function which adds a name to a set of supported CPUs.
Change-Id: Id7475d5dc8548802b5253f79839da8c76ef4d165
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48963
Reviewed-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Instruction fetch should not commence if there already is an
instruction-count event in the queue.
The most conspicuous scenario where this leads to obvious breakage,
is guest debugging. Imagine the first bytes in the program pointed to
by _start are invalid instruction encoding, and we pass the --wait-gdb
flag. Then in GDB we set $pc to point to valid instructions, and we
"continue". gem5 will abort with "invalid instruction".
This is not how real targets behave: neither software- (e.g. ptrace)
based debuggers, nor low-level (e.g. OpenOCD or XMD connected over
JTAG to debug early initialization code eg when the MMU has not been
switched on yet, etc.) Fetching should start from where $pc was set
to. This patch tries to model this behavior.
Change-Id: Ibce6fdbbb082edf1073ae96745bc7867878f99ca
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/27587
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Apply the gem5 namespace to the codebase.
Some anonymous namespaces could theoretically be removed,
but since this change's main goal was to keep conflicts
at a minimum, it was decided not to modify much the
general shape of the files.
A few missing comments of the form "// namespace X" that
occurred before the newly added "} // namespace gem5"
have been added for consistency.
std out should not be included in the gem5 namespace, so
they weren't.
ProtoMessage has not been included in the gem5 namespace,
since I'm not familiar with how proto works.
Regarding the SystemC files, although they belong to gem5,
they actually perform integration between gem5 and SystemC;
therefore, it deserved its own separate namespace.
Files that are automatically generated have been included
in the gem5 namespace.
The .isa files currently are limited to a single namespace.
This limitation should be later removed to make it easier
to accomodate a better API.
Regarding the files in util, gem5:: was prepended where
suitable. Notice that this patch was tested as much as
possible given that most of these were already not
previously compiling.
Change-Id: Ia53d404ec79c46edaa98f654e23bc3b0e179fe2d
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/46323
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
As part of recent decisions regarding namespace
naming conventions, all namespaces will be changed
to snake case.
::Stats became ::statistics.
"statistics" was chosen over "stats" to avoid generating
conflicts with the already existing variables (there are
way too many "stats" in the codebase), which would make
this patch even more disturbing for the users.
Change-Id: If877b12d7dac356f86e3b3d941bf7558a4fd8719
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45421
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
