It is possible from the MMU to traverse the entire hierarchy of
TLBs, starting from the DTB and ITB (generally speaking from the
first level) up to the last level via the nextLevel pointer. So
in theory no extra data should be stored in the BaseMMU.
This design makes some operations a bit more complex. For example
if we have a unified (I+D) L2, it will be pointed by both ITB and
DTB. If we want to invalidate all TLB entries, we should be
careful to not invalidate L2 twice, but if we simply follow the
next level pointer, we might do so. This is not a problem from
a functional perspective but alters the TLB statistics (a single
invalidation is recorded twice)
We then provide a different view of the set of TLBs in the system.
At the init phase we traverse the TLB hierarchy and we add every
TLB to the appropriate set. This makes invalidation (and any
operation targeting a specific kind of TLBs) easier.
JIRA: https://gem5.atlassian.net/browse/GEM5-790
Change-Id: Ieb833c2328e9daeaf50a32b79b970f77f3e874f7
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48146
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
This patch is moving most of the TLB code to the MMU.
In this way the TLB stops being the main translating agent and becomes a
simple "passive" translation cache.
All the logic behind virtual memory translation, like
* Checking permission/alignment
* Issuing page table walks
* etc
Is now embedded in the MMU model. This will allow us to stack multiple
TLBs and to compose arbitrary hierarchies as their sole purpose now is
to cache translations
JIRA: https://gem5.atlassian.net/browse/GEM5-790
Change-Id: I687c639a56263d5e3bb6633dd8c9666c85edba3a
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48141
Tested-by: kokoro <noreply+kokoro@google.com>
Now that we're using c++17, the type_traits with a ::value member have
a _v alias which reduces verbosity. Or on other words
std::is_integral<T>::value
can be replaced with
std::is_integral_v<T>
Make this substitution throughout the code base. In places where gem5
introduced it's own similar templates, add a V alias, spelled
differently to match gem5's internal style.
gem5: :IsVarArgs<T>::value => gem5::IsVarArgsV<T>
Change-Id: I1d84ffc4a236ad699471569e7916ec17fe5f109a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48604
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Memory space is not always outside of the CPU. For example the tightly
coupled memory (TCM) is inside of the core. To make gdb access those
kind of memory, we should use Iris memory API to read and write memory.
If we access a memory address not inside the CPU with Iris memory API.
The CPU would fire a request via amba transport_dbg. So the change also
covers the original behavior.
Change-Id: Ie223ab12f9a746ebafa21026a8680222f6ebd593
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45581
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
I don't have this header on one of the machines I build on, so this is
breaking the build for me. Removing this include seems to make the
build succeed, implying that it's not actually necessary. I looked at
the file it's used in and didn't see anything that looked like it came
from this header file.
Change-Id: If4a29063d6d0d25904183cab78c9713ff1f8daa6
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48603
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Currently, if the commit subject does have tags, the parser will
return the list of tags as a NoneType object, which will be
iterated later. This caused the gerrit bot to fail.
This change lets the parser return the list of tags as an empty
list rather than a NoneType object. Also, a commit subject without
a semicolon `:` will be assumed as having no tags and the whole
subject is the commit message.
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Change-Id: Ie8c90e14bb85c4ce1c583121d02e75aa87db7811
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48586
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
When clone is called with the VFORK flag, the calling process is
suspended until the child process either exits, or calls execve.
This patch adds in a new variable to Process, which is used to store the
context of the calling process if this process is created through a
clone with VFORK set.
This patch also adds the required support in clone to suspend the
calling thread, and in exitImpl and execveFunc to wake up the calling
thread when the child thread calls either of those functions
Change-Id: I85af67544ea1d5df7102dcff1331b5a6f6f4fa7c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48346
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
There were three things preventing execve from working
Firstly, the entrypoint for the new program wasn't correct. This was
fixed by calling Process::init, which adds a bias to the entrypoint.
Secondly, the uname string wasn't being copied over. This meant when the
new executable tried to run, it would think the kernel was too old to
run on, and would error out. This was fixed by copying over the uname
string (the `release` string in Process) when creating the new process.
Additionally, this patch also ensures we copy over the uname string in
the clone implementation, as otherwise a cloned thread that called
execve would crash.
Finally, we choose to not delete the new ProcessParams or the old
Process. This is done both because it matches what is done in cloneFunc,
but also because deleting the old process results in a segfault later
on.
Change-Id: I4ca201da689e9e37671b4cb477dc76fa12eecf69
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48345
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Scalar sources can either be a general-purpose register or a constant
register that holds a single value.
If we don't check for if the register is a general-purpose register,
it's possible that we get a constant register, which then causes all of
the register mapping code to break, as the constant registers aren't
supposed to be mapped like the general-purpose registers are.
This fix adds an isScalarReg check to the instruction encodings that
were missing it.
Change-Id: I3d7d5393aa324737301c3269cc227b60e8a159e4
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48344
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Add support for LDS accesses by allowing Flat instructions to dispatch
into the local memory pipeline if the requested address is in the group
aperture.
This requires implementing LDS accesses in the Flat initMemRead/Write
functions, in a similar fashion to the DS functions of the same name.
Because we now can potentially dispatch to the local memory pipeline,
this change also adds a check to regain any tokens we requested as a
flat instruction.
Change-Id: Id26191f7ee43291a5e5ca5f39af06af981ec23ab
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48343
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This implements the 96 and 128b ds_read/write instructions in a similar
fashion to the 3 and 4 dword flat_load/store instructions.
These instructions are treated as reads/writes of 3 or 4 dwords, instead
of as a single 96b/128b memory transaction, due to the limitations of
the VecOperand class used in the amdgpu code.
In order to handle treating the memory transaction as multiple dwords,
the patch also adds in new initMemRead/initMemWrite functions for ds
instructions. These are similar to the functions used in flat
instructions for the same purpose.
Change-Id: I0f2ba3cb7cf040abb876e6eae55a6d38149ee960
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48342
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alex Dutu <alexandru.dutu@amd.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Previously, we assumed that the maximum number of requests that would be
issued by an instruction was equal to the number of threads that were
active for that instruction.
However, if a thread has an access that crosses a cache line, that
thread has a misaligned access, and needs to request both cache lines.
This patch takes that into account by checking the status vector for
each thread in that instruction to determine the number of requests.
Change-Id: I1994962c46d504b48654dbd22bcd786c9f382fd9
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48341
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Currently, we are storing coalesced accesses in
an std::unordered_map indexed by a tick index, i.e.
issue tick / coalescing window. If there are
multiple coalesced requests, at different tick
indexes, to the same virtual address, then the
TLB coalescer will issue just the first one.
However, std::unordered_map is not a sorted
container and we issue coalesced requests by iterating
through such container. This means that the coalesced
request sent in TLBCoalescer::processProbeTLBEvent is
not necessarly the oldest one. Because of this, in
cases of high contention the oldest coalesced request
will have a huge TLB access latency.
To fix this issue, we will use an std::map which is
a sorted container and therefore guarantees the
oldest coalesced request will be sent first.
Change-Id: I9c7ab32c038d5e60f6b55236266a27b0cae8bfb0
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48340
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The c++-17 feature "if constexpr" allows you to put code inside a normal
if which would normally have to be separated out using templates. The
condition of the if must be compile time evaluated, and the not-taken
path is discarded by the compiler.
Change-Id: I026381b2dbb140ef7f1b5cb23803782683ec419c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48503
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Daniel Carvalho <odanrc@yahoo.com.br>
Tested-by: kokoro <noreply+kokoro@google.com>
The proxies are not used on the critical path, and it's usually implicit
whether they should be the FS or SE version.
Ideally in the future we won't need to worry about which version we need
to use, but the differences haven't quite been abstracted away, and
occasionally we need to decide between the two.
Change-Id: Idb363d6ddc681f7c1ad5e7aba69865f40aa30dc8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45907
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
The compiler is unhappy that one of the parameters in a call to sprintf
is also the buffer it's supposed to output to, when that parameter is
marked "restrict", which means it shouldn't alias to other arguments.
Also, this code can't go inside the gem5 namespace, since it has a
main() function in it. The linker will look for main(), not
gem5::main().
Change-Id: Ib17c601aefdc3e7201eba021dafb1c51204d54bc
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48423
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Tested-by: kokoro <noreply+kokoro@google.com>
These were never used with conditions, so the condition check just added
overhead. Also, the not-taken path through the instruction didn't
actually set the destination to something, meaning that it would set it
to something arbitrary and not actually leave it unmodified.
Change-Id: I33fef088979b14ad74adf22b26419a1cacf386dd
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45305
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
