| Age | Commit message (Collapse) | Author |
|---|
|
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.
|
|
This changeset add spaces in a few spots and removes an unnecessary comment.
|
|
This changeset adds the ability to set a close-on-exec flag for a given
file descriptor. It also reworks some of the logic surrounding setting and
retrieving flags from the file description.
|
|
|
|
|
|
Change-Id: I6149290d6d2ac1a4bd6165871c93d7b7d6a980ad
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Change-Id: I29f45733c5fad822bdd0d8dcc7939d86b2e8c97b
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Change-Id: I79c2662fc81630ab321db8a75be6cd15fa07d372
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Change-Id: If9ebb8488e8db587482ecfa99d2c12cfe5734fb9
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Change-Id: I4f3c2c027b1acaaf791a4c71086f34a9b9fbf4df
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Policies like the LRU need to be notified when a block is invalidated,
the helper function does this along with invalidating the block.
Change-Id: I3ed59cf07938caa7f394ee6054b0af9e00b267ea
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
This changeset updates an assert in src/mem/cache/mshr.cc which was
erroneously catching invalidated prefetch requests. These requests can
become invalidated if another component writes (an exclusive access)
to this location during the time that the read request is in
flight. The original assert made the assumption that these cases can
only occur for reads generated by the CPU, and hence
prefetcher-generated requests would sometimes trip the assert.
Change-Id: If4f043273a688c2bab8f7a641192a2b583e7b20e
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Previously the writeback visitor would not consider and set the secure
flag for the blocks that are written back to memory. This patch fixes
this.
Change-Id: Ie1a425fa9211407a70a4343f2c6b3d073371378f
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Change-Id: Ifb135c60e050c55769914e853b07a387c06e4007
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Change-Id: I7ae5fa44a937f641a2ddd242a49e0cd23f68b9f2
Reviewed-by: Sudhanshu Jha <sudhanshu.jha@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Change-Id: I0e373536897aa5bb4501b00945c2a0836100ddf4
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
CPU models (e.g., O3CPU) issue instruction fetches for the whole cache
block rather than a specific instruction. Consequently the TLB lookups
translate the cache block virtual address. When the TLB lookup fails,
however, the Prefetch Abort must be raised for the PC of the
instruction that caused the fault rather than for the address of the
block.
This change fixes the way we instantiate the PrefetchAbort faults to
use the PC of the request rather the address of the instruction fetch
request.
Change-Id: I8e45549da1c3be55ad204a060029c95ce822a851
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Rekai Gonzalez Alberquilla <rekai.gonzalezalberquilla@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Line everything up again.
|
|
The traversal of drainable objects could potentially be
non-deterministic when using an unordered set containing object
pointers. To ensure that the iteration is deterministic, we switch to
a vector. Note that the lookup and traversal of the drainable objects
is not performance critical, so the change has no negative consequences.
|
|
This patch fixes a bug where a deferred snoop ended up being to a
partial cache line, and not cache-line aligned, all due to how we copy
the packet.
|
|
Fix compilation errors due to missing include.
|
|
Several large changes happen in this patch.
The FDEntry class is rewritten so that file descriptors now correspond to
types: 'File' which is normal file-backed file with the file open on the
host machine, 'Pipe' which is a pipe that has been opened on the host machine,
and 'Device' which does not have an open file on the host yet acts as a pseudo
device with which to issue ioctls. Other types which might be added in the
future are directory entries and sockets (off the top of my head).
The FDArray class was create to hold most of the file descriptor handling
that was stuffed into the Process class. It uses shared pointers and
the std::array type to hold the FDEntries mentioned above.
The changes to these two classes needed to be propagated out to the rest
of the code so there were quite a few changes for that. Also, comments were
added where I thought they were needed to help others and extend our
DOxygen coverage.
|
|
|
|
Moves aux_vector into its own .hh and .cc files just to get it out of the
already crowded Process files. Arguably, it could stay there, but it's
probably better just to move it and give it files.
The changeset looks ugly around the Process header file, but the goal here is
to move methods and members around so that they're not defined randomly
throughout the entire header file. I expect this is likely one of the reasons
why I several unused variables related to this class. So, the methods are
declared first followed by members. I've tried to aggregate them together
so that similar entries reside near one another.
There are other changes coming to this code so this is by no means the
final product.
|
|
The numCpus method is misleading in that it's not really a measure of
how many CPUs might be executing a process, but how many thread contexts
are assigned to the process at any given point in time.
It's nice to highlight this distinction because thread contexts are never
reused in the same way that a CPU can be reused for multiple processes.
The reason that there is no reuse is that there is no CPU scheduler for SE.
The tru64 code intends to use this method and the accompanying contextIDs
field to support SMT and track the number of threads with some system calls.
With the up coming clone and exec patches, this paradigm must change. There
needs to be a 1:1 mapping between the thread contexts and processes so that
the process state between threads is allowed to vary when needed by Linux.
This should not break SMT for tru64 if the Process class is refactored so that
multiple Processes can share state between themselves. The following patches
will do the refactoring incrementally as features are added.
|
|
It looks like tru64 has some nxm* system calls, but the two fields that
are defined in the Process class are unused by any of the code. There doesn't
appear to be any reference in the tru64 code.
|
|
The EIOProcess class was removed recently and it was the only other class
which derived from Process. Since every Process invocation is also a
LiveProcess invocation, it makes sense to simplify the organization by
combining the fields from LiveProcess into Process.
|
|
Turns out that SPARC SE mode relied on M5_pid being "0" in
all cases. The entries in the SPARC TLBs are accessed with
M5_pid as their context. This is buggy in the sense that it
will never work with more than one process or any
initialization that doesn't have the M5_pid value passed in
as "0".
cd7f3a1dbf55 broke the SPARC build because it deletes M5_pid
and uses a _pid with a default of "100" instead. This caused
the SPARC TLB to never return any valid lookups for any
request; the program never moved past the first instruction
with SPARC SE in the regression tester.
The solution proposed in this changeset is to initialize
the address space identification register with the PID value
that is passed into the process class as a parameter from
Python. This should return the correct responses from the TLB
since the insertions and lookups into the page table will be
using the same PID.
Furthermore, there are corner cases in the code which elevate
privileges and revert to using context "0" as the context in
the TLB. I believe that these are related to kernel level
traps and hypervisor privilege escalations, but I'm not
completely sure. I've tried to address the corner cases
properly, but it would be beneficial to have someone who is
familiar with the SPARC architecture to take a look at this
fix.
|
|
|
|
Signed-off-by: Pierre-Yves Péneau <pierre-yves.peneau@lirmm.fr>
Reviewed-by: Tony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed at http://reviews.gem5.org/r/3802/
|
|
Signed-off-by: Pierre-Yves Péneau <pierre-yves.peneau@lirmm.fr>
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed at http://reviews.gem5.org/r/3801/
|
|
Assertion in the respondEvent erroneously fired.
The assertion verifies that the controller has not moved to a low-power
state prior to receiving read data from the memory.
The original assertion triggered if the state was not:
PWR_IDLE or PWR_ACT.
In the case that failed, a periodic refresh event occurred around the
read. The REF is stalled until the final read burst is issued
and the subsequent PRE closes the bank. While the PRE will temporarily
move the state to PWR_IDLE, state will immediately transition to PWR_REF
due to the pending refresh operation. This state does not match the
assertion, which is subsequently triggered.
Fixed the assertion by explicitly checking that the state is not a low
power state
!PWR_SREF && !PWR_PRE_PDN && !PWR_ACT_PDN
Change-Id: I82921a733bbeac2bcb5a487c2f981448d41ed50b
Reviewed-by: Radhika Jagtap <radhika.jagtap@arm.com>
|
|
This patch extends the example big.LITTLE configuration to enable
dist-gem5 simulations of big.LITTLE systems.
Change-Id: I49c095ab3c737b6a082f7c6f15f514c269217756
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
This patch prevents the body of the script getting executed when
the script is imported as a module.
Change-Id: I70a50f6295f1e7a088398017f5fa9d06fe90476a
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
This patch prepares future extensions and customisation of the example
big.LITTLE configuration script. It breaks out the major phases into
functions so they can be called from other python scripts.
Change-Id: I2cb7c207c410fe14602cf17af7482719abba6c24
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
KvmGic functionality has been subsumed within the new MuxingKvmGic
model, which has Pl390 fallback when not using KVM for fast emulation.
This simplifies configuration and will enable checkpointing between
KVM emulation and full-system simulation.
Change-Id: Ie61251720064c512843015c075e4ac419a4081e8
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Automatically use the MuxingKvmGic in the VExpress_GEM5_V1
platform. This removes the need to patch the host kernel or the
platform configuration when using KVM on ARM.
Change-Id: Ib1ed9b3b849b80c449ef1b62b83748f3f54ada26
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
|
|
This device allows us to, when KVM support is detected and compiled in,
instantiate the same Gic device whether the actual simulation is with
KVM cores or simulated cores. Checkpointing is not yet supported.
Change-Id: I67e4e0b6fb7ab5058e52c933f4f3d8e7ab24981e
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
A KVM VM is typically a child of the System object already, but for
solving future issues with configuration graph resolution, the most
logical way to keep track of this object is for it to be an actual
parameter of the System object.
Change-Id: I965ded22203ff8667db9ca02de0042ff1c772220
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Change-Id: Ifc65d42eebfd109c1c622c82c3c3b3e523819e85
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
Names of DRAM configurations were updated to reflect both
the channel and device data width.
Previous naming format was:
<DEVICE_TYPE>_<DATA_RATE>_<CHANNEL_WIDTH>
The following nomenclature is now used:
<DEVICE_TYPE>_<DATA_RATE>_<n>x<w>
where n = The number of devices per rank on the channel
x = Device width
Total channel width can be calculated by n*w
Example:
A 64-bit DDR4, 2400 channel consisting of 4-bit devices:
n = 16
w = 4
The resulting configuration name is:
DDR4_2400_16x4
Updated scripts to match new naming convention.
Added unique configurations for DDR4 for:
1) 16x4
2) 8x8
3) 4x16
Change-Id: Ibd7f763b7248835c624309143cb9fc29d56a69d1
Reviewed-by: Radhika Jagtap <radhika.jagtap@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
|
|
Provides a helpful error when tests.py is invoked without the gem5 binary.
Before:
Running 0 tests
After:
gem5 binary 'quick/...' not an executable file
Change-Id: I1566802206c9e21ca89bd03e91db22844168a085
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
The notion of forward dependencies is just expressing the same
dependency but at the other end of the dependency edge, i.e. at
the dependee rather than the depender. As there is no more
'power' here, it's strictly a convenience feature for handling
dependencies with tags that are not in the upstream repository.
Change-Id: Ic7c68de6aff4094aaa12de62cdf690a5dc65ccb5
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
This commit supports the use case of transitioning tags and their
associated checkpoint rewrites out of use for whatever reason. Just
replace the upgrader() method with a downgrader() method that performs
the appropriate inverse operation.
The tag name is still used, but only in this negative, 'zombie' state,
as it will be removed from the tags in the checkpoint and gem5 binary.
Change-Id: If9d26cccfe8449e026762b1a72f0c2ae5a9cf2d7
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
|
|
The system calls tested in rv64i.cpp in RISC-V's insttest suite have
different behavior depending on the operating system and file system they
are run on. This patch ignores the output of those tests and only
ensures that the instructions in RV64I complete successfully.
[Change deletion of ECALL test to block comment.]
[Restore ECALL test but remove test output to test only for completion
without error.]
[Update patch description and again try to push EMPTY files for rv64i
tests.]
|
|
The current TLM bridge only provides a Slave Port that allows the gem5
world to send request to the SystemC world. This patch series refractors
and cleans up the existing code, and adds a Master Port that allows the
SystemC world to send requests to the gem5 world.
This patch:
* Update the README
|
|
The rr arbiter pointer in garnet was getting updated on every request,
even if there is no grant. This was leading to a huge variance in wait
time at a router at high injection rates.
This patch corrects it to update upon a grant.
|
|
Rather than having the 1st line on the Log line and every other line on its
own, add a new line to have a common format for all of them. Makes parsing
a lot easier.
Reviewed at http://reviews.gem5.org/r/3808/
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
|
|
When in 64-bit mode, if the stack is accessed implicitly by an instruction
the alternate address prefix should be ignored if present.
This patch adds an extra flag to the ldstop which signifies when the
address override should be ignored. Then, for all of the affected
instructions, this patch adds two options to the ld and st opcode to use
the current stack addressing mode for all addresses and to ignore the
AddressSizeFlagBit. Finally, this patch updates the x86 TLB to not
truncate the address if it is in 64-bit mode and the IgnoreAddrSizeFlagBit
is set.
This fixes a problem when calling __libc_start_main with a binary that is
linked with a recent version of ld. This version of ld uses the address
override prefix (0x67) on the call instruction instead of a nop.
Note: This has not been tested in compatibility mode and only the call
instruction with the address override prefix has been tested.
See [1] page 9 (pdf page 45)
For instructions that are affected see [1] page 519 (pdf page 555).
[1] http://support.amd.com/TechDocs/24594.pdf
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
|
|
In some newer Linux distributions, env python default to Python 3.0. This
patch explicitly uses "python2" instead of just "python" for all scripts
that use #!
Reported-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
|
