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When remote GDB attaches to gem5, handle the initial communication (`qSupported` and alike) right away instead of scheduling a `DataEvent` and firing the simulation loop in hope that GDB will be quick enough to send initial packets before instructions are dispatched. This requires attach() to be always called at instruction boundary to make it safe to interact with the rest of gem5. When `--wait-gdb` is used, connect() is called from workflow startup, therefore on an instruction boundary and therefore needs not special handling. To handle case the GDB connects while simulation is already running, we arrange (new) assynchronous IncommingConnectionEvent on listening socket that, when there's a new connection being made, *only* schedules *synchronous* ConnectEvent that handles the rest, *including* calling an accept() on listening socket. This way it is safe to process commands in attach(). In order to make the code more systematic and easier to understands, detach() is also made to be called only synchronously (that is, at intruction boundary). Asynchronous events and event handlers are prefixed with "incoming". This seems to fix the race described in 44612 [1] [1]: https://gem5-review.googlesource.com/c/public/gem5/+/44612 Change-Id: I33b2922ba017205acabd51b6a8be3e6fb2d6409a Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48182 Reviewed-by: Boris Shingarov <shingarov@labware.com> Maintainer: Boris Shingarov <shingarov@labware.com> Tested-by: kokoro <noreply+kokoro@google.com>
This is the gem5 simulator. The main website can be found at http://www.gem5.org A good starting point is http://www.gem5.org/about, and for more information about building the simulator and getting started please see http://www.gem5.org/documentation and http://www.gem5.org/documentation/learning_gem5/introduction. To build gem5, you will need the following software: g++ or clang, Python (gem5 links in the Python interpreter), SCons, SWIG, zlib, m4, and lastly protobuf if you want trace capture and playback support. Please see http://www.gem5.org/documentation/general_docs/building for more details concerning the minimum versions of the aforementioned tools. Once you have all dependencies resolved, type 'scons build/<ARCH>/gem5.opt' where ARCH is one of ARM, NULL, MIPS, POWER, SPARC, or X86. This will build an optimized version of the gem5 binary (gem5.opt) for the the specified architecture. See http://www.gem5.org/documentation/general_docs/building for more details and options. The basic source release includes these subdirectories: - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - src: source code of the gem5 simulator - system: source for some optional system software for simulated systems - tests: regression tests - util: useful utility programs and files To run full-system simulations, you will need compiled system firmware (console and PALcode for Alpha), kernel binaries and one or more disk images. If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.