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The following deadlock was occuring in fetch_unit w/timingSim: 1. exec() is called, a wave is ready to fetch, so it sets pendingFetch 2. A packet is sent to ITLB to fetch for that wave 3. The wave executes a branch, causing the fetch buffer to be cleared 4. The packet is handled, and fetch() is called. However, because the fetch buffer was cleared, it returns doing nothing. 5. exec() gets called again, but the wave will never be scheduled to fetch, as pendingFetch is still set to true. This patch clears pendingFetch (and dropFetch) before returning in fetch() when the fetch buffer has been cleared. dropFetch needed to be cleared otherwise gem5 would crash. Change-Id: Iccbac7defc4849c19e8b17aa2492da641defb772 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/34555 Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com> Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com> Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.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.