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When a thread is activated by another thread calling a clone system call, the child thread's context is initialized in the middle of the clone system call and before the context is fully initialized. Therefore, the child thread starts fetching an unitialized PC, which could lead to a page fault. This patch adds a pipeline wakeup event that is scheduled later in the cycle when the thread is activated. This event ensures that the first fetch only happens after the thread context is fully initialized (e.g., in case of clone syscall, it is when the parent thread copies its context over to the child thread). When a thread first starts or wakes up, input queue to the Fetch2 stage needs to be drained since the execution flow is likely to change and previously fetched instructions in the queue may no longer be in the correct flow. This patch dumps/drains all inputs in the input queue of a thread context in the Fetch2 stage when the associated thread wakes up. Change-Id: Iad970638e435858b7289cd471158cc0afdbbb0e5 Reviewed-on: https://gem5-review.googlesource.com/c/8182 Reviewed-by: Brandon Potter <Brandon.Potter@amd.com> Reviewed-by: Jason Lowe-Power <jason@lowepower.com> Maintainer: Brandon Potter <Brandon.Potter@amd.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/Introduction, and for more information about building the simulator and getting started please see http://www.gem5.org/Documentation and http://www.gem5.org/Tutorials. 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/Dependencies 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 ALPHA, 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/Build_System for more details and options. With the simulator built, have a look at http://www.gem5.org/Running_gem5 for more information on how to use gem5. 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. Please see the gem5 download page for these items at http://www.gem5.org/Download If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.