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According to RISC V spec Volumn I, Section 11.1, the CSR will be written only if RS1 != 0 or imm != 0. However, after the change of CL(https://gem5-review.googlesource.com/c/public/gem5/+/67717), it will cause IllegalInstFault to write status CSR if we don't change the data. Example of Instruction Fault for mstatus ``` addi a5, zero, 8 csrc mstatus, a5 ``` It will cause instruction fault if mstatus value is 0 due to "newdata_all == olddata_all". We can just simply check if the data value is changed out of mask. Change-Id: Iab4ce7ac646a9105dc04e69c24d084572e28ebab Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67897 Reviewed-by: Yu-hsin Wang <yuhsingw@google.com> Maintainer: Jason Lowe-Power <power.jg@gmail.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, 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 these tools. Once you have all dependencies resolved, type 'scons build/<CONFIG>/gem5.opt' where CONFIG is one of the options in build_opts like ARM, NULL, MIPS, POWER, SPARC, X86, Garnet_standalone, etc. This will build an optimized version of the gem5 binary (gem5.opt) with the the specified configuration. See http://www.gem5.org/documentation/general_docs/building for more details and options. The main source tree includes these subdirectories: - build_opts: pre-made default configurations for gem5 - build_tools: tools used internally by gem5's build process. - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - include: include files for use in other programs - site_scons: modular components of the build system - 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 may need compiled system firmware, kernel binaries and one or more disk images, depending on gem5's configuration and what type of workload you're trying to run. Many of those resources can be downloaded from http://resources.gem5.org, and/or from the git repository here: https://gem5.googlesource.com/public/gem5-resources/ If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.