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The Linux Kernel's printk mechanism and data structures were overhauled in v5.10. This patch updates gem5's facility to dump the kernel Dmesg buffer on kernel panic to account for these changes. The new mechanism splits the Demsg ringbuffer into three separate ringbuffers, one containing the message data, one containing descriptors used for lock-free synchronisation, and one containing the message infos. For a detailed description please see the header of `kernel/printk/printk_ringbuffer.c` in the Linux source code. The new gem5 implementation tests for the correct version to run (pre-v5.10 or post-v5.10) by testing for the presence of symbols in the kernel. The new, post-v5.10 dump code is templated on types compatible with the kernel's atomic_long_t to account for differences between the 64-bit and 32-bit Linux kernels. Because the new Dmesg buffer dump code in gem5 is intended for disaster recovery, it intentionally prints the full Dmesg buffer with minimal checking of the validity of the messages. Partially finished and/or uncommitted messages will be printed along with the finalised messages. Change-Id: I62ac20735e0679f1ba2062ca7bb13692a5ca1eae Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/59509 Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu> Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com> Maintainer: Jason Lowe-Power <power.jg@gmail.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.