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The X86 local APIC doesn't actually use the pio_addr set in the config and instead computes what address it will respond to based on the initial ID of the CPU it's attached to. gem5's BasicPioDevice, which the X86LocalApic class inherits from, does not provide a default value for that parameter and will complain if *something* isn't set. The value used, 0x2000000000000000, is a dummy value which is the base of the region of the physical address space set aside for messages to local APICs from the CPU and from other local APICs. Also, the clock for the local APIC's timer is defined to be the bus clock. The assumption seems to be that this has a 16:1 ratio with the CPU clock, and I vaguely remember finding that that was more or less unofficially true, even if it isn't necessary stringently defined to be that. Since we were already just assuming that that ratio was correct and always setting up the local APICs clock that way, we can do that in the X86LocalApic class definition and remove some special x86 specific setup that we'd otherwise need for the x86 version of the Interrupt class. If that's not correct, it can still be overridden somewhere else in the config. Change-Id: I50e84f899f44b1191c2ad79d05803b44f07001f9 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19968 Reviewed-by: Gabe Black <gabeblack@google.com> Maintainer: Gabe Black <gabeblack@google.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/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.