This is a development snapshot of the Vienna Flight OS intended for future use in software contributions by the space instrumentation working group at the Department of Astrophysics of the University of Vienna.
The current focus is on LEON3/LEON4 SPARC processors, but ports to different architectures (such as RISC-V) may be added in the future if required for our purposes.
This is a development which has its roots in an evaluation study of the MPPB (Massively Parallel Processor Breadboarding) prototype hardware and was later expanded to target the SSDP (Scalable Sensor Data Processor), which was intended to become a next-generation space-rated system-on-chip that included Xentium DSPs in a Network-On-Chip which were to be controlled by a general-purpose LEON3 host CPU.
While the SSDP has been abandoned, the extensions needed to operate the NoC and the DSPs were never more than modular components (and are in fact still part of the source tree) of the operating system so its development is continued.
Please note that this was originally referred to as LeanOS as a working title, but since the name was not very descriptive of its intended purpose, it was recently changed to Vienna Flight OS. References in pre-rendered versions of the PDF documentation are thus still referring to LeanOS.
See Documentation/ subdirectory.
(extremely brief, will expand later)
NOTE use release v2.2.0 of bcc2, which appears to work best at this time
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v2.0.7 produces bad instructions for at least one instance (arch/sparc/kernel/bootmem.c)
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both v2.1.2 and v2.2.0 appears to have a major problems with inline optimisation, which can create recursive code paths even when used with -O2
To ensure that this does not happen, always include at least:
--param max-inline-recursive-depth=0
in your CFLAGS, but note that the compiler may still ignore that if a function is not declared inline, so BEWARE
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bcc or bcc2 (preferred) tool chain
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GR712 or GR740 develpment board
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grmon
The build system is based on a modified variant of kbuild as used with the Linux kernel, so you can configure the build with make menuconfig.
To run the copy performance/ threaded multicore demonstrator, copy gr712_demo-config or gr740_demo-config to .config, then run make.
You may need to change the cross-compiler prefix for your particular tool chain (default is sparc-gaisler-elf-). This can be achieved by editing the .config file or by running make menuconfig and in the General Setup submenu.
If you run into issues with cpu-specific compiler flags, you may want to have a look at arch/sparc/Makefile and change the options accordingly.
For an overview of the development history (in order), see:
https://indico.esa.int/event/182/contributions/1513/attachments/1430/1655/1220_-_Luntzer.pdf
http://microelectronics.esa.int/userday-gr740/16_10-Armin_Luntzer_gr740userday2019.pdf