The makefile in this directory contains a number of configuration options.
| Configuration opion | description |
|---|---|
| CFLAGS | Flags given to the c compiler |
| MEMORY | The amount of memory given to qemu. Until memory detection works, must be 1G |
| DEFINITIONS | These are variables given to the c preprocessor. Options for these are listed below. |
| KERNEL_PARAMS | Currently not supported and outdated |
| SOURCEDIR | The name of the directory containing the sourcecode. |
| BUILDDIR | The name of the directory containing object files and binaries |
| INCLUDEDIR | Any directory in SOURCEDIR with this name, will be globally included in every c file. This means they can be included with #include <something.h> instead of #include "something.h". |
| TEST_MAIN_FILE | The name of the file generated to contain all tests. |
| CPU | The cpu type emulated by qemu. Supported cpu types are the arm1176 and cortex-a7 |
| Definition | Action |
|---|---|
| ENABLE_TESTS | With this definition enabled, tests are compiled into the kernel |
| MEM_DEBUG | Every kernel heap memory allocation (kmalloc, kfree) will be logged at TRACE level. Tests will be checked for memory leaks. |
| LOG_LEVEL | Number between 1 and 4 describing the log level of the kernel. 1 means only WARN logs. 2 means also INFO logs. 3 means also DEBUG logs and 4 means also TRACE logs. |
The locations of header files are automatically detected. Even cmake automatically finds them. Any directory below the src
directory with the name include will form a global namespace of headers you can include with #include<the_header.h>.
That means that in contrast to what many c programs do (put all headers in one large folder), they are localized. For example,
the folder src/vm/include has all headers associated to virtual memory.
Just make test (aka compile with the definition ENABLE_TESTS=1) and then running the kernel with semihosting.
To debug the kernel in clion, one can use the provided run configuration (debug). The kernel will now wait on
boot until the second run configuration (attach debugger) is ran. Breakpoints will work as normal.
A similar configuration can be achieved by running make debug in the kernel/ directory (not in the project root) and
then in a second terminal/tmux window/whatever run make start_debug to attach gdb with the right arguments.
It's important to only ever run course_os with the provided makefile and never use cmake's run configuration. It doesn't work and can't ever work as the emulator must be started.