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kernel

Project ID: 1894
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kernel

Redox OS Microkernel

MIT licensed docs

Building the documentation

Try cargo doc --open --target x86_64-unknown-none.

Debugging the redox kernel

Running qemu with the -s flag will set up qemu to listen on port 1234 for a gdb client to connect to it. To debug the redox kernel run.

make qemu gdb=yes

This will start a VM with and listen on port 1234 for a gdb or lldb client.

gdb

If you are going to use gdb, run the following to load debug symbols and connect to your running kernel.

(gdb) symbol-file build/kernel.sym
(gdb) target remote localhost:1234

lldb

If you are going to use lldb, run the following to start debugging.

(lldb) target create -s build/kernel.sym build/kernel
(lldb) gdb-remote localhost:1234

Debugging

After connecting to your kernel you can set some interesting breakpoints and continue the process. See your debuggers man page for more information on useful commands to run.

Notes

  • When trying to access a slice, always use the common::GetSlice trait and the .get_slice() method to get a slice without causing the kernel to panic. The problem with slicing in regular Rust, e.g. foo[a..b], is that if someone tries to access with a range that is out of bounds of an array/string/slice, it will cause a panic at runtime, as a safety measure. Same thing when accessing an element.

  • Always use foo.get(n) instead of foo[n] and try to cover for the possibility of Option::None. Doing the regular way may work fine for applications, but never in the kernel. No possible panics should ever exist in kernel space, because then the whole OS would just stop working.

  • If you receive a kernel panic in QEMU, use pkill qemu-system to kill the frozen QEMU process.