fbos/kernel/initrd.c, branch main

Move initrd.c into lib

2024-11-26T21:44:45Z

Even if it's tightly coupled with the kernel (e.g. identifying specific tasks from the kernel), in the end it's a library and so it should be placed accordingly. Signed-off-by: Miquel Sabaté Solà

Move 'memcpy' to assembly

2024-11-26T21:27:02Z

And apparently 'memmove' is not needed anymore, so we dodged a bullet there. Signed-off-by: Miquel Sabaté Solà

Accept tasks as a parameter on initrd extraction

2024-11-24T22:27:13Z

This allows this functionality to be properly extracted for unit tests. Signed-off-by: Miquel Sabaté Solà

kernel: Remove old code from initrd.c

2024-11-24T22:03:34Z

And for the first time I saw this whole thing working with optimizations on :) Signed-off-by: Miquel Sabaté Solà

Simplify the entry address computation

2024-11-24T21:37:20Z

We actually don't need to preserve the initially computed base address for each binary, but we can just preserve the final entry address. Signed-off-by: Miquel Sabaté Solà

Simplify scheduling by introducing an init process

2024-11-24T21:22:48Z

Scheduling is easier if there is an init process which does nothing. This way we don't have to perform hacks in order to idle in S privilege mode while touching special registers in weird ways. For now this process is kind of costly since 'wfi' is not accepted in this context, but this can be further tuned down in the future by setting TW=1 on 'mstatus', or by handling the exception and allowing it if it comes from the proper process. All of that being said, there is still work to be done as things fail when optimitzations are on. Signed-off-by: Miquel Sabaté Solà

Fix initrd parsing because of a path change

2024-11-22T15:43:36Z

In commit 573a8c6b490a ("usr: Rename foo/bar to fizz/buzz") the path of the user-space binaries have changed. The `initrd` parsing code makes some decisions based on that naming, and so it needed to be updated as well. Fixes: 573a8c6b490a ("usr: Rename foo/bar to fizz/buzz") Signed-off-by: Miquel Sabaté Solà

Add basic parsing for underlying ELF executables

2024-11-22T06:58:15Z

The given initrd is a CPIO archive of multiple ELF executables. We are already able to parse the CPIO archive to detect where each file is located, this commit adds the mapping for each ELF executable to the corresponding task_struct. Note that this is still heavily under construction, since we cannot simply jump into the entry point of an executable as we have not yet setup the proper layout from performing context switches. Signed-off-by: Miquel Sabaté Solà

Initial parsing of the provided initrd file

2024-11-21T12:09:21Z

We expect a CPIO archive with the 'newc' format for the initrd. Parse this archive from the given initrd address and fetch the address for each ELF executable while also pairing which task correspond to which ELF. This commit leaves to do the actual parsing of the ELF file for each task, while also leaving some string utilities to be refined. Signed-off-by: Miquel Sabaté Solà