Banos is a stable WIP C driver API that is supposed to provide a simple
interface to interact with the kernel and load the modules dynamically.
It is WIP and atm this just implements module loading with a custom
banos_install syscall. Banos will not try to substitute parts of the
kernel instead it will just expose kernel functionality via a stable
BINARY API. Meaning binaries (should) remain forward and backward
compatible on a binary level.
Banos modules work similarly to those in linux, you expose symbols via
BANOS_EXPORT which allows you to export a name + addr paired symbol.
It puts it in the .banos-export section. Drivers provide metadata about
themselves in the REQUIRED .banos-driver section. Symbols are resolved
at runtime. The kernel exposes the driver functionality via the same
.banos-export export mechanism.
Banos modules are elf RELOCATABLE files (object files) which have
partial linking (only banos symbols should remain). Modules will
eventually define dependencies, will export symbols and will allow you
to build a complex object hierarchy.
This patch adds the banos_install syscall which takes in the driver
image to install and may only be executed by super users. The API
doesn't validate already loaded modules, as thats something the
userspace MAY choose to keep track of. Multi-instance functionality
shall be implemented via driver specific behaviuor (exposed in the dev
filesystem or some other means).
Modules are supposed to allow you to alter kernel behavior and extend
it, allowing you to create filesystems, drivers, networking
modifications, schedulers, probers, and more (hopefully) whilst
remaining binary compatible with any version of the kernel (again,
hopefully).
The old linked list allocator with power of two pool sizes was kinda
weird. Now we use 1MiB bitmap allocators for allocations <64KiB and
directly call mmap for larger allocations. This allows userspace to
actually free unused memory on `free` :)
This generates much nicer assembly as it does not have to read thread
pointer for every access to TCB (errno, cancel_state, cancelled) and
instead it can read it once and use the same value for all accesses
Kernel syscall API no longer zeros all unused argument registers and
libc now uses inlined syscall macro internally. This significantly
cleans up generated code for basic syscall wrapper functions.
Install SIGCANCEL handler for all threads.
Remove unneeded atomic stores and loads. States are only changed within
the thread itself.
Define pthread_testcancel as a macro so it gets inlined inside
cancellation points
