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` :)
There is really no need to have two implementation of the same thing.
Only difference now is that HashMap's value type has to be movable but
this wasn't an issue
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
Instead of calculating bit-by-bit crc32, we now calculate a lookup table
during compile time. The old crc32 calculation was taking almost 50% of
the decompression time.
Also handle multiple symbols at once without outputting to user. It is
much more efficient to output many bytes instead of the up to 258 that a
single symbol can decode to :^)
We no longer require the user to pass full compressed data in one go,
instead the decompressor reports to the user if it needs more input or
output space.
Instead of sending while serializing (what even was that), we serialize
the whole packet into a buffer which can be sent in one go. First of all
this reduces the number of sends by a lot. This also fixes WindowServer
ending up sending partial packets when client is not responsive.
Previously we would just try sending once, if any send failed the send
was aborted while partial packet was already transmitted. This lead to
packet stream being out of sync leading to the client killing itself.
Now we allow 64 KiB outgoing buffer per client. If this buffer ever fills
up, we will not send partial packets.
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
If the window does not have an alpha channel, we now set every pixel's
alpha to 0xFF. This is needed by the WindowServer when it does alpha
blending, there used to be some weird stuff happening on overlapping
windows.
Also when we are invalidating a region with width of the whole window,
we can do a single memcpy instead of a memcpy for each row separately.
