Problem:
- `static` variables consume memory and sometimes are less
optimizable.
- `static const` variables can be `constexpr`, usually.
- `static` function-local variables require an initialization check
every time the function is run.
Solution:
- If a global `static` variable is only used in a single function then
move it into the function and make it non-`static` and `constexpr`.
- Make all global `static` variables `constexpr` instead of `const`.
- Change function-local `static const[expr]` variables to be just
`constexpr`.
There is a slight race condition in our implementation of write().
We call File::can_write() before attempting to write to it (blocking if
it returns false). If it returns true, we assume that we can write to
the file, and our code assumes that File::write() cannot possibly fail
by being blocked. There is, however, the rare case where another process
writes to the file and prevents further writes in between the call to
Files::can_write() and File::write() in the first process. This would
result in the first process calling File::write() when it cannot be
written to.
We fix this by adding a mechanism for File::can_write() to signal that
it was blocked, making it the responsibilty of File::write() to check
whether it can write and then finally making sys$write() check if the
write failed due to it being blocked.
This commit adds support for initializing multiple serial ports per
PCI board, as well as initializing multiple different pci serial boards
Currently we just choose the first PCI serial port seen as the debug
port, but this should probably be made configurable some how in the
future.
This simple driver simply finds a device in a device definitions list
and then sets up a SerialDevice instance based on the definition.
The driver currently only supports "WCH CH382 2S" pci serial boards,
as that is the only device available for me to test with, but most
other pci serial devices should be as easily addable as adding a
board_definitions entry.
The line control option bits (parity, stop bits, word length) were
masked and then combined incorrectly, resulting in them not being set
when requested.
These were accidentally the wrong way around (LSB part of the divisor
into the MSB register, MSB part of the divisor into the LSB register)
as can be seen in the specification (and in the comments themselves)
As we removed the support of VBE modesetting that was done by GRUB early
on boot, we need to determine if we can modeset the resolution with our
drivers, and if not, we should enable text mode and ensure that
SystemServer knows about it too.
Also, SystemServer should first check if there's a framebuffer device
node, which is an indication that text mode was not even if it was
requested. Then, if it doesn't find it, it should check what boot_mode
argument the user specified (in case it's self-test). This way if we
try to use bochs-display device (which is not VGA compatible) and
request a text mode, it will not honor the request and will continue
with graphical mode.
Also try to print critical messages with mininum memory allocations
possible.
In LibVT, We make the implementation flexible for kernel-specific
methods that are implemented in ConsoleImpl class.
This new subsystem is replacing the old code that was used to
create device nodes of framebuffer devices in /dev.
This subsystem includes for now 3 roles:
1. GraphicsManagement singleton object that is used in the boot
process to enumerate and initialize display devices.
2. GraphicsDevice(s) that are used to control the display adapter.
3. FramebufferDevice(s) that are used to control the device node in
/dev.
For now, we support the Bochs display adapter and any other
generic VGA compatible adapter that was configured by the boot
loader to a known and fixed resolution.
Two improvements in the Bochs display adapter code are that
we can support native bochs-display device (this device doesn't
expose any VGA capabilities) and also that we use the MMIO region,
to configure the device, instead of setting IO ports for such tasks.
This device is a graphics display device that is not supporting
VGA functionality.
Therefore, it exposes a MMIO region to configure it, so we use that
region to set the framebuffer resolution.
The following KUBSAN crash on startup was reported on discord:
```
UHCI: Started
KUBSAN: reference binding to null pointer of type struct UHCIController
KUBSAN: at ../../Kernel/Devices/USB/UHCIController.cpp, line 67
```
After inspecting the code, it became clear that there's a window of time
where the kernel task which monitors the UHCI port can startup and start
executing before the UHCIController constructor completes. This leaves
the singleton pointing to nullptr, thus in the duration of this race
window the "UHCI port proc" thread will go an and de-reference the null
pointer when trying to read for status changes on the UHCI root ports.
Reported-by: @stelar7
Reported-by: @bcoles
Fixes: #6154
AnonymousVMObject::create_with_physical_page(s) can't be NonnullRefPtr
as it allocates internally. Fixing the API then surfaced an issue in
ScatterGatherList, where the code was attempting to create an
AnonymousVMObject in the constructor which will not be observable
during OOM.
Fix all of these issues and start propagating errors at the callers
of the AnonymousVMObject and ScatterGatherList APis.
We use a global setting to determine if Caps Lock should be remapped to
Control because we don't care how keyboard events come in, just that they
should be massaged into different scan codes.
The `proc` filesystem is able to manipulate this global variable using
the `sysctl` utility like so:
```
# sysctl caps_lock_to_ctrl=1
```
Our current implementation does not work in the special case in which
both shift keys are pressed, and then only one of the keys is released,
as this would result in writing lower case letters, instead of the
expected upper case letters.
This commit fixes that by keeping track of the amount of shift keys
that are pressed (instead of if any are at all), and only switching to
the unshifted keymap once all of them are released.
We had some inconsistencies before:
- Sometimes "The", sometimes "the"
- Sometimes trailing ".", sometimes no trailing "."
I picked the most common one (lowecase "the", trailing ".") and applied
it to all copyright headers.
By using the exact same string everywhere we can ensure nothing gets
missed during a global search (and replace), and that these
inconsistencies are not spread any further (as copyright headers are
commonly copied to new files).
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
The previous implementation could allocate on insertion into the completed / pending
sub request vectors. There's no reason these can't be intrusive lists instead.
This is a very minor step towards improving the ability to handle OOM, as tracked by #6369
It might also help improve performance on the IO path in certain situations.
I'll benchmark that later.
Pressing this combo will dump a list of all threads and their state
to the debug console.
This might be useful to figure out why the system is not responding.
Helps with bare metal debugging, as we can't be sure our implementation
will work with a given machine.
As reported by someone on Discord, their machine hangs when we attempt
the dummy transfer.
The first one is for disabling the PS2 controller, the other one is for
disabling physical storage enumeration.
We can't be sure any machine will work with our implementation,
therefore this will help us to test more machines.
The end goal of this commit is to allow to boot on bare metal with no
PS/2 device connected to the system. It turned out that the original
code relied on the existence of the PS/2 keyboard, so VirtualConsole
called it even though ACPI indicated the there's no i8042 controller on
my real machine because I didn't plug any PS/2 device.
The code is much more flexible, so adding HID support for other type of
hardware (e.g. USB HID) could be much simpler.
Briefly describing the change, we have a new singleton called
HIDManagement, which is responsible to initialize the i8042 controller
if exists, and to enumerate its devices. I also abstracted a bit
things, so now every Human interface device is represented with the
HIDDevice class. Then, there are 2 types of it - the MouseDevice and
KeyboardDevice classes; both are responsible to handle the interface in
the DevFS.
PS2KeyboardDevice, PS2MouseDevice and VMWareMouseDevice classes are
responsible for handling the hardware-specific interface they are
assigned to. Therefore, they are inheriting from the IRQHandler class.
We can't use deferred functions for anything that may require preemption,
such as copying from/to user or accessing the disk. For those purposes
we should use a work queue, which is essentially a kernel thread that
may be preempted or blocked.
Alot of code is shared between i386/i686/x86 and x86_64
and a lot probably will be used for compatability modes.
So we start by moving the headers into one Directory.
We will probalby be able to move some cpp files aswell.
