These files are not marked as block devices or character devices so they
are not meant to be used as device nodes. The filenames are formatted to
the pattern "major:minor", but a Userland program need to call the parse
these format and inspect the the major and minor numbers and create the
real device nodes in /dev.
Later on, it might be a good idea to ensure we don't create new
SysFSComponents on the heap for each Device, but rather generate
them only when required (and preferably to not create a SysFSComponent
at all if possible).
Devices might be removed and inserted at anytime, so let's ensure we
always do these kind of operations with a good known state of the
HashMap.
The VirtIO code was modified to create devices outside the IRQ handler,
so now it works with the new locking of the devices singleton, but a
better approach might be needed later on.
These methods are no longer needed because SystemServer is able to
populate the DevFS on its own.
Device absolute_path no longer assume a path to the /dev location,
because it really should not assume any path to a Device node.
Because StorageManagement still needs to know the storage name, we
declare a virtual method only for StorageDevices to override, but this
technique should really be removed later on.
A couple of things were changed:
1. Semantic changes - PCI segments are now called PCI domains, to better
match what they are really. It's also the name that Linux gave, and it
seems that Wikipedia also uses this name.
We also remove PCI::ChangeableAddress, because it was used in the past
but now it's no longer being used.
2. There are no WindowedMMIOAccess or MMIOAccess classes anymore, as
they made a bunch of unnecessary complexity. Instead, Windowed access is
removed entirely (this was tested, but never was benchmarked), so we are
left with IO access and memory access options. The memory access option
is essentially mapping the PCI bus (from the chosen PCI domain), to
virtual memory as-is. This means that unless needed, at any time, there
is only one PCI bus being mapped, and this is changed if access to
another PCI bus in the same PCI domain is needed. For now, we don't
support mapping of different PCI buses from different PCI domains at the
same time, because basically it's still a non-issue for most machines
out there.
2. OOM-safety is increased, especially when constructing the Access
object. It means that we pre-allocating any needed resources, and we try
to find PCI domains (if requested to initialize memory access) after we
attempt to construct the Access object, so it's possible to fail at this
point "gracefully".
3. All PCI API functions are now separated into a different header file,
which means only "clients" of the PCI subsystem API will need to include
that header file.
4. Functional changes - we only allow now to enumerate the bus after
a hardware scan. This means that the old method "enumerate_hardware"
is removed, so, when initializing an Access object, the initializing
function must call rescan on it to force it to find devices. This makes
it possible to fail rescan, and also to defer it after construction from
both OOM-safety terms and hotplug capabilities.
This expands the reach of error propagation greatly throughout the
kernel. Sadly, it also exposes the fact that we're allocating (and
doing other fallible things) in constructors all over the place.
This patch doesn't attempt to address that of course. That's work for
our future selves.
The default template argument is only used in one place, and it
looks like it was probably just an oversight. The rest of the Kernel
code all uses u8 as the type. So lets make that the default and remove
the unused template argument, as there doesn't seem to be a reason to
allow the size to be customizable.
This commit moves the KResult and KResultOr objects to Kernel/API to
signify that they may now be freely used by userspace code at points
where a syscall-related error result is to be expected. It also exposes
KResult and KResultOr to the global namespace to make it nicer to use
for userspace code.
This is the idiomatic way to declare type aliases in modern C++.
Flagged by Sonar Cloud as a "Code Smell", but I happen to agree
with this particular one. :^)
Previous implementation sometimes didn't release the key after pressing
and holding shift due to repeating key updates when holding keys. This
meant repeating updates would set/unset `m_both_shift_keys_pressed`
repeatedly, sometimes resulting in shift still being considered pressed
even after you released it.
Simplify left and right shift key pressed logic by tracking both key
states separately and always updating modifiers based on them.
Prior to this change, both uid_t and gid_t were typedef'ed to `u32`.
This made it easy to use them interchangeably. Let's not allow that.
This patch adds UserID and GroupID using the AK::DistinctNumeric
mechanism we've already been employing for pid_t/ProcessID.
Two new ioctl requests are used to get and set the sample rate of the
sound card. The SB16 device keeps track of the sample rate separately,
because I don't want to figure out how to read the sample rate from the
device; it's easier that way.
The soundcard write doesn't set the sample rate to 44100 Hz every time
anymore, as we want to change it externally.
Now that the old PCI::Device was removed, we can complete the PCI
changes by making the PCI::DeviceController to be named PCI::Device.
Really the entire purpose and the distinction between the two was about
interrupts, but since this is no longer a problem, just rename it to
simplify things further.
I created this class a long time ago just to be able to quickly make a
PCI device to also represent an interrupt handler (because PCI devices
have this capability for most devices).
Then after a while I introduced the PCI::DeviceController, which is
really almost the same thing (a PCI device class that has Address member
in it), but is not tied to interrupts so it can have no interrupts, or
spawn interrupt handlers however it wants to seems fit.
However I decided it's time to say goodbye for this class for
a couple of reasons:
1. It made a whole bunch of weird patterns where you had a PCI::Device
and a PCI::DeviceController being used in the topic of implementation,
where originally, they meant to be used mutually exclusively (you
can't and really don't want to use both).
2. We can really make all the classes that inherit from PCI::Device
to inherit from IRQHandler at this point. Later on, when we have MSI
interrupts support, we can go further and untie things even more.
3. It makes it possible to simplify the VirtIO implementation to a great
extent. While this commit almost doesn't change it, future changes
can untangle some complexity in the VirtIO code.
For UHCIController, E1000NetworkAdapter, NE2000NetworkAdapter,
RTL8139NetworkAdapter, RTL8168NetworkAdapter, E1000ENetworkAdapter we
are simply making them to inherit the IRQHandler. This makes some sense,
because the first 3 devices will never support anything besides IRQs.
For the last 2, they might have MSI support, so when we start to utilize
those, we might need to untie these classes from IRQHandler and spawn
IRQHandler(s) or MSIHandler(s) as needed.
The VirtIODevice class is also a case where we currently need to use
both PCI::DeviceController and IRQHandler classes as parents, but it
could also be untied from the latter.
This has several benefits:
1) We no longer just blindly derefence a null pointer in various places
2) We will get nicer runtime error messages if the current process does
turn out to be null in the call location
3) GCC no longer complains about possible nullptr dereferences when
compiling without KUBSAN
This makes for nicer handling of errors compared to checking whether a
RefPtr is null. Additionally, this will give way to return different
types of errors in the future.
...and also RangeAllocator => VirtualRangeAllocator.
This clarifies that the ranges we're dealing with are *virtual* memory
ranges and not anything else.
Now that all KResult and KResultOr are used consistently throughout the
kernel, it's no longer necessary to return negative error codes.
However, we were still doing that in some places, so let's fix all those
(bugs) by removing the minuses. :^)
It's easy to forget the responsibility of validating and safely copying
kernel parameters in code that is far away from syscalls. ioctl's are
one such example, and bugs there are just as dangerous as at the root
syscall level.
To avoid this case, utilize the AK::Userspace<T> template in the ioctl
kernel interface so that implementors have no choice but to properly
validate and copy ioctl pointer arguments.
GCC and Clang allow us to inject a call to a function named
__sanitizer_cov_trace_pc on every edge. This function has to be defined
by us. By noting down the caller in that function we can trace the code
we have encountered during execution. Such information is used by
coverage guided fuzzers like AFL and LibFuzzer to determine if a new
input resulted in a new code path. This makes fuzzing much more
effective.
Additionally this adds a basic KCOV implementation. KCOV is an API that
allows user space to request the kernel to start collecting coverage
information for a given user space thread. Furthermore KCOV then exposes
the collected program counters to user space via a BlockDevice which can
be mmaped from user space.
This work is required to add effective support for fuzzing SerenityOS to
the Syzkaller syscall fuzzer. :^) :^)
We don't need to have a dedicated API for creating a VMObject with a
single page, the multi-page API option works in all cases.
Also make the API take a Span<NonnullRefPtr<PhysicalPage>> instead of
a NonnullRefPtrVector<PhysicalPage>.
These small changes fix the remaining warnings that come up during
kernel compilation with Clang. These specific fixes were for benign
things: unused lambda captures and braces around scalar initializers.
The `#pragma GCC diagnostic` part is needed because the class has
virtual methods with the same name but different arguments, and Clang
tries to warn us that we are not actually overriding anything with
these.
Weirdly enough, GCC does not seem to care.
This hack allows self-test mode run-tests-and-shutdown.sh to give
TestProcFs a stat(2)-able /proc/self/fd/0. For some reason, when
stdin is a SerialDevice, /proc/self/fd/0 will be a symlink to the device
as expected, but, calling realpath or stat on /proc/self/fd/0 will error
out. realpath will give the string from Device::absolute_path() which
would be something like "device:4,64 (SerialDevice)". When VFS is trying
to resolve_path so that we can stat the file, it would bail out on this
fake-y path.
Change the fake path (that doesn't show up when you ls a device, nor
when checking the devices tab in SystemMonitor) from the major/minor
device number and class_name() to /dev/device_name(). There's probably
a very hairy yak standing behind this issue that was only discovered due
to the ProcFS rework.
The new ProcFS design consists of two main parts:
1. The representative ProcFS class, which is derived from the FS class.
The ProcFS and its inodes are much more lean - merely 3 classes to
represent the common type of inodes - regular files, symbolic links and
directories. They're backed by a ProcFSExposedComponent object, which
is responsible for the functional operation behind the scenes.
2. The backend of the ProcFS - the ProcFSComponentsRegistrar class
and all derived classes from the ProcFSExposedComponent class. These
together form the entire backend and handle all the functions you can
expect from the ProcFS.
The ProcFSExposedComponent derived classes split to 3 types in the
manner of lifetime in the kernel:
1. Persistent objects - this category includes all basic objects, like
the root folder, /proc/bus folder, main blob files in the root folders,
etc. These objects are persistent and cannot die ever.
2. Semi-persistent objects - this category includes all PID folders,
and subdirectories to the PID folders. It also includes exposed objects
like the unveil JSON'ed blob. These object are persistent as long as the
the responsible process they represent is still alive.
3. Dynamic objects - this category includes files in the subdirectories
of a PID folder, like /proc/PID/fd/* or /proc/PID/stacks/*. Essentially,
these objects are always created dynamically and when no longer in need
after being used, they're deallocated.
Nevertheless, the new allocated backend objects and inodes try to use
the same InodeIndex if possible - this might change only when a thread
dies and a new thread is born with a new thread stack, or when a file
descriptor is closed and a new one within the same file descriptor
number is opened. This is needed to actually be able to do something
useful with these objects.
The new design assures that many ProcFS instances can be used at once,
with one backend for usage for all instances.
This does the exact thing as `adopt_ref`, which is a recent addition to
AK.
Note that pointers returned by a bare new (without `nothrow`) are
guaranteed not to return null, so they can safely be converted into
references.
This commit converts naked `new`s to `AK::try_make` and `AK::try_create`
wherever possible. If the called constructor is private, this can not be
done, so we instead now use the standard-defined and compiler-agnostic
`new (nothrow)`.
Instead, try to create the device objects in separate static methods,
and if we fail for some odd reason to allocate memory for such devices,
just panic with that reason.
We now store the device descriptor obtained from the device
during enumeration in the device's object in memory instead
of exposing all of the different members contained within it.
If we are in a shared interrupt handler, the called handlers might
indicate it was not their interrupt, so we should not increment the
call counter of these handlers.
These are the actual structures that allow USB to work (i.e the ones
actually defined in the specification). This should provide us enough
of a baseline implementation that we can build on to support
different types of USB device.
The changes in commit 20743e8 removed the s_max_virtual_consoles
constant and hardcoded the number of consoles to 4. But in
PS2KeyboardDevice the keyboard shortcuts for switching to consoles were
hardcoded to 6.
I reintroduced the constant and added it in both places.
Previously reads and writes to /dev/zero, /dev/full, /dev/null and
/dev/random were limited to 4096 bytes.
This removes that restriction so that users can enjoy more zero bytes
in their buffers.
Instead of processing the input after receiving an IRQ, we shift the
responsibility to the io work queue to handle this for us, so if a page
fault occurs when trying to switch the VirtualConsole, the kernel can
handle that.
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.
