Problem:
- The implementation of `find` is coupled to the implementation of
`SinglyLinkedList`.
Solution:
- Decouple the implementation of `find` from the class by using a
generic `find` algorithm.
Problem:
- The implementation of `find` is coupled to the implementation of
`DoublyLinkedList`.
- `append` and `prepend` are implemented multiple times so that
r-value references can be moved from into the new node. This is
probably not called very often because a pr-value or x-value needs
to be used here.
Solution:
- Decouple the implementation of `find` from the class by using a
generic `find` algorithm.
- Make `append` and `prepend` be function templates so that they can
have binding references which can be forwarded.
These changes are arbitrarily divided into multiple commits to make it
easier to find potentially introduced bugs with git bisect.Everything:
The modifications in this commit were automatically made using the
following command:
find . -name '*.cpp' -exec sed -i -E 's/dbg\(\) << ("[^"{]*");/dbgln\(\1\);/' {} \;
We can now test a _very_ basic transaction via `do_debug_transfer()`.
This function merely attaches some TDs to the LSCTRL queue head
and points some input and output buffers. We then sense an interrupt
with USBSTS value of 1, meaning Interrupt On Completion
(of the transaction). At this point, the input buffer is filled with
some data.
According the USB spec/UHCI datasheet (as well as the Linux and
BSD source code), if we receive an IRQ and USBSTS is 0, then
the IRQ does not belong to us and we should immediately jump
out of the handler.
We can now read/write to the two root ports exposed to the
UHCI controller, and detect when a device is plugged in or
out via a kernel process that constantly scans the port
for any changes. This is very basic, but is a bit of fun to see
the kernel detecting hardware on the fly :^)
Implemented both Queue Heads and Transfer Descriptors. These
are required to actually perform USB transactions. The UHCI
driver sets up a pool of these that can be allocated when we
need them. It seems some drivers have these statically
allocated, so it might be worth looking into that, but
for now, the simple way seems to be to allocate them on
the fly as we need them, and then release them.
It seems that not setting the framelist address register
was causing the entire system to lock up as it generated an insane
interrupt storm in the IRQ handler for the UHCI controller.
We now allocate a 4KiB aligned page via
`MemoryManager::allocate_supervisor_physical_page()` and set every
value to 1. In effect, this creates a framelist with each entry
being a "TERMINATE" entry in which the controller stalls until its'
1mS time slice is up.
Some more registers have also been set for consistency, though it
seems like this don't need to be set explicitly in software.
Before this change, we would sometimes map a region into the address
space with !is_shared(), and then moments later call set_shared(true).
I found this very confusing while debugging, so this patch makes us pass
the initial shared flag to the Region constructor, ensuring that it's in
the correct state by the time we first map the region.
This new subsystem is somewhat replacing the IDE disk code we had with a
new flexible design.
StorageDevice is a generic class that represent a generic storage
device. It is meant that specific storage hardware will override the
interface. StorageController is a generic class that represent
a storage controller that can be found in a machine.
The IDEController class governs two IDEChannels. An IDEChannel is
responsible to manage the master & slave devices of the channel,
therefore an IDEChannel is an IRQHandler.
Fix some problems with join blocks where the joining thread block
condition was added twice, which lead to a crash when trying to
unblock that condition a second time.
Deferred block condition evaluation by File objects were also not
properly keeping the File object alive, which lead to some random
crashes and corruption problems.
Other problems were caused by the fact that the Queued state didn't
handle signals/interruptions consistently. To solve these issues we
remove this state entirely, along with Thread::wait_on and change
the WaitQueue into a BlockCondition instead.
Also, deliver signals even if there isn't going to be a context switch
to another thread.
Fixes#4336 and #4330
This makes the Scheduler a lot leaner by not having to evaluate
block conditions every time it is invoked. Instead evaluate them as
the states change, and unblock threads at that point.
This also implements some more waitid/waitpid/wait features and
behavior. For example, WUNTRACED and WNOWAIT are now supported. And
wait will now not return EINTR when SIGCHLD is delivered at the
same time.
Use the TimerQueue to expire blocking operations, which is one less thing
the Scheduler needs to check on every iteration.
Also, add a BlockTimeout class that will automatically handle relative or
absolute timeouts as well as overriding timeouts (e.g. socket timeouts)
more consistently.
Also, rework the TimerQueue class to be able to fire events from
any processor, which requires Timer to be RefCounted. Also allow
creating id-less timers for use by blocking operations.
We won't be receiving full PS/2 mouse packets when the VMWareBackdoor
absolute mouse mode is enabled. So, read just one byte every time
and retrieve the latest mouse packet from VMWareBackdoor immediately.
Fixes#4086
This allows issuing asynchronous requests for devices and waiting
on the completion of the request. The requests can cascade into
multiple sub-requests.
Since IRQs may complete at any time, if the current process is no
longer the same that started the process, we need to swich the
paging context before accessing user buffers.
Change the PATA driver to use this model.
Rework the PS/2 keyboard and mouse drivers to use a common 8042
controller driver. Also, reset and reconfigure the 8042 controller
as they are not guaranteed to be in the state that we expect.
This allows issuing asynchronous requests for devices and waiting
on the completion of the request. The requests can cascade into
multiple sub-requests.
Since IRQs may complete at any time, if the current process is no
longer the same that started the process, we need to swich the
paging context before accessing user buffers.
Change the PATA driver to use this model.
There are plenty of places in the kernel that aren't
checking if they actually got their allocation.
This fixes some of them, but definitely not all.
Fixes#3390Fixes#3391
Also, let's make find_one_free_page() return nullptr
if it doesn't get a free index. This stops the kernel
crashing when out of memory and allows memory purging
to take place again.
Fixes#3487
Since the CPU already does almost all necessary validation steps
for us, we don't really need to attempt to do this. Doing it
ourselves doesn't really work very reliably, because we'd have to
account for other processors modifying virtual memory, and we'd
have to account for e.g. pages not being able to be allocated
due to insufficient resources.
So change the copy_to/from_user (and associated helper functions)
to use the new safe_memcpy, which will return whether it succeeded
or not. The only manual validation step needed (which the CPU
can't perform for us) is making sure the pointers provided by user
mode aren't pointing to kernel mappings.
To make it easier to read/write from/to either kernel or user mode
data add the UserOrKernelBuffer helper class, which will internally
either use copy_from/to_user or directly memcpy, or pass the data
through directly using a temporary buffer on the stack.
Last but not least we need to keep syscall params trivial as we
need to copy them from/to user mode using copy_from/to_user.
MemoryManager cannot use the Singleton class because
MemoryManager::initialize is called before the global constructors
are run. That caused the Singleton to be re-initialized, causing
it to create another MemoryManager instance.
Fixes#3226
When trying to scroll up on virtualizers that don't use the VMware
backdoor and instead use PS2MouseDevice, it would actually scroll
down rapidly.
Looking into it, the mouse delta for scrolling down was 1 and 15
for scrolling up. 15 is suspiciously -1 for a nibble.
According to https://isdaman.com/alsos/hardware/mouse/ps2interface.htm
the Z is actually 4 bits for Intellimouse.
This fixes scrolling up on virtualizers such as VirtualBox.
