The Lock class still permits no reason, but for everything else
require a reason to be passed to Thread::wait_on. This makes it
easier to diagnose why a Thread is in Queued state.
Random now gets entropy from the following drivers:
- KeyboardDevice
- PATAChannel
- PS2MouseDevice
- E1000NetworkAdapter
- RTL8139NetworkAdapter
Of these devices, PS2MouseDevice and PATAChannel provide the vast
majority of the entropy.
This was supposed to be the foundation for some kind of pre-kernel
environment, but nobody is working on it right now, so let's move
everything back into the kernel and remove all the confusion.
The IOAPIC manual states that "Interrupt Mask-R/W. When this bit is 1,
the interrupt signal is masked. Edge-sensitive interrupts signaled on
a masked interrupt pin are ignored." - Therefore we have to ensure that
we disable interrupts globally with cli(), but also to ensure that we
invoke enable_irq() before sending the hardware command that generates
an IRQ almost immediately.
First, before this change, specifying 'force_pio' in the kernel
commandline was meaningless because we nevertheless set the DMA flag to
be enabled.
Also, we had a problem in which we used IO::repeated_out16() in PIO
write method. This might work on buggy emulators, but I suspect that on
real hardware this code will fail.
The most difficult problem was to restore the PIO read operation.
Apparently, it seems that we can't use IO::repeated_in16() here because
it will read zeroed data. Currently we rely on a simple loop that
invokes IO::in16() to a buffer. Also, the interrupt handling stage in
the PIO read method is moved to be handled inside the loop of reading
the requested sectors.
Also, duplicate data in dbg() and klog() calls were removed.
In addition, leakage of virtual address to kernel log is prevented.
This is done by replacing kprintf() calls to dbg() calls with the
leaked data instead.
Also, other kprintf() calls were replaced with klog().
Also, update the class implementation to use PCI::Device class
accordingly.
The create() helper will now search for an IDE controller in the
PCI bus, allowing to simplify the initialize() method.
System components that need an IRQ handling are now inheriting the
InterruptHandler class.
In addition to that, the initialization process of PATAChannel was
changed to fit the changes.
PATAChannel, E1000NetworkAdapter and RTL8139NetworkAdapter are now
inheriting from PCI::Device instead of InterruptHandler directly.
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.
For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.
Going forward, all new source files should include a license header.
The kernel and its static data structures are no longer identity-mapped
in the bottom 8MB of the address space, but instead move above 3GB.
The first 8MB above 3GB are pseudo-identity-mapped to the bottom 8MB of
the physical address space. But things don't have to stay this way!
Thanks to Jesse who made an earlier attempt at this, it was really easy
to get device drivers working once the page tables were in place! :^)
Fixes#734.
Instead of waking up repeatedly to check if a disk operation has
finished, use a WaitQueue and wake it up in the IRQ handler.
This simplifies the device driver a bit, and makes it more responsive
as well :^)
The kernel is now no longer identity mapped to the bottom 8MiB of
memory, and is now mapped at the higher address of `0xc0000000`.
The lower ~1MiB of memory (from GRUB's mmap), however is still
identity mapped to provide an easy way for the kernel to get
physical pages for things such as DMA etc. These could later be
mapped to the higher address too, as I'm not too sure how to
go about doing this elegantly without a lot of address subtractions.
Also added an option in the run script to force PIO operation mode with
the IDE controller.
In addition, we're no longer limited to PIIX3 and PIIX4 chipsets for DMA
This helps aid debugging of issues such as #695, where the bridge chip
that controls IDE is NOT a PIIX3/4 compatible controller. Instead of
just hanging when the DMA registers can't be accessed, the system will
inform the user that no valid IDE controller has been found. In this
case, the system will not attempt to initialise the DMA registers and
instead use PIO mode.
The alternate status register is not part of the same set of registers
as all the other stuff.
Also rename wait_400ns() to io_delay() since we had no guarantee that
it was waiting for 400ns..
The complication is around /proc/sys/ variables, which were attached
to inodes. Now they're their own thing, and the corresponding inodes
are lazily created (as all other ProcFS inodes are) and simply refer
to them by index.
Our logic for using the ATA_CMD_CACHE_FLUSH functionality was a bit wrong,
and now it's better.
The ATA spec says these two things:
> The device shall enter the interrupt pending state when:
> 1) any command except a PIO data-in command reaches command completion
> successfully;
> ...
> The device shall exit the interrupt pending state when:
> 1) the device is selected, BSY is cleared to zero, and the Status
> register is read;
This means that our sequence of actions was probably never going to work.
We were waiting in a loop checking the status register until it left the
busy state, _then_ waiting for an interrupt. Unfortunately by checking the
status register, we were _clearing_ the interrupt we were about to wait
for.
Now we just wait for the interrupt - we don't poll the status register at
all. This also means that once we get our `wait_for_irq` method sorted out
we'll spend a bunch less CPU time waiting for things to complete.
Apparently we need to poll the drive for its status after each sector we
read if we're not doing DMA. Previously we only did it at the start,
which resulted in every sector after the first in a batch having 12 bytes
of garbage on the end. This manifested as silent read corruption.
It is now possible to mount ext2 `DiskDevice` devices under Serenity on
any folder in the root filesystem. Currently any user can do this with
any permissions. There's a fair amount of assumptions made here too,
that might not be too good, but can be worked on in the future. This is
a good start to allow more dynamic operation under the OS itself.
It is also currently impossible to unmount and such, and devices will
fail to mount in Linux as the FS 'needs to be cleaned'. I'll work on
getting `umount` done ASAP to rectify this (as well as working on less
assumption-making in the mount syscall. We don't want to just be able
to mount DiskDevices!). This could probably be fixed with some `-t`
flag or something similar.
The previous implementation of the PIIX3/4 PATA/IDE channel driver only
supported a single drive, as the object model was wrong (the channel
inherits the IRQ, not the disk drive itself). This fixes it by 'attaching'
two `PATADiskDevices` to a `PATAChannel`, which makes more sense.
The reading/writing code is presented as is, which violates the spec
outlined by Seagate in the linked datasheet. That spec is rather old,
so it might not be 100% up to date, though may cause issues on real
hardware, so until we can actually test it, this will suffice.
2019-07-28 15:44:01 +02:00
Renamed from Kernel/Devices/IDEDiskDevice.cpp (Browse further)
