This allows us to get rid of all the custom 64-bit division helpers.
I wanted to do this ages ago but couldn't get it working. Turns out it
was unstable due to libgcc using the regular ABI and the kernel being
built with -mregparm=3.
Now that we build the kernel with regular calls, we can just link with
libgcc and get this stuff for free. :^)
Move the kernel image to the 1 MB physical mark. This prevents it from
colliding with stuff like the VGA memory. This was causing us to end
up with the BIOS screen contents sneaking into kernel memory sometimes.
This patch also bumps the kmalloc heap size from 1 MB to 3 MB. It's not
the perfect permanent solution (obviously) but it should get the OOM
monkey off our backs for a while.
Also added a script to handle creation of GPT partitioned disk (with
GRUB config file). Block limit will be used to disallow potential access
to other partitions.
This is a freelist allocator with static size classes that works as a
complement to the generic kmalloc(). It's a lot faster than kmalloc()
since allocation just means popping from the freelist.
It's also significantly more compact when there are a lot of objects
smaller than the minimum kmalloc chunk size (32 bytes.)
This patch enables it for the Region and PhysicalPage classes.
In the PhysicalPage (8 bytes) case, it's a huge improvement since we
no longer waste 75% of the storage allocated.
There are also a number of ways this can be improved, so let's keep
working on it going forward.
This implements a very basic VGA device using the information provided
to us by the bootloader in the multiboot header. This allows Serenity to
boot to the desktop on basically any halfway modern system.
We were forced to do this because the page fault code would fall apart
when trying to generate a backtrace for a non-current thread.
This issue has been fixed for a while now, so let's go back to lazily
loading executable pages which should make everything a little better.
InodeVMObject is a VMObject with an underlying Inode in the filesystem.
AnonymousVMObject has no Inode.
I'm happy that InodeVMObject::inode() can now return Inode& instead of
VMObject::inode() return Inode*. :^)
This class works by eagerly allocating 1MB of virtual memory but only
adding physical pages on demand. In other words, when you append to it,
its memory usage will increase by 1 page whenever you append across a
page boundary (4KB.)
We had some kernel-specific gizmos in AK that should really just be in the
Kernel subdirectory instead. The only thing remaining after moving those
was mmx_memcpy() which I moved to the ARCH(i386)-specific section of
LibC/string.cpp.
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.
This is expensive because we have to page in the entire executable for every
process up front for this to work. This is due to the page fault code not
being strong enough to run while another process is active.
Note that we already had userspace symbols in *crash* stacks. This patch
adds them generally, so they show up in /proc, Process Manager, etc.
There's room for improvement here, but the debugging benefits way overshadow
the performance penalty right now. :^)
The syscall is quite simple:
int watch_file(const char* path, int path_length);
It returns a file descriptor referring to a "InodeWatcher" object in the
kernel. It becomes readable whenever something changes about the inode.
Currently this is implemented by hooking the "metadata dirty bit" in
Inode which isn't perfect, but it's a start. :^)
A basic Floppy Disk Controller device driver for any system later than (and including) the IBM AT. The driver is based on the documentation supplied by QEMU, which is the datasheet for the Intel 82078 Floppy Disk controller (found here: https://wiki.qemu.org/images/f/f0/29047403.pdf)
Naturally, floppy disks are a _very_ outdated storage medium, however, as Serenity is a throwback to aesthetic 90s computing, it's a definite must have. Not to mention that there are still a lot of floppy disks around, with countless petabytes of software on them, so it would be nice if people could create images of said disks with serenity.
The code for this is mostly clean. however there are a LOT of values specified in the datasheet, so some of them might be wrong, not to mention that the actual specification itself is rather dirt and seemingly hacked together.
I'm also only supporting 3.5" floppy disks, without PIO polling (DMA only), so if you want anything more/less than 1.44MB HD Floppys, you'll have to do it yourself.
We were locking the list of references, and then destroying the
reference, which made things go a little crazy.
It's more straightforward to just remove the per-reference lock: the
syscalls all have to lock the full list anyway, so let's just do that
and avoid the hassle.
While I'm at it, also move the SharedBuffer code out to its own file as it's
getting a little long and unwieldly, and Process.cpp is already huge.
Also add an AudioServer that (right now) doesn't do much.
It tries to open, parse, and play a wav file. In the future, it can do more.
My general thinking here here is that /dev/audio will be "owned" by AudioServer,
and we'll do mixing in software before passing buffers off to the kernel
to play, but we have to start somewhere.
Also tweak the kernel's Makefile to use -nostdinc and -nostdinc++.
This prevents us from picking up random headers from ../Root, which may
include older versions of kernel headers.
Since we still need <initializer_list> for Vector, we specifically include
the necessary GCC path. This is a bit hackish but it works for now.
Update ProcessManager, top and WSCPUMonitor to handle the new format.
Since the kernel is not allowed to use floating-point math, we now compile
the JSON classes in AK without JsonValue::Type::Double support.
To accomodate large unsigned ints, I added a JsonValue::Type::UnsignedInt.
This significantly reduces the pressure on the kernel heap when
allocating a lot of pages.
Previously at about 250MB allocated, the free page list would outgrow
the kernel's heap. Given that there is no longer a page list, this does
not happen.
The next barrier will be the kernel memory used by the page records for
in-use memory. This kicks in at about 1GB.
After reading a bunch of POSIX specs, I've learned that a file descriptor
is the number that refers to a file description, not the description itself.
So this patch renames FileDescriptor to FileDescription, and Process now has
FileDescription* file_description(int fd).
This implements a passthrough disk driver that translates the read/write
block addresses by a fixed offset. This could form the basis of MBR
partition support if we were to parse the MBR table at boot and create that
OffsetDiskDevice dynamically, rather than seeking to a fixed offset.
This also introduces a dependency in the form of grub. You'll need to have
32-bit grub binaries installed to build the project now.
As a bonus, divorcing Serenity from qemu's kernel loading means we can now
*technically* boot on real hardware. It just... doesn't get very far yet.
If you write the `_disk_image` file to an IDE hard drive and boot it in a
machine that supports all the basic PC hardware, it *will* start loading
the kernel.
A custody is kind of a directory entry abstraction that represents a single
entry in a parent directory that tells us the name of a child inode.
The idea here is for path resolution to produce a chain of custody objects.
This is in preparation for eventually using it in userspace.
LinearAddress.h has not been moved for the time being (as it seems to be
only used by a very small part of the code).
This replaces the previous virtual address allocator which was basically
just "m_next_address += size;"
With this in place, virtual addresses can get reused, which cuts down on
the number of page tables created. When we implement ASLR some day, we'll
probably have to do page table deallocation, but for now page tables are
only deallocated once the process dies.
Hook this up in Terminal so that the '\a' character generates a beep.
Finally emit an '\a' character in the shell line editing code when
backspacing at the start of the line.
