Make use of the new FileDescription::try_serialize_absolute_path() to
avoid String in favor of KString throughout much of sys$execve() and
its helpers.
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 change adds a static lock hierarchy / ranking to the Kernel with
the goal of reducing / finding deadlocks when running with SMP enabled.
We have seen quite a few lock ordering deadlocks (locks taken in a
different order, on two different code paths). As we properly annotate
locks in the system, then these facilities will find these locking
protocol violations automatically
The `LockRank` enum documents the various locks in the system and their
rank. The implementation guarantees that a thread holding one or more
locks of a lower rank cannot acquire an additional lock with rank that
is greater or equal to any of the currently held locks.
There are certain checks that we should skip if the system is crashing.
The system can avoid stack overflow during crash, or even triple
faulting while while handling issues that can causes recursive panics
or aborts.
I had to look at this for a moment before I realized that sys$execve()
and the spawning of /bin/SystemServer at boot are taking two different
paths out of exec().
Add a comment to help the next person looking at it. :^)
Before this patch, we were leaking a ref on the open file description
used for the interpreter (the dynamic loader) in sys$execve().
This surfaced when adapting the syscall to use TRY(), since we were now
correctly transferring ownership of the interpreter to Process::exec()
and no longer holding on to a local copy of it (in `elf_result`).
Fixing the leak uncovered another problem. The interpreter description
would now get destroyed when returning from do_exec(), which led to a
kernel panic when attempting to acquire a mutex.
This happens because we're in a particularly delicate state when
returning from do_exec(). Everything is primed for the upcoming context
switch into the new executable image, and trying to block the thread
at this point will panic the kernel.
We fix this by destroying the interpreter description earlier in
do_exec(), at the point where we no longer need it.
When executing a dynamically linked program, we need to pass the main
program executable via a file descriptor to the dynamic loader.
Before this patch, we were allocating an FD for this purpose long after
it was safe to do anything fallible. If we were unable to allocate an
FD we would simply panic the kernel(!)
We now hoist the allocation so it can fail before we've committed to
a new executable.
Due to the use of ELF::Image::for_each_program_header(), we were
previously unable to use TRY() in the ELF loading code (since the return
statement inside TRY() would only return from the iteration callback.)
There's only a couple of cases like this, but there are some locale
paths in the CLDR that contain variants. For example, there isn't a
en-US path, but there is a en-US-POSIX path. This interferes with the
operation to search for locales by name. The algorithm is such that
searching for en-US will not result in en-US-POSIX being found. To
resolve this, we should remove variants from the locale name.
This data informs consumers how to join lists of values. For example,
in en-US, the list ["a", "b", "c"] formatted to a string should become
"a, b, and c".
A previous commit I made broke layer dragging since the hole_index
was always being computed with respect to the top of the layer list
widget, however we were now drawing layers from the bottom. When
you didn't have enough layers to fill up the full height, dragging
them around would be weird.
This patch computes the hole index correctly using the same offset
we start drawing from, and fixes the behavior.
In addition to adding the action, this commit also makes the
`did_change_rect()` method take in an optional rect, which
represents the new rect position. By default it is the same as
`rect()`.
When we are cropping an image, we don't want to move the whole
cropped section to the top-left of the original image in the
ImageEditor widget, so this allows us to keep the cropped image's
position fixed.
