The kernel caps the size limit of shared memory to 8589930496 bytes (or
(1GB - 512 bytes) * 8), so approximately 8GB, where every GB has a 512
byte sector taken off of it.
It also ensures the shared memory is created with either read or
read/write permissions for both permission types passed in, allowing the
remote permissions to also be set as "don't care".
Part of the checking done by the kernel is to check if the given
address and size are 4KB aligned, as well as checking if the size isn't
zero. It also only allows mapping shared memory as readable or
read/write, but nothing else, and so we shouldn't allow mapping as
anything else either.
While unlikely, it does avoid constructing a std::string and
unnecessarily calling into the memory code if a game or executable
decides to be really silly about their logging.
Now that we have a class representing the kernel in some capacity, we
now have a place to put the named port map, so we move it over and get
rid of another piece of global state within the core.
The follow-up to e2457418da, which
replaces most of the includes in the core header with forward declarations.
This makes it so that if any of the headers the core header was
previously including change, then no one will need to rebuild the bulk
of the core, due to core.h being quite a prevalent inclusion.
This should make turnaround for changes much faster for developers.
As means to pave the way for getting rid of global state within core,
This eliminates kernel global state by removing all globals. Instead
this introduces a KernelCore class which acts as a kernel instance. This
instance lives in the System class, which keeps its lifetime contained
to the lifetime of the System class.
This also forces the kernel types to actually interact with the main
kernel instance itself instead of having transient kernel state placed
all over several translation units, keeping everything together. It also
has a nice consequence of making dependencies much more explicit.
This also makes our initialization a tad bit more correct. Previously we
were creating a kernel process before the actual kernel was initialized,
which doesn't really make much sense.
The KernelCore class itself follows the PImpl idiom, which allows
keeping all the implementation details sealed away from everything else,
which forces the use of the exposed API and allows us to avoid any
unnecessary inclusions within the main kernel header.
We already have the variable itself set up to perform this task, so we
can just return its value from the currently executing process instead
of always stubbing it to zero.
The current core may have nothing to do with the core where the new thread was scheduled to run. In case it's the same core, then the following PrepareReshedule call will take care of that.
Exit from AddMutexWaiter early if the thread is already waiting for a mutex owned by the owner thread.
This accounts for the possibility of a thread that is waiting on a condition variable being awakened twice in a row.
Also added more validation asserts.
This should fix one of the random crashes in Breath Of The Wild.
The reason this would never be true is that ideal_processor is a u8 and
THREADPROCESSORID_DEFAULT is an s32. In this case, it boils down to how
arithmetic conversions are performed before performing the comparison.
If an unsigned value has a lesser conversion rank (aka smaller size)
than the signed type being compared, then the unsigned value is promoted
to the signed value (i.e. u8 -> s32 happens before the comparison). No
sign-extension occurs here either.
An alternative phrasing:
Say we have a variable named core and it's given a value of -2.
u8 core = -2;
This becomes 254 due to the lack of sign. During integral promotion to
the signed type, this still remains as 254, and therefore the condition
will always be true, because no matter what value the u8 is given it
will never be -2 in terms of 32 bits.
Now, if one type was a s32 and one was a u32, this would be entirely
different, since they have the same bit width (and the signed type would
be converted to unsigned instead of the other way around) but would
still have its representation preserved in terms of bits, allowing the
comparison to be false in some cases, as opposed to being true all the
time.
---
We also get rid of two signed/unsigned comparison warnings while we're
at it.
