One behavior that we weren't handling properly in our heap allocation
process was the ability for the heap to be shrunk down in size if a
larger size was previously requested.
This adds the basic behavior to do so and also gets rid of HeapFree, as
it's no longer necessary now that we have allocations and deallocations
going through the same API function.
While we're at it, fully document the behavior that this function
performs.
Makes it more obvious that this function is intending to stand in for
the actual supervisor call itself, and not acting as a general heap
allocation function.
Also the following change will merge the freeing behavior of HeapFree
into this function, so leaving it as HeapAllocate would be misleading.
In cases where HeapAllocate is called with the same size of the current
heap, we can simply do nothing and return successfully.
This avoids doing work where we otherwise don't have to. This is also
what the kernel itself does in this scenario.
Another holdover from citra that can be tossed out is the notion of the
heap needing to be allocated in different addresses. On the switch, the
base address of the heap will always be managed by the memory allocator
in the kernel, so this doesn't need to be specified in the function's
interface itself.
The heap on the switch is always allocated with read/write permissions,
so we don't need to add specifying the memory permissions as part of the
heap allocation itself either.
This also corrects the error code returned from within the function.
If the size of the heap is larger than the entire heap region, then the
kernel will report an out of memory condition.
Makes it more evident that one is for actual code and one is for actual
data. Mutable and static are less than ideal terms here, because
read-only data is technically not mutable, but we were mapping it with
that label.
Given this is utilized by the loaders, this allows avoiding inclusion of
the kernel process definitions where avoidable.
This also keeps the loading format for all executable data separate from
the kernel objects.
Rather than make a global accessor for this sort of thing. We can make
it a part of the thread interface itself. This allows getting rid of a
hidden global accessor in the kernel code.
This condition was checking against the nominal thread priority, whereas
the kernel itself checks against the current priority instead. We were
also assigning the nominal priority, when we should be assigning
current_priority, which takes priority inheritance into account.
This can lead to the incorrect priority being assigned to a thread.
Given we recursively update the relevant threads, we don't need to go
through the whole mutex waiter list. This matches what the kernel does
as well (only accessing the first entry within the waiting list).
Makes it an instantiable class like it is in the actual kernel. This
will also allow removing reliance on global accessors in a following
change, now that we can encapsulate a reference to the system instance
in the class.
With this, all kernel objects finally have all of their data members
behind an interface, making it nicer to reason about interactions with
other code (as external code no longer has the freedom to totally alter
internals and potentially messing up invariants).
There's no real need to use a shared lifetime here, since we don't
actually expose them to anything else. This is also kind of an
unnecessary use of the heap given the objects themselves are so small;
small enough, in fact that changing over to optionals actually reduces
the overall size of the HLERequestContext struct (818 bytes to 808
bytes).
Now that we have the address arbiter extracted to its own class, we can
fix an innaccuracy with the kernel. Said inaccuracy being that there
isn't only one address arbiter. Each process instance contains its own
AddressArbiter instance in the actual kernel.
This fixes that and gets rid of another long-standing issue that could
arise when attempting to create more than one process.
Similar to how WaitForAddress was isolated to its own function, we can
also move the necessary conditional checking into the address arbiter
class itself, allowing us to hide the implementation details of it from
public use.
Rather than let the service call itself work out which function is the
proper one to call, we can make that a behavior of the arbiter itself,
so we don't need to directly expose those implementation details.
Places all of the functions for address arbiter operation into a class.
This will be necessary for future deglobalizing efforts related to both
the memory and system itself.
