Many users of VFS didn't check for nullptr or 0 results leading to
various potential issues, to mitigate this introduce error checking to
VFS by default. The original variants can still be used through the
*Unchecked family of functions.
This allows better validation and simplified default argument handling.
Could also be useful in the future when we switch to proper VFS error
reporting.
* Pushbuffer data is now stored in a member buffer to avoid reallocating
it for each pushbuffer which hampered performance before.
* Don't prefetch pushbuffers as it puts unnecessary load on the guest
thread that is better suited for the GPFIFO thread.
* Clean up some misc code to avoid pointless casts of a 4 byte object
and handle GPFIFO control opcodes.
NvHostEvents were renamed to SyncpointEvents which is a much clearer
name that more accurately describes them. Locking is needed as IOCTLs
can be called asynchronously and so event registration and signalling
can race.
The following scheduler bugs were fixed:
* It was assumed that all non-cooperative `Rotate` calls were from a preemptive yield and changed the state of `KThread::isPreempted` incorrectly which could lead to UB, an example of a scenario with it would be:
* * Preemptive thread A gets a signal to yield from cooperative thread B due to it being ready to schedule and higher priority
* * A complies with this request but there's an assumption that the signal was actually from it's preemption timer therefore it doesn't reset it (As it isn't required if the timer was responsible for the signal)
* * A receives the actual preemption signal a while later, causing UB as the signal handler is invoked twice
* `Scheduler::UpdatePriority`
* * A check for `currentIt == core->queue.begin()` existed which caused an incorrect early return
* * The preemption timer was armed correctly when a priority transition from cooperative priority -> preemption priority occurred but not disarmed when a transition from preemption priority -> cooperative priority occurred
* * The timer was unnecessarily disarmed in the case of updating the priority of a non-running thread, this isn't as much a bug as it is just pointless
* Priority inheritance in `KProcess::MutexLock` is fundamentally broken as it performs UB with `waitThread` being accessed prior to being assigned
* When a thread sets its own priority using `SvcSetThreadCoreMask` and its current core is no longer in the affinity mask, it wouldn't actually move to the new thread until the next time the thread is load balanced
This addresses all CR comments including more codebase-wide changes arising from certain review comments like proper usage of its/it's and consistent contraction of it is into it's.
An overhaul was made to the presentation and formatting of `KThread.h` and `LoadBalance` works has been superseded by `GetOptimalCoreForThread` which can be used alongside `InsertThread` or `MigrateToCore`. It makes the API far more atomic and neater. This was a major point of contention for the design prior, it's simplified some code and potentially improved performance.
The case of a thread not being in the core queue during a non-cooperative core affinity change would break things as the thread was non-conditionally removed and inserted, this has been fixed by adding a check to see if the thread exists in the core's queue prior to migration. In addition, `yieldWithCoreMigration` was broken by the previous commit as the fallthrough was intentional and removing it cause core migration without a yield which led to breakage in certain circumstances. The mutex locking logic was also improved in `ConditionalVariableWait` to use atomics in a more effective manner with less atomic operations being performed overall.
The code region's size was previously set at the same value as it is for 36-bit ASes, this value is inadequate for certain larger games and needed to be expanded. We've chosen 4GiB as the new value which should easily encompass all Switch games.
The SVCs improvements are as follows:
* Make SVC logs more concise for:
* * `SleepThread`
* * `ClearEvent`
* * `CloseHandle`
* * `ResetSignal`
* * `WaitSynchronization` (Special case for single handle)
* * `ArbitrateLock`
* * `ArbitrateUnlock`
* * `WaitProcessWideKeyAtomic`
* * `SignalProcessWideKey`
* Fix unintentional fallthrough into `yieldWithoutCoreMigration` from `yieldWithCoreMigration` in `SleepThread`
* Return `result::InvalidState` when an unsignalled handle is reset in `ResetSignal`
* Return `Result{}` (Success) in `CancelSynchronization`
* Do not return `result::InvalidCurrentMemory` in `ArbitrateLock` as it's not a failure condition
* Make `count` in `WaitProcessWideKeyAtomic` a `i32` from a `u32`, zero and all negative values result in waking all waiters
The entirety of the address arbiter is implemented in this commit, all three arbitration types: `WaitIfLessThan`, `DecrementAndWaitIfLessThan` and `WaitIfEqual`, and all three signal types: `Signal`, `SignalAndIncrementIfEqual` and `SignalAndModifyBasedOnWaitingThreadCountIfEqual` have been implemented.
This allows any application which uses levent (Light Events) to function which includes titles such as ARMS.
We did not support migration of threads which were running in a non-cooperative manner, this was partially due to the dependence on per-core conditional variables rather than per-thread which made this harder to do programmatically. This has been fixed by moving to per-thread cvars and therefore the limitation can be removed, this feature is used by Unity games.
SvcClearEvent previously set the `signalled` flag directly rather than
calling `ResetSignal`, which skipped the locking necessary to make it
globally visible. Switch it to use `ResetSignal` to fix this.
We've moved to using RS and GS from ASCII as delimiters rather than
'\n' and '|', this allows more robust parsing and increases the
readability of the log files
This prevents a race where two threads could read at the same time and
end up using the wrong IV leading to garbage data being read. This
caused crashes in several games including Celeste.
This was causing a significant amount of sched thrashing and pinning a
core to 100% as games constantly updated audren, now change it to only
signal on buffer release.
This caused the menus in Sonic Mania to be nonfunctional, futhermore,
default init is not ran for the input structs so the default max
definition in CommonHeader never actually applied.
CircularQueue was looping around too early resulting in the wrong
pushbuffers being used. The debug logging is useful for interpreting the
GPU method call logs.
Exefs loading was changed to check if an NSO exists before trying to
read it, preventing exceptions that get annoying while debugging.
* 'Fix' memory accounting to not measure reserved regions
* Fix some copy bugs introduced by switch to span
* Correct remap the behaviour of Modify so it actually works
An exceptional signal handler allows us to convert an OS signal into a C++ exception, this allows us to alleviate a lot of crashes that would otherwise occur from signals being thrown during execution of games and be able to handle them gracefully.
