Skyline's `exception` class now stores a list of all stack frames during the invocation of the exception. These can later be parsed by the exception handler to generate a human-readable stack trace. To assist with more complete stack traces, `-fno-omit-frame-pointer` is now passed on debug builds which forces the inclusion of frames on function calls.
A lot of logs are incomplete due to being unable to flush inside the signal handler, now we flush after any exceptions so that there is a guarantee of any exceptions being logged as this is crucial for proper debugging.
We cannot ignore accesses from the host to a region protected by the NCE Memory Trapping API, there's often access to regions which have overlap with a protected region unintentionally and those accesses need to be handled correctly rather than leading to a crash. This is done by implementing an additional signal handler `NCE::HostSignalHandler` to lookup any potential traps on a `SIGSEGV` and handle them correctly or when there isn't a corresponding trap raise a `SIGTRAP` when debugger is connected or delegate to `signal::ExceptionalSignalHandler` when it isn't.
The Host1x block of the TX1 supports 14 separate channels to which commands can be issued, these all run asynchronously so are emulated the same way as GPU channels with one FIFO emulation thread each. The command FIFO itself is very similar to the GPFIFO found in the GPU however there are some differences, mainly the introduction of classes (similar to engines) and the Mask opcode (which allows writing to a specific set of offsets much more efficiently).
There is an internal Host1x class which functions similar to the GPFIFO class in the GPU, handling general operations such as syncpoint waits, this is accessed via the simple method interface. Other channels such as NVDEC and VIC are behind the 'Tegra Host Interface' (THI) in HW, this abstracts out the classes internal details and provides a uniform method interface ontop of the Host1x method one. We emulate the THI as a templated wrapper for the underlying class.
Syncpoint increments in Host1x are different to GPU, the THI allows submitting increment requests that will be queued up and only be applied after a specific condition in the associated engine is met; however the option to for immediate increments is also available.
