Due to the way this syscall handles siginfo_t, we only need to shift
data through the padding.
This is due to the syscall not allowing you to send siginfo_t with
si_code being positive. Which is what the kernel uses to interpret the
data if it is reinterpreting it.
This isn't quite a 100% clean sweep of IWYU.
There are some false positives where clang fails.
Additionally there are still a few missed in the frontend side of things
that I didn't get to
We already support receiving user signals in our signal handlers for this.
Just need to push through syscalls.
This fixes Dead Island Definitive Edition so it runs.
This is a base implementation of signalfd.
Signalfd allows the application to receive siginfo_t information through an FD.
The FD is either provided by the application or created by the kernel depending.
This specifically doesn't pick up *true* synchronous signals. tgkill of the number
should theoretically go through this interface.
This very specifically skips our internal required signals for now.
This means it won't pick up SIGILL, SIGBUS, or SIG63.
This is enough to capture an application that just wants to poll for SIGCHLD.
Anything more complex has the same problems of the guest handling a siginfo_t.
The vast majoirty of syscalls don't need anything in thread or frame.
So lets save an indirection for all those syscalls.
Most of the syscalls which do need Thread (or CTX via
Thread are in Thread.cpp or Memory.cpp
These have all been modifiy to fetch Thread from Frame
Sadly these things can't be split without breaking functionality so it
turns in to a bit of a mess.
SyscallHandler is very much something that is a Linux only construct and
shouldn't be in FEXCore itself. Lets the frontend register a
Syscallhandler with FEXCore. FEXCore itself is then aware of the current
syscall ABI and handles the ABI in an optimal fashion.
So it is not a 100% clean break otherwise we would lose performance.
The SignalDelegator then needs to move to the frontend since the
SyscallHandler requires it for signal based syscalls.
The CPU backend signal handling still needs to happen in FEXCore because
it is a very tight coupling with the CPU backend.
Once we need to support more Signal handling we can give the backends
cleaner support to select which specific OS handler to handle.
Ryan Houdek