The unaligned signal handler will backpatch these with DMBs.
Previously generating corrupted code. This will fix that corruption but not the atomicity problem
This cuts start up time from 8.962ms to 3.949ms and lets us use less physical memory.
We pay a small amortized cost from the faulting to populate pages which will be fairly low
In the case that there is an immediate configuration failure. Use stderr specifically for outputting.
These errors won't be output typically because silent logging is enabled by default.
In the case of executable missing or rootfs configuration failure, print directly to stderr.
Previously it looked like FEX just exited for no reason.
We had multiple users encounter this and be confused
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.
These are in place to let applications know that we do our own thermal management
TM was introduced with Pentium M, it would dispatch idle uops to counter thermals.
TM2 was later and is what allows the CPU to dynamically change its multiplier and frequency.
All in an effort to not cook themselves.
Our ARM CPUs also do all this. Claim it as well.
There were two bugs in here.
The first bug here is with with the CMPXCHG emulation.
1) If the *Expected* value did *NOT* match what was in memory
2) *AND* The *Desired* value matched the memory value
3) The CAS would incorrectly return success for this CMPXCHG
4) Thus setting ZF incorrectly
The second bug comes from atomic memory operations (Add, CLR, EOR, SET, SWAP).
This operation is a Load + <Op> + CAS
1) If the memory backing between the Load and CAS changes
2) The CAS would then fail
3) On Atomic memory operations this should then retry to ensure it completes successfully
4) We were not retrying on failure in this case
5) Thus something like `LOCK INC` would have never atomically incremented correctly
6) We can't use our ASM unit tests to test this, since it needs thread contention.
This makes it a little more straightforward to see what these return
values mean without needing to look at the implementation.
These tuples were also getting a little bit large.
Ryan Houdek