With WOW, all allocations from 64-bit code use the full address space
and limiting is handled on the syscall thunk side so theres need to
worry about STL allocations stealing AS.
Removes the @PREFIX_ARCH@ replacement string in the thunks path.
The library prefix paths now get generated upfront and everything gets
replaced to handle the differences between multiarch distros.
Fixes Thunks on Arch and Fedora.
In libstdc++ version 13, they moved the implementation of
`polymorphic_allocator` to `bits/memory_resource.h`.
In doing so they forgot to move the template's default argument to that
header. This causes the problem that `bits/memory_resource.h` is
included first without the template's default argument defined. This
breaking the automatic type deducation of `std::byte`.
Still broken in
[upstream](be240fc6ac/libstdc%2B%2B-v3/include/std/memory_resource (L79-L83))
and is unlikely to be fixed and backported. Since this is the only place
we use this type, just fix it here.
When a fork occurs FEX needs to be incredibly careful as any thread
(that isn't forking) that holds a lock will vanish when the fork occurs.
At this point if the newly forked process tries to use these mutexes
then the process hangs indefinitely.
The three major mutexes that need to be held during a fork:
- Code Invalidation mutex
- This is the highest priority and causes us to hang frequently.
- This is highly likely to occur when one thread is loading shared
libraries and another thread is forking.
- Happens frequently with Wine and steam.
- VMA tracking mutex
- This one happens when one thread is allocating memory while a fork
occurs.
- This closely relates to the code invalidation mutex, just happens at
the syscall layer instead of the FEXCore layer.
- Happens as frequently as the code invalidation mutex.
- Allocation mutex
- This mutex is used for FEX's 64-bit Allocator, this happens when FEX
is allocating memory on one thread and a fork occurs.
- Fairly infrequent because jemalloc doesn't allocate VMA regions that
often.
While this likely doesn't hit all of the FEX mutexes, this hits the ones
that are burning fires and are happening frequently.
- FEXCore: Adds forkable mutex/locks
Necessary since we have a few locations in FEX that need to be locked
before and after a fork.
When a fork occurs the locks must be locked prior to the fork. Then
afterwards they either need to unlock or be set to default
initialization state.
- Parent
- Does an unlock
- Child
- Sets the lock to default initialization state
- This is because it pthreads does TID based ownership checking on
unique locks and refcount based waiting for shared locks.
- No way to "unlock" after fork in this case other than default
initializing.
This is part of FEXCore since it pulls in InternalThreadData, but is
related to the FHU signal mutex class.
Necessary to allow deferring signals in C++ code rather than right in
the JIT.
These use std::filesystem and should be moved over to WIN32 specific
code.
Added comments to explain that these are currently placeholders and
since we don't do mingw+glibc fault testing these won't get picked up
anyway.
Noticed recently that `FEXServer -w` was broken and couldn't understand
why. Turns out that FHU syscall handling was /always/ falling down the
`#else` path in the handlers since cmake `add_definitions` follows
folder scoping rules.
This means it was always returning -1, which was causing FEXServer's
pidfd_open usage to always receive -1, which meant the sendmsg with FD
was always failing, which meant the `FEXServer -w` would forever wait
for a message that was never sent.
Converting the utility over to a target not only fixes definition
scoping problems, but also makes the other paths actually work.
This found some compiling bugs and instead lets us define SYS_pidfd_open
if it doesn't exist. Letting the kernel return the ENOSYS if it doesn't
exist on that platform.
Main thing, fixes FEXServer -w hanging forever.
In the case of an AArch64 builder is using 16kb or 64kb pages like is
common on servers then it would fail to compile, even if the resulting
application would only ever run on 4k page hosts.
Resolve this by removing the build check and hardcoding 4kb pages for
each of our uses. We still require 4kb pages to run, so this mostly just
removes the weirdness where it is 16kb builder + 4k runner. Would have
broken some of our assumptions when running.
Adds a header only include utility folder that can be included from
everywhere.
Contains syscall helpers for older glibc and defines for older Linux
uapi headers missing some defines.
