a7a1365cf7
When attempting to debug #3162 I had noticed spurious behaviour around what I assumed to be eflags getting corrupt around inlined syscalls. This turned out to be a red herring but to ensure we are still testing this, create a fully fleshed out unit test. This test ensures a couple of things. 1) A flag that is set or unset before a syscall doesn't have its data corrupt 2) An inline syscall doesn't corrupt the eflags, checking the eflag result after returning from the syscall. 3) A signal occuring while in an inline syscall returns the correct eflags information in the signal handler information This test gets accomplished by setting or unsetting a particular flag and then calling the futex syscall in a way that is guaranteed to be inlined and also wait forever. Then the parent thread will signal with a SIGTERM and read back the signal information. It does this multiple times for each flag we care about.
FEX - Fast x86 emulation frontend
FEX allows you to run x86 and x86-64 binaries on an AArch64 host, similar to qemu-user and box86. It has native support for a rootfs overlay, so you don't need to chroot, as well as some thunklibs so it can forward things like GL to the host. FEX presents a Linux 5.0 interface to the guest, and supports both AArch64 and x86-64 as hosts. FEX is very much work in progress, so expect things to change.
Quick start guide
For Ubuntu 20.04, 21.04, 21.10, 22.04
Execute the following command in the terminal to install FEX through a PPA.
curl --silent https://raw.githubusercontent.com/FEX-Emu/FEX/main/Scripts/InstallFEX.py --output /tmp/InstallFEX.py && python3 /tmp/InstallFEX.py && rm /tmp/InstallFEX.py
This command will walk you through installing FEX through a PPA, and downloading a RootFS for use with FEX.
Ubuntu PPA is updated with our monthly releases.
For everyone else
Please see Building FEX.
Getting Started
FEX has been tested to build and run on ARMv8.0, ARMv8.1+, and x86-64(AVX or newer) hardware. ARMv7 and older x86 hardware will not work. Expected operating system usage is Linux. FEX has been tested with Ubuntu 20.04, 20.10, and 21.04. Also Arch Linux.
On AArch64 hosts the user MUST have an x86-64 RootFS Creating a RootFS.
Navigating the Source
See the Source Outline for more information.
Building FEX
Follow the guide on the official FEX-Emu Wiki here.
RootFS generation
AArch64 hosts require a rootfs for running applications. Follow the guide on the wiki page for seeing how to set up the rootfs from scratch https://wiki.fex-emu.com/index.php/Development:Setting_up_RootFS
