Hello! I'm trying to understand how the TLS is setup for the root server on x64 (to access for example the IPC buffer) but I'm failing to connect the pieces and how the server is correctly setting the FS register. For example the sel4_Send function is codegen like this (using -ftls-model=local-exec) Function: seL4_Send push r15 mov rdx,0FFFFFFFFFFFFFFFDh push rbx mov rax,[fs:0] mov r10,[rax+8] mov r8,[rax+10h] mov r9,[rax+18h] mov r15,[rax+20h] mov rbx,rsp syscall mov rsp,rbx pop rbx pop r15 ret The instruction `mov rax,[fs:0]` is accessing the seL4_IPCBuffer* and the the executable has a TLS segments of 8 bytes for the pointer. all good. Now, I'm failing to find in the codebase where the ELF loader is actually detecting the TLS segment and the according setup with the TLS register. And I'm wondering if the setup for the codegen is not wrong on my side (e.g the local-exec is not working), so that instead of having a FS register it would be a direct memory access. Does anyone have a clue about this? Thank you!