Re: [seL4] Understand how TLS is setup in the root server for x64

Hi Alexandre, There is detailed documentation for the TLS change on the page for RFC- 3. https://sel4.atlassian.net/browse/RFC-3 In essence, the new TLS model stores the address of the IPC buffer in a thread-local variable which must be initialised by your process or threading runtime along with general TLS intialisation. https://github.com/seL4/seL4/blob/master/libsel4/include/sel4/functions.h#L… To assist with this there is a simple sel4runtime library which provides a minimal C-runtime and tools for initialising TLS. https://github.com/SEL4PROJ/sel4runtime On x86_64 the TLS register can be set without calling into the kernel by using the `wrfsbase` instruction or by using the `sel4runtime_set_tls_base` function from the sel4runtime library. The ELF loader is not responsible for TLS initialisation, the C-runtime is responsible for configuring TLS of the initial thread. https://bitbucket.ts.data61.csiro.au/projects/SEL4PROJ/repos/sel4runtime/br… In general I would recommend having the initial thread in a process initialise its own TLS via the runtime and any new thread configure its own TLS in the initialisation code before the main function call of that thread with the `sel4runtime_set_tls_base`. Each new thread will also need to use `seL4_SetIPCBuffer` to initialise the IPC buffer address in its TLS before performing any invocations or any other system calls. Cheers, Curtis Millar Systems Engineer, Trustworthy Systems, CSIRO's Data61 curtis.millar(a)data61.csiro.au Data61, CSIRO Level 3, K17 Building UNSW Gate 14, Barker St Kensington NSW 2033 Australia