On 24.06.21 11:41, Peter Zijlstra wrote: > The asm_cpu_bringup_and_idle() function is required to push the return > value on the stack in order to make ORC happy, but the only reason > objtool doesn't complain is because of a happy accident. > > The thing is that asm_cpu_bringup_and_idle() doesn't return, so > validate_branch() never terminates and falls through to the next > function, which in the normal case is the hypercall_page. And that, as > it happens, is 4095 NOPs and a RET. > > Make asm_cpu_bringup_and_idle() terminate on it's own, by making the > function it calls as a dead-end. This way we no longer rely on what > code happens to come after. > > Fixes: c3881eb58d56 ("x86/xen: Make the secondary CPU idle tasks reliable") > Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Juergen Gross Juergen