On Wed, Feb 03, 2021 at 02:58:58PM -0800, Yu-cheng Yu wrote: > When an indirect CALL/JMP instruction is executed and before it reaches > the target, it is in 'WAIT_ENDBR' status, which can be read from > MSR_IA32_U_CET. The status is part of a task's status before a signal is > raised and preserved in the signal frame. It is restored for sigreturn. > > IBT state machine is described in Intel SDM Vol. 1, Sec. 18.3. > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -- Kees Cook