When I said processes, my impression was that the kernel was responsible for switching the CPU into / out of 32-bit mode through a privileged operation (ie that

When I said processes, my impression was that the kernel was responsible for switching the CPU into / out of 32-bit mode through a privileged operation (ie that’s the process boundary). Turns out that’s not the case and it’s in the unprivileged CS register which can be mutated calling jmp/call with a target segment set to 0x33. Thanks for correcting me! [1] https://stackoverflow.com/questions/24113729/switch-from-32bit-mode-to-64-bit-long-mode-on-64bit-linux#32384358 https://stackoverflow.com/questions/24113729/switch-from-32b...