• Jeffrey Lee's avatar
    Add AP 1 emulation for long descriptor page tables · f93d930d
    Jeffrey Lee authored
    The long descriptor page table format doesn't support RISC OS access
    privilege 1 (user RX, privileged RWX). Previously we were downgrading
    this to AP 0 (user RWX, privielged RWX), which obviously weakens the
    security of the memory. However now that we have an AbortTrap
    implementation, we can map the memory as "user none, privileged RWX" and
    provide user read support via AbortTrap's instruction decode & execute
    There's no support for executing usermode code from the memory, but the
    compatibility issues caused by that are likely to be minimal.