• Jeffrey Lee's avatar
    Make supervisor stack inaccessible to user mode · bbc7ad20
    Jeffrey Lee authored
    Previously the supervisor stack was read-only in user mode, but since
    the supervisor stack is typically empty when the CPU is in user mode,
    it's questionable whether any software actually makes use of this
    facility.
    
    To simplify support for the long descriptor page table format (which
    doesn't support the user-RO + privileged-RW access mode), let's
    try and remove usermode SVC stack access completely.
    
    Tested on Raspberry Pi 4
    
    Version 6.48. Tagged as 'Kernel-6_48'
    bbc7ad20
VersionASM 846 Bytes