• Thomas Gleixner's avatar
    x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table · 945fd17a
    Thomas Gleixner authored
    The separation of the cpu_entry_area from the fixmap missed the fact that
    on 32bit non-PAE kernels the cpu_entry_area mapping might not be covered in
    initial_page_table by the previous synchronizations.
    
    This results in suspend/resume failures because 32bit utilizes initial page
    table for resume. The absence of the cpu_entry_area mapping results in a
    triple fault, aka. insta reboot.
    
    With PAE enabled this works by chance because the PGD entry which covers
    the fixmap and other parts incindentally provides the cpu_entry_area
    mapping as well.
    
    Synchronize the initial page table after setting up the cpu entry
    area. Instead of adding yet another copy of the same code, move it to a
    function and invoke it from the various places.
    
    It needs to be investigated if the existing calls in setup_arch() and
    setup_per_cpu_areas() can be replaced by the later invocation from
    setup_cpu_entry_areas(), but that's beyond the scope of this fix.
    
    Fixes: 92a0f81d ("x86/cpu_entry_area: Move it out of the fixmap")
    Reported-by: default avatarWoody Suwalski <terraluna977@gmail.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Tested-by: default avatarWoody Suwalski <terraluna977@gmail.com>
    Cc: William Grant <william.grant@canonical.com>
    Cc: stable@vger.kernel.org
    Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1802282137290.1392@nanos.tec.linutronix.de
    945fd17a
setup_percpu.c 8.47 KB