• Paul Mundt's avatar
    sh: Merge legacy and dynamic PMB modes. · d01447b3
    Paul Mundt authored
    This implements a bit of rework for the PMB code, which permits us to
    kill off the legacy PMB mode completely. Rather than trusting the boot
    loader to do the right thing, we do a quick verification of the PMB
    contents to determine whether to have the kernel setup the initial
    mappings or whether it needs to mangle them later on instead.
    
    If we're booting from legacy mappings, the kernel will now take control
    of them and make them match the kernel's initial mapping configuration.
    This is accomplished by breaking the initialization phase out in to
    multiple steps: synchronization, merging, and resizing. With the recent
    rework, the synchronization code establishes page links for compound
    mappings already, so we build on top of this for promoting mappings and
    reclaiming unused slots.
    
    At the same time, the changes introduced for the uncached helpers also
    permit us to dynamically resize the uncached mapping without any
    particular headaches. The smallest page size is more than sufficient for
    mapping all of kernel text, and as we're careful not to jump to any far
    off locations in the setup code the mapping can safely be resized
    regardless of whether we are executing from it or not.
    Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
    d01447b3
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