• Ard Biesheuvel's avatar
    arm64: allow kernel Image to be loaded anywhere in physical memory · a7f8de16
    Ard Biesheuvel authored
    This relaxes the kernel Image placement requirements, so that it
    may be placed at any 2 MB aligned offset in physical memory.
    This is accomplished by ignoring PHYS_OFFSET when installing
    memblocks, and accounting for the apparent virtual offset of
    the kernel Image. As a result, virtual address references
    below PAGE_OFFSET are correctly mapped onto physical references
    into the kernel Image regardless of where it sits in memory.
    Special care needs to be taken for dealing with memory limits passed
    via mem=, since the generic implementation clips memory top down, which
    may clip the kernel image itself if it is loaded high up in memory. To
    deal with this case, we simply add back the memory covering the kernel
    image, which may result in more memory to be retained than was passed
    as a mem= parameter.
    Since mem= should not be considered a production feature, a panic notifier
    handler is installed that dumps the memory limit at panic time if one was
    Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
    Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
head.S 18.3 KB