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    Subject[PATCH v3 0/3] Handle memmap and mem kernel options in boot stage kaslr
    Date
    People reported kernel panic occurs during system boots up with mem boot option.
    After checking code, several problems are found about memmap= and mem= in boot stage
    kaslr.

    *) In commit f28442497b5c ("x86/boot: Fix KASLR and memmap= collision"), only one memmap
    entry is considered and only the last one if multiple memmap entries are specified.

    *) mem= and memmap=nn[KMG] are not considered yet. They are used to limit max address
    of system. Kernel can't be randomized to be above the limit.

    *) kernel-parameters.txt doesn't tell the updated behaviour of memmap=.

    This patchset tries to solve above issues, and it sits on top of
    tip:x86/boot branch.

    Changelog

    v2->v3:
    No functionality change in this round.
    a)Use local static variable insted of global variable
    mem_avoid_memmap_index in patch 1/3.
    b)Fix a typo in patch 3/3.

    v1->v2:
    a)The original patch 1/4 has been put in tip:x86/boot and no update,
    so it's not included in this post.
    b)Use patch log Ingo reorganized.
    c)lib/ctype.c and lib/cmdline.c are needed for kaslr.c, while those
    EXPORT_SYMBOL(x) contained caused failure of build on 32-bit allmodconfig:
    ......
    ld: -r and -shared may not be used together
    scripts/Makefile.build:294: recipe for target 'arch/x86/boot/compressed/kaslr.o' failed
    ......
    Disabling the symbol exporting removes the build failure.
    d)Use dynamic allocation to allocate memory to contain copied kernel cmdline
    buffer, it's implemented in include/linux/decompress/mm.h.



    Baoquan He (3):
    KASLR: Parse all memmap entries in cmdline
    KASLR: Handle memory limit specified by memmap and mem option
    Documentation/kernel-parameters.txt: Update 'memmap=' option
    description

    Documentation/admin-guide/kernel-parameters.txt | 9 ++
    arch/x86/boot/compressed/cmdline.c | 2 +-
    arch/x86/boot/compressed/kaslr.c | 183 +++++++++++++++---------
    arch/x86/boot/string.c | 8 ++
    4 files changed, 136 insertions(+), 66 deletions(-)

    --
    2.5.5

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