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    efi/arm/libstub: Pack FDT after populating it · d1cbbc39
    Ard Biesheuvel 提交于
    commit 72a58a63a164b4e9d2d914e65caeb551846883f1 upstream.
    
    Commit:
    
      24d7c494 ("efi/arm-stub: Round up FDT allocation to mapping size")
    
    increased the allocation size for the FDT image created by the stub to a
    fixed value of 2 MB, to simplify the former code that made several
    attempts with increasing values for the size. This is reasonable
    given that the allocation is of type EFI_LOADER_DATA, which is released
    to the kernel unless it is explicitly memblock_reserve()d by the early
    boot code.
    
    However, this allocation size leaked into the 'size' field of the FDT
    header metadata, and so the entire allocation remains occupied by the
    device tree binary, even if most of it is not used to store device tree
    information.
    
    So call fdt_pack() to shrink the FDT data structure to its minimum size
    after populating all the fields, so that the remaining memory is no
    longer wasted.
    Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: <stable@vger.kernel.org> # v4.12+
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: linux-efi@vger.kernel.org
    Fixes: 24d7c494 ("efi/arm-stub: Round up FDT allocation to mapping size")
    Link: http://lkml.kernel.org/r/20181114175544.12860-4-ard.biesheuvel@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
    Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    d1cbbc39
fdt.c 10.6 KB