efi/libstub: Simplify efi_high_alloc() and rename to efi_allocate_pages()

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The implementation of efi_high_alloc() uses a complicated way of
traversing the memory map to find an available region that is located
as close as possible to the provided upper limit, and calls AllocatePages
subsequently to create the allocation at that exact address.

This is precisely what the EFI_ALLOCATE_MAX_ADDRESS allocation type
argument to AllocatePages() does, and considering that EFI_ALLOC_ALIGN
only exceeds EFI_PAGE_SIZE on arm64, let's use AllocatePages() directly
and implement the alignment using code that the compiler can remove if
it does not exceed EFI_PAGE_SIZE.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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This commit is contained in:

Ard Biesheuvel 2020-02-10 17:02:35 +01:00

parent f57db62c67

commit a7495c28c8

4 changed files with 23 additions and 91 deletions

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5

drivers/firmware/efi/libstub/efi-stub-helper.c

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3

drivers/firmware/efi/libstub/fdt.c

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102

drivers/firmware/efi/libstub/mem.c

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4

include/linux/efi.h

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