1. 19 Aug, 2014 1 commit
    • Ard Biesheuvel's avatar
      arm64: align randomized TEXT_OFFSET on 4 kB boundary · 4190312b
      Ard Biesheuvel authored
      When booting via UEFI, the kernel Image is loaded at a 4 kB boundary and
      the embedded EFI stub is executed in place. The EFI stub relocates the
      Image to reside TEXT_OFFSET bytes above a 2 MB boundary, and jumps into
      the kernel proper.
      
      In AArch64, PC relative symbol references are emitted using adrp/add or
      adrp/ldr pairs, where the offset into a 4 kB page is resolved using a
      separate :lo12: relocation. This implicitly assumes that the code will
      always be executed at the same relative offset with respect to a 4 kB
      boundary, or the references will point to the wrong address.
      
      This means we should link the kernel at a 4 kB aligned base address in
      order to remain compatible with the base address the UEFI loader uses
      when doing the initial load of Image. So update the code that generates
      TEXT_OFFSET to choose a multiple of 4 kB.
      
      At the same time, update the code so it chooses from the interval [0..2MB)
      as the author originally intended.
      Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
      Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      4190312b
  2. 18 Aug, 2014 3 commits
  3. 16 Aug, 2014 36 commits