1. 29 Apr, 2020 1 commit
    • Andre Przywara's avatar
      fdt/wrappers: Replace fdtw_read_cells() implementation · ff4e6c35
      Andre Przywara authored
      Our fdtw_read_cells() implementation goes to great lengths to
      sanity-check every parameter and result, but leaves a big hole open:
      The size of the storage the value pointer points at needs to match the
      number of cells given. This can't be easily checked at compile time,
      since we lose the size information by using a void pointer.
      Regardless the current usage of this function is somewhat wrong anyways,
      since we use it on single-element, fixed-length properties only, for
      which the DT binding specifies the size.
      Typically we use those functions dealing with a number of cells in DT
      context to deal with *dynamically* sized properties, which depend on
      other properties (#size-cells, #clock-cells, ...), to specify the number
      of cells needed.
      
      Another problem with the current implementation is the use of
      ambiguously sized types (uintptr_t, size_t) together with a certain
      expectation about their size. In general there is no relation between
      the length of a DT property and the bitness of the code that parses the
      DTB: AArch64 code could encounter 32-bit addresses (where the physical
      address space is limited to 4GB [1]), while AArch32 code could read
      64-bit sized properties (/memory nodes on LPAE systems, [2]).
      
      To make this more clear, fix the potential issues and also align more
      with other DT users (Linux and U-Boot), introduce functions to explicitly
      read uint32 and uint64 properties. As the other DT consumers, we do this
      based on the generic "read array" function.
      Convert all users to use either of those two new functions, and make
      sure we never use a pointer to anything other than uint32_t or uint64_t
      variables directly.
      
      This reveals (and fixes) a bug in plat_spmd_manifest.c, where we write
      4 bytes into a uint16_t variable (passed via a void pointer).
      
      Also we change the implementation of the function to better align with
      other libfdt users, by using the right types (fdt32_t) and common
      variable names (*prop, prop_names).
      
      [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi#n874
      [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/ecx-2000.dts
      
      
      
      Change-Id: I718de960515117ac7a3331a1b177d2ec224a3890
      Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
      ff4e6c35
  2. 12 Mar, 2020 1 commit
  3. 03 Mar, 2020 1 commit
  4. 10 Feb, 2020 1 commit