[PATCH] D64930: [ELF][AArch64] Allow PT_LOAD to have overlapping p_offset ranges

[Peter Smith via Phabricator via llvm-commits]

peter.smith added a comment.

I think I know what is causing the kernel to fault the ELF file

The specific problem is the PT_LOAD before the PT_DYNAMIC, the p_vaddr is not congruent to the p_offset modulo p_align. It should be 0x19A0. If I hex edit the binary to make this the case I can get the ELF file to run. I think that this misalignment might be caused because p_filesz is 0, which might skip the alignment of the p_offset (not checked). When -znow is removed the ordering of some sections changes and there is no PT_LOAD with 0 p_filesz so everything gets aligned.

  ProgramHeader {
    Type: PT_LOAD (0x1)
    Offset: 0x16B0
    VirtualAddress: 0x36B0
    PhysicalAddress: 0x36B0
    FileSize: 744
    MemSize: 744
    Flags [ (0x6)
      PF_R (0x4)
      PF_W (0x2)
    ]
    Alignment: 4096
  }
  ProgramHeader {
    Type: PT_LOAD (0x1)
    Offset: 0x1998
    VirtualAddress: 0x49A0
    PhysicalAddress: 0x49A0
    FileSize: 0
    MemSize: 65552
    Flags [ (0x6)
      PF_R (0x4)
      PF_W (0x2)
    ]
    Alignment: 4096
  }
  ProgramHeader {
    Type: PT_DYNAMIC (0x2)
    Offset: 0x16E8
    VirtualAddress: 0x36E8
    PhysicalAddress: 0x36E8
    FileSize: 480
    MemSize: 480
    Flags [ (0x6)
      PF_R (0x4)
      PF_W (0x2)
    ]
    Alignment: 8
  }

@MaskRay are you ok to take it from here?


Repository:
  rL LLVM

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  https://reviews.llvm.org/D64930/new/

https://reviews.llvm.org/D64930