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Add relocation types for code pointers
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‎aaelf64-morello/aaelf64-morello.rst‎

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@@ -476,6 +476,11 @@ The following nomenclature is used in the descriptions of relocation operations:
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the second entry holds a platform-specific offset or pointer. The pair of
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pointer-sized entries will be relocated with ``R_MORELLO_TLSDESC(S+A)``.
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- ``Delta(S)`` if ``S`` is a normal symbol, resolves to the difference between the
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static link address of ``S`` and the execution address of ``S``. If ``S`` is the
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null symbol (ELF symbol index 0), resolves to the difference between the static
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link address of ``P`` and the execution address of ``P``.
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- ``TPREL(S)`` resolves to a pair of two 64-bit values. The first value
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contains the offset in the static TLS block of the thread-local symbol ``S``.
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The second value contains the size of the symbol ``S``
@@ -688,31 +693,40 @@ Dynamic Morello relocations
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.. table:: Dynamic relocations
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+-------+-------------------------+-----------------------------------------+------------------------------------------+
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| ELF64 | Name | Operation | Comment |
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| Code | | | |
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+=======+=========================+=========================================+==========================================+
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| 59392 | ``R_MORELLO_CAPINIT`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-------------------------+-----------------------------------------+------------------------------------------+
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| 59393 | ``R_MORELLO_GLOB_DAT`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-------------------------+-----------------------------------------+------------------------------------------+
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| 59394 | ``R_MORELLO_JUMP_SLOT`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-------------------------+-----------------------------------------+------------------------------------------+
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| 59395 | ``R_MORELLO_RELATIVE`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-------------------------+-----------------------------------------+------------------------------------------+
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| 59396 | ``R_MORELLO_IRELATIVE`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-------------------------+-----------------------------------------+------------------------------------------+
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| 59397 | ``R_MORELLO_TLSDESC`` | ``TLSDESC(S+A)`` | Identifies a TLS descriptor to be filled.|
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| | | | |
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+-------+-------------------------+-----------------------------------------+------------------------------------------+
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| 59398 | ``R_MORELLO_TPREL128`` | ``TPREL(S)`` | See note below. |
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| | | | |
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+-------+-------------------------+-----------------------------------------+------------------------------------------+
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| ELF64 | Name | Operation | Comment |
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| Code | | | |
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+=======+=============================+=========================================+==========================================+
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| 59392 | ``R_MORELLO_CAPINIT`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| 59393 | ``R_MORELLO_GLOB_DAT`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| 59394 | ``R_MORELLO_JUMP_SLOT`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| 59395 | ``R_MORELLO_RELATIVE`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| 59396 | ``R_MORELLO_IRELATIVE`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| 59397 | ``R_MORELLO_TLSDESC`` | ``TLSDESC(S+A)`` | Identifies a TLS descriptor to be filled.|
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| 59398 | ``R_MORELLO_TPREL128`` | ``TPREL(S)`` | See note below. |
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| 59399 | ``R_MORELLO_CODE_CAPINIT`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| 59400 | ``R_MORELLO_FUNC_RELATIVE`` | ``CAP_INIT(S, A, CAP_SIZE, CAP_PERM)`` | See note below. |
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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| 59401 | ``R_AARCH64_FUNC_RELATIVE`` | ``Delta(S) + A`` | See note below. |
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| | | | |
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+-------+-----------------------------+-----------------------------------------+------------------------------------------+
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.. note::
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@@ -759,6 +773,21 @@ Dynamic Morello relocations
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``| 64-bits offset | 64-bits size |``
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``R_MORELLO_CODE_CAPINIT`` is similar to ``R_MORELLO_CAPINIT`` but signifies
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that the capability being relocated is a code pointer as opposed to a data
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pointer or function pointer. As such, it must only be used against
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``STT_FUNC`` symbols. This relocation type is needed for library-based
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compartmentalization (c18n). Currently for security reasons this relocation
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may only be used against non-preemptible symbols, and thus will be converted
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to ``R_MORELLO_RELATIVE`` at link time, making it in effect a static
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relocation. However, this restriction may be removed in future if needed, and
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it is therefore classed as a dynamic relocation.
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``R_MORELLO_FUNC_RELATIVE`` and ``R_AARCH64_FUNC_RELATIVE`` : similar to
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their non-``_FUNC`` counterparts but signify that the capability being
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relocated is a function pointer as opposed to a data pointer or code pointer.
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This distinction is needed for library-based compartmentalization (c18n).
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Static linking with Morello
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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