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authorCatalin Marinas <catalin.marinas@arm.com>2022-01-31 16:54:56 +0000
committerWill Deacon <will@kernel.org>2022-02-15 22:53:29 +0000
commit731451ab3c0c6fe88142dbc73a74c71bd92a5cff (patch)
tree8ea0a4475e8fb0f751c8fc2d0920771bd527e4b5 /Documentation/arm64/memory-tagging-extension.rst
parent6dd8b1a0b6cb3ed93d24110e02e67ff9d006610a (diff)
arm64: mte: Document the core dump file format
Add the program header definition and data layout for the PT_ARM_MEMTAG_MTE segments. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Luis Machado <luis.machado@linaro.org> Link: https://lore.kernel.org/r/20220131165456.2160675-6-catalin.marinas@arm.com Signed-off-by: Will Deacon <will@kernel.org>
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-rw-r--r--Documentation/arm64/memory-tagging-extension.rst23
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diff --git a/Documentation/arm64/memory-tagging-extension.rst b/Documentation/arm64/memory-tagging-extension.rst
index 7b99c8f428eb..5a70d7a3ca12 100644
--- a/Documentation/arm64/memory-tagging-extension.rst
+++ b/Documentation/arm64/memory-tagging-extension.rst
@@ -213,6 +213,29 @@ address ABI control and MTE configuration of a process as per the
Documentation/arm64/tagged-address-abi.rst and above. The corresponding
``regset`` is 1 element of 8 bytes (``sizeof(long))``).
+Core dump support
+-----------------
+
+The allocation tags for user memory mapped with ``PROT_MTE`` are dumped
+in the core file as additional ``PT_ARM_MEMTAG_MTE`` segments. The
+program header for such segment is defined as:
+
+:``p_type``: ``PT_ARM_MEMTAG_MTE``
+:``p_flags``: 0
+:``p_offset``: segment file offset
+:``p_vaddr``: segment virtual address, same as the corresponding
+ ``PT_LOAD`` segment
+:``p_paddr``: 0
+:``p_filesz``: segment size in file, calculated as ``p_mem_sz / 32``
+ (two 4-bit tags cover 32 bytes of memory)
+:``p_memsz``: segment size in memory, same as the corresponding
+ ``PT_LOAD`` segment
+:``p_align``: 0
+
+The tags are stored in the core file at ``p_offset`` as two 4-bit tags
+in a byte. With the tag granule of 16 bytes, a 4K page requires 128
+bytes in the core file.
+
Example of correct usage
========================