[PATCH v2 5/5] arm64: mte: Document the core dump file format
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2022-01-31 17:11:13
Subsystem:
documentation, the rest · Maintainers:
Jonathan Corbet, Linus Torvalds
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 <redacted> --- .../arm64/memory-tagging-extension.rst | 23 +++++++++++++++++++ 1 file changed, 23 insertions(+)
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 ========================
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