From 731451ab3c0c6fe88142dbc73a74c71bd92a5cff Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Mon, 31 Jan 2022 16:54:56 +0000 Subject: [PATCH] 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 Acked-by: Luis Machado Link: https://lore.kernel.org/r/20220131165456.2160675-6-catalin.marinas@arm.com Signed-off-by: Will Deacon --- .../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 7b99c8f428eb6..5a70d7a3ca129 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 ======================== -- 2.30.2