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[v2,5/5] arm64: mte: Document the core dump file format

Message ID 20220131165456.2160675-6-catalin.marinas@arm.com (mailing list archive)
State New, archived
Headers show
Series arm64: mte: add core dump support | expand

Commit Message

Catalin Marinas Jan. 31, 2022, 4:54 p.m. UTC 
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>
---
 .../arm64/memory-tagging-extension.rst        | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)
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Patch

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
 ========================