path: root/Documentation/arm64
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authorCatalin Marinas <catalin.marinas@arm.com>2021-04-23 18:51:34 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2021-04-29 10:23:45 +0100
commit75516c75a72b5629736c611cf45058d95978a9f2 (patch)
tree7c8cdef56eb9ba013ab42f5ec5cf286f725a761c /Documentation/arm64
parentpsci: Remove unneeded semicolon (diff)
arm64: doc: Add brk/mmap/mremap() to the Tagged Address ABI Exceptions
Prior to commit dcde237319e6 ("mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()"), the kernel allowed tagged addresses to be passed to the brk/mmap/mremap() syscalls. This relaxation was tightened in 5.6 (backported to stable 5.4) but the tagged-address-abi.rst document was only partially updated. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Fixes: dcde237319e6 ("mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()") Reported-by: Peter Maydell <peter.maydell@linaro.org> Cc: Will Deacon <will@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lore.kernel.org/r/20210423175134.14838-1-catalin.marinas@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'Documentation/arm64')
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/arm64/tagged-address-abi.rst b/Documentation/arm64/tagged-address-abi.rst
index cbc4d4500241..459e6b66ff68 100644
--- a/Documentation/arm64/tagged-address-abi.rst
+++ b/Documentation/arm64/tagged-address-abi.rst
@@ -113,6 +113,12 @@ ABI relaxation:
- ``shmat()`` and ``shmdt()``.
+- ``brk()`` (since kernel v5.6).
+- ``mmap()`` (since kernel v5.6).
+- ``mremap()``, the ``new_address`` argument (since kernel v5.6).
Any attempt to use non-zero tagged pointers may result in an error code
being returned, a (fatal) signal being raised, or other modes of