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arm64: doc: Add brk/mmap/mremap() to the Tagged Address ABI Exceptions

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Prior to commit dcde237319 ("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: dcde237319 ("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>
This commit is contained in:
Catalin Marinas 2021-04-23 18:51:34 +01:00
parent 9b924f4f0d
commit 75516c75a7
1 changed files with 6 additions and 0 deletions
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6
Documentation/arm64/tagged-address-abi.rst
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@ -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
failure.