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| author | Catalin Marinas <catalin.marinas@arm.com> | 2021-04-23 18:51:34 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-04-29 10:23:45 +0100 |
| commit | 75516c75a72b5629736c611cf45058d95978a9f2 (patch) | |
| tree | 7c8cdef56eb9ba013ab42f5ec5cf286f725a761c /Documentation/arm64 | |
| parent | 9b924f4f0d8f9557f4ef8a8d1468d507a662cef1 (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')
| -rw-r--r-- | Documentation/arm64/tagged-address-abi.rst | 6 |
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 failure. |