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| author | Aníbal Limón <anibal.limon@linaro.org> | 2020-03-05 08:54:47 -0600 |
|---|---|---|
| committer | Aníbal Limón <anibal.limon@linaro.org> | 2020-03-05 08:54:47 -0600 |
| commit | 8c79b3d123550fde184d9ef6b3d5e2e530abe0bd (patch) | |
| tree | 5cbfd139e838d4c377d52e48a61584900172657a /Documentation | |
| parent | e77fe54672b5971dbc9039f58b498328c54bdf4d (diff) | |
| parent | bfe3046ecafdd71ba6932deebe2eb357048b7bfc (diff) | |
Merge tag 'v5.4.23' into release/qcomlt-5.4
This is the 5.4.23 stable release
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/arm64/tagged-address-abi.rst | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/Documentation/arm64/tagged-address-abi.rst b/Documentation/arm64/tagged-address-abi.rst index d4a85d535bf99..4a9d9c794ee5d 100644 --- a/Documentation/arm64/tagged-address-abi.rst +++ b/Documentation/arm64/tagged-address-abi.rst @@ -44,8 +44,15 @@ The AArch64 Tagged Address ABI has two stages of relaxation depending how the user addresses are used by the kernel: 1. User addresses not accessed by the kernel but used for address space - management (e.g. ``mmap()``, ``mprotect()``, ``madvise()``). The use - of valid tagged pointers in this context is always allowed. + management (e.g. ``mprotect()``, ``madvise()``). The use of valid + tagged pointers in this context is allowed with the exception of + ``brk()``, ``mmap()`` and the ``new_address`` argument to + ``mremap()`` as these have the potential to alias with existing + user addresses. + + NOTE: This behaviour changed in v5.6 and so some earlier kernels may + incorrectly accept valid tagged pointers for the ``brk()``, + ``mmap()`` and ``mremap()`` system calls. 2. User addresses accessed by the kernel (e.g. ``write()``). This ABI relaxation is disabled by default and the application thread needs to |