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| author |   Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2020-06-06 10:45:37 -0700 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2020-06-06 10:45:37 -0700 |
| commit | 8dd06ef34b6e2f41b29fbf5fc1663780f2524285 (patch) | |
| tree | d59152f37ea7b36c3cf1778e20b85239f89c4e77 /Documentation/arm64/tagged-address-abi.rst | |
| parent | Input: synaptics - add a second working PNP_ID for Lenovo T470s (diff) | |
| parent | Input: iqs269a - add missing I2C dependency (diff) | |
| download | linux-dev-8dd06ef34b6e2f41b29fbf5fc1663780f2524285.tar.xz linux-dev-8dd06ef34b6e2f41b29fbf5fc1663780f2524285.zip | |
Merge branch 'next' into for-linus
Prepare input updates for 5.8 merge window.
Diffstat (limited to 'Documentation/arm64/tagged-address-abi.rst')
| -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 d4a85d535bf9..4a9d9c794ee5 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 |