diff options
Diffstat (limited to 'Documentation/arm64')
| -rw-r--r-- | Documentation/arm64/memory-tagging-extension.rst | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/Documentation/arm64/memory-tagging-extension.rst b/Documentation/arm64/memory-tagging-extension.rst index 42677d48a114..7e812a51e506 100644 --- a/Documentation/arm64/memory-tagging-extension.rst +++ b/Documentation/arm64/memory-tagging-extension.rst @@ -88,7 +88,6 @@ bit-field: (ignored if combined with other options) - ``PR_MTE_TCF_SYNC`` - *Synchronous* tag check fault mode - ``PR_MTE_TCF_ASYNC`` - *Asynchronous* tag check fault mode -- ``PR_MTE_TCF_ASYMM`` - *Asymmetric* tag check fault mode If no modes are specified, tag check faults are ignored. If a single mode is specified, the program will run in that mode. If multiple @@ -149,17 +148,19 @@ default preferred mode for each CPU is ``async``. To allow a program to potentially run in the CPU's preferred tag checking mode, the user program may set multiple tag check fault mode bits in the ``flags`` argument to the ``prctl(PR_SET_TAGGED_ADDR_CTRL, -flags, 0, 0, 0)`` system call. If the CPU's preferred tag checking -mode is in the task's set of provided tag checking modes, that -mode will be selected. Otherwise, one of the modes in the task's mode -selected by the kernel using the preference order: +flags, 0, 0, 0)`` system call. If both synchronous and asynchronous +modes are requested then asymmetric mode may also be selected by the +kernel. If the CPU's preferred tag checking mode is in the task's set +of provided tag checking modes, that mode will be selected. Otherwise, +one of the modes in the task's mode will be selected by the kernel +from the task's mode set using the preference order: 1. Asynchronous 2. Asymmetric 3. Synchronous -If asymmetric mode is specified by the program but not supported by -either the system or the kernel then an error will be returned. +Note that there is no way for userspace to request multiple modes and +also disable asymmetric mode. Initial process state --------------------- |