shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-07 03:15:31 +09:00
Code Issues Packages Projects Releases Wiki Activity

Revert "FROMLIST: arm64/mte: Document ABI for asymmetric mode"

Browse Source 
This FROMLIST change has been updated. Reverting to be replaced with the
final version FROMGIT.

This reverts commit 926ce98105.

Bug: 217221156
Change-Id: I4e5c19675fc88987da9804a39a050ef050e2453a
Signed-off-by: Evgenii Stepanov <eugenis@google.com>
This commit is contained in:
Evgenii Stepanov
2022-03-09 13:04:42 -08:00
committed by Todd Kjos
parent 0578215e0d
commit f9985441a7
1 changed files with 5 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
Documentation/arm64/memory-tagging-extension.rst
View File

@@ -76,9 +76,6 @@ configurable behaviours:
with ``.si_code = SEGV_MTEAERR`` and ``.si_addr = 0`` (the faulting
address is unknown).
- *Asymmetric* - Reads are handled as for synchronous mode while writes
are handled as for asynchronous mode.
The user can select the above modes, per thread, using the
``prctl(PR_SET_TAGGED_ADDR_CTRL, flags, 0, 0, 0)`` system call where ``flags``
contains any number of the following values in the ``PR_MTE_TCF_MASK``
@@ -88,7 +85,6 @@ 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
@@ -143,14 +139,16 @@ tag checking mode as the CPU's preferred tag checking mode.
The preferred tag checking mode for each CPU is controlled by
``/sys/devices/system/cpu/cpu<N>/mte_tcf_preferred``, to which a
privileged user may write the value ``async``, ``sync`` or ``asymm``. The
default preferred mode for each CPU is ``async``.
privileged user may write the value ``async`` or ``sync``. The 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 is in the task's set of provided tag checking modes (this will
always be the case at present because the kernel only supports two
tag checking modes, but future kernels may support more modes), that
mode will be selected. Otherwise, one of the modes in the task's mode
set will be selected in a currently unspecified manner.