From 997c798e1444ad02e8af8b18c869fff5c61867da Mon Sep 17 00:00:00 2001 From: Stephen Kitt Date: Fri, 15 May 2020 23:24:44 +0200 Subject: [PATCH] docs: sysctl/kernel: document unaligned controls This documents ignore-unaligned-usertrap, unaligned-dump-stack, and unaligned-trap, based on arch/arc/kernel/unaligned.c, arch/ia64/kernel/unaligned.c, and arch/parisc/kernel/unaligned.c. While we're at it, integrate unaligned-memory-access.txt into the docs tree. Signed-off-by: Stephen Kitt Link: https://lore.kernel.org/r/20200515212443.5012-1-steve@sk2.org Signed-off-by: Jonathan Corbet --- Documentation/admin-guide/sysctl/kernel.rst | 51 ++++++++++++++++++++++ Documentation/process/index.rst | 1 + .../unaligned-memory-access.rst} | 0 3 files changed, 52 insertions(+) rename Documentation/{unaligned-memory-access.txt => process/unaligned-memory-access.rst} (100%) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 6b313b6..4752d9a 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -402,6 +402,25 @@ Controls whether the panic kmsg data should be reported to Hyper-V. = ========================================================= +ignore-unaligned-usertrap +========================= + +On architectures where unaligned accesses cause traps, and where this +feature is supported (``CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN``; +currently, ``arc`` and ``ia64``), controls whether all unaligned traps +are logged. + += ============================================================= +0 Log all unaligned accesses. +1 Only warn the first time a process traps. This is the default + setting. += ============================================================= + +See also `unaligned-trap`_ and `unaligned-dump-stack`_. On ``ia64``, +this allows system administrators to override the +``IA64_THREAD_UAC_NOPRINT`` ``prctl`` and avoid logs being flooded. + + kexec_load_disabled =================== @@ -1261,6 +1280,38 @@ See :doc:`/admin-guide/kernel-parameters` and :doc:`/trace/boottime-trace`. +.. _unaligned-dump-stack: + +unaligned-dump-stack (ia64) +=========================== + +When logging unaligned accesses, controls whether the stack is +dumped. + += =================================================== +0 Do not dump the stack. This is the default setting. +1 Dump the stack. += =================================================== + +See also `ignore-unaligned-usertrap`_. + + +unaligned-trap +============== + +On architectures where unaligned accesses cause traps, and where this +feature is supported (``CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW``; currently, +``arc`` and ``parisc``), controls whether unaligned traps are caught +and emulated (instead of failing). + += ======================================================== +0 Do not emulate unaligned accesses. +1 Emulate unaligned accesses. This is the default setting. += ======================================================== + +See also `ignore-unaligned-usertrap`_. + + unknown_nmi_panic ================= diff --git a/Documentation/process/index.rst b/Documentation/process/index.rst index 6399d92..f07c925 100644 --- a/Documentation/process/index.rst +++ b/Documentation/process/index.rst @@ -61,6 +61,7 @@ lack of a better place. botching-up-ioctls clang-format ../riscv/patch-acceptance + unaligned-memory-access .. only:: subproject and html diff --git a/Documentation/unaligned-memory-access.txt b/Documentation/process/unaligned-memory-access.rst similarity index 100% rename from Documentation/unaligned-memory-access.txt rename to Documentation/process/unaligned-memory-access.rst -- 2.7.4