Sebastian Andrzej Siewior 5edf1547ac Documentation: Extend the real-time hardware bits with some firmware bits ... I have been reviewing how OP‑TEE is implemented and how secure‑world invocations behave. The goal was to determine whether an OP‑TEE call can delay the Linux side and introduce latency depending on the time spent in the secure world. Similar latency effects are already known for EFI runtime services, but this was not documented. To mitigate the impact, EFI runtime invocations can be restricted to specific CPUs so that real‑time workloads on other CPUs remain unaffected. This mechanism, however, is only described in the commit that introduced it. This change adds a firmware section that documents these behaviours explicitly. It highlights cases where firmware can delay the kernel, information that may be unfamiliar to some users and surprising-or concerning-to others. Assisted-by: Microsoft-Copilot Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Message-ID: <20260718175041.QXn9iOFK@linutronix.de>		2026-08-13 09:26:18 -06:00
..
irq	Documentation: Add managed interrupts	2026-04-11 07:07:02 -06:00
kho	kho: add support for linked-block serialization	2026-06-03 21:15:46 +03:00
real-time	Documentation: Extend the real-time hardware bits with some firmware bits	2026-08-13 09:26:18 -06:00
wrappers	docs: put atomic*.txt and memory-barriers.txt into the core-api book	2022-09-29 12:55:06 -06:00
asm-annotations.rst	docs: move x86 documentation into Documentation/arch/	2023-03-30 12:58:51 -06:00
assoc_array.rst	Documentation: assoc_array: Format internal tree layout tables	2025-10-17 14:23:04 -06:00
boot-time-mm.rst	docs/boot-time-mm: remove bootmem documentation	2018-10-31 08:54:16 -07:00
cachetlb.rst	mm: remove ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO	2023-08-24 16:20:19 -07:00
cgroup.rst	doc/cgroup: Fix title underline length	2025-01-15 09:46:18 +01:00
circular-buffers.rst	doc: Remove ".vnet" from paulmck email addresses	2019-05-28 09:02:57 -07:00
cleanup.rst	cleanup: Add usage and style documentation	2024-08-05 16:54:41 +02:00
cpu_hotplug.rst	Documentation: core-api/cpu_hotplug: Remove stale cpu0_hotplug docs	2026-05-15 08:44:24 -06:00
debug-objects.rst	doc: debugobjects: actually pull in the kerneldoc comments	2016-11-29 14:44:14 -07:00
debugging-via-ohci1394.rst	Documentation: Drop or replace remaining mentions of IA64	2023-09-11 08:13:18 +00:00
dma-api-howto.rst	docs: dma-api: document __dma_from_device_group_begin()/end()	2025-12-31 19:28:12 -05:00
dma-api.rst	docs: dma-api: remove needless bracket	2026-07-15 10:51:28 -06:00
dma-attributes.rst	dma-mapping: Introduce DMA require coherency attribute	2026-03-20 12:05:36 +01:00
dma-isa-lpc.rst	docs: core-api: avoid using ReST :doc:foo markup	2021-06-17 13:24:37 -06:00
entry.rst	Documentation: core-api: entry: Replace deprecated KVM entry/exit functions	2025-07-24 08:32:59 -06:00
errseq.rst	errseq: add missing bracket	2026-07-15 10:51:28 -06:00
floating-point.rst	arch: add ARCH_HAS_KERNEL_FPU_SUPPORT	2024-05-19 14:36:17 -07:00
folio_queue.rst	docs: folio_queue: Fix minor typo in folio_queue page	2025-08-12 12:40:15 -06:00
genalloc.rst	lib/genalloc.c: rename addr_in_gen_pool to gen_pool_has_addr	2019-12-04 19:44:13 -08:00
generic-radix-tree.rst	generic radix trees	2019-03-12 10:04:02 -07:00
genericirq.rst	treewide: Update email address	2026-01-11 06:09:11 -10:00
gfp_mask-from-fs-io.rst	docs: core-api/gfp_mask-from-fs-io: indicate that vmalloc supports GFP_NOFS/GFP_NOIO	2024-11-22 10:42:37 -07:00
housekeeping.rst	docs: housekeeping: Fix struct member access in code example	2026-05-15 08:25:16 -06:00
idr.rst	IDR: Note that the IDR API is deprecated	2022-07-10 21:17:30 -04:00
index.rst	Docs: SMP: add an SMP docbook chapter	2026-07-15 10:51:27 -06:00
kernel-api.rst	block: Include bvec.h kernel-doc in the htmldocs	2026-05-29 05:34:25 -06:00
kobject.rst	docs: Update documentation to avoid mentioning of kernel.h	2025-12-22 14:59:18 -07:00
kref.rst	Documentation: adopt new coding style of type-aware kmalloc-family	2026-05-03 08:54:21 -06:00
librs.rst	treewide: Update email address	2026-01-11 06:09:11 -10:00
list.rst	Docs: list: Fix bracket	2026-07-15 10:51:27 -06:00
liveupdate.rst	liveupdate: luo_flb: introduce File-Lifecycle-Bound global state	2026-02-08 00:13:33 -08:00
local_ops.rst	timers: Update the documentation to reflect on the new timer_shutdown() API	2022-11-24 15:09:12 +01:00
maple_tree.rst	maple_tree: update the documentation of maple tree	2023-12-10 16:51:32 -08:00
memory-allocation.rst	docs/core-api: memory-allocation: GFP_NOWAIT doesn't need __GFP_NOWARN	2024-07-29 15:10:25 -06:00
memory-hotplug.rst	docs: memory-hotplug: fix typo 'fo' -> 'for' in NODE_ADDED_FIRST_MEMORY description	2026-03-17 08:42:05 -06:00
min_heap.rst	Documentation/core-api: min_heap: remove documented but unimplemented min_heap_empty()	2026-07-22 10:24:49 -06:00
mm-api.rst	mm: rename balloon_compaction.(c|h) to balloon.(c|h)	2026-01-31 14:22:35 -08:00
netlink.rst	doc/netlink: Update genetlink-legacy documentation	2023-08-27 17:17:09 -07:00
packing.rst	docs: packing: fix brackets	2026-07-15 10:51:27 -06:00
padata.rst	Documentation: core-api: padata: correct spelling	2023-02-16 16:58:01 -07:00
parser.rst	Documentation: core-api: add generic parser docbook	2024-12-11 09:07:40 -07:00
pin_user_pages.rst	mm: remove page_mkclean()	2024-07-03 19:30:17 -07:00
printk-basics.rst	Documentation: printk: Add section about avoiding lockups	2026-03-17 08:37:49 -06:00
printk-formats.rst	vsprintf: Add upper case flavour to %p[mM]	2026-06-12 14:20:25 +02:00
printk-index.rst	docs:core-api: fixed typos and grammar in printk-index page	2024-05-07 08:01:11 -06:00
protection-keys.rst	Documentation/protection-keys: add AArch64 to documentation	2024-10-14 17:27:48 +01:00
rbtree.rst	Docs/core-api: fix typos in rbtree.rst	2026-02-14 10:11:43 -07:00
refcount-vs-atomic.rst	refcount: provide ops for cases when object's memory can be reused	2025-03-16 22:06:19 -07:00
SMP.rst	Docs: SMP: add an SMP docbook chapter	2026-07-15 10:51:27 -06:00
swiotlb.rst	docs/core-api: swiotlb: fix typos	2024-10-17 09:37:05 -06:00
symbol-namespaces.rst	docs: symbol-namespaces: mention sysfs attribute	2026-03-19 22:49:37 +00:00
this_cpu_ops.rst	docs: Improve discussion of this_cpu_ptr(), add raw_cpu_ptr()	2025-02-04 21:50:06 -08:00
timekeeping.rst	timekeeping: Introduce fast accessor to clock tai	2022-04-14 16:19:30 +02:00
tracepoint.rst	doc: Sphinxify the tracepoint docbook	2016-11-29 14:44:23 -07:00
unaligned-memory-access.rst	move asm/unaligned.h to linux/unaligned.h	2024-10-02 17:23:23 -04:00
union_find.rst	Documentation: Fix the compilation errors in union_find.rst	2024-08-02 08:58:16 -10:00
watch_queue.rst	Documentation: move watch_queue to core-api	2022-04-22 09:47:25 -06:00
workqueue.rst	docs: workqueue: document WQ_AFFN_CACHE_SHARD affinity scope	2026-04-01 10:24:18 -10:00
xarray.rst	xarray: add xas_try_split() to split a multi-index entry	2025-03-17 22:06:59 -07:00