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Add a command line opt-in option for posted MSI if CONFIG_X86_POSTED_MSI=y.
Also introduce a helper function for testing if posted MSI is supported on
the platform.
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240423174114.526704-12-jacob.jun.pan@linux.intel.com
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This document mainly describe the functionality of IPU6 and IPU6 isys
driver, and gives an example that how user can do imaging capture with
tools.
Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
- Make the CPU_MITIGATIONS=n interaction with conflicting
mitigation-enabling boot parameters a bit saner.
- Re-enable CPU mitigations by default on non-x86
- Fix TDX shared bit propagation on mprotect()
- Fix potential show_regs() system hang when PKE initialization
is not fully finished yet.
- Add the 0x10-0x1f model IDs to the Zen5 range
- Harden #VC instruction emulation some more
* tag 'x86-urgent-2024-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu: Ignore "mitigations" kernel parameter if CPU_MITIGATIONS=n
cpu: Re-enable CPU mitigations by default for !X86 architectures
x86/tdx: Preserve shared bit on mprotect()
x86/cpu: Fix check for RDPKRU in __show_regs()
x86/CPU/AMD: Add models 0x10-0x1f to the Zen5 range
x86/sev: Check for MWAITX and MONITORX opcodes in the #VC handler
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After commit 443cbaf9e2fd ("crash: split vmcoreinfo exporting code out
from crash_core.c"), Kconfig item CRASH_CORE has gone away in kernel.
Items VMCORE_INFO and CRASH_RESERVE are used instead.
So clean up the outdated description about CRASH_CORE and update it
accordingly.
Link: https://lkml.kernel.org/r/20240329132825.1102459-3-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Introduce "max_pages" param to recompress device attribute which sets an
upper limit on the number of entries (pages) zram attempts to recompress
(in this particular recompression call). S/W recompression can be quite
expensive so limiting the number of pages recompress touches can be quite
helpful.
Link: https://lkml.kernel.org/r/20240329094050.2815699-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Brian Geffon <bgeffon@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Implements the "init_mlocked_on_free" boot option. When this boot option
is enabled, any mlock'ed pages are zeroed on free. If
the pages are munlock'ed beforehand, no initialization takes place.
This boot option is meant to combat the performance hit of
"init_on_free" as reported in commit 6471384af2a6 ("mm: security:
introduce init_on_alloc=1 and init_on_free=1 boot options"). With
"init_mlocked_on_free=1" only relevant data is freed while everything
else is left untouched by the kernel. Correspondingly, this patch
introduces no performance hit for unmapping non-mlock'ed memory. The
unmapping overhead for purely mlocked memory was measured to be
approximately 13%. Realistically, most systems mlock only a fraction of
the total memory so the real-world system overhead should be close to
zero.
Optimally, userspace programs clear any key material or other
confidential memory before exit and munlock the according memory
regions. If a program crashes, userspace key managers fail to do this
job. Accordingly, no munlock operations are performed so the data is
caught and zeroed by the kernel. Should the program not crash, all
memory will ideally be munlocked so no overhead is caused.
CONFIG_INIT_MLOCKED_ON_FREE_DEFAULT_ON can be set to enable
"init_mlocked_on_free" by default.
Link: https://lkml.kernel.org/r/20240329145605.149917-1-yjnworkstation@gmail.com
Signed-off-by: York Jasper Niebuhr <yjnworkstation@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: York Jasper Niebuhr <yjnworkstation@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Mostly rewording, but remove entirely the copy of page_fixed_fake_head()
in the documentation; we can refer people to the actual source if
necessary.
Link: https://lkml.kernel.org/r/20240326171045.410737-10-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add some description of the hugetlb migration strategy.
Link: https://lkml.kernel.org/r/63fb16e7a4ebc5cb69ce655af86e29b2d8e9ba34.1709719720.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Introduce CONFIG_MEM_ALLOC_PROFILING which provides definitions to easily
instrument memory allocators. It registers an "alloc_tags" codetag type
with /proc/allocinfo interface to output allocation tag information when
the feature is enabled.
CONFIG_MEM_ALLOC_PROFILING_DEBUG is provided for debugging the memory
allocation profiling instrumentation.
Memory allocation profiling can be enabled or disabled at runtime using
/proc/sys/vm/mem_profiling sysctl when CONFIG_MEM_ALLOC_PROFILING_DEBUG=n.
CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT enables memory allocation
profiling by default.
[surenb@google.com: Documentation/filesystems/proc.rst: fix allocinfo title]
Link: https://lkml.kernel.org/r/20240326073813.727090-1-surenb@google.com
[surenb@google.com: do limited memory accounting for modules with ARCH_NEEDS_WEAK_PER_CPU]
Link: https://lkml.kernel.org/r/20240402180933.1663992-2-surenb@google.com
[klarasmodin@gmail.com: explicitly include irqflags.h in alloc_tag.h]
Link: https://lkml.kernel.org/r/20240407133252.173636-1-klarasmodin@gmail.com
[surenb@google.com: fix alloc_tag_init() to prevent passing NULL to PTR_ERR()]
Link: https://lkml.kernel.org/r/20240417003349.2520094-1-surenb@google.com
Link: https://lkml.kernel.org/r/20240321163705.3067592-14-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Co-developed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Klara Modin <klarasmodin@gmail.com>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Explicitly disallow enabling mitigations at runtime for kernels that were
built with CONFIG_CPU_MITIGATIONS=n, as some architectures may omit code
entirely if mitigations are disabled at compile time.
E.g. on x86, a large pile of Kconfigs are buried behind CPU_MITIGATIONS,
and trying to provide sane behavior for retroactively enabling mitigations
is extremely difficult, bordering on impossible. E.g. page table isolation
and call depth tracking require build-time support, BHI mitigations will
still be off without additional kernel parameters, etc.
[ bp: Touchups. ]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240420000556.2645001-3-seanjc@google.com
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Commit 839195352d82 ("mm/shuffle: remove dynamic reconfiguration")
removed the dynamic reconfiguration capabilities from the shuffle page
allocator. This means that, now, we don't have any perspective of an
"autodetection of memory-side-cache" that triggers the enablement of the
shuffle page allocator.
Therefore, let the documentation reflect that the only way to enable
the shuffle page allocator is by setting `page_alloc.shuffle=1`.
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240422142007.1062231-1-mcanal@igalia.com
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sched_core_share_pid() copies the cookie to userspace with
put_user(id, (u64 __user *)uaddr), expecting 64 bits of space.
The "unsigned long" datatype that is documented in core-scheduling.rst
however is only 32 bits large on 32 bit architectures.
Document "unsigned long long" as the correct data type that is always
64bits large.
This matches what the selftest cs_prctl_test.c has been doing all along.
Fixes: 0159bb020ca9 ("Documentation: Add usecases, design and interface for core scheduling")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/util-linux/df7a25a0-7923-4f8b-a527-5e6f0064074d@t-8ch.de/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Chris Hyser <chris.hyser@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240423-core-scheduling-cookie-v1-1-5753a35f8dfc@weissschuh.net
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The optional shift of the clock used by thermal/hw load avg has been
introduced to handle case where the signal was not always a high frequency
hw signal. Now that cpufreq provides a signal for firmware and
SW pressure, we can remove this exception and always keep this PELT signal
aligned with other signals.
Mark sysctl_sched_migration_cost boot parameter as deprecated
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Qais Yousef <qyousef@layalina.io>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://lore.kernel.org/r/20240326091616.3696851-6-vincent.guittot@linaro.org
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We want the tty fixes in here as well, and it resolves a merge conflict
in:
drivers/tty/serial/serial_core.c
as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Pull documentation fixes from Jonathan Corbet:
"A set of updates from Thorsten to his (new) guide to verifying bugs
and tracking down regressions"
* tag 'docs-6.9-fixes2' of git://git.lwn.net/linux:
docs: verify/bisect: stable regressions: first stable, then mainline
docs: verify/bisect: describe how to use a build host
docs: verify/bisect: explain testing reverts, patches and newer code
docs: verify/bisect: proper headlines and more spacing
docs: verify/bisect: add and fetch stable branches ahead of time
docs: verify/bisect: use git switch, tag kernel, and various fixes
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To allow setting an appropriate parent for the struct pmu device
remove existing references to /sys/devices/ path.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240412161057.14099-14-Jonathan.Cameron@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
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To allow setting an appropriate parent for the struct pmu device
remove existing references to /sys/devices/ path.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240412161057.14099-11-Jonathan.Cameron@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
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To allow setting an appropriate parent for the struct pmu device
remove existing references to /sys/devices/ path.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240412161057.14099-9-Jonathan.Cameron@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
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To allow setting an appropriate parent for the struct pmu device
remove existing references to /sys/devices/ path.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240412161057.14099-5-Jonathan.Cameron@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
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Having assigned a parent to the device, the suggested path is
no longer valid. As /sys/bus/event_sources based path is also
provided, simply drop mention of alternative.
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240412161057.14099-3-Jonathan.Cameron@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
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This patch add two entries (pids.peak and pids.events) for pids
controller, and also update pids.current because it's on non-root.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Since kernel virtual and physical address spaces are
uncoupled the kernel is mapped at the top of the virtual
address space in case KASLR is disabled.
That does not pose any issue with regard to the kernel
booting and operation, but makes it difficult to use a
generated vmlinux with some debugging tools (e.g. gdb),
because the exact location of the kernel image in virtual
memory is unknown. Make that location known and introduce
CONFIG_KERNEL_IMAGE_BASE configuration option.
A custom CONFIG_KERNEL_IMAGE_BASE value that would break
the virtual memory layout leads to a build error.
The kernel image size is defined by KERNEL_IMAGE_SIZE
macro and set to 512 MB, by analogy with x86.
Suggested-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
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When WQ_HIGHPRI was used for the dm-crypt kcryptd workqueue it was
reported that dm-crypt performs badly when the system is loaded[1].
Because of reports of audio skipping, dm-crypt stopped using
WQ_HIGHPRI with commit f612b2132db5 (Revert "dm crypt: use WQ_HIGHPRI
for the IO and crypt workqueues").
But it has since been determined that WQ_HIGHPRI provides improved
performance (with reduced latency) for highend systems with much more
resources than those laptop/desktop users which suffered from the use
of WQ_HIGHPRI.
As such, add an option "high_priority" that allows the use of
WQ_HIGHPRI for dm-crypt's workqueues and also sets the write_thread to
nice level MIN_NICE (-20). This commit makes it optional, so that
normal users won't be harmed by it.
[1] https://listman.redhat.com/archives/dm-devel/2023-February/053410.html
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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A call to a synchronize_rcu() can be optimized from a latency
point of view. Workloads which depend on this can benefit of it.
The delay of wakeme_after_rcu() callback, which unblocks a waiter,
depends on several factors:
- how fast a process of offloading is started. Combination of:
- !CONFIG_RCU_NOCB_CPU/CONFIG_RCU_NOCB_CPU;
- !CONFIG_RCU_LAZY/CONFIG_RCU_LAZY;
- other.
- when started, invoking path is interrupted due to:
- time limit;
- need_resched();
- if limit is reached.
- where in a nocb list it is located;
- how fast previous callbacks completed;
Example:
1. On our embedded devices i can easily trigger the scenario when
it is a last in the list out of ~3600 callbacks:
<snip>
<...>-29 [001] d..1. 21950.145313: rcu_batch_start: rcu_preempt CBs=3613 bl=28
...
<...>-29 [001] ..... 21950.152578: rcu_invoke_callback: rcu_preempt rhp=00000000b2d6dee8 func=__free_vm_area_struct.cfi_jt
<...>-29 [001] ..... 21950.152579: rcu_invoke_callback: rcu_preempt rhp=00000000a446f607 func=__free_vm_area_struct.cfi_jt
<...>-29 [001] ..... 21950.152580: rcu_invoke_callback: rcu_preempt rhp=00000000a5cab03b func=__free_vm_area_struct.cfi_jt
<...>-29 [001] ..... 21950.152581: rcu_invoke_callback: rcu_preempt rhp=0000000013b7e5ee func=__free_vm_area_struct.cfi_jt
<...>-29 [001] ..... 21950.152582: rcu_invoke_callback: rcu_preempt rhp=000000000a8ca6f9 func=__free_vm_area_struct.cfi_jt
<...>-29 [001] ..... 21950.152583: rcu_invoke_callback: rcu_preempt rhp=000000008f162ca8 func=wakeme_after_rcu.cfi_jt
<...>-29 [001] d..1. 21950.152625: rcu_batch_end: rcu_preempt CBs-invoked=3612 idle=....
<snip>
2. We use cpuset/cgroup to classify tasks and assign them into
different cgroups. For example "backgrond" group which binds tasks
only to little CPUs or "foreground" which makes use of all CPUs.
Tasks can be migrated between groups by a request if an acceleration
is needed.
See below an example how "surfaceflinger" task gets migrated.
Initially it is located in the "system-background" cgroup which
allows to run only on little cores. In order to speed it up it
can be temporary moved into "foreground" cgroup which allows
to use big/all CPUs:
cgroup_attach_task():
-> cgroup_migrate_execute()
-> cpuset_can_attach()
-> percpu_down_write()
-> rcu_sync_enter()
-> synchronize_rcu()
-> now move tasks to the new cgroup.
-> cgroup_migrate_finish()
<snip>
rcuop/1-29 [000] ..... 7030.528570: rcu_invoke_callback: rcu_preempt rhp=00000000461605e0 func=wakeme_after_rcu.cfi_jt
PERFD-SERVER-1855 [000] d..1. 7030.530293: cgroup_attach_task: dst_root=3 dst_id=22 dst_level=1 dst_path=/foreground pid=1900 comm=surfaceflinger
TimerDispatch-2768 [002] d..5. 7030.537542: sched_migrate_task: comm=surfaceflinger pid=1900 prio=98 orig_cpu=0 dest_cpu=4
<snip>
"Boosting a task" depends on synchronize_rcu() latency:
- first trace shows a completion of synchronize_rcu();
- second shows attaching a task to a new group;
- last shows a final step when migration occurs.
3. To address this drawback, maintain a separate track that consists
of synchronize_rcu() callers only. After completion of a grace period
users are deferred to a dedicated worker to process requests.
4. This patch reduces the latency of synchronize_rcu() approximately
by ~30-40% on synthetic tests. The real test case, camera launch time,
shows(time is in milliseconds):
1-run 542 vs 489 improvement 9%
2-run 540 vs 466 improvement 13%
3-run 518 vs 468 improvement 9%
4-run 531 vs 457 improvement 13%
5-run 548 vs 475 improvement 13%
6-run 509 vs 484 improvement 4%
Synthetic test(no "noise" from other callbacks):
Hardware: x86_64 64 CPUs, 64GB of memory
Linux-6.6
- 10K tasks(simultaneous);
- each task does(1000 loops)
synchronize_rcu();
kfree(p);
default: CONFIG_RCU_NOCB_CPU: takes 54 seconds to complete all users;
patch: CONFIG_RCU_NOCB_CPU: takes 35 seconds to complete all users.
Running 60K gives approximately same results on my setup. Please note
it is without any interaction with another type of callbacks, otherwise
it will impact a lot a default case.
5. By default it is disabled. To enable this perform one of the
below sequence:
echo 1 > /sys/module/rcutree/parameters/rcu_normal_wake_from_gp
or pass a boot parameter "rcutree.rcu_normal_wake_from_gp=1"
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Co-developed-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
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Rearrange the instructions so that readers facing a regression within a
stable or longterm series first test its latest release before testing
mainline. This is less scary for some people. It also reduces the chance
that something goes sideways for readers that compile their first
kernel, as mainline can cause slightly more trouble.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/efd3cb9c68db450091021326bf9c334553df0ec2.1712647788.git.linux@leemhuis.info
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Describe how to build kernels on another system (with and without
cross-compiling), as building locally can be quite painfully on some
slow systems. This is done in an add-on section, as it would make the
step-by-step guide to complicated if this special case would be
described there.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/288160cb4769e46a3280250ca71da0abc4aa002d.1712647788.git.linux@leemhuis.info
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Rename 'Supplementary tasks' to 'Complementary tasks' while introducing
a section 'Optional tasks: test reverts, patches, or later versions':
the latter is something readers occasionally will have to do after
reporting a bug and thus is best covered here.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/dacf26a4c48e9e8f04ecbc77e0a74c9b2a6a1103.1712647788.git.linux@leemhuis.info
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Various small improvements and fixes:
* Separate ref links from their target with a space for better
readability.
* Add a proper heading for the note at the end of the step-by-step
guide.
* Use proper 3rd and 4th level headlines in the reference section and
add short intros for the 2nd level headlines that lacked one.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/f59f0f235a2192ed93899a7338153e4cb71075f0.1712647788.git.linux@leemhuis.info
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Add and fetch all required stable branches ahead of time. This fixes a
bug, as readers that wanted to bisect a regression within a stable or
longterm series otherwise did not have them available at the right time.
This way also matches the flow somewhat better and avoids some "if you
haven't already added it" phrases that otherwise become necessary in
future changes.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/57dcf312959476abe6151bf3d35eb79e3e9a83d1.1712647788.git.linux@leemhuis.info
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Various small improvements and fixes:
* Use the more modern 'git switch' instead of 'git checkout', which
makes it more obvious what's happening (among others due to the
--discard-changes parameter that is more clear than --force).
* Provide a hint how a mainline version number and one from a stable
series look like.
* When trying to validate the bisection result with a revert, add a
special tag to facilitate the identification.
* Sync version numbers used in various examples for consistency: stick
to 6.0.13, 6.0.15, and 6.1.5.
* Fix a few typos and oddities.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/85029aa004447b0eeb5043fb014630f2acafacec.1712647788.git.linux@leemhuis.info
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In order to be able to limit the amount of memory that is allocated
by IOMMU subsystem, the memory must be accounted.
Account IOMMU as part of the secondary pagetables as it was discussed
at LPC.
The value of SecPageTables now contains mmeory allocation by IOMMU
and KVM.
There is a difference between GFP_ACCOUNT and what NR_IOMMU_PAGES shows.
GFP_ACCOUNT is set only where it makes sense to charge to user
processes, i.e. IOMMU Page Tables, but there more IOMMU shared data
that should not really be charged to a specific process.
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20240413002522.1101315-12-pasha.tatashin@soleen.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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Unlike most other mitigations' "auto" options, spectre_bhi=auto only
mitigates newer systems, which is confusing and not particularly useful.
Remove it.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/412e9dc87971b622bbbaf64740ebc1f140bff343.1712813475.git.jpoimboe@kernel.org
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When terminal is unresponsive, one cannot use dmesg to view
the printk ring buffer messages. Also, syslog services may be
disabled, especially on embedded systems, to check the messages
after a reboot. In this scenario, replay the messages in printk
ring buffer on consoles via sysrq by pressing sysrq+R.
The console loglevel will determine which all kernel log messages
are displayed. The messages will be displayed only when
console_trylock() succeeds. Users could repeat the sysrq key when
it fails. If the owner of console subsystem lock is stuck,
repeating the key won't work.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Shimoyashiki Taichi <taichi.shimoyashiki@sony.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sreenath Vijayan <sreenath.vijayan@sony.com>
Link: https://lore.kernel.org/r/cc3b9b1aae60a236c6aed1dc7b0ffa2c7cd1f183.1710220326.git.sreenath.vijayan@sony.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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While syscall hardening helps prevent some BHI attacks, there's still
other low-hanging fruit remaining. Don't classify it as a mitigation
and make it clear that the system may still be vulnerable if it doesn't
have a HW or SW mitigation enabled.
Fixes: ec9404e40e8f ("x86/bhi: Add BHI mitigation knob")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/b5951dae3fdee7f1520d5136a27be3bdfe95f88b.1712813475.git.jpoimboe@kernel.org
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Fix up some inaccuracies in the BHI documentation.
Fixes: ec9404e40e8f ("x86/bhi: Add BHI mitigation knob")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/8c84f7451bfe0dd08543c6082a383f390d4aa7e2.1712813475.git.jpoimboe@kernel.org
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Quoting of the '"no regressions" rule' expression differs between
occurrences, sometimes being presented as '"no regressions rule"'. Unify
the quoting using the first form which seems semantically correct or is
at least used dominantly, albeit marginally.
One of the occurrences is obviously missing the 'rule' part -- add it.
Signed-off-by: Karel Balej <balejk@matfyz.cz>
Reviewed-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240328194342.11760-2-balejk@matfyz.cz
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Document the console option for DEVNAME:0.0 style addressing for serial
ports.
Suggested-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20240327110021.59793-8-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Pull x86 mitigations from Thomas Gleixner:
"Mitigations for the native BHI hardware vulnerabilty:
Branch History Injection (BHI) attacks may allow a malicious
application to influence indirect branch prediction in kernel by
poisoning the branch history. eIBRS isolates indirect branch targets
in ring0. The BHB can still influence the choice of indirect branch
predictor entry, and although branch predictor entries are isolated
between modes when eIBRS is enabled, the BHB itself is not isolated
between modes.
Add mitigations against it either with the help of microcode or with
software sequences for the affected CPUs"
[ This also ends up enabling the full mitigation by default despite the
system call hardening, because apparently there are other indirect
calls that are still sufficiently reachable, and the 'auto' case just
isn't hardened enough.
We'll have some more inevitable tweaking in the future - Linus ]
* tag 'nativebhi' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
KVM: x86: Add BHI_NO
x86/bhi: Mitigate KVM by default
x86/bhi: Add BHI mitigation knob
x86/bhi: Enumerate Branch History Injection (BHI) bug
x86/bhi: Define SPEC_CTRL_BHI_DIS_S
x86/bhi: Add support for clearing branch history at syscall entry
x86/syscall: Don't force use of indirect calls for system calls
x86/bugs: Change commas to semicolons in 'spectre_v2' sysfs file
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The original description refers to the comment on
cgroup_for_each_descendant_pre() for more details. However, the macro
cgroup_for_each_descendant_pre() no longer exist, we replace it with the
corresponding macro cgroup_for_each_live_descendant_pre().
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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BHI mitigation mode spectre_bhi=auto does not deploy the software
mitigation by default. In a cloud environment, it is a likely scenario
where userspace is trusted but the guests are not trusted. Deploying
system wide mitigation in such cases is not desirable.
Update the auto mode to unconditionally mitigate against malicious
guests. Deploy the software sequence at VMexit in auto mode also, when
hardware mitigation is not available. Unlike the force =on mode,
software sequence is not deployed at syscalls in auto mode.
Suggested-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Branch history clearing software sequences and hardware control
BHI_DIS_S were defined to mitigate Branch History Injection (BHI).
Add cmdline spectre_bhi={on|off|auto} to control BHI mitigation:
auto - Deploy the hardware mitigation BHI_DIS_S, if available.
on - Deploy the hardware mitigation BHI_DIS_S, if available,
otherwise deploy the software sequence at syscall entry and
VMexit.
off - Turn off BHI mitigation.
The default is auto mode which does not deploy the software sequence
mitigation. This is because of the hardening done in the syscall
dispatch path, which is the likely target of BHI.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Fix the mgb4 driver documentation structure that breaks the
"Video4Linux (V4L) driver-specific documentation" outline.
Signed-off-by: Martin Tůma <martin.tuma@digiteqautomotive.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
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Format the shell commands as code block to keep the documentation in the
same style
Signed-off-by: Weiji Wang <nebclllo0444@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240319114253.2647-1-nebclllo0444@gmail.com
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kernel-parameters.txt incorrectly states that workings of
kernel.tracepoint_printk sysctl depends on "tracepoint_printk kernel
cmdline option", this is a bit misleading for new users since the actual
cmdline option name is tp_printk.
Fixes: 0daa2302968c ("tracing: Add tp_printk cmdline to have tracepoints go to printk()")
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240323231704.1217926-1-vt@altlinux.org
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The limitation that all RT processes have to be in the root cgroup
before enabling cpu controller only applies if the CONFIG_RT_GROUP_SCHED
option is enabled in the running kernel. If a kernel does not have
CONFIG_RT_GROUP_SCHED enabled, RT processes can exist in a non-root
cgroup even when cpu controller is enabled. CPU sharing of RT processes
will not be under cgroup control, but other resources like memory can be.
Clarify this limitation to avoid confusion to users that are using
cgroup v2.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Pull more documentation updates from Jonathan Corbet:
"A handful of late-arriving documentation fixes and enhancements"
* tag 'docs-6.9-2' of git://git.lwn.net/linux:
docs: verify/bisect: remove a level of indenting
docs: verify/bisect: drop 'v' prefix, EOL aspect, and assorted fixes
docs: verify/bisect: check taint flag
docs: verify/bisect: improve install instructions
docs: handling-regressions.rst: Update regzbot command fixed-by to fix
docs: *-regressions.rst: Add colon to regzbot commands
doc: Fix typo in admin-guide/cifs/introduction.rst
README: Fix spelling
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:
"Main user visible change:
- User events can now have "multi formats"
The current user events have a single format. If another event is
created with a different format, it will fail to be created. That
is, once an event name is used, it cannot be used again with a
different format. This can cause issues if a library is using an
event and updates its format. An application using the older format
will prevent an application using the new library from registering
its event.
A task could also DOS another application if it knows the event
names, and it creates events with different formats.
The multi-format event is in a different name space from the single
format. Both the event name and its format are the unique
identifier. This will allow two different applications to use the
same user event name but with different payloads.
- Added support to have ftrace_dump_on_oops dump out instances and
not just the main top level tracing buffer.
Other changes:
- Add eventfs_root_inode
Only the root inode has a dentry that is static (never goes away)
and stores it upon creation. There's no reason that the thousands
of other eventfs inodes should have a pointer that never gets set
in its descriptor. Create a eventfs_root_inode desciptor that has a
eventfs_inode descriptor and a dentry pointer, and only the root
inode will use this.
- Added WARN_ON()s in eventfs
There's some conditionals remaining in eventfs that should never be
hit, but instead of removing them, add WARN_ON() around them to
make sure that they are never hit.
- Have saved_cmdlines allocation also include the map_cmdline_to_pid
array
The saved_cmdlines structure allocates a large amount of data to
hold its mappings. Within it, it has three arrays. Two are already
apart of it: map_pid_to_cmdline[] and saved_cmdlines[]. More memory
can be saved by also including the map_cmdline_to_pid[] array as
well.
- Restructure __string() and __assign_str() macros used in
TRACE_EVENT()
Dynamic strings in TRACE_EVENT() are declared with:
__string(name, source)
And assigned with:
__assign_str(name, source)
In the tracepoint callback of the event, the __string() is used to
get the size needed to allocate on the ring buffer and
__assign_str() is used to copy the string into the ring buffer.
There's a helper structure that is created in the TRACE_EVENT()
macro logic that will hold the string length and its position in
the ring buffer which is created by __string().
There are several trace events that have a function to create the
string to save. This function is executed twice. Once for
__string() and again for __assign_str(). There's no reason for
this. The helper structure could also save the string it used in
__string() and simply copy that into __assign_str() (it also
already has its length).
By using the structure to store the source string for the
assignment, it means that the second argument to __assign_str() is
no longer needed.
It will be removed in the next merge window, but for now add a
warning if the source string given to __string() is different than
the source string given to __assign_str(), as the source to
__assign_str() isn't even used and will be going away.
- Added checks to make sure that the source of __string() is also the
source of __assign_str() so that it can be safely removed in the
next merge window.
Included fixes that the above check found.
- Other minor clean ups and fixes"
* tag 'trace-v6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (34 commits)
tracing: Add __string_src() helper to help compilers not to get confused
tracing: Use strcmp() in __assign_str() WARN_ON() check
tracepoints: Use WARN() and not WARN_ON() for warnings
tracing: Use div64_u64() instead of do_div()
tracing: Support to dump instance traces by ftrace_dump_on_oops
tracing: Remove second parameter to __assign_rel_str()
tracing: Add warning if string in __assign_str() does not match __string()
tracing: Add __string_len() example
tracing: Remove __assign_str_len()
ftrace: Fix most kernel-doc warnings
tracing: Decrement the snapshot if the snapshot trigger fails to register
tracing: Fix snapshot counter going between two tracers that use it
tracing: Use EVENT_NULL_STR macro instead of open coding "(null)"
tracing: Use ? : shortcut in trace macros
tracing: Do not calculate strlen() twice for __string() fields
tracing: Rework __assign_str() and __string() to not duplicate getting the string
cxl/trace: Properly initialize cxl_poison region name
net: hns3: tracing: fix hclgevf trace event strings
drm/i915: Add missing ; to __assign_str() macros in tracepoint code
NFSD: Fix nfsd_clid_class use of __string_len() macro
...
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Currently ftrace only dumps the global trace buffer on an OOPs. For
debugging a production usecase, instance trace will be helpful to
check specific problems since global trace buffer may be used for
other purposes.
This patch extend the ftrace_dump_on_oops parameter to dump a specific
or multiple trace instances:
- ftrace_dump_on_oops=0: as before -- don't dump
- ftrace_dump_on_oops[=1]: as before -- dump the global trace buffer
on all CPUs
- ftrace_dump_on_oops=2 or =orig_cpu: as before -- dump the global
trace buffer on CPU that triggered the oops
- ftrace_dump_on_oops=<instance_name>: new behavior -- dump the
tracing instance matching <instance_name>
- ftrace_dump_on_oops[=2/orig_cpu],<instance1_name>[=2/orig_cpu],
<instrance2_name>[=2/orig_cpu]: new behavior -- dump the global trace
buffer and multiple instance buffer on all CPUs, or only dump on CPU
that triggered the oops if =2 or =orig_cpu is given
Also, the sysctl node can handle the input accordingly.
Link: https://lore.kernel.org/linux-trace-kernel/20240223083126.1817731-1-quic_hyiwei@quicinc.com
Cc: Ross Zwisler <zwisler@google.com>
Cc: <mhiramat@kernel.org>
Cc: <mark.rutland@arm.com>
Cc: <mcgrof@kernel.org>
Cc: <keescook@chromium.org>
Cc: <j.granados@samsung.com>
Cc: <mathieu.desnoyers@efficios.com>
Cc: <corbet@lwn.net>
Signed-off-by: Huang Yiwei <quic_hyiwei@quicinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Remove a unnecessary level of indenting in some areas of the reference
section. No text changes.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <01f1a407e92b92d9f8614bd34882956694bab123.1710750972.git.linux@leemhuis.info>
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A bunch of minor fixes and improvements and two other things:
- Explain the 'v' version prefix when it's first used, but drop it
everywhere in the text for consistency. Also drop single quotes around
a few version numbers.
- Point out that testing a stable/longterm kernel only makes sense if
the series is still supported.
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <f13d203d5975419608996300992eaa2e4fcc2dc1.1710750972.git.linux@leemhuis.info>
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