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2022-12-02exit: Allow oops_limit to be disabledKees Cook
In preparation for keeping oops_limit logic in sync with warn_limit, have oops_limit == 0 disable checking the Oops counter. Cc: Jann Horn <jannh@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Huang Ying <ying.huang@intel.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-doc@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
2022-12-02powerpc/64s/hash: add stress_hpt kernel boot option to increase hash faultsNicholas Piggin
This option increases the number of hash misses by limiting the number of kernel HPT entries, by keeping a per-CPU record of the last kernel HPTEs installed, and removing that from the hash table on the next hash insertion. A timer round-robins CPUs removing remaining kernel HPTEs and clearing the TLB (in the case of bare metal) to increase and slightly randomise kernel fault activity. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Add comment about NR_CPUS usage, fixup whitespace] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221024030150.852517-1-npiggin@gmail.com
2022-12-01exit: Put an upper limit on how often we can oopsJann Horn
Many Linux systems are configured to not panic on oops; but allowing an attacker to oops the system **really** often can make even bugs that look completely unexploitable exploitable (like NULL dereferences and such) if each crash elevates a refcount by one or a lock is taken in read mode, and this causes a counter to eventually overflow. The most interesting counters for this are 32 bits wide (like open-coded refcounts that don't use refcount_t). (The ldsem reader count on 32-bit platforms is just 16 bits, but probably nobody cares about 32-bit platforms that much nowadays.) So let's panic the system if the kernel is constantly oopsing. The speed of oopsing 2^32 times probably depends on several factors, like how long the stack trace is and which unwinder you're using; an empirically important one is whether your console is showing a graphical environment or a text console that oopses will be printed to. In a quick single-threaded benchmark, it looks like oopsing in a vfork() child with a very short stack trace only takes ~510 microseconds per run when a graphical console is active; but switching to a text console that oopses are printed to slows it down around 87x, to ~45 milliseconds per run. (Adding more threads makes this faster, but the actual oops printing happens under &die_lock on x86, so you can maybe speed this up by a factor of around 2 and then any further improvement gets eaten up by lock contention.) It looks like it would take around 8-12 days to overflow a 32-bit counter with repeated oopsing on a multi-core X86 system running a graphical environment; both me (in an X86 VM) and Seth (with a distro kernel on normal hardware in a standard configuration) got numbers in that ballpark. 12 days aren't *that* short on a desktop system, and you'd likely need much longer on a typical server system (assuming that people don't run graphical desktop environments on their servers), and this is a *very* noisy and violent approach to exploiting the kernel; and it also seems to take orders of magnitude longer on some machines, probably because stuff like EFI pstore will slow it down a ton if that's active. Signed-off-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20221107201317.324457-1-jannh@google.com Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221117234328.594699-2-keescook@chromium.org
2022-11-30docs: admin-guide: cgroup-v1: update description of inactive_fileJian Wen
MADV_FREE pages have been moved into the LRU_INACTIVE_FILE list by commit f7ad2a6cb9f7 ("mm: move MADV_FREE pages into LRU_INACTIVE_FILE list"). Link: https://lkml.kernel.org/r/20221111034639.3593380-1-wenjian1@xiaomi.com Signed-off-by: Jian Wen <wenjian1@xiaomi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30zram: add incompressible flag to read_block_state()Sergey Senozhatsky
Add a new flag to zram block state that shows if the page is incompressible: that none of the algorithm (including secondary ones) could compress it. Link: https://lkml.kernel.org/r/20221109115047.2921851-14-senozhatsky@chromium.org Suggested-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Alexey Romanov <avromanov@sberdevices.ru> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Suleiman Souhlal <suleiman@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30zram: add incompressible writebackSergey Senozhatsky
Add support for incompressible pages writeback: echo incompressible > /sys/block/zramX/writeback Link: https://lkml.kernel.org/r/20221109115047.2921851-13-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Alexey Romanov <avromanov@sberdevices.ru> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Suleiman Souhlal <suleiman@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30documentation: add zram recompression documentationSergey Senozhatsky
Document user-space visible device attributes that are enabled by ZRAM_MULTI_COMP. Link: https://lkml.kernel.org/r/20221109115047.2921851-12-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Alexey Romanov <avromanov@sberdevices.ru> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Suleiman Souhlal <suleiman@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30zram: add recompress flag to read_block_state()Sergey Senozhatsky
Add a new flag to zram block state that shows if the page was recompressed (using alternative compression algorithm). Link: https://lkml.kernel.org/r/20221109115047.2921851-6-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Alexey Romanov <avromanov@sberdevices.ru> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Suleiman Souhlal <suleiman@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30Docs/admin-guide/mm/damon/usage: document schemes/<s>/tried_regions sysfs ↵SeongJae Park
directory Document 'tried_regions' directory in DAMON sysfs interface usage in the administrator guide. Link: https://lkml.kernel.org/r/20221101220328.95765-8-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30mm: vmscan: split khugepaged stats from direct reclaim statsJohannes Weiner
Direct reclaim stats are useful for identifying a potential source for application latency, as well as spotting issues with kswapd. However, khugepaged currently distorts the picture: as a kernel thread it doesn't impose allocation latencies on userspace, and it explicitly opts out of kswapd reclaim. Its activity showing up in the direct reclaim stats is misleading. Counting it as kswapd reclaim could also cause confusion when trying to understand actual kswapd behavior. Break out khugepaged from the direct reclaim counters into new pgsteal_khugepaged, pgdemote_khugepaged, pgscan_khugepaged counters. Test with a huge executable (CONFIG_READ_ONLY_THP_FOR_FS): pgsteal_kswapd 1342185 pgsteal_direct 0 pgsteal_khugepaged 3623 pgscan_kswapd 1345025 pgscan_direct 0 pgscan_khugepaged 3623 Link: https://lkml.kernel.org/r/20221026180133.377671-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Eric Bergen <ebergen@meta.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30Docs/admin-guide/mm/damon/usage: fix wrong usage example of init_regions fileSeongJae Park
DAMON debugfs interface assumes the users will write all inputs at once. However, redirecting a string of multiple lines sometimes end up writing line by line. Therefore, the example usage of 'init_regions' file, which writes input as a string of multiple lines can fail. Fix it to use a single line string instead. Also update the description of the usage to not assume users will write inputs in multiple lines. Link: https://lkml.kernel.org/r/20221024174619.15600-3-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Vinicius Petrucci <vpetrucci@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30Docs/admin-guide/mm/damon/usage: describe the rules of sysfs region directoriesSeongJae Park
Patch series "Docs/admin-buide/mm/damon/usage: minor fixes". DAMON usage document contains an unclear description and a wrong usage example. This patchset fixes the two minor problems. This patch (of 2): Target region directories of DAMON sysfs interface should contain no overlap and sorted by the address, but not clearly documented. Actually, a user had an issue[1] due to the poor documentation. Add clear description of it on the usage document. [1] https://lore.kernel.org/damon/CAEZ6=UNUcH2BvJj++OrT=XQLdkidU79wmCO=tantSOB36pPNTg@mail.gmail.com/ Link: https://lkml.kernel.org/r/20221024174619.15600-1-sj@kernel.org Link: https://lkml.kernel.org/r/20221024174619.15600-2-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Reported-by: Vinicius Petrucci <vpetrucci@gmail.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30Merge tag 'drm-accel-2022-11-22' of ↵Dave Airlie
https://git.kernel.org/pub/scm/linux/kernel/git/ogabbay/accel into drm-next This tag contains the patches that add the new compute acceleration subsystem, which is part of the DRM subsystem. The patches: - Add a new directory at drivers/accel. - Add a new major (261) for compute accelerators. - Add a new DRM minor type for compute accelerators. - Integrate the accel core code with DRM core code. - Add documentation for the accel subsystem. Signed-off-by: Dave Airlie <airlied@redhat.com> some acks from the list (some are in the patch series): Acked-by: Daniel Stone <daniels@collabora.com> Acked-by: Sonal Santan <sonal.santan@amd.com> Acked-by: Maxime Ripard <maxime@cerno.tech> Acked-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com> Tested-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com> Acked-by: Alex Deucher <alexander.deucher@amd.com> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> From: Oded Gabbay <ogabbay@kernel.org> Link: https://patchwork.freedesktop.org/patch/msgid/20221122112222.GA352082@ogabbay-vm-u20.habana-labs.com
2022-11-29drivers/perf: hisi: Add TLP filter supportYicong Yang
The PMU support to filter the TLP when counting the bandwidth with below options: - only count the TLP headers - only count the TLP payloads - count both TLP headers and payloads In the current driver it's default to count the TLP payloads only, which will have an implicity side effects that on the traffic only have header only TLPs, we'll get no data. Make this user configuration through "len_mode" parameter and make it default to count both TLP headers and payloads when user not specified. Also update the documentation for it. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Link: https://lore.kernel.org/r/20221117084136.53572-5-yangyicong@huawei.com Signed-off-by: Will Deacon <will@kernel.org>
2022-11-29Documentation: perf: Indent filter options list of hisi-pcie-pmuBagas Sanjaya
The "Filter options" list have a rather ugly indentation. Also, the first paragraph after list name is rendered without separator (as continuation from the name). Align the list by indenting the list items and add a blank line separator for each list name. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Link: https://lore.kernel.org/r/20221117084136.53572-4-yangyicong@huawei.com Signed-off-by: Will Deacon <will@kernel.org>
2022-11-29docs: perf: Fix PMU instance name of hisi-pcie-pmuYicong Yang
The PMU instance will be called hisi_pcie<sicl>_core<core> rather than hisi_pcie<sicl>_<core>. Fix this in the documentation. Fixes: c8602008e247 ("docs: perf: Add description for HiSilicon PCIe PMU driver") Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Link: https://lore.kernel.org/r/20221117084136.53572-3-yangyicong@huawei.com Signed-off-by: Will Deacon <will@kernel.org>
2022-11-25media: vivid.rst: fix TV and S-Video Inputs sectionDeming Wang
remove the double word 'in'. Signed-off-by: Deming Wang <wangdeming@inspur.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
2022-11-25media: admin-guide: cec.rstHans Verkuil
Document administration details about CEC devices. This was formerly documented in a cec-status.txt I kept on my website, but this really belongs here as an admin guide. Updated the original cec-status.txt, and converted it to .rst. Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
2022-11-25media: visl: add virtual stateless decoder driverDaniel Almeida
A virtual stateless device for stateless uAPI development purposes. This tool's objective is to help the development and testing of userspace applications that use the V4L2 stateless API to decode media. A userspace implementation can use visl to run a decoding loop even when no hardware is available or when the kernel uAPI for the codec has not been upstreamed yet. This can reveal bugs at an early stage. This driver can also trace the contents of the V4L2 controls submitted to it. It can also dump the contents of the vb2 buffers through a debugfs interface. This is in many ways similar to the tracing infrastructure available for other popular encode/decode APIs out there and can help develop a userspace application by using another (working) one as a reference. Note that no actual decoding of video frames is performed by visl. The V4L2 test pattern generator is used to write various debug information to the capture buffers instead. Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
2022-11-24Backmerge tag 'v6.1-rc6' into drm-nextDave Airlie
Linux 6.1-rc6 This is needed for drm-misc-next and tegra. Signed-off-by: Dave Airlie <airlied@redhat.com>
2022-11-23tracing: Add trace_trigger kernel command line optionSteven Rostedt (Google)
Allow triggers to be enabled at kernel boot up. For example: trace_trigger="sched_switch.stacktrace if prev_state == 2" The above will enable the stacktrace trigger on top of the sched_switch event and only trigger if its prev_state is 2 (TASK_UNINTERRUPTIBLE). Then at boot up, a stacktrace will trigger and be recorded in the tracing ring buffer every time the sched_switch happens where the previous state is TASK_INTERRUPTIBLE. Another useful trigger would be "traceoff" which can stop tracing on an event if a field of the event matches a certain value defined by the filter ("if" statement). Link: https://lore.kernel.org/linux-trace-kernel/20221020210056.0d8d0a5b@gandalf.local.home Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-11-22Documentation: add amd-pstate kernel command line optionsPerry Yuan
Add a new amd pstate driver command line option to enable driver passive working mode via MSR and shared memory interface to request desired performance within abstract scale and the power management firmware (SMU) convert the perf requests into actual hardware pstates. Also the `disable` parameter can disable the pstate driver loading by adding `amd_pstate=disable` to kernel command line. Acked-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Tested-by: Wyes Karny <wyes.karny@amd.com> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-11-22Documentation: amd-pstate: add driver working mode introductionPerry Yuan
Introduce the `amd_pstate` driver new working mode with `amd_pstate=passive` added to kernel command line. If there is no passive mode enabled by user, amd_pstate driver will be disabled by default for now. Acked-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Tested-by: Wyes Karny <wyes.karny@amd.com> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-11-22drivers/accel: define kconfig and register a new majorOded Gabbay
Add a new Kconfig for the accel subsystem. The Kconfig currently contains only the basic CONFIG_DRM_ACCEL option that will be used to decide whether to compile the accel registration code. Therefore, the kconfig option is defined as bool. The accel code will be compiled as part of drm.ko and will be called directly from the DRM core code. The reason we compile it as part of drm.ko and not as a separate module is because of cyclic dependency between drm.ko and the separate module (if it would have existed). This is due to the fact that DRM core code calls accel functions and vice-versa. The accelerator devices will be exposed to the user space with a new, dedicated major number - 261. The accel init function registers the new major number as a char device and create corresponding sysfs and debugfs root entries, similar to what is done in DRM init function. I added a new header called drm_accel.h to include/drm/, that will hold the prototypes of the drm_accel.c functions. In case CONFIG_DRM_ACCEL is set to 'N', that header will contain empty inline implementations of those functions, to allow DRM core code to compile successfully without dependency on CONFIG_DRM_ACCEL. I Updated the MAINTAINERS file accordingly with the newly added folder and I have taken the liberty to appropriate the dri-devel mailing list and the dri-devel IRC channel for the accel subsystem. Signed-off-by: Oded Gabbay <ogabbay@kernel.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com> Reviewed-by: Dave Airlie <airlied@redhat.com> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Acked-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com> Tested-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com> Reviewed-by: Melissa Wen <mwen@igalia.com>
2022-11-21docs/perf: Add documentation for the Amlogic G12 DDR PMUJiucheng Xu
Add a user guide to show how to use DDR PMU to monitor DDR bandwidth on Amlogic G12 SoC Signed-off-by: Jiucheng Xu <jiucheng.xu@amlogic.com> Reviewed-by: Chris Healy <healych@amazon.com> Link: https://lore.kernel.org/r/20221121021602.3306998-2-jiucheng.xu@amlogic.com Signed-off-by: Will Deacon <will@kernel.org>
2022-11-19iommu/amd: Fix ill-formed ivrs_ioapic, ivrs_hpet and ivrs_acpihid optionsKim Phillips
Currently, these options cause the following libkmod error: libkmod: ERROR ../libkmod/libkmod-config.c:489 kcmdline_parse_result: \ Ignoring bad option on kernel command line while parsing module \ name: 'ivrs_xxxx[XX:XX' Fix by introducing a new parameter format for these options and throw a warning for the deprecated format. Users are still allowed to omit the PCI Segment if zero. Adding a Link: to the reason why we're modding the syntax parsing in the driver and not in libkmod. Fixes: ca3bf5d47cec ("iommu/amd: Introduces ivrs_acpihid kernel parameter") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/linux-modules/20200310082308.14318-2-lucas.demarchi@intel.com/ Reported-by: Kim Phillips <kim.phillips@amd.com> Co-developed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Kim Phillips <kim.phillips@amd.com> Link: https://lore.kernel.org/r/20220919155638.391481-2-kim.phillips@amd.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2022-11-18core_pattern: add CPU specifierOleksandr Natalenko
Statistically, in a large deployment regular segfaults may indicate a CPU issue. Currently, it is not possible to find out what CPU the segfault happened on. There are at least two attempts to improve segfault logging with this regard, but they do not help in case the logs rotate. Hence, lets make sure it is possible to permanently record a CPU the task ran on using a new core_pattern specifier. Link: https://lkml.kernel.org/r/20220903064330.20772-1-oleksandr@redhat.com Signed-off-by: Oleksandr Natalenko <oleksandr@redhat.com> Suggested-by: Renaud Métrich <rmetrich@redhat.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Grzegorz Halat <ghalat@redhat.com> Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Joel Savitz <jsavitz@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Rob Herring <robh@kernel.org> Cc: Stephen Kitt <steve@sk2.org> Cc: Will Deacon <will@kernel.org> Cc: Xiaoming Ni <nixiaoming@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-18arm64: kdump: Support crashkernel=X fall back to reserve region above DMA zonesZhen Lei
For crashkernel=X without '@offset', select a region within DMA zones first, and fall back to reserve region above DMA zones. This allows users to use the same configuration on multiple platforms. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Acked-by: Baoquan He <bhe@redhat.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20221116121044.1690-3-thunder.leizhen@huawei.com Signed-off-by: Will Deacon <will@kernel.org>
2022-11-18arm64: kdump: Provide default size when crashkernel=Y,low is not specifiedZhen Lei
Try to allocate at least 128 MiB low memory automatically for the case that crashkernel=,high is explicitly specified, while crashkenrel=,low is omitted. This allows users to focus more on the high memory requirements of their business rather than the low memory requirements of the crash kernel booting. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Acked-by: Baoquan He <bhe@redhat.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20221116121044.1690-2-thunder.leizhen@huawei.com Signed-off-by: Will Deacon <will@kernel.org>
2022-11-18random: use random.trust_{bootloader,cpu} command line option onlyJason A. Donenfeld
It's very unusual to have both a command line option and a compile time option, and apparently that's confusing to people. Also, basically everybody enables the compile time option now, which means people who want to disable this wind up having to use the command line option to ensure that anyway. So just reduce the number of moving pieces and nix the compile time option in favor of the more versatile command line option. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-11-16drm: Move nomodeset kernel parameter to drivers/videoThomas Zimmermann
Move the nomodeset kernel parameter to drivers/video to make it available to non-DRM drivers. Adapt the interface, but keep the DRM interface drm_firmware_drivers_only() to avoid churn within DRM. The function should later be inlined into callers. The parameter disables any DRM graphics driver that would replace a driver for firmware-provided scanout buffers. It is an option to easily fallback to basic graphics output if the hardware's native driver is broken. Moving it to a more prominent location wil make it available to fbdev as well. v2: * clarify the meaning of the nomodeset parameter (Javier) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221111133024.9897-2-tzimmermann@suse.de
2022-11-15perf: arm_cspmu: Add support for NVIDIA SCF and MCF attributeBesar Wicaksono
Add support for NVIDIA System Cache Fabric (SCF) and Memory Control Fabric (MCF) PMU attributes for CoreSight PMU implementation in NVIDIA devices. Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Besar Wicaksono <bwicaksono@nvidia.com> Link: https://lore.kernel.org/r/20221111222330.48602-3-bwicaksono@nvidia.com Signed-off-by: Will Deacon <will@kernel.org>
2022-11-10x86/split_lock: Add sysctl to control the misery modeGuilherme G. Piccoli
Commit b041b525dab9 ("x86/split_lock: Make life miserable for split lockers") changed the way the split lock detector works when in "warn" mode; basically, it not only shows the warn message, but also intentionally introduces a slowdown through sleeping plus serialization mechanism on such task. Based on discussions in [0], seems the warning alone wasn't enough motivation for userspace developers to fix their applications. This slowdown is enough to totally break some proprietary (aka. unfixable) userspace[1]. Happens that originally the proposal in [0] was to add a new mode which would warns + slowdown the "split locking" task, keeping the old warn mode untouched. In the end, that idea was discarded and the regular/default "warn" mode now slows down the applications. This is quite aggressive with regards proprietary/legacy programs that basically are unable to properly run in kernel with this change. While it is understandable that a malicious application could DoS by split locking, it seems unacceptable to regress old/proprietary userspace programs through a default configuration that previously worked. An example of such breakage was reported in [1]. Add a sysctl to allow controlling the "misery mode" behavior, as per Thomas suggestion on [2]. This way, users running legacy and/or proprietary software are allowed to still execute them with a decent performance while still observing the warning messages on kernel log. [0] https://lore.kernel.org/lkml/20220217012721.9694-1-tony.luck@intel.com/ [1] https://github.com/doitsujin/dxvk/issues/2938 [2] https://lore.kernel.org/lkml/87pmf4bter.ffs@tglx/ [ dhansen: minor changelog tweaks, including clarifying the actual problem ] Fixes: b041b525dab9 ("x86/split_lock: Make life miserable for split lockers") Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Andre Almeida <andrealmeid@igalia.com> Link: https://lore.kernel.org/all/20221024200254.635256-1-gpiccoli%40igalia.com
2022-11-09docs: admin-guide: hw_random: Make document title more generic and conciseJonathan Neuschäfer
The hw_random subsystem no longer works only on specific Intel chipsets; make the title of hw_random.rst reflect this fact. While we're at it, also remove the words "Linux support for", since it's clear from context that this is a document about Linux. Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Link: https://lore.kernel.org/r/20221101160119.955997-1-j.neuschaefer@gmx.net Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-11-09Docs/admin-guide/mm/zswap: remove a paragraph about zswap being a new featureDavid Heidelberg
Nine years have passed since Linux 3.11. Signed-off-by: David Heidelberg <david@ixit.cz> Link: https://lore.kernel.org/r/20221104122612.14906-1-david@ixit.cz Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-11-08media: vimc: Update device configuration in the documentationDafna Hirschfeld
Current configuration in the document is outdated and doesn't work. Update it to match the configuration described in the following commit: commit 9b4a9b31b9ae ("media: vimc: Enable set resolution at the scaler src pad") Fixed commit description: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Dafna Hirschfeld <dafna@fastmail.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
2022-11-01Documentation: amd-pstate: Add tbench and gitsource test introductionMeng Li
Introduce tbench and gitsource test cases design and implementation. Monitor cpus changes about performance and power consumption etc. Signed-off-by: Meng Li <li.meng@amd.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2022-10-26s390/con3215: Drop console data printout when buffer fullThomas Richter
Using z/VM the 3270 terminal emulator also emulates an IBM 3215 console which outputs line by line. When the screen is full, the console enters the MORE... state and waits for the operator to confirm the data on the screen by pressing a clear key. If this does not happen in the default time frame (currently 50 seconds) the console enters the HOLDING state. It then waits another time frame (currently 10 seconds) before the output continues on the next screen. When the operator presses the clear key during these wait times, the output continues immediately. This may lead to a very long boot time when the console has to print many messages, also the system may hang because of the console's limited buffer space and the system waits for the console output to drain and finally to finish. This problem can only occur when a terminal emulator is actually connected to the 3215 console driver. If not z/VM simply drops console output. Remedy this rare situation and add a kernel boot command line parameter con3215_drop. It can be set to 0 (do not drop) or 1 (do drop) which is the default. This instructs the kernel drop console data when the console buffer is full. This speeds up the boot time considerable and also does not hang the system anymore. Add a sysfs attribute file for console IBM 3215 named con_drop. This allows for changing the behavior after the boot, for example when during interactive debugging a panic/crash is expected. Here is a test of the new behavior using the following test program: #/bin/bash declare -i cnt=4 mode=$(cat /sys/bus/ccw/drivers/3215/con_drop) [ $mode = yes ] && cnt=25 echo "cons_drop $(cat /sys/bus/ccw/drivers/3215/con_drop)" echo "vmcp term more 5 2" vmcp term more 5 2 echo "Run $cnt iterations of "'echo t > /proc/sysrq-trigger' for i in $(seq $cnt) do echo "$i. command 'echo t > /proc/sysrq-trigger' at $(date +%F,%T)" echo t > /proc/sysrq-trigger sleep 1 done echo "droptest done" > /dev/kmsg # Output with sysfs attribute con_drop set to 1: # ./droptest.sh cons_drop yes vmcp term more 5 2 Run 25 iterations of echo t > /proc/sysrq-trigger 1. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:09 2. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:10 3. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:11 4. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:12 5. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:13 6. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:14 7. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:15 8. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:16 9. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:17 10. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:18 11. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:19 12. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:20 13. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:21 14. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:22 15. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:23 16. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:24 17. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:25 18. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:26 19. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:27 20. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:28 21. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:29 22. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:30 23. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:31 24. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:32 25. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:15:33 # There are no hangs anymore. Output with sysfs attribute con_drop set to 0 and identical setting for z/VM console 'term more 5 2'. Sometimes hitting the clear key at the x3270 console to progress output. # ./droptest.sh cons_drop no vmcp term more 5 2 Run 4 iterations of echo t > /proc/sysrq-trigger 1. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:20:58 2. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:24:32 3. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:28:04 4. command 'echo t > /proc/sysrq-trigger' at 2022-09-02,10:31:37 # Details: Enable function raw3215_write() to handle tab expansion and newlines and feed it with input not larger than the console buffer of 65536 bytes. Function raw3125_putchar() just forwards its character for output to raw3215_write(). This moves tab to blank conversion to one function raw3215_write() which also does call raw3215_make_room() to wait for enough free buffer space. Function handle_write() loops over all its input and segments input into chunks of console buffer size (should the input be larger). Rework tab expansion handling logic to avoid code duplication. Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2022-10-25media: vivid.rst: loop_video is set on the capture devnodeHans Verkuil
The example on how to use and test Capture Overlay specified the wrong video device node. Back in 2015 the loop_video control moved from the output device to the capture device, but this example code is still referring to the output video device. Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
2022-10-21Merge tag 'acpi-6.1-rc2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull ACPI fixes from Rafael Wysocki: "These fix issues introduced during this merge window (ACPI/PCI, device enumeration and documentation) and some other ones found recently. Specifics: - Add missing device reference counting to acpi_get_pci_dev() after changing it recently (Rafael Wysocki) - Fix resource list walk in acpi_dma_get_range() (Robin Murphy) - Add IRQ override quirk for LENOVO IdeaPad and extend the IRQ override warning message (Jiri Slaby) - Fix integer overflow in ghes_estatus_pool_init() (Ashish Kalra) - Fix multiple error records handling in one of the ACPI extlog driver code paths (Tony Luck) - Prune DSDT override documentation from index after dropping it (Bagas Sanjaya)" * tag 'acpi-6.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: ACPI: scan: Fix DMA range assignment ACPI: PCI: Fix device reference counting in acpi_get_pci_dev() ACPI: resource: note more about IRQ override ACPI: resource: do IRQ override on LENOVO IdeaPad ACPI: extlog: Handle multiple records ACPI: APEI: Fix integer overflow in ghes_estatus_pool_init() Documentation: ACPI: Prune DSDT override documentation from index
2022-10-21Merge branches 'acpi-scan', 'acpi-resource', 'acpi-apei', 'acpi-extlog' and ↵Rafael J. Wysocki
'acpi-docs' Merge assorted ACPI fixes for 6.1-rc2: - Fix resource list walk in acpi_dma_get_range() (Robin Murphy). - Add IRQ override quirk for LENOVO IdeaPad and extend the IRQ override warning message (Jiri Slaby). - Fix integer overflow in ghes_estatus_pool_init() (Ashish Kalra). - Fix multiple error records handling in one of the ACPI extlog driver code paths (Tony Luck). - Prune DSDT override documentation from index after dropping it (Bagas Sanjaya). * acpi-scan: ACPI: scan: Fix DMA range assignment * acpi-resource: ACPI: resource: note more about IRQ override ACPI: resource: do IRQ override on LENOVO IdeaPad * acpi-apei: ACPI: APEI: Fix integer overflow in ghes_estatus_pool_init() * acpi-extlog: ACPI: extlog: Handle multiple records * acpi-docs: Documentation: ACPI: Prune DSDT override documentation from index
2022-10-19docs: sysctl/fs: re-order, prettifyStephen Kitt
This brings the text markup in line with sysctl/abi and sysctl/kernel: * the entries are ordered alphabetically * the table of contents is automatically generated * markup is used as appropriate for constants etc. The content isn't fully up-to-date but the obsolete entries are gone, so remove the kernel version mention. Signed-off-by: Stephen Kitt <steve@sk2.org> Link: https://lore.kernel.org/r/20220930102937.135841-6-steve@sk2.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-10-19docs: sysctl/fs: remove references to super-max/-nrStephen Kitt
These were removed in 2.4.7.8. Remove references to super-max and super-nr in the sysctl documentation. Signed-off-by: Stephen Kitt <steve@sk2.org> Link: https://lore.kernel.org/r/20220930102937.135841-5-steve@sk2.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-10-19docs: sysctl/fs: merge the aio sectionsStephen Kitt
There are two sections documenting aio-nr and aio-max-nr, merge them. I kept the second explanation of aio-nr, which seems clearer to me, along with the effects of the values from the first section. Signed-off-by: Stephen Kitt <steve@sk2.org> Link: https://lore.kernel.org/r/20220930102937.135841-4-steve@sk2.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-10-19docs: sysctl/fs: remove references to dquot-max/-nrStephen Kitt
dquot-max was removed in 2.4.10.5; dquot-nr was replaced with dqstats in 2.5.18 which is now /proc/sys/fs/quota. Remove references to dquot-max and dquot-nr in the sysctl documentation. Signed-off-by: Stephen Kitt <steve@sk2.org> Link: https://lore.kernel.org/r/20220930102937.135841-3-steve@sk2.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-10-19docs: sysctl/fs: remove references to inode-maxStephen Kitt
inode-max was removed in 2.3.20pre1, remove references to it in the sysctl documentation. Signed-off-by: Stephen Kitt <steve@sk2.org> Link: https://lore.kernel.org/r/20220930102937.135841-2-steve@sk2.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-10-18dm verity: Add documentation for try_verify_in_tasklet optionMilan Broz
Add documentation that was missing from commit 5721d4e5a9cd ("dm verity: Add optional "try_verify_in_tasklet" feature"). Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-10-14Merge tag 'sched-psi-2022-10-14' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull PSI updates from Ingo Molnar: - Various performance optimizations, resulting in a 4%-9% speedup in the mmtests/config-scheduler-perfpipe micro-benchmark. - New interface to turn PSI on/off on a per cgroup level. * tag 'sched-psi-2022-10-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/psi: Per-cgroup PSI accounting disable/re-enable interface sched/psi: Cache parent psi_group to speed up group iteration sched/psi: Consolidate cgroup_psi() sched/psi: Add PSI_IRQ to track IRQ/SOFTIRQ pressure sched/psi: Remove NR_ONCPU task accounting sched/psi: Optimize task switch inside shared cgroups again sched/psi: Move private helpers to sched/stats.h sched/psi: Save percpu memory when !psi_cgroups_enabled sched/psi: Don't create cgroup PSI files when psi_disabled sched/psi: Fix periodic aggregation shut off
2022-10-13Documentation: ACPI: Prune DSDT override documentation from indexBagas Sanjaya
Commit d206cef03c4827 ("ACPI: docs: Drop useless DSDT override documentation") removes useless DSDT override documentation. However, the commit forgets to prune the documentation entry from table of contents of ACPI admin guide documentation, hence triggers Sphinx warning: Documentation/admin-guide/acpi/index.rst:8: WARNING: toctree contains reference to nonexisting document 'admin-guide/acpi/dsdt-override' Prune the entry to fix the warning. Fixes: d206cef03c4827 ("ACPI: docs: Drop useless DSDT override documentation") Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-10-12Merge tag 'for-linus-6.1-rc1-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from Juergen Gross: - Some minor typo fixes - A fix of the Xen pcifront driver for supporting the device model to run in a Linux stub domain - A cleanup of the pcifront driver - A series to enable grant-based virtio with Xen on x86 - A cleanup of Xen PV guests to distinguish between safe and faulting MSR accesses - Two fixes of the Xen gntdev driver - Two fixes of the new xen grant DMA driver * tag 'for-linus-6.1-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen: Kconfig: Fix spelling mistake "Maxmium" -> "Maximum" xen/pv: support selecting safe/unsafe msr accesses xen/pv: refactor msr access functions to support safe and unsafe accesses xen/pv: fix vendor checks for pmu emulation xen/pv: add fault recovery control to pmu msr accesses xen/virtio: enable grant based virtio on x86 xen/virtio: use dom0 as default backend for CONFIG_XEN_VIRTIO_FORCE_GRANT xen/virtio: restructure xen grant dma setup xen/pcifront: move xenstore config scanning into sub-function xen/gntdev: Accommodate VMA splitting xen/gntdev: Prevent leaking grants xen/virtio: Fix potential deadlock when accessing xen_grant_dma_devices xen/virtio: Fix n_pages calculation in xen_grant_dma_map(unmap)_page() xen/xenbus: Fix spelling mistake "hardward" -> "hardware" xen-pcifront: Handle missed Connected state
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