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2022-08-31USB: serial: cp210x: add Decagon UCA device idJohan Hovold1-0/+1
Add the device id for Decagon Devices USB Cable Adapter. Link: https://lore.kernel.org/r/trinity-819f9db2-d3e1-40e9-a669-9c245817c046-1661523546680@msvc-mesg-web108 Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold <johan@kernel.org>
2022-08-31ASoC: SOF: compress: Add support for timestamp on captureMark Brown1-8/+39
Merge series from Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>: The purpose of this patch series is to add support for timestamping on capture direction using the compress API. This is simply done by splitting sof_compr_copy into 2 functions: sof_compr_copy_playback and sof_compr_copy_capture. Each of these functions handles one of the possible directions: capture or playback and is called in sof_compr_copy based on the stream's direction. The only difference between sof_compr_copy_playback and sof_compr_copy_capture is the fact that on playback case we need to copy data from user space and on capture we need to copy data to user space.
2022-08-31dt-bindings: gpio: mpfs-gpio: allow parsing of hog child nodes.Conor Dooley1-0/+18
The SD card and eMMC on PolarFire SoC are sometimes muxed using a GPIO by the bootloader. Add a hog child property to facilitate this. Signed-off-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-08-31gpio/rockchip: Convert to generic_handle_domain_irq()Jeffy Chen1-16/+5
Follow commit dbd1c54fc820 ("gpio: Bulk conversion to generic_handle_domain_irq()"). Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-08-31perf metric: Return early if no CPU PMU table existsIan Rogers1-0/+3
Previous behavior is to segfault if there is no CPU PMU table and a metric is sought. To reproduce compile with NO_JEVENTS=1 then request a metric, for example, "perf stat -M IPC true". Committer testing: Before: $ make -k NO_JEVENTS=1 BUILD_BPF_SKEL=1 O=/tmp/build/perf-urgent -C tools/perf install-bin $ perf stat -M IPC true Segmentation fault (core dumped) $ After: $ perf stat -M IPC true Usage: perf stat [<options>] [<command>] -M, --metrics <metric/metric group list> monitor specified metrics or metric groups (separated by ,) $ Fixes: 00facc760903be66 ("perf jevents: Switch build to use jevents.py") Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Caleb Biggers <caleb.biggers@intel.com> Cc: Florian Fischer <florian.fischer@muhq.space> Cc: Ian Rogers <rogers.email@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Garry <john.garry@huawei.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kshipra Bopardikar <kshipra.bopardikar@intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Miaoqian Lin <linmq006@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Perry Taylor <perry.taylor@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Richter <tmricht@linux.ibm.com> Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com> Link: https://lore.kernel.org/r/20220830164846.401143-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-08-31drm/i915: move and group fdi members under display.fdiJani Nikula4-10/+12
Move display fdi related members under drm_i915_private display sub-struct. Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/b66fe7cf2c6f9e5b7bbfcaff40400492ac706721.1661779055.git.jani.nikula@intel.com
2022-08-31drm/i915: move and group power related members under display.powerJani Nikula8-110/+111
Move display power related members under drm_i915_private display sub-struct. Arguably chv_phy_control and chv_phy_assert could be placed in a phy substruct, but they are only used in the power code. Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/57bfa82f6fe85a775f80c398b2a7dff77b9452b0.1661779055.git.jani.nikula@intel.com
2022-08-31drm/i915: move fbc to display.fbcJani Nikula5-8/+7
Move display FBC related members under drm_i915_private display sub-struct. Pointers and arrays of pointers to structs that we defined are fine without a sub-struct wrapping. Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/1151469ec13d392df86b72a375f490fd70a3257a.1661779055.git.jani.nikula@intel.com
2022-08-31drm/i915: move vbt to display.vbtJani Nikula15-187/+188
Move display VBT related members under drm_i915_private display sub-struct. v2: Rebase Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/db4b648b201ea0b79654fec2028120999a735db0.1661779055.git.jani.nikula@intel.com
2022-08-31drm/i915: move mipi_mmio_base to display.dsiJani Nikula4-98/+102
Move display DSI related members under drm_i915_private display sub-struct. Prefer adding anonymous sub-structs even for single members that aren't our own structs. Abstract mmio base member access in register definitions in a macro. Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/dc7c5a871fe558a809ea943eca5c71dfff1740a8.1661779055.git.jani.nikula@intel.com
2022-08-31selftests/nolibc: Avoid generated files being committedFernanda Ma'rouf1-0/+4
After running the nolibc tests, the "git status" is not clean because the generated files are not ignored. Create a `.gitignore` inside the selftests/nolibc directory to ignore them. Cc: Ammar Faizi <ammarfaizi2@gnuweeb.org> Cc: Fernanda Ma'rouf <fernandafmr2@gmail.com> Signed-off-by: Fernanda Ma'rouf <fernandafmr12@gnuweeb.org> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: add a "help" targetWilly Tarreau1-1/+26
It presents the supported targets, and becomes the default target to save the user from having to read the makefile. The "all" target was placed after it and now points to "run" to do everything since it's no longer the default one. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: "sysroot" target installs a local copy of the sysrootWilly Tarreau1-2/+11
It's not convenient to rely on a sysroot built in another directory, especially when running cross-compilation tests, where one has to switch back and forth between directories. Let's make it possible to install the sysroot directly in the test directory. It's not big and even benefits from being copied by arch so that it's easier to switch between archs if needed. The new "sysroot" target does this, it just calls "headers_standalone" from nolibc to install the sysroot right here. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: add a "run" target to start the kernel in QEMUWilly Tarreau1-0/+33
The "run" target will build the kernel and start it in QEMU. The "rerun" target will not have the kernel dependency and will just try to start QEMU. The QEMU architecture used to start the kernel is derived from the configured ARCH. This might need to be improved for archs which include different variants under the same name (mips vs mipsel, +/-64, riscv32 vs riscv64). This could be tested for i386, x86, arm, arm64, mips and riscv (the later two reporting issues on some tests). It is possible to pass a test specification for nolibc-test in the TEST variable, which will be passed as-is as NOLIBC_TEST. On success, the number of successful tests is printed. On failure, failed lines are individually printed. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: add a "defconfig" targetWilly Tarreau1-0/+12
While most archs will work fine with "make defconfig", not all will do, and it's not always easy to remember the most suitable choice to use for a specific architecture. This adds a "defconfig" target to the Makefile so that one may easily run "make -C ... defconfig" and make sure to clean and rebuild a fresh config. This is *not* used by default because we want to preserve the user's config by default. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: add a "kernel" target to build the kernel with the initramfsWilly Tarreau1-0/+13
The "kernel" target rebuilds the kernel with the current config for the selected arch, with an initramfs containing the nolibc-test utility. Since image names depend on the architecture, the currently supported ones are referenced and resolved based on the architecture. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: support glibc as wellWilly Tarreau1-2/+45
Adding support for glibc can be useful to distinguish between bugs in nolibc and bugs in the kernel when a syscall reports an unusual value. It's not that much work and should not affect the long term maintainability of the tests. The necessary changes can essentially be summed up like this: - set _GNU_SOURCE a the top to access some definitions - many includes added when we know we don't come from nolibc (missing the stdio include guard) - disable gettid() which is not exposed by glibc - disable gettimeofday's support of bad pointers since these crash in glibc - add a simple itoa() for errorname(); strerror() is too verbose (no way to get short messages). strerrorname_np() was added in modern glibc (2.32) to do exactly this but that 's too recent to be usable as the default fallback. - use the standard ioperm() definition. May be we need to implement ioperm() in nolibc if that's useful. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: condition some tests on /proc existenceWilly Tarreau1-5/+9
If /proc is not available (program run inside a chroot or without sufficient permissions), it's better to disable the associated tests. Some will be preserved like the ones which check for a failure to create some entries there since they're still supposed to fail. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: recreate and populate /dev and /proc if missingWilly Tarreau1-0/+56
Most of the time the program will be run alone in an initramfs. There is no value in requiring the user to populate /dev and /proc for such tests, we can do it ourselves, and it participates to the tests at the same time. What's done here is that when called as init (getpid()==1) we check if /dev exists or create it, if /dev/console and /dev/null exists, otherwise we try to mount a devtmpfs there, and if it fails we fall back to mknod. The console is reopened if stdout was closed. Finally /proc is created and mounted if /proc/self cannot be found. This is sufficient for most tests. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: on x86, support exiting with isa-debug-exitWilly Tarreau1-0/+9
QEMU, when started with "-device isa-debug-exit -no-reboot" will exit with status code 2N+1 when N is written to 0x501. This is particularly convenient for automated tests but this is not portable. As such we only enable this on x86_64 when pid==1. In addition, this requires an ioperm() call but in order not to have to define arch-specific syscalls we just perform the syscall by hand there. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: exit with poweroff on success when getpid() == 1Willy Tarreau1-0/+14
The idea is to ease automated testing under qemu. If the test succeeds while running as PID 1, indicating the system was booted with init=/test, let's just power off so that qemu can exit with a successful code. In other situations it will exit and provoke a panic, which may be caught for example with CONFIG_PVPANIC. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: add a few tests for some libc functionsWilly Tarreau1-0/+35
The test series called "stdlib" covers some libc functions (string, stdlib etc). By default they are automatically run after "syscall" but may be requested in argument or in variable NOLIBC_TEST. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: implement a few tests for various syscallsWilly Tarreau1-0/+110
This adds 63 tests covering about 34 syscalls. Both successes and failures are tested. Two tests fail when run as unprivileged user (link_dir which returns EACCESS instead of EPERM, and chroot which returns EPERM). One test (execve("/")) expects to fail on EACCESS, but needs to have valid arguments otherwise the kernel will log a message. And a few tests require /proc to be mounted. The code is not pretty since all tests are one-liners, sometimes resulting in long lines, especially when using compount statements to preset a line, but it's convenient and doesn't obfuscate the code, which is important to understand what failed. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: support a test definition formatWilly Tarreau1-0/+91
It now becomes possible to pass a string either in argv[1] or in the NOLIBC_TEST environment variable (the former having precedence), to specify which tests to run. The format is: testname[:range]*[,testname...] Where a range is either a single value or the min and max numbers of the test IDs in a sequence, delimited by a dash. Multiple ranges are possible. This should provide enough flexibility to focus on certain failing parts just by playing with the boot command line in a boot loader or in qemu depending on what is accessible. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31selftests/nolibc: add basic infrastructure to ease creation of nolibc testsWilly Tarreau3-0/+439
This creates a "nolibc" selftest that intends to test various parts of the nolibc component, both in terms of build and execution for a given architecture. The aim is for it to be as simple to run as a kernel build, by just passing the compiler (for the build) and the ARCH (for kernel and execution). It brings a basic squeleton made of a single C file that will ease testing and error reporting. The code will be arranged so that it remains easy to add basic tests for syscalls or library calls that may rely on a condition to be executed, and whose result is compared to a value or to an error with a specific errno value. Tests will just use a relative line number in switch/case statements as an index, saving the user from having to maintain arrays and complicated functions which can often just be one-liners. MAINTAINERS was updated. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31tools/nolibc: make sys_mmap() automatically use the right __NR_mmap definitionWilly Tarreau1-1/+1
__NR_mmap2 was used for i386 but it's also needed for other archs such as RISCV32 or ARM. Let's decide to use it based on the __NR_mmap2 definition as it's not defined on other archs. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31tools/nolibc: fix build warning in sys_mmap() when my_syscall6 is not definedWilly Tarreau1-1/+1
We return -ENOSYS when there's no syscall6() operation, but we must cast it to void* to avoid a warning. Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31tools/nolibc: make argc 32-bit in riscv startup codeWilly Tarreau1-1/+1
The "ld a0, 0(sp)" instruction doesn't build on RISCV32 because that would load a 64-bit value into a 32-bit register. But argc 32-bit, not 64, so we ought to use "lw" here. Tested on both RISCV32 and RISCV64. Cc: Pranith Kumar <bobby.prani@gmail.com> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31tools/memory-model: Clarify LKMM's limitations in litmus-tests.txtPaul Heidekrüger1-10/+27
As discussed, clarify LKMM not recognizing certain kinds of orderings. In particular, highlight the fact that LKMM might deliberately make weaker guarantees than compilers and architectures. [ paulmck: Fix whitespace issue noted by checkpatch.pl. ] Link: https://lore.kernel.org/all/YpoW1deb%2FQeeszO1@ethstick13.dse.in.tum.de/T/#u Co-developed-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Paul Heidekrüger <paul.heidekrueger@in.tum.de> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Charalampos Mainas <charalampos.mainas@gmail.com> Cc: Pramod Bhatotia <pramod.bhatotia@in.tum.de> Cc: Soham Chakraborty <s.s.chakraborty@tudelft.nl> Cc: Martin Fink <martin.fink@in.tum.de> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31docs/memory-barriers.txt: Fixup long linesAkira Yokosawa1-46/+47
Substitution of "data dependency barrier" with "address-dependency barrier" left quite a lot of lines exceeding 80 columns. Reflow those lines as well as a few short ones not related to the substitution. No changes in documentation text. Signed-off-by: Akira Yokosawa <akiyks@gmail.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Will Deacon <will@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Andrea Parri <parri.andrea@gmail.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Daniel Lustig <dlustig@nvidia.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31docs/memory-barriers.txt: Fix confusing name of 'data dependency barrier'Akira Yokosawa1-52/+64
The term "data dependency barrier", which has been in memory-barriers.txt ever since it was first authored by David Howells, has become confusing due to the fact that in LKMM's explanations.txt and elsewhere, "data dependency" is used mostly for load-to-store data dependency. To prevent further confusions, do the changes listed below: - substitute "data dependency barrier" with "address-dependency barrier"; - add note on the removal of kernel APIs for explicit address- dependency barriers in kernel release v5.9; - note that address-dependency barriers are not necessary for load-to-store situations; - use READ_ONCE_OLD() for pre-4.15 READ_ONCE() (no implicit address- dependency barrier); - fix count of kernel memory barrier APIs; - and a few more context adjustments. Note: Cleanups of long lines are deferred to a followup patch. Reported-by: "Michael S. Tsirkin" <mst@redhat.com> Link: https://lore.kernel.org/r/20211011064233-mutt-send-email-mst@kernel.org/ Signed-off-by: Akira Yokosawa <akiyks@gmail.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Will Deacon <will@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Andrea Parri <parri.andrea@gmail.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Daniel Lustig <dlustig@nvidia.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31pinctrl: aspeed: Force to disable the function's signalBilly Tsai1-10/+1
When the driver want to disable the signal of the function, it doesn't need to query the state of the mux function's signal on a pin. The condition below will miss the disable of the signal: Ball | Default | P0 Signal | P0 Expression | Other -----+---------+-----------+-----------------------------+---------- E21 GPIOG0 SD2CLK SCU4B4[16]=1 & SCU450[1]=1 GPIOG0 -----+---------+-----------+-----------------------------+---------- B22 GPIOG1 SD2CMD SCU4B4[17]=1 & SCU450[1]=1 GPIOG1 -----+---------+-----------+-----------------------------+---------- Assume the register status like below: SCU4B4[16] == 1 & SCU4B4[17] == 1 & SCU450[1]==1 After the driver set the Ball E21 to the GPIOG0: SCU4B4[16] == 0 & SCU4B4[17] == 1 & SCU450[1]==0 When the driver want to set the Ball B22 to the GPIOG1, the condition of the SD2CMD will be false causing SCU4B4[17] not to be cleared. Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com> Acked-by: Andrew Jeffery <andrew@aj.id.au> Link: https://lore.kernel.org/r/20220818101839.28860-1-billy_tsai@aspeedtech.com Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2022-08-31rcu-tasks: Make RCU Tasks Trace check for userspace executionZqiang2-6/+2
Userspace execution is a valid quiescent state for RCU Tasks Trace, but the scheduling-clock interrupt does not currently report such quiescent states. Of course, the scheduling-clock interrupt is not strictly speaking userspace execution. However, the only way that this code is not in a quiescent state is if something invoked rcu_read_lock_trace(), and that would be reflected in the ->trc_reader_nesting field in the task_struct structure. Furthermore, this field is checked by rcu_tasks_trace_qs(), which is invoked by rcu_tasks_qs() which is in turn invoked by rcu_note_voluntary_context_switch() in kernels building at least one of the RCU Tasks flavors. It is therefore safe to invoke rcu_tasks_trace_qs() from the rcu_sched_clock_irq(). But rcu_tasks_qs() also invokes rcu_tasks_classic_qs() for RCU Tasks, which lacks the read-side markers provided by RCU Tasks Trace. This raises the possibility that an RCU Tasks grace period could start after the interrupt from userspace execution, but before the call to rcu_sched_clock_irq(). However, it turns out that this is safe because the RCU Tasks grace period waits for an RCU grace period, which will wait for the entire scheduling-clock interrupt handler, including any RCU Tasks read-side critical section that this handler might contain. This commit therefore updates the rcu_sched_clock_irq() function's check for usermode execution and its call to rcu_tasks_classic_qs() to instead check for both usermode execution and interrupt from idle, and to instead call rcu_note_voluntary_context_switch(). This consolidates code and provides more faster RCU Tasks Trace reporting of quiescent states in kernels that do scheduling-clock interrupts for userspace execution. [ paulmck: Consolidate checks into rcu_sched_clock_irq(). ] Signed-off-by: Zqiang <qiang1.zhang@intel.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcu-tasks: Ensure RCU Tasks Trace loops have quiescent statesPaul E. McKenney1-0/+3
The RCU Tasks Trace grace-period kthread loops across all CPUs, and there can be quite a few CPUs, with some commercially available systems sporting well over a thousand of them. Some of these loops can feature IPIs, which can take some time. This commit therefore places a call to cond_resched_tasks_rcu_qs() in each such loop. Link: https://docs.google.com/document/d/1V0YnG1HTWMt9WHJjroiJL9lf-hMrud4v8Fn3fhyY0cI/edit?usp=sharing Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcu-tasks: Convert RCU_LOCKDEP_WARN() to WARN_ONCE()Zqiang1-1/+1
Kernels built with CONFIG_PROVE_RCU=y and CONFIG_DEBUG_LOCK_ALLOC=y attempt to emit a warning when the synchronize_rcu_tasks_generic() function is called during early boot while the rcu_scheduler_active variable is RCU_SCHEDULER_INACTIVE. However the warnings is not actually be printed because the debug_lockdep_rcu_enabled() returns false, exactly because the rcu_scheduler_active variable is still equal to RCU_SCHEDULER_INACTIVE. This commit therefore replaces RCU_LOCKDEP_WARN() with WARN_ONCE() to force these warnings to actually be printed. Signed-off-by: Zqiang <qiang1.zhang@intel.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31srcu: Make Tiny SRCU use full-sized grace-period countersPaul E. McKenney2-10/+10
This commit makes Tiny SRCU use full-sized grace-period counters to further avoid counter-wrap issues when using polled grace-period APIs. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31srcu: Make Tiny SRCU poll_state_synchronize_srcu() more precisePaul E. McKenney1-2/+2
This commit applies the more-precise grace-period-state check used by rcu_seq_done_exact() to poll_state_synchronize_srcu(). This is important because Tiny SRCU uses a 16-bit counter, which can wrap quite quickly. If counter wrap continues to be a problem, then expanding ->srcu_idx and ->srcu_idx_max to 32 bits might be warranted. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31srcu: Add GP and maximum requested GP to Tiny SRCU rcutorture outputPaul E. McKenney1-2/+4
This commit adds the ->srcu_idx and ->srcu_max_idx fields to the Tiny SRCU rcutorture output for additional diagnostics. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcutorture: Make "srcud" option also test polled grace-period APIPaul E. McKenney1-0/+3
This commit brings the "srcud" (dynamically allocated) SRCU test in line with the "srcu" (statically allocated) test, so that both test the full SRCU polled grace-period API. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcutorture: Limit read-side polling-API testingPaul E. McKenney1-18/+23
RCU's polled grace-period API is reasonably lightweight, but still contains heavyweight memory barriers. This commit therefore limits testing of this API from rcutorture's readers in order to avoid the false negatives that these heavyweight operations could provoke. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcu: Add functions to compare grace-period state valuesPaul E. McKenney3-0/+63
This commit adds same_state_synchronize_rcu() and same_state_synchronize_rcu_full() functions to compare grace-period state values, for example, those obtained from get_state_synchronize_rcu() and get_state_synchronize_rcu_full(). These functions allow small structures to omit these state values by placing them in list headers for lists containing structures with the same token value. Presumably the per-structure list pointers are the same ones used to link the structures into whatever reader-accessible data structure was used. This commit also adds both NUM_ACTIVE_RCU_POLL_OLDSTATE and NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE, which define the maximum number of distinct unsigned long values and rcu_gp_oldstate values, respectively, corresponding to not-yet-completed grace periods. These values can be used to size arrays of the list headers described above. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcutorture: Expand rcu_torture_write_types() first "if" statementPaul E. McKenney1-6/+23
This commit expands the rcu_torture_write_types() function's first "if" condition and body, placing one element per line, in order to make the compiler's error messages more helpful. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcutorture: Use 1-suffixed variable in rcu_torture_write_types() checkPaul E. McKenney1-1/+1
This commit changes the use of gp_poll_exp to gp_poll_exp1 in the first check in rcu_torture_write_types(). No functional effect, but consistency is a good thing. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcu: Make synchronize_rcu() fastpath update only boot-CPU countersPaul E. McKenney1-2/+16
Large systems can have hundreds of rcu_node structures, and updating counters in each of them might slow down booting. This commit therefore updates only the counters in those rcu_node structures corresponding to the boot CPU, up to and including the root rcu_node structure. The counters for the remaining rcu_node structures are updated by the rcu_scheduler_starting() function, which executes just before the first non-boot kthread is spawned. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcutorture: Adjust rcu_poll_need_2gp() for rcu_gp_oldstate field removalPaul E. McKenney1-1/+1
Now that rcu_gp_oldstate can accurately track both normal and expedited grace periods regardless of system state, rcutorture's rcu_poll_need_2gp() function need only call for a second grace period for the old single-unsigned-long grace-period polling APIs This commit therefore adjusts rcu_poll_need_2gp() accordingly. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcu: Remove ->rgos_polled field from rcu_gp_oldstate structurePaul E. McKenney2-6/+1
Because both normal and expedited grace periods increment their respective counters on their pre-scheduler early boot fastpaths, the rcu_gp_oldstate structure no longer needs its ->rgos_polled field. This commit therefore removes this field, shrinking this structure so that it is the same size as an rcu_head structure. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcu: Make synchronize_rcu_expedited() fast path update .expedited_sequencePaul E. McKenney1-0/+6
This commit causes the early boot single-CPU synchronize_rcu_expedited() fastpath to update the rcu_state structure's ->expedited_sequence counter. This will allow the full-state polled grace-period APIs to detect all expedited grace periods without the need to track the special combined polling-only counter, which is another step towards removing the ->rgos_polled field from the rcu_gp_oldstate, thereby reducing its size by one third. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcu: Remove expedited grace-period fast-path forward-progress helperPaul E. McKenney1-2/+0
Now that the expedited grace-period fast path can only happen during the pre-scheduler portion of early boot, this fast path can no longer block run-time RCU Trace grace periods. This commit therefore removes the conditional cond_resched() invocation. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcu: Make synchronize_rcu() fast path update ->gp_seq countersPaul E. McKenney1-13/+26
This commit causes the early boot single-CPU synchronize_rcu() fastpath to update the rcu_state and rcu_node structures' ->gp_seq and ->gp_seq_needed counters. This will allow the full-state polled grace-period APIs to detect all normal grace periods without the need to track the special combined polling-only counter, which is a step towards removing the ->rgos_polled field from the rcu_gp_oldstate, thereby reducing its size by one third. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-08-31rcu-tasks: Remove grace-period fast-path rcu-tasks helperPaul E. McKenney1-2/+0
Now that the grace-period fast path can only happen during the pre-scheduler portion of early boot, this fast path can no longer block run-time RCU Tasks and RCU Tasks Trace grace periods. This commit therefore removes the conditional cond_resched_tasks_rcu_qs() invocation. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>