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2021-07-16locking/atomic: add arch_atomic_long*()Mark Rutland
Now that all architectures provide arch_{atomic,atomic64}_*(), we can build arch_atomic_long_*() atop these, which can be safely used in noinstr code. The regular atomic_long_*() wrappers are built atop these, as we do for {atomic,atomic64}_*() atop arch_{atomic,atomic64}_*(). We don't provide arch_* versions of the cond_read*() variants, as we don't have arch_* versions of the underlying atomic/atomic64 functions (nor the smp_cond_load*() helpers these are typically based on). Note that the headers in this patch under include/linux/atomic/ are generated by the scripts in scripts/atomic/. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210713105253.7615-5-mark.rutland@arm.com
2021-07-16locking/atomic: centralize generated headersMark Rutland
The generated atomic headers are only intended to be included directly by <linux/atomic.h>, but are spread across include/linux/ and include/asm-generic/, where people mnay be encouraged to include them. This patch centralizes them under include/linux/atomic/. Other than the header guards and hashes, there is no change to any of the generated headers as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210713105253.7615-4-mark.rutland@arm.com
2021-07-16locking/atomic: remove ARCH_ATOMIC remanantsMark Rutland
Now that gen-atomic-fallback.sh is only used to generate the arch_* fallbacks, we don't need to also generate the non-arch_* forms, and can removethe infrastructure this needed. There is no change to any of the generated headers as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210713105253.7615-3-mark.rutland@arm.com
2021-07-16locking/atomic: simplify ifdef generationMark Rutland
In gen-atomic-fallback.sh's gen_proto_order_variants(), we generate some ifdeferry with: | local basename="${arch}${atomic}_${pfx}${name}${sfx}" | ... | printf "#ifdef ${basename}\n" | ... | printf "#endif /* ${arch}${atomic}_${pfx}${name}${sfx} */\n\n" For clarity, use ${basename} for both sides, rather than open-coding the string generation. There is no change to any of the generated headers as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210713105253.7615-2-mark.rutland@arm.com
2021-05-26locking/atomics: atomic-instrumented: simplify ifdefferyMark Rutland
Now that all architectures implement ARCH_ATOMIC, the fallbacks are generated before the instrumented wrappers are generated. Due to this, in atomic-instrumented.h we can assume that the whole set of atomic functions has been generated. Likewise, atomic-instrumented.h doesn't need to provide a preprocessor definition for every atomic it wraps. This patch removes the redundant ifdeffery. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210525140232.53872-34-mark.rutland@arm.com
2021-05-26locking/atomic: delete !ARCH_ATOMIC remnantsMark Rutland
Now that all architectures implement ARCH_ATOMIC, we can make it mandatory, removing the Kconfig symbol and logic for !ARCH_ATOMIC. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210525140232.53872-33-mark.rutland@arm.com
2020-11-07locking/atomics: Regenerate the atomics-check SHA1'sIngo Molnar
The include/asm-generic/atomic-instrumented.h checksum got out of sync, so regenerate it. (No change to actual code.) Also make scripts/atomic/gen-atomics.sh executable, to make it easier to use. The auto-generated atomic header signatures are now fine: thule:~/tip> scripts/atomic/check-atomics.sh thule:~/tip> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: linux-kernel@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-11-07Merge branch 'linus' into perf/kprobesIngo Molnar
Conflicts: include/asm-generic/atomic-instrumented.h kernel/kprobes.c Use the upstream atomic-instrumented.h checksum, and pick the kprobes version of kernel/kprobes.c, which effectively reverts this upstream workaround: 645f224e7ba2: ("kprobes: Tell lockdep about kprobe nesting") Since the new code *should* be fine without nesting. Knock on wood ... Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-10-12asm-generic/atomic: Add try_cmpxchg() fallbacksPeter Zijlstra
Only x86 provides try_cmpxchg() outside of the atomic_t interfaces, provide generic fallbacks to create this interface from the widely available cmpxchg() function. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/159870621515.1229682.15506193091065001742.stgit@devnote2
2020-10-09Merge branch 'kcsan' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into locking/core Pull KCSAN updates for v5.10 from Paul E. McKenney: - Improve kernel messages. - Be more permissive with bitops races under KCSAN_ASSUME_PLAIN_WRITES_ATOMIC=y. - Optimize debugfs stat counters. - Introduce the instrument_*read_write() annotations, to provide a finer description of certain ops - using KCSAN's compound instrumentation. Use them for atomic RNW and bitops, where appropriate. Doing this might find new races. (Depends on the compiler having tsan-compound-read-before-write=1 support.) - Support atomic built-ins, which will help certain architectures, such as s390. - Misc enhancements and smaller fixes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-10-07locking/atomics: Check atomic-arch-fallback.h tooPaul Bolle
The sha1sum of include/linux/atomic-arch-fallback.h isn't checked by check-atomics.sh. It's not clear why it's skipped so let's check it too. Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Link: https://lkml.kernel.org/r/20201001202028.1048418-1-pebolle@tiscali.nl
2020-08-24locking/atomics: Use read-write instrumentation for atomic RMWsMarco Elver
Use instrument_atomic_read_write() for atomic RMW ops. Cc: Will Deacon <will@kernel.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: <linux-arch@vger.kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-06-25locking/atomics: Provide the arch_atomic_ interface to generic codePeter Zijlstra
Architectures with instrumented (KASAN/KCSAN) atomic operations natively provide arch_atomic_ variants that are not instrumented. It turns out that some generic code also requires arch_atomic_ in order to avoid instrumentation, so provide the arch_atomic_ interface as a direct map into the regular atomic_ interface for non-instrumented architectures. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-06-11Rebase locking/kcsan to locking/urgentThomas Gleixner
Merge the state of the locking kcsan branch before the read/write_once() and the atomics modifications got merged. Squash the fallout of the rebase on top of the read/write once and atomic fallback work into the merge. The history of the original branch is preserved in tag locking-kcsan-2020-06-02. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-06-11locking/atomics: Flip fallbacks and instrumentationPeter Zijlstra
Currently instrumentation of atomic primitives is done at the architecture level, while composites or fallbacks are provided at the generic level. The result is that there are no uninstrumented variants of the fallbacks. Since there is now need of such variants to isolate text poke from any form of instrumentation invert this ordering. Doing this means moving the instrumentation into the generic code as well as having (for now) two variants of the fallbacks. Notes: - the various *cond_read* primitives are not proper fallbacks and got moved into linux/atomic.c. No arch_ variants are generated because the base primitives smp_cond_load*() are instrumented. - once all architectures are moved over to arch_atomic_ one of the fallback variants can be removed and some 2300 lines reclaimed. - atomic_{read,set}*() are no longer double-instrumented Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lkml.kernel.org/r/20200505134058.769149955@linutronix.de
2020-06-11asm-generic/atomic: Use __always_inline for fallback wrappersMarco Elver
Use __always_inline for atomic fallback wrappers. When building for size (CC_OPTIMIZE_FOR_SIZE), some compilers appear to be less inclined to inline even relatively small static inline functions that are assumed to be inlinable such as atomic ops. This can cause problems, for example in UACCESS regions. While the fallback wrappers aren't pure wrappers, they are trivial nonetheless, and the function they wrap should determine the final inlining policy. For x86 tinyconfig we observe: - vmlinux baseline: 1315988 - vmlinux with patch: 1315928 (-60 bytes) [ tglx: Cherry-picked from KCSAN ] Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marco Elver <elver@google.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-03-21asm-generic, atomic-instrumented: Use generic instrumented.hMarco Elver
This switches atomic-instrumented.h to use the generic instrumentation wrappers provided by instrumented.h. No functional change intended. Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Marco Elver <elver@google.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-01-07asm-generic/atomic: Use __always_inline for fallback wrappersMarco Elver
Use __always_inline for atomic fallback wrappers. When building for size (CC_OPTIMIZE_FOR_SIZE), some compilers appear to be less inclined to inline even relatively small static inline functions that are assumed to be inlinable such as atomic ops. This can cause problems, for example in UACCESS regions. While the fallback wrappers aren't pure wrappers, they are trivial nonetheless, and the function they wrap should determine the final inlining policy. For x86 tinyconfig we observe: - vmlinux baseline: 1315988 - vmlinux with patch: 1315928 (-60 bytes) Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marco Elver <elver@google.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-01-07asm-generic/atomic: Use __always_inline for pure wrappersMarco Elver
Prefer __always_inline for atomic wrappers. When building for size (CC_OPTIMIZE_FOR_SIZE), some compilers appear to be less inclined to inline even relatively small static inline functions that are assumed to be inlinable such as atomic ops. This can cause problems, for example in UACCESS regions. By using __always_inline, we let the real implementation and not the wrapper determine the final inlining preference. For x86 tinyconfig we observe: - vmlinux baseline: 1316204 - vmlinux with patch: 1315988 (-216 bytes) This came up when addressing UACCESS warnings with CC_OPTIMIZE_FOR_SIZE in the KCSAN runtime: http://lkml.kernel.org/r/58708908-84a0-0a81-a836-ad97e33dbb62@infradead.org Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Marco Elver <elver@google.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-11-16locking/atomics, kcsan: Add KCSAN instrumentationMarco Elver
This adds KCSAN instrumentation to atomic-instrumented.h. Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-06-25locking/atomics: Use sed(1) instead of non-standard head(1) optionMichael Forney
POSIX says the -n option must be a positive decimal integer. Not all implementations of head(1) support negative numbers meaning offset from the end of the file. Instead, the sed expression '$d' has the same effect of removing the last line of the file. Signed-off-by: Michael Forney <mforney@mforney.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190618053306.730-1-mforney@mforney.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-19locking/atomics: Don't assume that scripts are executableAndrew Morton
patch(1) doesn't set the x bit on files. So if someone downloads and applies patch-4.21.xz, their kernel won't build. Fix that by executing /bin/sh. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-13locking/atomics: Check atomic headers with sha1sumMark Rutland
We currently check the atomic headers at build-time to ensure they haven't been modified directly, and these checks require regenerating the headers in full. As this takes a few seconds, even when parallelized, this is too slow to run for every kernel build. Instead, we can generate a hash of each header as we generate them, which we can cheaply check at build time (~0.16s for all headers). This patch does so, updating headers with their hashes using the new gen-atomics.sh script. As some users apparently build the kernel wihout coreutils, lacking sha1sum, the checks are skipped in this case. Presumably, most developers have a working coreutils installation. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: anders.roxell@linaro.org Cc: linux-kernel@vger.kernel.rg Cc: naresh.kamboju@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-11locking/atomics: Change 'fold' to 'grep'Anders Roxell
Some distibutions and build systems doesn't include 'fold' from coreutils default. .../scripts/atomic/atomic-tbl.sh: line 183: fold: command not found Rework to use 'grep' instead of 'fold' to use a dependency that is already used a lot in the kernel. [Mark: rework commit message] Suggested-by: Will Deacon <will.deacon@arm.com> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: linux-kernel@vger.kernel.rg Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-11-01locking/atomics: Fix scripts/atomic/ script permissionsIngo Molnar
Mark all these scripts executable. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: linuxdrivers@attotech.com Cc: dvyukov@google.com Cc: boqun.feng@gmail.com Cc: arnd@arndb.de Cc: aryabinin@virtuozzo.com Cc: glider@google.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-11-01locking/atomics: Check generated headers are up-to-dateMark Rutland
Now that all the generated atomic headers are in place, it would be good to ensure that: a) the headers are up-to-date when scripting changes. b) developers don't directly modify the generated headers. To ensure both of these properties, let's add a Kbuild step to check that the generated headers are up-to-date. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com Cc: Will Deacon <will.deacon@arm.com> Cc: linuxdrivers@attotech.com Cc: dvyukov@google.com Cc: Boqun Feng <boqun.feng@gmail.com> Cc: arnd@arndb.de Cc: aryabinin@virtuozzo.com Cc: glider@google.com Link: http://lkml.kernel.org/r/20180904104830.2975-6-mark.rutland@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-11-01locking/atomics: Add common header generation filesMark Rutland
To minimize repetition, to allow for future rework, and to ensure regularity of the various atomic APIs, we'd like to automatically generate (the bulk of) a number of headers related to atomics. This patch adds the infrastructure to do so, leaving actual conversion of headers to subsequent patches. This infrastructure consists of: * atomics.tbl - a table describing the functions in the atomics API, with names, prototypes, and metadata describing the variants that exist (e.g fetch/return, acquire/release/relaxed). Note that the return type is dependent on the particular variant. * atomic-tbl.sh - a library of routines useful for dealing with atomics.tbl (e.g. querying which variants exist, or generating argument/parameter lists for a given function variant). * gen-atomic-fallback.sh - a script which generates a header of fallbacks, covering cases where architecture omit certain functions (e.g. omitting relaxed variants). * gen-atomic-long.sh - a script which generates wrappers providing the atomic_long API atomic of the relevant atomic or atomic64 API, ensuring the APIs are consistent. * gen-atomic-instrumented.sh - a script which generates atomic* wrappers atop of arch_atomic* functions, with automatically generated KASAN instrumentation. * fallbacks/* - a set of fallback implementations for atomics, which should be used when no implementation of a given atomic is provided. These are used by gen-atomic-fallback.sh to generate fallbacks, and these are also used by other scripts to determine the set of optional atomics (as required to generate preprocessor guards correctly). Fallbacks may use the following variables: ${atomic} atomic prefix: atomic/atomic64/atomic_long, which can be used to derive the atomic type, and to prefix functions ${int} integer type: int/s64/long ${pfx} variant prefix, e.g. fetch_ ${name} base function name, e.g. add ${sfx} variant suffix, e.g. _return ${order} order suffix, e.g. _relaxed ${atomicname} full name, e.g. atomic64_fetch_add_relaxed ${ret} return type of the function, e.g. void ${retstmt} a return statement (with a trailing space), unless the variant returns void ${params} parameter list for the function declaration, e.g. "int i, atomic_t *v" ${args} argument list for invoking the function, e.g. "i, v" ... for clarity, ${ret}, ${retstmt}, ${params}, and ${args} are open-coded for fallbacks where these do not vary, or are critical to understanding the logic of the fallback. The MAINTAINERS entry for the atomic infrastructure is updated to cover the new scripts. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com Cc: Will Deacon <will.deacon@arm.com> Cc: linuxdrivers@attotech.com Cc: dvyukov@google.com Cc: Boqun Feng <boqun.feng@gmail.com> Cc: arnd@arndb.de Cc: aryabinin@virtuozzo.com Cc: glider@google.com Link: http://lkml.kernel.org/r/20180904104830.2975-2-mark.rutland@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>