[ Upstream commit dc1b4df09a ]
Arnd reports that on 32-bit architectures, the fallbacks for
atomic64_read_acquire() and atomic64_set_release() are broken as they
use smp_load_acquire() and smp_store_release() respectively, which do
not work on types larger than the native word size.
Since those contain compiletime_assert_atomic_type(), any attempt to use
those fallbacks will result in a build-time error. e.g. with the
following added to arch/arm/kernel/setup.c:
| void test_atomic64(atomic64_t *v)
| {
| atomic64_set_release(v, 5);
| atomic64_read_acquire(v);
| }
The compiler will complain as follows:
| In file included from <command-line>:
| In function 'arch_atomic64_set_release',
| inlined from 'test_atomic64' at ./include/linux/atomic/atomic-instrumented.h:669:2:
| ././include/linux/compiler_types.h:346:38: error: call to '__compiletime_assert_9' declared with attribute error: Need native word sized stores/loads for atomicity.
| 346 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| | ^
| ././include/linux/compiler_types.h:327:4: note: in definition of macro '__compiletime_assert'
| 327 | prefix ## suffix(); \
| | ^~~~~~
| ././include/linux/compiler_types.h:346:2: note: in expansion of macro '_compiletime_assert'
| 346 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| | ^~~~~~~~~~~~~~~~~~~
| ././include/linux/compiler_types.h:349:2: note: in expansion of macro 'compiletime_assert'
| 349 | compiletime_assert(__native_word(t), \
| | ^~~~~~~~~~~~~~~~~~
| ./include/asm-generic/barrier.h:133:2: note: in expansion of macro 'compiletime_assert_atomic_type'
| 133 | compiletime_assert_atomic_type(*p); \
| | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| ./include/asm-generic/barrier.h:164:55: note: in expansion of macro '__smp_store_release'
| 164 | #define smp_store_release(p, v) do { kcsan_release(); __smp_store_release(p, v); } while (0)
| | ^~~~~~~~~~~~~~~~~~~
| ./include/linux/atomic/atomic-arch-fallback.h:1270:2: note: in expansion of macro 'smp_store_release'
| 1270 | smp_store_release(&(v)->counter, i);
| | ^~~~~~~~~~~~~~~~~
| make[2]: *** [scripts/Makefile.build:288: arch/arm/kernel/setup.o] Error 1
| make[1]: *** [scripts/Makefile.build:550: arch/arm/kernel] Error 2
| make: *** [Makefile:1831: arch/arm] Error 2
Fix this by only using smp_load_acquire() and smp_store_release() for
native atomic types, and otherwise falling back to the regular barriers
necessary for acquire/release semantics, as we do in the more generic
acquire and release fallbacks.
Since the fallback templates are used to generate the atomic64_*() and
atomic_*() operations, the __native_word() check is added to both. For
the atomic_*() operations, which are always 32-bit, the __native_word()
check is redundant but not harmful, as it is always true.
For the example above this works as expected on 32-bit, e.g. for arm
multi_v7_defconfig:
| <test_atomic64>:
| push {r4, r5}
| dmb ish
| pldw [r0]
| mov r2, #5
| mov r3, #0
| ldrexd r4, [r0]
| strexd r4, r2, [r0]
| teq r4, #0
| bne 484 <test_atomic64+0x14>
| ldrexd r2, [r0]
| dmb ish
| pop {r4, r5}
| bx lr
... and also on 64-bit, e.g. for arm64 defconfig:
| <test_atomic64>:
| bti c
| paciasp
| mov x1, #0x5
| stlr x1, [x0]
| ldar x0, [x0]
| autiasp
| ret
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20220207101943.439825-1-mark.rutland@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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
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
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
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
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
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
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>
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>
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
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>
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
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>
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>
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>
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
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Mark Rutland
Ingo Molnar
Peter Zijlstra
Paul Bolle
Marco Elver
Thomas Gleixner
Michael Forney
Andrew Morton
Anders Roxell