From: Peter Zijlstra <peterz@infradead.org>
To: Marco Elver <elver@google.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
Alexander Potapenko <glider@google.com>,
Boqun Feng <boqun.feng@gmail.com>, Borislav Petkov <bp@alien8.de>,
Dmitry Vyukov <dvyukov@google.com>,
Ingo Molnar <mingo@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Waiman Long <longman@redhat.com>, Will Deacon <will@kernel.org>,
kasan-dev@googlegroups.com, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org
Subject: Re: [PATCH -rcu/kcsan 05/23] kcsan: Add core memory barrier instrumentation functions
Date: Tue, 5 Oct 2021 13:45:34 +0200 [thread overview]
Message-ID: <YVw63tqctCMm+d7M@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YVw53mP3VkWyCzxn@hirez.programming.kicks-ass.net>
On Tue, Oct 05, 2021 at 01:41:18PM +0200, Peter Zijlstra wrote:
> On Tue, Oct 05, 2021 at 12:58:47PM +0200, Marco Elver wrote:
> > +static __always_inline void kcsan_atomic_release(int memorder)
> > +{
> > + if (memorder == __ATOMIC_RELEASE ||
> > + memorder == __ATOMIC_SEQ_CST ||
> > + memorder == __ATOMIC_ACQ_REL)
> > + __kcsan_release();
> > +}
> > +
> > #define DEFINE_TSAN_ATOMIC_LOAD_STORE(bits) \
> > u##bits __tsan_atomic##bits##_load(const u##bits *ptr, int memorder); \
> > u##bits __tsan_atomic##bits##_load(const u##bits *ptr, int memorder) \
> > { \
> > + kcsan_atomic_release(memorder); \
> > if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \
> > check_access(ptr, bits / BITS_PER_BYTE, KCSAN_ACCESS_ATOMIC, _RET_IP_); \
> > } \
> > @@ -1156,6 +1187,7 @@ EXPORT_SYMBOL(__tsan_init);
> > void __tsan_atomic##bits##_store(u##bits *ptr, u##bits v, int memorder); \
> > void __tsan_atomic##bits##_store(u##bits *ptr, u##bits v, int memorder) \
> > { \
> > + kcsan_atomic_release(memorder); \
> > if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \
> > check_access(ptr, bits / BITS_PER_BYTE, \
> > KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC, _RET_IP_); \
> > @@ -1168,6 +1200,7 @@ EXPORT_SYMBOL(__tsan_init);
> > u##bits __tsan_atomic##bits##_##op(u##bits *ptr, u##bits v, int memorder); \
> > u##bits __tsan_atomic##bits##_##op(u##bits *ptr, u##bits v, int memorder) \
> > { \
> > + kcsan_atomic_release(memorder); \
> > if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \
> > check_access(ptr, bits / BITS_PER_BYTE, \
> > KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | \
> > @@ -1200,6 +1233,7 @@ EXPORT_SYMBOL(__tsan_init);
> > int __tsan_atomic##bits##_compare_exchange_##strength(u##bits *ptr, u##bits *exp, \
> > u##bits val, int mo, int fail_mo) \
> > { \
> > + kcsan_atomic_release(mo); \
> > if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \
> > check_access(ptr, bits / BITS_PER_BYTE, \
> > KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | \
> > @@ -1215,6 +1249,7 @@ EXPORT_SYMBOL(__tsan_init);
> > u##bits __tsan_atomic##bits##_compare_exchange_val(u##bits *ptr, u##bits exp, u##bits val, \
> > int mo, int fail_mo) \
> > { \
> > + kcsan_atomic_release(mo); \
> > if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \
> > check_access(ptr, bits / BITS_PER_BYTE, \
> > KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | \
> > @@ -1246,6 +1281,7 @@ DEFINE_TSAN_ATOMIC_OPS(64);
> > void __tsan_atomic_thread_fence(int memorder);
> > void __tsan_atomic_thread_fence(int memorder)
> > {
> > + kcsan_atomic_release(memorder);
> > __atomic_thread_fence(memorder);
> > }
> > EXPORT_SYMBOL(__tsan_atomic_thread_fence);
>
> I find that very hard to read.. kcsan_atomic_release() it not in fact a
> release. It might be a release if @memorder implies one.
Also, what's the atomic part signify? Is that because you're modeling
the difference in acquire/release semantics between
smp_load_{acquire,release}() and atomic*_{acquire,release}() ?
next prev parent reply other threads:[~2021-10-05 11:45 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 10:58 [PATCH -rcu/kcsan 00/23] kcsan: Support detecting a subset of missing memory barriers Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 01/23] kcsan: Refactor reading of instrumented memory Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 02/23] kcsan: Remove redundant zero-initialization of globals Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 03/23] kcsan: Avoid checking scoped accesses from nested contexts Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 04/23] kcsan: Add core support for a subset of weak memory modeling Marco Elver
2021-10-05 12:52 ` Peter Zijlstra
2021-10-05 13:13 ` Marco Elver
2021-10-05 14:20 ` Peter Zijlstra
2021-10-05 10:58 ` [PATCH -rcu/kcsan 05/23] kcsan: Add core memory barrier instrumentation functions Marco Elver
2021-10-05 11:41 ` Peter Zijlstra
2021-10-05 11:45 ` Peter Zijlstra [this message]
2021-10-05 11:50 ` Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 06/23] kcsan, kbuild: Add option for barrier instrumentation only Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 07/23] kcsan: Call scoped accesses reordered in reports Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 08/23] kcsan: Show location access was reordered to Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 09/23] kcsan: Document modeling of weak memory Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 10/23] kcsan: test: Match reordered or normal accesses Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 11/23] kcsan: test: Add test cases for memory barrier instrumentation Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 12/23] kcsan: Ignore GCC 11+ warnings about TSan runtime support Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 13/23] kcsan: selftest: Add test case to check memory barrier instrumentation Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 14/23] locking/barriers, kcsan: Add instrumentation for barriers Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 15/23] locking/barriers, kcsan: Support generic instrumentation Marco Elver
2021-10-05 10:58 ` [PATCH -rcu/kcsan 16/23] locking/atomics, kcsan: Add instrumentation for barriers Marco Elver
2021-10-05 12:02 ` Peter Zijlstra
2021-10-05 12:16 ` Marco Elver
2021-10-05 10:59 ` [PATCH -rcu/kcsan 18/23] x86/barriers, kcsan: Use generic instrumentation for non-smp barriers Marco Elver
2021-10-05 10:59 ` [PATCH -rcu/kcsan 19/23] x86/qspinlock, kcsan: Instrument barrier of pv_queued_spin_unlock() Marco Elver
2021-10-05 10:59 ` [PATCH -rcu/kcsan 20/23] mm, kcsan: Enable barrier instrumentation Marco Elver
2021-10-05 10:59 ` [PATCH -rcu/kcsan 21/23] sched, kcsan: Enable memory " Marco Elver
2021-10-05 10:59 ` [PATCH -rcu/kcsan 22/23] objtool, kcsan: Add memory barrier instrumentation to whitelist Marco Elver
2021-10-05 10:59 ` [PATCH -rcu/kcsan 23/23] objtool, kcsan: Remove memory barrier instrumentation from noinstr Marco Elver
2021-10-05 14:37 ` Peter Zijlstra
2021-10-05 15:13 ` Marco Elver
2021-11-11 10:11 ` Marco Elver
2021-11-11 11:35 ` Peter Zijlstra
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