From: Marco Elver <elver@google.com>
To: elver@google.com, "Paul E. McKenney" <paulmck@kernel.org>
Cc: 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>,
Peter Zijlstra <peterz@infradead.org>,
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: [PATCH v2 01/23] kcsan: Refactor reading of instrumented memory
Date: Thu, 18 Nov 2021 09:10:05 +0100 [thread overview]
Message-ID: <20211118081027.3175699-2-elver@google.com> (raw)
In-Reply-To: <20211118081027.3175699-1-elver@google.com>
Factor out the switch statement reading instrumented memory into a
helper read_instrumented_memory().
No functional change.
Signed-off-by: Marco Elver <elver@google.com>
---
kernel/kcsan/core.c | 51 +++++++++++++++------------------------------
1 file changed, 17 insertions(+), 34 deletions(-)
diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
index 4b84c8e7884b..6bfd3040f46b 100644
--- a/kernel/kcsan/core.c
+++ b/kernel/kcsan/core.c
@@ -325,6 +325,21 @@ static void delay_access(int type)
udelay(delay);
}
+/*
+ * Reads the instrumented memory for value change detection; value change
+ * detection is currently done for accesses up to a size of 8 bytes.
+ */
+static __always_inline u64 read_instrumented_memory(const volatile void *ptr, size_t size)
+{
+ switch (size) {
+ case 1: return READ_ONCE(*(const u8 *)ptr);
+ case 2: return READ_ONCE(*(const u16 *)ptr);
+ case 4: return READ_ONCE(*(const u32 *)ptr);
+ case 8: return READ_ONCE(*(const u64 *)ptr);
+ default: return 0; /* Ignore; we do not diff the values. */
+ }
+}
+
void kcsan_save_irqtrace(struct task_struct *task)
{
#ifdef CONFIG_TRACE_IRQFLAGS
@@ -482,23 +497,7 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type, unsigned
* Read the current value, to later check and infer a race if the data
* was modified via a non-instrumented access, e.g. from a device.
*/
- old = 0;
- switch (size) {
- case 1:
- old = READ_ONCE(*(const u8 *)ptr);
- break;
- case 2:
- old = READ_ONCE(*(const u16 *)ptr);
- break;
- case 4:
- old = READ_ONCE(*(const u32 *)ptr);
- break;
- case 8:
- old = READ_ONCE(*(const u64 *)ptr);
- break;
- default:
- break; /* ignore; we do not diff the values */
- }
+ old = read_instrumented_memory(ptr, size);
/*
* Delay this thread, to increase probability of observing a racy
@@ -511,23 +510,7 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type, unsigned
* racy access.
*/
access_mask = ctx->access_mask;
- new = 0;
- switch (size) {
- case 1:
- new = READ_ONCE(*(const u8 *)ptr);
- break;
- case 2:
- new = READ_ONCE(*(const u16 *)ptr);
- break;
- case 4:
- new = READ_ONCE(*(const u32 *)ptr);
- break;
- case 8:
- new = READ_ONCE(*(const u64 *)ptr);
- break;
- default:
- break; /* ignore; we do not diff the values */
- }
+ new = read_instrumented_memory(ptr, size);
diff = old ^ new;
if (access_mask)
--
2.34.0.rc2.393.gf8c9666880-goog
next prev parent reply other threads:[~2021-11-18 8:11 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-18 8:10 [PATCH v2 00/23] kcsan: Support detecting a subset of missing memory barriers Marco Elver
2021-11-18 8:10 ` Marco Elver [this message]
2021-11-18 11:08 ` [PATCH v2 01/23] kcsan: Refactor reading of instrumented memory Mark Rutland
2021-11-18 8:10 ` [PATCH v2 02/23] kcsan: Remove redundant zero-initialization of globals Marco Elver
2021-11-18 11:09 ` Mark Rutland
2021-11-18 8:10 ` [PATCH v2 03/23] kcsan: Avoid checking scoped accesses from nested contexts Marco Elver
2021-11-29 8:47 ` Boqun Feng
2021-11-29 10:57 ` Marco Elver
2021-11-29 14:26 ` Boqun Feng
2021-11-29 14:42 ` Marco Elver
2021-11-18 8:10 ` [PATCH v2 04/23] kcsan: Add core support for a subset of weak memory modeling Marco Elver
2021-11-18 8:10 ` [PATCH v2 05/23] kcsan: Add core memory barrier instrumentation functions Marco Elver
2021-11-18 8:10 ` [PATCH v2 06/23] kcsan, kbuild: Add option for barrier instrumentation only Marco Elver
2021-11-18 8:10 ` [PATCH v2 07/23] kcsan: Call scoped accesses reordered in reports Marco Elver
2021-11-18 8:10 ` [PATCH v2 08/23] kcsan: Show location access was reordered to Marco Elver
2021-11-18 8:10 ` [PATCH v2 09/23] kcsan: Document modeling of weak memory Marco Elver
2021-11-18 8:10 ` [PATCH v2 10/23] kcsan: test: Match reordered or normal accesses Marco Elver
2021-11-18 8:10 ` [PATCH v2 11/23] kcsan: test: Add test cases for memory barrier instrumentation Marco Elver
2021-11-18 8:10 ` [PATCH v2 12/23] kcsan: Ignore GCC 11+ warnings about TSan runtime support Marco Elver
2021-11-18 8:10 ` [PATCH v2 13/23] kcsan: selftest: Add test case to check memory barrier instrumentation Marco Elver
2021-11-18 8:10 ` [PATCH v2 14/23] locking/barriers, kcsan: Add instrumentation for barriers Marco Elver
2021-11-18 8:10 ` [PATCH v2 15/23] locking/barriers, kcsan: Support generic instrumentation Marco Elver
2021-11-18 8:10 ` [PATCH v2 16/23] locking/atomics, kcsan: Add instrumentation for barriers Marco Elver
2021-11-18 8:10 ` [PATCH v2 17/23] asm-generic/bitops, " Marco Elver
2021-11-18 8:10 ` [PATCH v2 18/23] x86/barriers, kcsan: Use generic instrumentation for non-smp barriers Marco Elver
2021-11-18 8:10 ` [PATCH v2 19/23] x86/qspinlock, kcsan: Instrument barrier of pv_queued_spin_unlock() Marco Elver
2021-11-18 8:10 ` [PATCH v2 20/23] mm, kcsan: Enable barrier instrumentation Marco Elver
2021-11-18 8:10 ` [PATCH v2 21/23] sched, kcsan: Enable memory " Marco Elver
2021-11-18 8:10 ` [PATCH v2 22/23] objtool, kcsan: Add memory barrier instrumentation to whitelist Marco Elver
2021-11-18 8:10 ` [PATCH v2 23/23] objtool, kcsan: Remove memory barrier instrumentation from noinstr Marco Elver
2021-11-19 20:31 ` Josh Poimboeuf
2021-11-19 21:31 ` Marco Elver
2021-11-23 11:29 ` Marco Elver
2021-11-24 17:53 ` Josh Poimboeuf
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