[PATCH tip/core/rcu 09/10] kcsan: Remove existing special atomic rules

From: paulmck
Date: Mon Jun 22 2020 - 20:43:45 EST


From: Marco Elver <elver@xxxxxxxxxx>

Remove existing special atomic rules from kcsan_is_atomic_special()
because they are no longer needed. Since we rely on the compiler
emitting instrumentation distinguishing volatile accesses, the rules
have become redundant.

Let's keep kcsan_is_atomic_special() around, so that we have an obvious
place to add special rules should the need arise in future.

Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
kernel/kcsan/atomic.h | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/kcsan/atomic.h b/kernel/kcsan/atomic.h
index be9e625..75fe701 100644
--- a/kernel/kcsan/atomic.h
+++ b/kernel/kcsan/atomic.h
@@ -3,8 +3,7 @@
#ifndef _KERNEL_KCSAN_ATOMIC_H
#define _KERNEL_KCSAN_ATOMIC_H

-#include <linux/jiffies.h>
-#include <linux/sched.h>
+#include <linux/types.h>

/*
* Special rules for certain memory where concurrent conflicting accesses are
@@ -13,8 +12,7 @@
*/
static bool kcsan_is_atomic_special(const volatile void *ptr)
{
- /* volatile globals that have been observed in data races. */
- return ptr == &jiffies || ptr == &current->state;
+ return false;
}

#endif /* _KERNEL_KCSAN_ATOMIC_H */
--
2.9.5