diff mbox series

[v2,2/5] powerpc: kcsan: Exclude udelay to prevent recursive instrumentation

Message ID 20230201043438.1301212-3-rmclure@linux.ibm.com (mailing list archive)
State Superseded
Headers show
Series powerpc: Add KCSAN support | expand

Commit Message

Rohan McLure Feb. 1, 2023, 4:34 a.m. UTC 
In order for KCSAN to increase its likelihood of observing a data race,
it sets a watchpoint on memory accesses and stalls, allowing for
detection of conflicting accesses by other kernel threads or interrupts.

Stalls are implemented by injecting a call to udelay in instrumented code.
To prevent recursive instrumentation, exclude udelay from being instrumented.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
---
 arch/powerpc/kernel/time.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index d68de3618741..b894029f53db 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -356,7 +356,7 @@  void vtime_flush(struct task_struct *tsk)
 }
 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
-void __delay(unsigned long loops)
+void __no_kcsan __delay(unsigned long loops)
 {
 	unsigned long start;
 
@@ -377,7 +377,7 @@  void __delay(unsigned long loops)
 }
 EXPORT_SYMBOL(__delay);
 
-void udelay(unsigned long usecs)
+void __no_kcsan udelay(unsigned long usecs)
 {
 	__delay(tb_ticks_per_usec * usecs);
 }