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Subject[tip: x86/entry] nmi, tracing: Make hardware latency tracing noinstr safe
The following commit has been merged into the x86/entry branch of tip:

Commit-ID: 1e826b1d2265d1e8ba5f51827a8dba2aa0295f6c
Gitweb: https://git.kernel.org/tip/1e826b1d2265d1e8ba5f51827a8dba2aa0295f6c
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 21 May 2020 22:05:14 +02:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 26 May 2020 19:06:27 +02:00

nmi, tracing: Make hardware latency tracing noinstr safe

The hardware latency tracer calls into instrumentable functions. Move the
calls into the RCU watching sections and annotate them.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20200521202116.904176298@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/hardirq.h | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index e07cf85..29b862a 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -87,20 +87,24 @@ extern void rcu_nmi_exit(void);
arch_nmi_enter(); \
printk_nmi_enter(); \
lockdep_off(); \
- ftrace_nmi_enter(); \
BUG_ON(in_nmi() == NMI_MASK); \
__preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET); \
rcu_nmi_enter(); \
lockdep_hardirq_enter(); \
+ instrumentation_begin(); \
+ ftrace_nmi_enter(); \
+ instrumentation_end(); \
} while (0)

#define nmi_exit() \
do { \
+ instrumentation_begin(); \
+ ftrace_nmi_exit(); \
+ instrumentation_end(); \
lockdep_hardirq_exit(); \
rcu_nmi_exit(); \
BUG_ON(!in_nmi()); \
__preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET); \
- ftrace_nmi_exit(); \
lockdep_on(); \
printk_nmi_exit(); \
arch_nmi_exit(); \
\
 
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