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Message-Id: <20200512213809.678944067@linutronix.de>
Date: Tue, 12 May 2020 23:01:02 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: x86@...nel.org, "Paul E. McKenney" <paulmck@...nel.org>,
Andy Lutomirski <luto@...nel.org>,
Alexandre Chartre <alexandre.chartre@...cle.com>,
Frederic Weisbecker <frederic@...nel.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <sean.j.christopherson@...el.com>,
Masami Hiramatsu <mhiramat@...nel.org>,
Petr Mladek <pmladek@...e.com>,
Steven Rostedt <rostedt@...dmis.org>,
Joel Fernandes <joel@...lfernandes.org>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Juergen Gross <jgross@...e.com>,
Brian Gerst <brgerst@...il.com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Will Deacon <will@...nel.org>,
Tom Lendacky <thomas.lendacky@....com>,
Wei Liu <wei.liu@...nel.org>,
Michael Kelley <mikelley@...rosoft.com>,
Jason Chen CJ <jason.cj.chen@...el.com>,
Zhao Yakui <yakui.zhao@...el.com>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>
Subject: [patch V5 03/38] nmi, tracing: Provide nmi_enter/exit_notrace()
To fully isolate #DB and #BP from instrumentable code it's necessary to
avoid invoking the hardware latency tracer on nmi_enter/exit().
Provide nmi_enter/exit() variants which are not invoking the hardware
latency tracer. That allows to put calls explicitely into the call sites
outside of the kprobe handling.
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
V5: New patch
---
include/linux/hardirq.h | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -77,28 +77,38 @@ extern void irq_exit(void);
/*
* nmi_enter() can nest up to 15 times; see NMI_BITS.
*/
-#define nmi_enter() \
+#define nmi_enter_notrace() \
do { \
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(); \
} while (0)
-#define nmi_exit() \
+#define nmi_enter() \
+ do { \
+ nmi_enter_notrace(); \
+ ftrace_nmi_enter(); \
+ } while (0)
+
+#define nmi_exit_notrace() \
do { \
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(); \
} while (0)
+#define nmi_exit() \
+ do { \
+ ftrace_nmi_exit(); \
+ nmi_exit_notrace(); \
+ } while (0)
+
#endif /* LINUX_HARDIRQ_H */
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