[PATCH v4 14/16] powerpc/traps: system reset do not trace

[Nicholas Piggin <npiggin@gmail.com>]

Similarly to the previous patch, do not trace system reset. This code
is used when there is a crash or hang, and tracing disturbs the system
more and has been known to crash in the crash handling path.

Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kernel/traps.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 9f6852322e59..ee209c5a1ad7 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -443,6 +443,9 @@ void system_reset_exception(struct pt_regs *regs)
 	unsigned long hsrr0, hsrr1;
 	bool nested = in_nmi();
 	bool saved_hsrrs = false;
+	u8 ftrace_enabled = this_cpu_get_ftrace_enabled();
+
+	this_cpu_set_ftrace_enabled(0);
 
 	/*
 	 * Avoid crashes in case of nested NMI exceptions. Recoverability
@@ -524,6 +527,8 @@ void system_reset_exception(struct pt_regs *regs)
 	if (!nested)
 		nmi_exit();
 
+	this_cpu_set_ftrace_enabled(ftrace_enabled);
+
 	/* What should we do here? We could issue a shutdown or hard reset. */
 }
 
-- 
2.23.0