[PATCH v3 3/6] powerpc/kexec: Disable ftrace before switching to the new kernel

["Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>]

If function_graph tracer is enabled during kexec, we see the below
exception in the simulator:
	root@(none):/# kexec -e
	kvm: exiting hardware virtualization
	kexec_core: Starting new kernel
	[   19.262020070,5] OPAL: Switch to big-endian OS
	kexec: Starting switchover sequence.
	Interrupt to 0xC000000000004380 from 0xC000000000004380
	** Execution stopped: Continuous Interrupt, Instruction caused exception,  **

Now that we have a more effective way to disable ftrace, let's use that
before switching to a new kernel during kexec.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/machine_kexec.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index 2694d078741d..4a1b24a9dd61 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -95,16 +95,14 @@ void arch_crash_save_vmcoreinfo(void)
  */
 void machine_kexec(struct kimage *image)
 {
-	int save_ftrace_enabled;
-
-	save_ftrace_enabled = __ftrace_enabled_save();
+	get_paca()->ftrace_disabled = 1;
 
 	if (ppc_md.machine_kexec)
 		ppc_md.machine_kexec(image);
 	else
 		default_machine_kexec(image);
 
-	__ftrace_enabled_restore(save_ftrace_enabled);
+	get_paca()->ftrace_disabled = 0;
 
 	/* Fall back to normal restart if we're still alive. */
 	machine_restart(NULL);
-- 
2.16.2