kexec jump: fix for ftrace

Ftrace depends on some processor state that we destroyed during kexec and
restored by restore_processor_state().  So save_processor_state() and
restore_processor_state() are moved into machine_kexec() and ftrace is
restored after restore_processor_state().

Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 15 insertions, 3 deletions

diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c
index 5c8e7735c896..0732adba05ca 100644
--- a/arch/x86/kernel/machine_kexec_32.c
+++ b/arch/x86/kernel/machine_kexec_32.c
@@ -12,6 +12,7 @@
 #include <linux/init.h>
 #include <linux/numa.h>
 #include <linux/ftrace.h>
+#include <linux/suspend.h>
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -113,6 +114,7 @@ void machine_kexec(struct kimage *image)
 {
         unsigned long page_list[PAGES_NR];
         void *control_page;
+        int save_ftrace_enabled;
         asmlinkage unsigned long
                 (*relocate_kernel_ptr)(unsigned long indirection_page,
                                        unsigned long control_page,
@@ -120,7 +122,12 @@ void machine_kexec(struct kimage *image)
                                        unsigned int has_pae,
                                        unsigned int preserve_context);
 
-        tracer_disable();
+#ifdef CONFIG_KEXEC_JUMP
+        if (kexec_image->preserve_context)
+                save_processor_state();
+#endif
+
+        save_ftrace_enabled = __ftrace_enabled_save();
 
         /* Interrupts aren't acceptable while we reboot */
         local_irq_disable();
@@ -178,6 +185,13 @@ void machine_kexec(struct kimage *image)
                                            (unsigned long)page_list,
                                            image->start, cpu_has_pae,
                                            image->preserve_context);
+
+#ifdef CONFIG_KEXEC_JUMP
+        if (kexec_image->preserve_context)
+                restore_processor_state();
+#endif
+
+        __ftrace_enabled_restore(save_ftrace_enabled);
 }
 
 void arch_crash_save_vmcoreinfo(void)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 17c80fdc453b..9fc6f7cbd8a8 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1469,7 +1469,6 @@ int kernel_kexec(void)
                 error = device_power_down(PMSG_FREEZE);
                 if (error)
                         goto Enable_irqs;
-                save_processor_state();
         } else
 #endif
         {
@@ -1482,7 +1481,6 @@ int kernel_kexec(void)
 
 #ifdef CONFIG_KEXEC_JUMP
         if (kexec_image->preserve_context) {
-                restore_processor_state();
                 device_power_up(PMSG_RESTORE);
  Enable_irqs:
                 local_irq_enable();