5 files changed, 20 insertions, 3 deletions

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index c198b7e13e7b..b6a770132b67 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -122,7 +122,6 @@ config DEBUG_NX_TEST
 config DOUBLEFAULT
         default y
         bool "Enable doublefault exception handler" if EXPERT
-        depends on X86_32
         ---help---
           This option allows trapping of rare doublefault exceptions that
           would otherwise cause a system to silently reboot. Disabling this
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 22224b3b43bb..5b87d52eed0b 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -981,5 +981,5 @@ bool xen_set_default_idle(void);
 #endif
 
 void stop_this_cpu(void *dummy);
-
+void df_debug(struct pt_regs *regs, long error_code);
 #endif /* _ASM_X86_PROCESSOR_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 7bd3bd310106..4ce822ed58f5 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -67,7 +67,7 @@ obj-$(CONFIG_KEXEC)		+= relocate_kernel_$(BITS).o crash.o
 obj-$(CONFIG_CRASH_DUMP)        += crash_dump_$(BITS).o
 obj-y                           += kprobes/
 obj-$(CONFIG_MODULES)           += module.o
-obj-$(CONFIG_DOUBLEFAULT)       += doublefault_32.o
+obj-$(CONFIG_DOUBLEFAULT)       += doublefault.o
 obj-$(CONFIG_KGDB)              += kgdb.o
 obj-$(CONFIG_VM86)              += vm86_32.o
 obj-$(CONFIG_EARLY_PRINTK)      += early_printk.o
diff --git a/arch/x86/kernel/doublefault_32.c b/arch/x86/kernel/doublefault.c
index 155a13f33ed8..5d3fe8d36e4a 100644
--- a/arch/x86/kernel/doublefault_32.c
+++ b/arch/x86/kernel/doublefault.c
@@ -9,6 +9,8 @@
 #include <asm/processor.h>
 #include <asm/desc.h>
 
+#ifdef CONFIG_X86_32
+
 #define DOUBLEFAULT_STACKSIZE (1024)
 static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
 #define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
@@ -67,3 +69,16 @@ struct tss_struct doublefault_tss __cacheline_aligned = {
                 .__cr3          = __pa_nodebug(swapper_pg_dir),
         }
 };
+
+/* dummy for do_double_fault() call */
+void df_debug(struct pt_regs *regs, long error_code) {}
+
+#else /* !CONFIG_X86_32 */
+
+void df_debug(struct pt_regs *regs, long error_code)
+{
+        pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
+        show_regs(regs);
+        panic("Machine halted.");
+}
+#endif
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 772e2a846dec..167d481c5fd3 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -254,6 +254,9 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
         tsk->thread.error_code = error_code;
         tsk->thread.trap_nr = X86_TRAP_DF;
 
+#ifdef CONFIG_DOUBLEFAULT
+        df_debug(regs, error_code);
+#endif
         /*
          * This is always a kernel trap and never fixable (and thus must
          * never return).