From f6802ba976a431847ff41479da163bb8710d8e7b Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy@goop.org>
Date: Wed, 25 Jun 2008 00:19:14 -0400
Subject: [PATCH] --- yaml --- r: 99948 b: refs/heads/master c:
 97349135fea7f0ba8464534433df3bfd1dc0e9a6 h: refs/heads/master v: v3

---
 [refs]                           | 2 +-
 trunk/arch/x86/Kconfig           | 7 +++++++
 trunk/include/asm-x86/paravirt.h | 8 ++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 63cb67fd4ab1..9d2c13bd645f 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d8d5900ef8afc562088f8470feeaf17c4747790f
+refs/heads/master: 97349135fea7f0ba8464534433df3bfd1dc0e9a6
diff --git a/trunk/arch/x86/Kconfig b/trunk/arch/x86/Kconfig
index 9441e46cb49b..67e5275f03c8 100644
--- a/trunk/arch/x86/Kconfig
+++ b/trunk/arch/x86/Kconfig
@@ -435,6 +435,13 @@ config PARAVIRT_CLOCK
 
 endif
 
+config PARAVIRT_DEBUG
+       bool "paravirt-ops debugging"
+       depends on PARAVIRT && DEBUG_KERNEL
+       help
+         Enable to debug paravirt_ops internals.  Specifically, BUG if
+	 a paravirt_op is missing when it is called.
+
 config MEMTEST
 	bool "Memtest"
 	depends on X86_64
diff --git a/trunk/include/asm-x86/paravirt.h b/trunk/include/asm-x86/paravirt.h
index 5467e2cff4bc..198293bed46f 100644
--- a/trunk/include/asm-x86/paravirt.h
+++ b/trunk/include/asm-x86/paravirt.h
@@ -459,10 +459,17 @@ int paravirt_disable_iospace(void);
 #define VEXTRA_CLOBBERS	 , "rax", "r8", "r9", "r10", "r11"
 #endif
 
+#ifdef CONFIG_PARAVIRT_DEBUG
+#define PVOP_TEST_NULL(op)	BUG_ON(op == NULL)
+#else
+#define PVOP_TEST_NULL(op)	((void)op)
+#endif
+
 #define __PVOP_CALL(rettype, op, pre, post, ...)			\
 	({								\
 		rettype __ret;						\
 		PVOP_CALL_ARGS;					\
+		PVOP_TEST_NULL(op);					\
 		/* This is 32-bit specific, but is okay in 64-bit */	\
 		/* since this condition will never hold */		\
 		if (sizeof(rettype) > sizeof(unsigned long)) {		\
@@ -491,6 +498,7 @@ int paravirt_disable_iospace(void);
 #define __PVOP_VCALL(op, pre, post, ...)				\
 	({								\
 		PVOP_VCALL_ARGS;					\
+		PVOP_TEST_NULL(op);					\
 		asm volatile(pre					\
 			     paravirt_alt(PARAVIRT_CALL)		\
 			     post					\