[PATCH 2/2] spurious check tace point

[Luming Yu]

Add a trace point for debugging spurious fault problem.

Signed-off-by: Luming Yu <luming.yu@xxxxxxxxx>
Signed-off-by: Yongkai Wu <yongkaiwu@xxxxxxxxxxx>
---
 arch/x86/include/asm/trace/exceptions.h | 30 ++++++++++++++++++++++++++++++
 arch/x86/mm/fault.c                     |  2 ++
 2 files changed, 32 insertions(+)

diff --git a/arch/x86/include/asm/trace/exceptions.h b/arch/x86/include/asm/trace/exceptions.h
index 69615e387973..0cae50c5fcb2 100644
--- a/arch/x86/include/asm/trace/exceptions.h
+++ b/arch/x86/include/asm/trace/exceptions.h
@@ -44,6 +44,36 @@ DEFINE_EVENT_FN(x86_exceptions, name,				\
 DEFINE_PAGE_FAULT_EVENT(page_fault_user);
 DEFINE_PAGE_FAULT_EVENT(page_fault_kernel);
 
+DECLARE_EVENT_CLASS(spurious_fault_check,
+
+	TP_PROTO(unsigned long error_code,
+		unsigned long pte),
+	TP_ARGS(error_code,
+		pte),
+	TP_STRUCT__entry(
+		__field(unsigned long, error_code)
+		__field(unsigned long, pte)
+	),
+	TP_fast_assign(
+		__entry->error_code = error_code;
+		__entry->pte = pte;
+	),
+	TP_printk("error_code=%lx pte=%lx",
+		 __entry->error_code,
+		 __entry->pte
+		)
+);
+
+#define DEFINE_SPURIOUS_FAULT_CHECK_EVENT(name)	\
+DEFINE_EVENT_FN(spurious_fault_check, name,	\
+	TP_PROTO(unsigned long error_code,	\
+		 unsigned long pte),			\
+	TP_ARGS(error_code, pte),	\
+	trace_pagefault_reg,		\
+	trace_pagefault_unreg);
+
+DEFINE_SPURIOUS_FAULT_CHECK_EVENT(spurious_fault_1_sample);
+
 #undef TRACE_INCLUDE_PATH
 #define TRACE_INCLUDE_PATH .
 #define TRACE_INCLUDE_FILE exceptions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 5e2a49010d87..aa9bc9609c68 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1001,6 +1001,8 @@ static int spurious_kernel_fault_check(unsigned long error_code, pte_t *pte)
 	if ((error_code & X86_PF_INSTR) && !pte_exec(*pte))
 		return 0;
 
+	trace_spurious_fault_1_sample(error_code, (unsigned long)pte);
+
 	return 1;
 }
 
-- 
2.14.4