arm64: stacktrace: Factor out on_accessible_stack_common()

Move common on_accessible_stack checks to stacktrace/common.h. This is
used in the implementation of the nVHE hypervisor unwinder later in
this series.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-3-kaleshsingh@google.com

arch/arm64/include/asm/stacktrace.h

@@ -65,8 +65,8 @@ static inline bool on_accessible_stack(const struct task_struct *tsk,
 				       unsigned long sp, unsigned long size,
 				       struct stack_info *info)
 {
-	if (info)
-		info->type = STACK_TYPE_UNKNOWN;
+	if (on_accessible_stack_common(tsk, sp, size, info))
+		return true;
 
 	if (on_task_stack(tsk, sp, size, info))
 		return true;
@@ -74,8 +74,6 @@ static inline bool on_accessible_stack(const struct task_struct *tsk,
 		return false;
 	if (on_irq_stack(sp, size, info))
 		return true;
-	if (on_overflow_stack(sp, size, info))
-		return true;
 	if (on_sdei_stack(sp, size, info))
 		return true;
 

arch/arm64/include/asm/stacktrace/common.h

@@ -62,6 +62,9 @@ struct unwind_state {
 	struct task_struct *task;
 };
 
+static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
+				     struct stack_info *info);
+
 static inline bool on_stack(unsigned long sp, unsigned long size,
 			    unsigned long low, unsigned long high,
 			    enum stack_type type, struct stack_info *info)
@@ -80,6 +83,21 @@ static inline bool on_stack(unsigned long sp, unsigned long size,
 	return true;
 }
 
+static inline bool on_accessible_stack_common(const struct task_struct *tsk,
+					      unsigned long sp,
+					      unsigned long size,
+					      struct stack_info *info)
+{
+	if (info)
+		info->type = STACK_TYPE_UNKNOWN;
+
+	/*
+	 * Both the kernel and nvhe hypervisor make use of
+	 * an overflow_stack
+	 */
+	return on_overflow_stack(sp, size, info);
+}
+
 static inline void unwind_init_common(struct unwind_state *state,
 				      struct task_struct *task)
 {