[PATCH v2 06/19] powerpc: add interrupt wrapper entry / exit stub functions

[Nicholas Piggin]

These will be used by subsequent patches.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 arch/powerpc/include/asm/interrupt.h | 66 ++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
index 04b7bdf97a44..3a94153ff0d4 100644
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -5,6 +5,50 @@
 #include <linux/context_tracking.h>
 #include <asm/ftrace.h>
 
+struct interrupt_state {
+};
+
+static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrupt_state *state)
+{
+}
+
+/*
+ * Care should be taken to note that interrupt_exit_prepare and
+ * interrupt_async_exit_prepare do not necessarily return immediately to
+ * regs context (e.g., if regs is usermode, we don't necessarily return to
+ * user mode). Other interrupts might be taken between here and return,
+ * context switch / preemption may occur in the exit path after this, or a
+ * signal may be delivered, etc.
+ *
+ * The real interrupt exit code is platform specific, e.g.,
+ * interrupt_exit_user_prepare / interrupt_exit_kernel_prepare for 64s.
+ *
+ * However interrupt_nmi_exit_prepare does return directly to regs, because
+ * NMIs do not do "exit work" or replay soft-masked interrupts.
+ */
+static inline void interrupt_exit_prepare(struct pt_regs *regs, struct interrupt_state *state)
+{
+}
+
+static inline void interrupt_async_enter_prepare(struct pt_regs *regs, struct interrupt_state *state)
+{
+}
+
+static inline void interrupt_async_exit_prepare(struct pt_regs *regs, struct interrupt_state *state)
+{
+}
+
+struct interrupt_nmi_state {
+};
+
+static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)
+{
+}
+
+static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)
+{
+}
+
 /**
  * DECLARE_INTERRUPT_HANDLER_RAW - Declare raw interrupt handler function
  * @func:	Function name of the entry point
@@ -59,7 +103,13 @@ static __always_inline void ___##func(struct pt_regs *regs);		\
 									\
 __visible noinstr void func(struct pt_regs *regs)			\
 {									\
+	struct interrupt_state state;					\
+									\
+	interrupt_enter_prepare(regs, &state);				\
+									\
 	___##func (regs);						\
+									\
+	interrupt_exit_prepare(regs, &state);				\
 }									\
 									\
 static __always_inline void ___##func(struct pt_regs *regs)
@@ -87,10 +137,15 @@ static __always_inline long ___##func(struct pt_regs *regs);		\
 									\
 __visible noinstr long func(struct pt_regs *regs)			\
 {									\
+	struct interrupt_state state;					\
 	long ret;							\
 									\
+	interrupt_enter_prepare(regs, &state);				\
+									\
 	ret = ___##func (regs);						\
 									\
+	interrupt_exit_prepare(regs, &state);				\
+									\
 	return ret;							\
 }									\
 									\
@@ -117,7 +172,13 @@ static __always_inline void ___##func(struct pt_regs *regs);		\
 									\
 __visible noinstr void func(struct pt_regs *regs)			\
 {									\
+	struct interrupt_state state;					\
+									\
+	interrupt_async_enter_prepare(regs, &state);			\
+									\
 	___##func (regs);						\
+									\
+	interrupt_async_exit_prepare(regs, &state);			\
 }									\
 									\
 static __always_inline void ___##func(struct pt_regs *regs)
@@ -145,10 +206,15 @@ static __always_inline long ___##func(struct pt_regs *regs);		\
 									\
 __visible noinstr long func(struct pt_regs *regs)			\
 {									\
+	struct interrupt_nmi_state state;				\
 	long ret;							\
 									\
+	interrupt_nmi_enter_prepare(regs, &state);			\
+									\
 	ret = ___##func (regs);						\
 									\
+	interrupt_nmi_exit_prepare(regs, &state);			\
+									\
 	return ret;							\
 }									\
 									\
-- 
2.23.0