[PATCH v8 6/8] arm64: entry: Refactor preempt_schedule_irq() check code

[Jinjie Ruan]

To align the structure of the code with irqentry_exit_cond_resched()
from the generic entry code, hoist the need_irq_preemption()
and IS_ENABLED() check earlier. And different preemption check functions
are defined based on whether dynamic preemption is enabled.

Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
 arch/arm64/include/asm/preempt.h |  6 ++++++
 arch/arm64/kernel/entry-common.c | 37 +++++++++++++++++++-------------
 2 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h
index 0159b625cc7f..c2437ea0790f 100644
--- a/arch/arm64/include/asm/preempt.h
+++ b/arch/arm64/include/asm/preempt.h
@@ -85,6 +85,7 @@ static inline bool should_resched(int preempt_offset)
 void preempt_schedule(void);
 void preempt_schedule_notrace(void);
 
+void raw_irqentry_exit_cond_resched(void);
 #ifdef CONFIG_PREEMPT_DYNAMIC
 
 DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
@@ -92,13 +93,18 @@ void dynamic_preempt_schedule(void);
 #define __preempt_schedule()		dynamic_preempt_schedule()
 void dynamic_preempt_schedule_notrace(void);
 #define __preempt_schedule_notrace()	dynamic_preempt_schedule_notrace()
+void dynamic_irqentry_exit_cond_resched(void);
+#define irqentry_exit_cond_resched()	dynamic_irqentry_exit_cond_resched()
 
 #else /* CONFIG_PREEMPT_DYNAMIC */
 
 #define __preempt_schedule()		preempt_schedule()
 #define __preempt_schedule_notrace()	preempt_schedule_notrace()
+#define irqentry_exit_cond_resched()	raw_irqentry_exit_cond_resched()
 
 #endif /* CONFIG_PREEMPT_DYNAMIC */
+#else /* CONFIG_PREEMPTION */
+#define irqentry_exit_cond_resched()	{}
 #endif /* CONFIG_PREEMPTION */
 
 #endif /* __ASM_PREEMPT_H */
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 1ba1d40fa6a7..64066c643f97 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -286,19 +286,8 @@ static void noinstr arm64_exit_el1_dbg(struct pt_regs *regs,
 		lockdep_hardirqs_on(CALLER_ADDR0);
 }
 
-#ifdef CONFIG_PREEMPT_DYNAMIC
-DEFINE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
-#define need_irq_preemption() \
-	(static_branch_unlikely(&sk_dynamic_irqentry_exit_cond_resched))
-#else
-#define need_irq_preemption()	(IS_ENABLED(CONFIG_PREEMPTION))
-#endif
-
 static inline bool arm64_preempt_schedule_irq(void)
 {
-	if (!need_irq_preemption())
-		return false;
-
 	/*
 	 * DAIF.DA are cleared at the start of IRQ/FIQ handling, and when GIC
 	 * priority masking is used the GIC irqchip driver will clear DAIF.IF
@@ -682,6 +671,26 @@ static __always_inline void __el1_pnmi(struct pt_regs *regs,
 	arm64_exit_nmi(regs, state);
 }
 
+#ifdef CONFIG_PREEMPTION
+void raw_irqentry_exit_cond_resched(void)
+{
+	if (!preempt_count()) {
+		if (need_resched() && arm64_preempt_schedule_irq())
+			preempt_schedule_irq();
+	}
+}
+#endif
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+DEFINE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
+void dynamic_irqentry_exit_cond_resched(void)
+{
+	if (!static_branch_unlikely(&sk_dynamic_irqentry_exit_cond_resched))
+		return;
+	raw_irqentry_exit_cond_resched();
+}
+#endif
+
 static __always_inline void __el1_irq(struct pt_regs *regs,
 				      void (*handler)(struct pt_regs *))
 {
@@ -693,10 +702,8 @@ static __always_inline void __el1_irq(struct pt_regs *regs,
 	do_interrupt_handler(regs, handler);
 	irq_exit_rcu();
 
-	if (!preempt_count() && need_resched()) {
-		if (arm64_preempt_schedule_irq())
-			preempt_schedule_irq();
-	}
+	if (IS_ENABLED(CONFIG_PREEMPTION))
+		irqentry_exit_cond_resched();
 
 	exit_to_kernel_mode(regs, state);
 }
-- 
2.34.1