From: Jinjie Ruan <ruanjinjie@huawei.com>
Date: Fri, 15 Aug 2025 03:06:28 +0000 (+0800)
Subject: arm64: entry: Rework arm64_preempt_schedule_irq()
X-Git-Tag: v6.18-rc1~210^2~8^2~6
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=77c1953946391e38c1e5120230f8df14f85219a7;p=thirdparty%2Flinux.git

arm64: entry: Rework arm64_preempt_schedule_irq()

The generic entry code has the form:

| raw_irqentry_exit_cond_resched()
| {
| 	if (!preempt_count()) {
| 		...
| 		if (need_resched())
| 			preempt_schedule_irq();
| 	}
| }

In preparation for moving arm64 over to the generic entry code, align
the structure of the arm64 code with raw_irqentry_exit_cond_resched() from
the generic entry code.

Reviewed-by: Ada Couprie Diaz <ada.coupriediaz@arm.com>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
---

diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 93c95fc51cc0b..dd7903f371ad6 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -294,10 +294,10 @@ DEFINE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
 #define need_irq_preemption()	(IS_ENABLED(CONFIG_PREEMPTION))
 #endif
 
-static void __sched arm64_preempt_schedule_irq(void)
+static inline bool arm64_preempt_schedule_irq(void)
 {
 	if (!need_irq_preemption())
-		return;
+		return false;
 
 	/*
 	 * Note: thread_info::preempt_count includes both thread_info::count
@@ -305,7 +305,7 @@ static void __sched arm64_preempt_schedule_irq(void)
 	 * preempt_count().
 	 */
 	if (READ_ONCE(current_thread_info()->preempt_count) != 0)
-		return;
+		return false;
 
 	/*
 	 * DAIF.DA are cleared at the start of IRQ/FIQ handling, and when GIC
@@ -314,7 +314,7 @@ static void __sched arm64_preempt_schedule_irq(void)
 	 * DAIF we must have handled an NMI, so skip preemption.
 	 */
 	if (system_uses_irq_prio_masking() && read_sysreg(daif))
-		return;
+		return false;
 
 	/*
 	 * Preempting a task from an IRQ means we leave copies of PSTATE
@@ -324,8 +324,10 @@ static void __sched arm64_preempt_schedule_irq(void)
 	 * Only allow a task to be preempted once cpufeatures have been
 	 * enabled.
 	 */
-	if (system_capabilities_finalized())
-		preempt_schedule_irq();
+	if (!system_capabilities_finalized())
+		return false;
+
+	return true;
 }
 
 static void do_interrupt_handler(struct pt_regs *regs,
@@ -699,7 +701,8 @@ static __always_inline void __el1_irq(struct pt_regs *regs,
 	do_interrupt_handler(regs, handler);
 	irq_exit_rcu();
 
-	arm64_preempt_schedule_irq();
+	if (arm64_preempt_schedule_irq())
+		preempt_schedule_irq();
 
 	exit_to_kernel_mode(regs, state);
 }