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 93c95fc51cc0b4ad011bcdfdfcfb92e4cbab8ec1..dd7903f371ad65ef19b7c651602c862c7f83c995 100644 (file)
--- 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);
 }