@@ -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);
@@ -92,11 +93,14 @@ 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 */
#endif /* CONFIG_PREEMPTION */
@@ -281,19 +281,8 @@ 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
@@ -576,6 +565,24 @@ static __always_inline void __el1_pnmi(struct pt_regs *regs,
arm64_exit_nmi(regs, state);
}
+void raw_irqentry_exit_cond_resched(void)
+{
+ if (!preempt_count()) {
+ if (need_resched() && arm64_preempt_schedule_irq())
+ preempt_schedule_irq();
+ }
+}
+
+#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 *))
{
@@ -585,10 +592,8 @@ 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);
}
@@ -142,6 +142,20 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
return ret;
}
+/**
+ * arch_irqentry_exit_need_resched - Architecture specific need resched function
+ *
+ * Invoked from raw_irqentry_exit_cond_resched() to check if need resched.
+ * Defaults return true.
+ *
+ * The main purpose is to permit arch to skip preempt a task from an IRQ.
+ */
+static inline bool arch_irqentry_exit_need_resched(void);
+
+#ifndef arch_irqentry_exit_need_resched
+static inline bool arch_irqentry_exit_need_resched(void) { return true; }
+#endif
+
void raw_irqentry_exit_cond_resched(void)
{
if (!preempt_count()) {
@@ -149,7 +163,7 @@ void raw_irqentry_exit_cond_resched(void)
rcu_irq_exit_check_preempt();
if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
WARN_ON_ONCE(!on_thread_stack());
- if (need_resched())
+ if (need_resched() && arch_irqentry_exit_need_resched())
preempt_schedule_irq();
}
}
ARM64 requires an additional check whether to reschedule on return from interrupt. So add arch_irqentry_exit_need_resched() as the default NOP implementation and hook it up into the need_resched() condition in raw_irqentry_exit_cond_resched(). This allows ARM64 to implement the architecture specific version for switching over to the generic entry code. 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. Suggested-by: Mark Rutland <mark.rutland@arm.com> Suggested-by: Kevin Brodsky <kevin.brodsky@arm.com> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- v6: - Update the commit message. - Hoist the IS_ENABLED() and need_irq_preemption() check earlier. - Merge the 4 pathes. --- arch/arm64/include/asm/preempt.h | 4 ++++ arch/arm64/kernel/entry-common.c | 35 ++++++++++++++++++-------------- kernel/entry/common.c | 16 ++++++++++++++- 3 files changed, 39 insertions(+), 16 deletions(-)