From 3c973c51bfbaf356367afa46b94f9100a7d672f2 Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Fri, 15 Aug 2025 11:06:30 +0800 Subject: entry: Add arch_irqentry_exit_need_resched() for arm64 Compared to the generic entry code, ARM64 does additional checks when deciding to reschedule on return from interrupt. So introduce arch_irqentry_exit_need_resched() in the need_resched() condition of the generic raw_irqentry_exit_cond_resched(), with a NOP default. This will allow ARM64 to implement the architecture specific version for switching over to the generic entry code. Suggested-by: Ada Couprie Diaz Suggested-by: Mark Rutland Suggested-by: Kevin Brodsky Suggested-by: Thomas Gleixner Signed-off-by: Jinjie Ruan Acked-by: Catalin Marinas Signed-off-by: Will Deacon --- kernel/entry/common.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'kernel/entry/common.c') diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 408d28b5179d..f62e1d1b2063 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -143,6 +143,20 @@ 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 resched is needed. + * Defaults return true. + * + * The main purpose is to permit arch to avoid preemption of 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()) { @@ -150,7 +164,7 @@ 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(); } } -- cgit