linux-kernel - [RFC PATCH 08/86] Revert "arm64: Support PREEMPT

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Message-Id: <20231107215742.363031-9-ankur.a.arora@oracle.com>
Date:   Tue,  7 Nov 2023 13:56:54 -0800
From:   Ankur Arora <ankur.a.arora@...cle.com>
To:     linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de, peterz@...radead.org,
        torvalds@...ux-foundation.org, paulmck@...nel.org,
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        Ankur Arora <ankur.a.arora@...cle.com>
Subject: [RFC PATCH 08/86] Revert "arm64: Support PREEMPT_DYNAMIC"

This reverts commit 1b2d3451ee50a0968cb9933f726e50b368ba5073.

Signed-off-by: Ankur Arora <ankur.a.arora@...cle.com>
---
 arch/arm64/Kconfig               |  1 -
 arch/arm64/include/asm/preempt.h | 19 ++-----------------
 arch/arm64/kernel/entry-common.c | 10 +---------
 3 files changed, 3 insertions(+), 27 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 78f20e632712..856d7be2ee45 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -221,7 +221,6 @@ config ARM64
 	select HAVE_PERF_EVENTS_NMI if ARM64_PSEUDO_NMI
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
-	select HAVE_PREEMPT_DYNAMIC_KEY
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
 	select HAVE_FUNCTION_ARG_ACCESS_API
diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h
index 0159b625cc7f..e83f0982b99c 100644
--- a/arch/arm64/include/asm/preempt.h
+++ b/arch/arm64/include/asm/preempt.h
@@ -2,7 +2,6 @@
 #ifndef __ASM_PREEMPT_H
 #define __ASM_PREEMPT_H
 
-#include <linux/jump_label.h>
 #include <linux/thread_info.h>
 
 #define PREEMPT_NEED_RESCHED	BIT(32)
@@ -81,24 +80,10 @@ static inline bool should_resched(int preempt_offset)
 }
 
 #ifdef CONFIG_PREEMPTION
-
 void preempt_schedule(void);
+#define __preempt_schedule() preempt_schedule()
 void preempt_schedule_notrace(void);
-
-#ifdef CONFIG_PREEMPT_DYNAMIC
-
-DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
-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()
-
-#else /* CONFIG_PREEMPT_DYNAMIC */
-
-#define __preempt_schedule()		preempt_schedule()
-#define __preempt_schedule_notrace()	preempt_schedule_notrace()
-
-#endif /* CONFIG_PREEMPT_DYNAMIC */
+#define __preempt_schedule_notrace() preempt_schedule_notrace()
 #endif /* CONFIG_PREEMPTION */
 
 #endif /* __ASM_PREEMPT_H */
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 0fc94207e69a..5d9c9951562b 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -225,17 +225,9 @@ 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 void __sched arm64_preempt_schedule_irq(void)
 {
-	if (!need_irq_preemption())
+	if (!IS_ENABLED(CONFIG_PREEMPTION))
 		return;
 
 	/*
-- 
2.31.1