linux-kernel - [RFC PATCH 01/86] Revert "riscv: support PREEMPT

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Message-Id: <20231107215742.363031-2-ankur.a.arora@oracle.com>
Date:   Tue,  7 Nov 2023 13:56:47 -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,
        linux-mm@...ck.org, x86@...nel.org, akpm@...ux-foundation.org,
        luto@...nel.org, bp@...en8.de, dave.hansen@...ux.intel.com,
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        boris.ostrovsky@...cle.com, konrad.wilk@...cle.com,
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        David.Laight@...LAB.COM, richard@....at, mjguzik@...il.com,
        Ankur Arora <ankur.a.arora@...cle.com>
Subject: [RFC PATCH 01/86] Revert "riscv: support PREEMPT_DYNAMIC with static keys"

As a consequence of making the scheduler responsible for driving
voluntary preemption, we can do away with explicit preemption points.

This means that most of the CONFIG_PREEMPT_DYNAMIC logic, which uses
static calls to switch between varieties of preemption points,
can be removed.

This reverts commit 4e90d0522a688371402ced1d1958ee7381b81f05.

Signed-off-by: Ankur Arora <ankur.a.arora@...cle.com>
---
 arch/riscv/Kconfig            |  1 -
 include/asm-generic/preempt.h | 14 +-------------
 2 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 9c48fecc6719..4003436e6dad 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -134,7 +134,6 @@ config RISCV
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
-	select HAVE_PREEMPT_DYNAMIC_KEY if !XIP_KERNEL
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RETHOOK if !XIP_KERNEL
 	select HAVE_RSEQ
diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
index 51f8f3881523..b4d43a4af5f7 100644
--- a/include/asm-generic/preempt.h
+++ b/include/asm-generic/preempt.h
@@ -80,21 +80,9 @@ static __always_inline bool should_resched(int preempt_offset)
 
 #ifdef CONFIG_PREEMPTION
 extern asmlinkage void preempt_schedule(void);
-extern asmlinkage void preempt_schedule_notrace(void);
-
-#if defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
-
-void dynamic_preempt_schedule(void);
-void dynamic_preempt_schedule_notrace(void);
-#define __preempt_schedule()		dynamic_preempt_schedule()
-#define __preempt_schedule_notrace()	dynamic_preempt_schedule_notrace()
-
-#else /* !CONFIG_PREEMPT_DYNAMIC || !CONFIG_HAVE_PREEMPT_DYNAMIC_KEY*/
-
 #define __preempt_schedule() preempt_schedule()
+extern asmlinkage void preempt_schedule_notrace(void);
 #define __preempt_schedule_notrace() preempt_schedule_notrace()
-
-#endif /* CONFIG_PREEMPT_DYNAMIC && CONFIG_HAVE_PREEMPT_DYNAMIC_KEY*/
 #endif /* CONFIG_PREEMPTION */
 
 #endif /* __ASM_PREEMPT_H */
-- 
2.31.1