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From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: mark.rutland@arm.com, vladimir.murzin@arm.com,
	ryan.roberts@arm.com, peterz@infradead.org,
	catalin.marinas@arm.com, david.laight.linux@gmail.com,
	stable@vger.kernel.org, ruanjinjie@huawei.com,
	james.morse@arm.com, yang@os.amperecomputing.com, cl@gentwo.org,
	maz@kernel.org, david@kernel.org, ljs@kernel.org,
	will@kernel.org, ardb@kernel.org
Subject: [PATCH v2 20/20] arm64: percpu: Remove _pcp_protect*() wrappers
Date: Tue,  4 Aug 2026 18:05:03 +0100	[thread overview]
Message-ID: <20260804170503.3513916-21-mark.rutland@arm.com> (raw)
In-Reply-To: <20260804170503.3513916-1-mark.rutland@arm.com>

Now that all this_cpu_*() operations are preemptible, there are no users
of _pcp_protect() or _pcp_protect_return().

Remove them both, along with the associated comment regarding
preemption.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ada Couprie Diaz <ada.coupriediaz@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jinjie Ruan <ruanjinjie@huawei.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
---
 arch/arm64/include/asm/percpu.h | 27 ---------------------------
 1 file changed, 27 deletions(-)

diff --git a/arch/arm64/include/asm/percpu.h b/arch/arm64/include/asm/percpu.h
index 8087ed6e12241..d868a88960123 100644
--- a/arch/arm64/include/asm/percpu.h
+++ b/arch/arm64/include/asm/percpu.h
@@ -368,33 +368,6 @@ PERCPU_CMPXCHG_OP(x,  , 64)
 #undef PERCPU_XCHG_OP
 #undef PERCPU_CMPXCHG_OP
 
-/*
- * It would be nice to avoid the conditional call into the scheduler when
- * re-enabling preemption for preemptible kernels, but doing that in a way
- * which builds inside a module would mean messing directly with the preempt
- * count. If you do this, peterz and tglx will hunt you down.
- *
- * Not to mention it'll break the actual preemption model for missing a
- * preemption point when TIF_NEED_RESCHED gets set while preemption is
- * disabled.
- */
-
-#define _pcp_protect(op, pcp, ...)					\
-({									\
-	preempt_disable_notrace();					\
-	op(raw_cpu_ptr(&(pcp)), __VA_ARGS__);				\
-	preempt_enable_notrace();					\
-})
-
-#define _pcp_protect_return(op, pcp, args...)				\
-({									\
-	typeof(pcp) __retval;						\
-	preempt_disable_notrace();					\
-	__retval = (typeof(pcp))op(raw_cpu_ptr(&(pcp)), ##args);	\
-	preempt_enable_notrace();					\
-	__retval;							\
-})
-
 #define _pcp_wrap(op, pcp, ...)						\
 ({									\
 	op(&(pcp), __VA_ARGS__);					\
-- 
2.30.2



      parent reply	other threads:[~2026-08-04 17:06 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-04 17:04 [PATCH v2 00/20] arm64: Preemptible this_cpu_*() operations Mark Rutland
2026-08-04 17:04 ` [PATCH v2 01/20] arm64: percpu: Fix this_cpu_write() casting Mark Rutland
2026-08-05  8:37   ` David Laight
2026-08-04 17:04 ` [PATCH v2 02/20] arm64: percpu: Fix this_cpu_and() mask generation Mark Rutland
2026-08-05  9:14   ` David Laight
2026-08-05 13:02     ` Mark Rutland
2026-08-06  8:28       ` David Laight
2026-08-06 10:23         ` Mark Rutland
2026-08-04 17:04 ` [PATCH v2 03/20] arm64: cmpxchg: LL/SC: Avoid redundant extension Mark Rutland
2026-08-04 17:04 ` [PATCH v2 04/20] arm64: cmpxchg128: LSE: Remove redundant operands Mark Rutland
2026-08-04 17:04 ` [PATCH v2 05/20] arm64: preempt: Simplify and optimize __preempt_count_dec_and_test() Mark Rutland
2026-08-04 17:04 ` [PATCH v2 06/20] arm64: preempt: Treat should_resched() as unlikely Mark Rutland
2026-08-04 17:04 ` [PATCH v2 07/20] arm64: ptrace: Always inline pt_regs_[read,write}_reg() Mark Rutland
2026-08-04 17:04 ` [PATCH v2 08/20] arm64: percpu: Factor out percpu offset asm Mark Rutland
2026-08-04 17:04 ` [PATCH v2 09/20] arm64: gpr-num: Add wxN aliases for wN registers Mark Rutland
2026-08-04 17:04 ` [PATCH v2 10/20] arm64: gpr-num: add __GPR_NUM() helper Mark Rutland
2026-08-04 17:04 ` [PATCH v2 11/20] arm64: entry: sdei: Restore all clobberable GPRs Mark Rutland
2026-08-04 17:04 ` [PATCH v2 12/20] arm64: entry: sdei: Make 'tsk' available Mark Rutland
2026-08-04 17:04 ` [PATCH v2 13/20] arm64: percpu: Add infrastructure for preemptible this_cpu_*() ops Mark Rutland
2026-08-04 22:45   ` Pedro Falcato
2026-08-05 10:27     ` David Laight
2026-08-05 12:50       ` Pedro Falcato
2026-08-05  6:45   ` David Hildenbrand (Arm)
2026-08-05  6:47     ` David Hildenbrand (Arm)
2026-08-06 11:21       ` Mark Rutland
2026-08-06 11:32         ` David Hildenbrand (Arm)
2026-08-06 12:02           ` Mark Rutland
2026-08-06 13:25           ` David Laight
2026-08-06 13:30             ` David Hildenbrand (Arm)
2026-08-04 17:04 ` [PATCH v2 14/20] arm64: percpu: Implement preemptible read/write ops Mark Rutland
2026-08-05  9:24   ` Ryan Roberts
2026-08-05 12:08     ` David Laight
2026-08-05 13:34     ` Mark Rutland
2026-08-04 17:04 ` [PATCH v2 15/20] arm64: percpu: Implement preemptible void RMW ops Mark Rutland
2026-08-04 17:04 ` [PATCH v2 16/20] arm64: percpu: Implement preemptible return " Mark Rutland
2026-08-04 17:05 ` [PATCH v2 17/20] arm64: percpu: Implement preemptible XCHG ops Mark Rutland
2026-08-04 17:05 ` [PATCH v2 18/20] arm64: percpu: Implement preemptible CMPXCHG ops Mark Rutland
2026-08-04 17:05 ` [PATCH v2 19/20] arm64: percpu: Implement preemptible CMPXCHG128 ops Mark Rutland
2026-08-04 17:05 ` Mark Rutland [this message]

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