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From: Heiko Carstens <hca@linux.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Juergen Christ <jchrist@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: [PATCH 6/9] s390/percpu: Use new percpu code section for arch_this_cpu_[and|or]()
Date: Tue, 17 Mar 2026 20:54:33 +0100	[thread overview]
Message-ID: <20260317195436.2276810-7-hca@linux.ibm.com> (raw)
In-Reply-To: <20260317195436.2276810-1-hca@linux.ibm.com>

Convert arch_this_cpu_[and|or]() to make use of the new percpu code
section infrastructure.

There is no user of this_cpu_and() and only one user of this_cpu_or()
within the kernel. Therefore this conversion has hardly any effect,
and also removes only preempt_schedule_notrace() function call.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 arch/s390/include/asm/percpu.h | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h
index 6e932f45f128..f26f03b0889c 100644
--- a/arch/s390/include/asm/percpu.h
+++ b/arch/s390/include/asm/percpu.h
@@ -208,17 +208,29 @@
 
 #define arch_this_cpu_to_op(pcp, val, op)				\
 {									\
+	unsigned long lc_pcpr, lc_pcpo;					\
 	typedef typeof(pcp) pcp_op_T__; 				\
 	pcp_op_T__ val__ = (val);					\
 	pcp_op_T__ old__, *ptr__;					\
-	preempt_disable_notrace();					\
-	ptr__ = raw_cpu_ptr(&(pcp));	 				\
-	asm volatile(							\
-		op "    %[old__],%[val__],%[ptr__]"			\
-		: [old__] "=d" (old__), [ptr__] "+Q" (*ptr__)		\
-		: [val__] "d" (val__)					\
+									\
+	lc_pcpr = offsetof(struct lowcore, percpu_register);		\
+	lc_pcpo = offsetof(struct lowcore, percpu_offset);		\
+	ptr__ = &(pcp);							\
+	asm_inline volatile(						\
+		MVIY_PERCPU("%[disppcpr]", "%[dispaltpcpr]", "%[ptr__]")\
+		AG_ALT("%[disppcpo]", "%[dispaltpcpo]", "%[ptr__]")	\
+		op "    %[old__],%[val__],0(%[ptr__])\n"		\
+		MVIY_ALT("%[disppcpr]", "%[dispaltpcpr]", "%%r0")	\
+		: [old__] "=&d" (old__),				\
+		  [ptr__] "+&a" (ptr__), "+m" (*ptr__),			\
+		  "=m" (((struct lowcore *)0)->percpu_register)		\
+		: [val__] "d" (val__),					\
+		  [disppcpr] "i" (lc_pcpr),				\
+		  [disppcpo] "i" (lc_pcpo),				\
+		  [dispaltpcpr] "i" (lc_pcpr + LOWCORE_ALT_ADDRESS),	\
+		  [dispaltpcpo] "i" (lc_pcpo + LOWCORE_ALT_ADDRESS),	\
+		  "m" (((struct lowcore *)0)->percpu_offset)		\
 		: "cc");						\
-	preempt_enable_notrace();					\
 }
 
 #define this_cpu_and_4(pcp, val)	arch_this_cpu_to_op(pcp, val, "lan")
-- 
2.51.0


  parent reply	other threads:[~2026-03-17 19:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-17 19:54 [PATCH 0/9] s390: Improve this_cpu operations Heiko Carstens
2026-03-17 19:54 ` [PATCH 1/9] s390/percpu: Provide arch_raw_cpu_ptr() Heiko Carstens
2026-03-17 19:54 ` [PATCH 2/9] s390/alternatives: Add new ALT_TYPE_PERCPU type Heiko Carstens
2026-03-17 19:54 ` [PATCH 3/9] s390/percpu: Infrastructure for more efficient this_cpu operations Heiko Carstens
2026-03-17 19:54 ` [PATCH 4/9] s390/percpu: Use new percpu code section for arch_this_cpu_add() Heiko Carstens
2026-03-17 19:54 ` [PATCH 5/9] s390/percpu: Use new percpu code section for arch_this_cpu_add_return() Heiko Carstens
2026-03-17 19:54 ` Heiko Carstens [this message]
2026-03-17 19:54 ` [PATCH 7/9] s390/percpu: Provide arch_this_cpu_read() implementation Heiko Carstens
2026-03-17 19:54 ` [PATCH 8/9] s390/percpu: Provide arch_this_cpu_write() implementation Heiko Carstens
2026-03-17 19:54 ` [PATCH 9/9] s390/percpu: Remove one and two byte this_cpu operation implementation Heiko Carstens
2026-03-17 21:08 ` [PATCH 0/9] s390: Improve this_cpu operations Peter Zijlstra
2026-03-23 10:26 ` Juergen Christ

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