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From: Heiko Carstens <hca@linux.ibm.com>
To: Alexander Gordeev <agordeev@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Mete Durlu <meted@linux.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Juergen Christ <jchrist@linux.ibm.com>,
	Ilya Leoshkevich <iii@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: [PATCH v2 04/12] s390/percpu: Let MVIY_PERCPU() calculate alternative displacement
Date: Fri, 18 Sep 2026 10:48:34 +0200	[thread overview]
Message-ID: <20260918084842.2333237-5-hca@linux.ibm.com> (raw)
In-Reply-To: <20260918084842.2333237-1-hca@linux.ibm.com>

Let MVIY_PERCPU() calculate the alternative lowcore displacement instead
of passing the same value(s) again and again in all percpu inline
assemblies.

This shortens the inline assemblies and makes them a bit more readable.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 arch/s390/include/asm/percpu.h | 68 +++++++++++++++-------------------
 1 file changed, 29 insertions(+), 39 deletions(-)

diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h
index 9888b38dedab..3bc448c4c2dd 100644
--- a/arch/s390/include/asm/percpu.h
+++ b/arch/s390/include/asm/percpu.h
@@ -99,7 +99,9 @@
  *   MVIY_ALT(...)    <- end of percpu code section
  */
 
-#define MVIY_PERCPU(disp, dispalt, reg)						\
+#define LC_ALT_ADDR	__stringify(LOWCORE_ALT_ADDRESS)
+
+#define MVIY_PERCPU(disp, reg)							\
 	".macro GEN_MVIY disp, reg\n"						\
 	".set	.Lreg,255\n"							\
 	".irp	rs,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15\n"			\
@@ -112,19 +114,19 @@
 	".endif\n"								\
 	"mviy	\\disp(%%r0),.Lreg\n"						\
 	".endm\n"								\
-	ALTERNATIVE("GEN_MVIY " disp    ", " reg "\n",				\
-		    "GEN_MVIY " dispalt ", " reg "\n",				\
+	ALTERNATIVE("GEN_MVIY " disp		     " , " reg "\n",		\
+		    "GEN_MVIY " disp "+" LC_ALT_ADDR " , " reg "\n",		\
 		    ALT_FEATURE(MFEATURE_LOWCORE))				\
 	".purgem GEN_MVIY\n"
 
-#define MVIY_ALT(disp, dispalt)							\
-	ALTERNATIVE("	mviy	" disp	  "(%%r0),0\n",				\
-		    "	mviy	" dispalt "(%%r0),0\n",				\
+#define MVIY_ALT(disp)								\
+	ALTERNATIVE("	mviy	" disp		       "(%%r0),0\n",		\
+		    "	mviy	" disp "+" LC_ALT_ADDR "(%%r0),0\n",		\
 		    ALT_FEATURE(MFEATURE_LOWCORE))
 
-#define AG_ALT(disp, dispalt, reg)						\
-	ALTERNATIVE("	ag	" reg ", " disp	   "(%%r0)\n",			\
-		    "	ag	" reg ", " dispalt "(%%r0)\n",			\
+#define AG_ALT(disp, reg)							\
+	ALTERNATIVE("	ag	" reg ", " disp			"(%%r0)\n",	\
+		    "	ag	" reg ", " disp "+" LC_ALT_ADDR "(%%r0)\n",	\
 		    ALT_FEATURE(MFEATURE_LOWCORE))
 
 #ifndef MARCH_HAS_Z196_FEATURES
@@ -153,33 +155,29 @@ do {										\
 	if (__builtin_constant_p(val__) &&					\
 	    ((szcast)val__ > -129) && ((szcast)val__ < 128)) {			\
 		asm volatile(							\
-			MVIY_PERCPU("%[disppcpr]", "%[dispaltpcpr]", "%[ptr__]")\
-			AG_ALT("%[disppcpo]", "%[dispaltpcpo]", "%[ptr__]")	\
+			MVIY_PERCPU("%[disppcpr]","%[ptr__]")			\
+			AG_ALT("%[disppcpo]", "%[ptr__]")			\
 			op2 "   0(%[ptr__]),%[val__]\n"				\
-			MVIY_ALT("%[disppcpr]", "%[dispaltpcpr]")		\
+			MVIY_ALT("%[disppcpr]")					\
 			: [ptr__] "+&a" (ptr__), "+m" (*ptr__),			\
 			  "=m" (((struct lowcore *)0)->percpu_register)		\
 			: [val__] "i" ((szcast)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");						\
 	} else {								\
 		asm volatile(							\
-			MVIY_PERCPU("%[disppcpr]", "%[dispaltpcpr]", "%[ptr__]")\
-			AG_ALT("%[disppcpo]", "%[dispaltpcpo]", "%[ptr__]")	\
+			MVIY_PERCPU("%[disppcpr]", "%[ptr__]")			\
+			AG_ALT("%[disppcpo]", "%[ptr__]")			\
 			op1 "   %[old__],%[val__],0(%[ptr__])\n"		\
-			MVIY_ALT("%[disppcpr]", "%[dispaltpcpr]")		\
+			MVIY_ALT("%[disppcpr]")					\
 			: [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");						\
 	}									\
@@ -199,18 +197,16 @@ do {										\
 	lc_pcpo = offsetof(struct lowcore, percpu_offset);		\
 	ptr__ = PERCPU_PTR(&(pcp));					\
 	asm_inline volatile(						\
-		MVIY_PERCPU("%[disppcpr]", "%[dispaltpcpr]", "%[ptr__]")\
-		AG_ALT("%[disppcpo]", "%[dispaltpcpo]", "%[ptr__]")	\
+		MVIY_PERCPU("%[disppcpr]","%[ptr__]")			\
+		AG_ALT("%[disppcpo]","%[ptr__]")			\
 		op "	%[old__],%[val__],0(%[ptr__])\n"		\
-		MVIY_ALT("%[disppcpr]", "%[dispaltpcpr]")		\
+		MVIY_ALT("%[disppcpr]")					\
 		: [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");						\
 	old__ + val__;							\
@@ -230,18 +226,16 @@ do {									\
 	lc_pcpo = offsetof(struct lowcore, percpu_offset);		\
 	ptr__ = PERCPU_PTR(&(pcp));					\
 	asm_inline volatile(						\
-		MVIY_PERCPU("%[disppcpr]", "%[dispaltpcpr]", "%[ptr__]")\
-		AG_ALT("%[disppcpo]", "%[dispaltpcpo]", "%[ptr__]")	\
+		MVIY_PERCPU("%[disppcpr]","%[ptr__]")			\
+		AG_ALT("%[disppcpo]","%[ptr__]")			\
 		op "    %[old__],%[val__],0(%[ptr__])\n"		\
-		MVIY_ALT("%[disppcpr]", "%[dispaltpcpr]")		\
+		MVIY_ALT("%[disppcpr]")					\
 		: [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");						\
 } while (0)
@@ -263,16 +257,14 @@ do {									\
 	lc_pcpo = offsetof(struct lowcore, percpu_offset);		\
 	ptr__ = PERCPU_PTR(&(pcp));					\
 	asm_inline volatile(						\
-		MVIY_PERCPU("%[disppcpr]", "%[dispaltpcpr]", "%[ptr__]")\
-		AG_ALT("%[disppcpo]", "%[dispaltpcpo]", "%[ptr__]")	\
+		MVIY_PERCPU("%[disppcpr]","%[ptr__]")			\
+		AG_ALT("%[disppcpo]","%[ptr__]")			\
 		op "	%[res__],0(%[ptr__])\n"				\
-		MVIY_ALT("%[disppcpr]", "%[dispaltpcpr]")		\
+		MVIY_ALT("%[disppcpr]")					\
 		: [res__] "=&d" (res__), [ptr__] "+&a" (ptr__),		\
 		  "=m" (((struct lowcore *)0)->percpu_register)		\
 		: [disppcpr] "i" (lc_pcpr),				\
 		  [disppcpo] "i" (lc_pcpo),				\
-		  [dispaltpcpr] "i" (lc_pcpr + LOWCORE_ALT_ADDRESS),	\
-		  [dispaltpcpo] "i" (lc_pcpo + LOWCORE_ALT_ADDRESS),	\
 		  "m" (*ptr__),						\
 		  "m" (((struct lowcore *)0)->percpu_offset)		\
 		: "cc");						\
@@ -294,17 +286,15 @@ do {									\
 	lc_pcpo = offsetof(struct lowcore, percpu_offset);		\
 	ptr__ = PERCPU_PTR(&(pcp));					\
 	asm_inline volatile(						\
-		MVIY_PERCPU("%[disppcpr]", "%[dispaltpcpr]", "%[ptr__]")\
-		AG_ALT("%[disppcpo]", "%[dispaltpcpo]", "%[ptr__]")	\
+		MVIY_PERCPU("%[disppcpr]","%[ptr__]")			\
+		AG_ALT("%[disppcpo]","%[ptr__]")			\
 		op "    %[val__],0(%[ptr__])\n"				\
-		MVIY_ALT("%[disppcpr]", "%[dispaltpcpr]")		\
+		MVIY_ALT("%[disppcpr]")					\
 		: [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");						\
 } while (0)
-- 
2.53.0


  parent reply	other threads:[~2026-09-18  8:48 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-18  8:48 [PATCH v2 00/12] s390: More this_cpu_*() changes Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 01/12] s390/percpu: Fix comment typo Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 02/12] s390/percpu: Add sanity check to GEN_MVIY macro Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 03/12] s390/lowcore: Remove _AC() from LOWCORE_ALT_ADDRESS Heiko Carstens
2026-09-18  8:48 ` Heiko Carstens [this message]
2026-09-18  8:48 ` [PATCH v2 05/12] s390/percpu/lowcore: Add and use LC_PERCPU lowcore offset defines Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 06/12] s390/percpu: Rename inline assembly symbolic names Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 07/12] s390/percpu: Use __PCPU_BEGIN() and __PCPU_END() for inline assemblies Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 08/12] s390/percpu: Use percpu code section for this_cpu_cmpxchg128() Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 09/12] s390/percpu: Use percpu code section for this_cpu_xchg() Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 10/12] s390/percpu: Use percpu code section for this_cpu_cmpxchg() Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 11/12] s390: Add CC_HAS_ASM_M_FORMAT_FLAG config option Heiko Carstens
2026-09-18  8:48 ` [PATCH v2 12/12] s390/percpu: Rework to simplify percpu_entry() and percpu_exit() Heiko Carstens
2026-09-18  9:53   ` Heiko Carstens
2026-09-18 10:40   ` Mark Rutland
2026-09-18 11:02     ` Heiko Carstens
2026-09-18 10:31 ` [PATCH v2 00/12] s390: More this_cpu_*() changes Mark Rutland
2026-09-18 10:59   ` Heiko Carstens
2026-09-18 11:24     ` Mark Rutland

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