MIPS: rework local_t operation on MIPS64

+. remove "asm/war.h" since R10000_LLSC_WAR became a config option

+. clean up

Suggested-by:  Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Huang Pei <huangpei@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

2 files changed, 32 insertions, 45 deletions

diff --git a/arch/mips/include/asm/asm.h b/arch/mips/include/asm/asm.h
index 2f8ce94ebaaf..f3302b13d3e0 100644
--- a/arch/mips/include/asm/asm.h
+++ b/arch/mips/include/asm/asm.h
@@ -19,6 +19,7 @@
 
 #include <asm/sgidefs.h>
 #include <asm/asm-eva.h>
+#include <asm/isa-rev.h>
 
 #ifndef __VDSO__
 /*
@@ -211,6 +212,8 @@ symbol		=	value
 #define LONG_SUB	sub
 #define LONG_SUBU	subu
 #define LONG_L		lw
+#define LONG_LL		ll
+#define LONG_SC		sc
 #define LONG_S		sw
 #define LONG_SP		swp
 #define LONG_SLL	sll
@@ -236,6 +239,8 @@ symbol		=	value
 #define LONG_SUB	dsub
 #define LONG_SUBU	dsubu
 #define LONG_L		ld
+#define LONG_LL		lld
+#define LONG_SC		scd
 #define LONG_S		sd
 #define LONG_SP		sdp
 #define LONG_SLL	dsll
@@ -320,6 +325,19 @@ symbol		=	value
 
 #define SSNOP		sll zero, zero, 1
 
+/*
+ * Using a branch-likely instruction to check the result of an sc instruction
+ * works around a bug present in R10000 CPUs prior to revision 3.0 that could
+ * cause ll-sc sequences to execute non-atomically.
+ */
+#ifdef CONFIG_WAR_R10000_LLSC
+# define SC_BEQZ	beqzl
+#elif MIPS_ISA_REV >= 6
+# define SC_BEQZ	beqzc
+#else
+# define SC_BEQZ	beqz
+#endif
+
 #ifdef CONFIG_SGI_IP28
 /* Inhibit speculative stores to volatile (e.g.DMA) or invalid addresses. */
 #include <asm/cacheops.h>
diff --git a/arch/mips/include/asm/local.h b/arch/mips/include/asm/local.h
index 3fa634090388..d4d47c846bb2 100644
--- a/arch/mips/include/asm/local.h
+++ b/arch/mips/include/asm/local.h
@@ -8,7 +8,7 @@
 #include <asm/asm.h>
 #include <asm/cmpxchg.h>
 #include <asm/compiler.h>
-#include <asm/war.h>
+#include <asm/asm.h>
 
 typedef struct
 {
@@ -32,34 +32,18 @@ static __inline__ long local_add_return(long i, local_t * l)
 {
 	unsigned long result;
 
-	if (kernel_uses_llsc && IS_ENABLED(CONFIG_WAR_R10000_LLSC)) {
-		unsigned long temp;
-
-		__asm__ __volatile__(
-		"	.set	push					\n"
-		"	.set	arch=r4000				\n"
-			__SYNC(full, loongson3_war) "			\n"
-		"1:"	__LL	"%1, %2		# local_add_return	\n"
-			__stringify(LONG_ADDU)	"	%0, %1, %3	\n"
-			__SC	"%0, %2					\n"
-		"	beqzl	%0, 1b					\n"
-		"	addu	%0, %1, %3				\n"
-		"	.set	pop					\n"
-		: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
-		: "Ir" (i), "m" (l->a.counter)
-		: "memory");
-	} else if (kernel_uses_llsc) {
+	if (kernel_uses_llsc) {
 		unsigned long temp;
 
 		__asm__ __volatile__(
 		"	.set	push					\n"
 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
-			__SYNC(full, loongson3_war) "			\n"
-		"1:"	__LL	"%1, %2		# local_add_return	\n"
+			__SYNC(full, loongson3_war) "                   \n"
+		"1:"	__stringify(LONG_LL)	"	%1, %2		\n"
+			__stringify(LONG_ADDU)	"	%0, %1, %3	\n"
+			__stringify(LONG_SC)	"	%0, %2		\n"
+			__stringify(SC_BEQZ)	"	%0, 1b		\n"
 			__stringify(LONG_ADDU)	"	%0, %1, %3	\n"
-			__SC	"%0, %2					\n"
-		"	beqz	%0, 1b					\n"
-		"	addu	%0, %1, %3				\n"
 		"	.set	pop					\n"
 		: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
 		: "Ir" (i), "m" (l->a.counter)
@@ -81,34 +65,19 @@ static __inline__ long local_sub_return(long i, local_t * l)
 {
 	unsigned long result;
 
-	if (kernel_uses_llsc && IS_ENABLED(CONFIG_WAR_R10000_LLSC)) {
-		unsigned long temp;
-
-		__asm__ __volatile__(
-		"	.set	push					\n"
-		"	.set	arch=r4000				\n"
-			__SYNC(full, loongson3_war) "			\n"
-		"1:"	__LL	"%1, %2		# local_sub_return	\n"
-			__stringify(LONG_SUBU)	"	%0, %1, %3	\n"
-			__SC	"%0, %2					\n"
-		"	beqzl	%0, 1b					\n"
-		"	subu	%0, %1, %3				\n"
-		"	.set	pop					\n"
-		: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
-		: "Ir" (i), "m" (l->a.counter)
-		: "memory");
-	} else if (kernel_uses_llsc) {
+	if (kernel_uses_llsc) {
 		unsigned long temp;
 
 		__asm__ __volatile__(
 		"	.set	push					\n"
 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
-			__SYNC(full, loongson3_war) "			\n"
-		"1:"	__LL	"%1, %2		# local_sub_return	\n"
+			__SYNC(full, loongson3_war) "                   \n"
+		"1:"	__stringify(LONG_LL)	"	%1, %2		\n"
+			__stringify(LONG_SUBU)	"	%0, %1, %3	\n"
+			__stringify(LONG_SUBU)	"	%0, %1, %3	\n"
+			__stringify(LONG_SC)	"	%0, %2		\n"
+			__stringify(SC_BEQZ)	"	%0, 1b		\n"
 			__stringify(LONG_SUBU)	"	%0, %1, %3	\n"
-			__SC	"%0, %2					\n"
-		"	beqz	%0, 1b					\n"
-		"	subu	%0, %1, %3				\n"
 		"	.set	pop					\n"
 		: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
 		: "Ir" (i), "m" (l->a.counter)