linux-kernel - [PATCH v2 04/36] MIPS: barrier: Clean up rmb() & wmb() definitions

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Message-ID: <20191001215249.4157062-5-paul.burton@mips.com>
Date:   Tue, 1 Oct 2019 21:53:08 +0000
From:   Paul Burton <paul.burton@...s.com>
To:     "linux-mips@...r.kernel.org" <linux-mips@...r.kernel.org>
CC:     Huacai Chen <chenhc@...ote.com>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Paul Burton <pburton@...ecomp.com>
Subject: [PATCH v2 04/36] MIPS: barrier: Clean up rmb() & wmb() definitions

Simplify our definitions of rmb() & wmb() using the new __SYNC()
infrastructure.

The fast_rmb() & fast_wmb() macros are removed, since they only provided
a level of indirection that made the code less readable & weren't
directly used anywhere in the kernel tree.

The Octeon #ifdef'ery is removed, since the "syncw" instruction
previously used is merely an alias for "sync 4" which __SYNC() will emit
for the wmb sync type when the kernel is configured for an Octeon CPU.
Similarly __SYNC() will emit nothing for the rmb sync type in Octeon
configurations.

Signed-off-by: Paul Burton <paul.burton@...s.com>
---

Changes in v2: None

 arch/mips/include/asm/barrier.h | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/arch/mips/include/asm/barrier.h b/arch/mips/include/asm/barrier.h
index 5ad39bfd3b6d..f36cab87cfde 100644
--- a/arch/mips/include/asm/barrier.h
+++ b/arch/mips/include/asm/barrier.h
@@ -26,6 +26,18 @@
 #define __sync()	do { } while(0)
 #endif
 
+static inline void rmb(void)
+{
+	asm volatile(__SYNC(rmb, always) ::: "memory");
+}
+#define rmb rmb
+
+static inline void wmb(void)
+{
+	asm volatile(__SYNC(wmb, always) ::: "memory");
+}
+#define wmb wmb
+
 #define __fast_iob()				\
 	__asm__ __volatile__(			\
 		".set	push\n\t"		\
@@ -37,16 +49,9 @@
 		: "m" (*(int *)CKSEG1)		\
 		: "memory")
 #ifdef CONFIG_CPU_CAVIUM_OCTEON
-# define OCTEON_SYNCW_STR	".set push\n.set arch=octeon\nsyncw\nsyncw\n.set pop\n"
-# define __syncw()	__asm__ __volatile__(OCTEON_SYNCW_STR : : : "memory")
-
-# define fast_wmb()	__syncw()
-# define fast_rmb()	barrier()
 # define fast_mb()	__sync()
 # define fast_iob()	do { } while (0)
 #else /* ! CONFIG_CPU_CAVIUM_OCTEON */
-# define fast_wmb()	__sync()
-# define fast_rmb()	__sync()
 # define fast_mb()	__sync()
 # ifdef CONFIG_SGI_IP28
 #  define fast_iob()				\
@@ -83,19 +88,14 @@
 
 #endif /* !CONFIG_CPU_HAS_WB */
 
-#define wmb()		fast_wmb()
-#define rmb()		fast_rmb()
-
 #if defined(CONFIG_WEAK_ORDERING)
 # ifdef CONFIG_CPU_CAVIUM_OCTEON
 #  define __smp_mb()	__sync()
-#  define __smp_rmb()	barrier()
-#  define __smp_wmb()	__syncw()
 # else
 #  define __smp_mb()	__asm__ __volatile__("sync" : : :"memory")
-#  define __smp_rmb()	__asm__ __volatile__("sync" : : :"memory")
-#  define __smp_wmb()	__asm__ __volatile__("sync" : : :"memory")
 # endif
+# define __smp_rmb()	rmb()
+# define __smp_wmb()	wmb()
 #else
 #define __smp_mb()	barrier()
 #define __smp_rmb()	barrier()
-- 
2.23.0