linux-kernel - [PATCH 02/37] MIPS: Use compact branch for LL/SC loops on MIPSr6+

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Message-ID: <20190930230806.2940505-3-paul.burton@mips.com>
Date:   Mon, 30 Sep 2019 23:08:16 +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 02/37] MIPS: Use compact branch for LL/SC loops on MIPSr6+

When targeting MIPSr6 or higher make use of a compact branch in LL/SC
loops, preventing the insertion of a delay slot nop that only serves to
waste space.

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

 arch/mips/include/asm/llsc.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/mips/include/asm/llsc.h b/arch/mips/include/asm/llsc.h
index 9b19f38562ac..d240a4a2d1c4 100644
--- a/arch/mips/include/asm/llsc.h
+++ b/arch/mips/include/asm/llsc.h
@@ -9,6 +9,8 @@
 #ifndef __ASM_LLSC_H
 #define __ASM_LLSC_H
 
+#include <asm/isa-rev.h>
+
 #if _MIPS_SZLONG == 32
 #define SZLONG_LOG 5
 #define SZLONG_MASK 31UL
@@ -32,6 +34,8 @@
  */
 #if R10000_LLSC_WAR
 # define __SC_BEQZ "beqzl	"
+#elif MIPS_ISA_REV >= 6
+# define __SC_BEQZ "beqzc	"
 #else
 # define __SC_BEQZ "beqz	"
 #endif
-- 
2.23.0