linux-kernel - [PATCH v2 21/36] MIPS: bitops: Allow immediates in test_and_{set,clear,change}

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Message-ID: <20191001215249.4157062-22-paul.burton@mips.com>
Date:   Tue, 1 Oct 2019 21:53:31 +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 21/36] MIPS: bitops: Allow immediates in
 test_and_{set,clear,change}_bit

The logical operations or & xor used in the test_and_set_bit_lock(),
test_and_clear_bit() & test_and_change_bit() functions currently force
the value 1<<bit to be placed in a register. If the bit is compile-time
constant & fits within the immediate field of an or/xor instruction (ie.
16 bits) then we can make use of the ori/xori instruction variants &
avoid the use of an extra register. Add the extra "i" constraints in
order to allow use of these immediate encodings.

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

Changes in v2: None

 arch/mips/include/asm/bitops.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h
index ea35a2e87b6d..7314ba5a3683 100644
--- a/arch/mips/include/asm/bitops.h
+++ b/arch/mips/include/asm/bitops.h
@@ -261,7 +261,7 @@ static inline int test_and_set_bit_lock(unsigned long nr,
 		"	and	%2, %0, %3				\n"
 		"	.set	pop					\n"
 		: "=&r" (temp), "+m" (*m), "=&r" (res)
-		: "r" (1UL << bit)
+		: "ir" (1UL << bit)
 		: __LLSC_CLOBBER);
 	} else {
 		loongson_llsc_mb();
@@ -274,7 +274,7 @@ static inline int test_and_set_bit_lock(unsigned long nr,
 			"	" __SC	"%2, %1				\n"
 			"	.set	pop				\n"
 			: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
-			: "r" (1UL << bit)
+			: "ir" (1UL << bit)
 			: __LLSC_CLOBBER);
 		} while (unlikely(!res));
 
@@ -332,7 +332,7 @@ static inline int test_and_clear_bit(unsigned long nr,
 		"	and	%2, %0, %3				\n"
 		"	.set	pop					\n"
 		: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
-		: "r" (1UL << bit)
+		: "ir" (1UL << bit)
 		: __LLSC_CLOBBER);
 	} else if ((MIPS_ISA_REV >= 2) && __builtin_constant_p(nr)) {
 		loongson_llsc_mb();
@@ -358,7 +358,7 @@ static inline int test_and_clear_bit(unsigned long nr,
 			"	" __SC	"%2, %1				\n"
 			"	.set	pop				\n"
 			: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
-			: "r" (1UL << bit)
+			: "ir" (1UL << bit)
 			: __LLSC_CLOBBER);
 		} while (unlikely(!res));
 
@@ -400,7 +400,7 @@ static inline int test_and_change_bit(unsigned long nr,
 		"	and	%2, %0, %3				\n"
 		"	.set	pop					\n"
 		: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
-		: "r" (1UL << bit)
+		: "ir" (1UL << bit)
 		: __LLSC_CLOBBER);
 	} else {
 		loongson_llsc_mb();
@@ -413,7 +413,7 @@ static inline int test_and_change_bit(unsigned long nr,
 			"	" __SC	"\t%2, %1			\n"
 			"	.set	pop				\n"
 			: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (*m), "=&r" (res)
-			: "r" (1UL << bit)
+			: "ir" (1UL << bit)
 			: __LLSC_CLOBBER);
 		} while (unlikely(!res));
 
-- 
2.23.0