From 3d2920cf4fd41a27730083ef395a0c49d4750474 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Tue, 1 Oct 2019 21:53:26 +0000 Subject: MIPS: bitops: Only use ins for bit 16 or higher set_bit() can set bits 0-15 using an ori instruction, rather than loading the value -1 into a register & then using an ins instruction. That is, rather than the following: li t0, -1 ll t1, 0(t2) ins t1, t0, 4, 1 sc t1, 0(t2) We can have the simpler: ll t1, 0(t2) ori t1, t1, 0x10 sc t1, 0(t2) The or path already allows immediates to be used, so simply restricting the ins path to bits that don't fit in immediates is sufficient to take advantage of this. Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Huacai Chen Cc: Jiaxun Yang Cc: linux-kernel@vger.kernel.org --- arch/mips/include/asm/bitops.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/mips/include') diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h index e300960717e0..1e5739191ddf 100644 --- a/arch/mips/include/asm/bitops.h +++ b/arch/mips/include/asm/bitops.h @@ -77,7 +77,7 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *addr) } #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6) - if (__builtin_constant_p(bit)) { + if (__builtin_constant_p(bit) && (bit >= 16)) { loongson_llsc_mb(); do { __asm__ __volatile__( -- cgit v1.2.3