From: Paul Burton <paul.burton@mips.com>
To: "linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>
Cc: Huacai Chen <chenhc@lemote.com>,
Jiaxun Yang <jiaxun.yang@flygoat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Paul Burton <pburton@wavecomp.com>
Subject: [PATCH v2 17/36] MIPS: bitops: Only use ins for bit 16 or higher
Date: Tue, 1 Oct 2019 21:53:26 +0000 [thread overview]
Message-ID: <20191001215249.4157062-18-paul.burton@mips.com> (raw)
In-Reply-To: <20191001215249.4157062-1-paul.burton@mips.com>
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 <paul.burton@mips.com>
---
Changes in v2: None
arch/mips/include/asm/bitops.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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__(
--
2.23.0
next prev parent reply other threads:[~2019-10-01 21:53 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-01 21:53 [PATCH v2 00/36] MIPS: barriers & atomics cleanups Paul Burton
2019-10-01 21:53 ` [PATCH v2 01/36] MIPS: Unify sc beqz definition Paul Burton
2019-10-01 21:53 ` [PATCH v2 02/36] MIPS: Use compact branch for LL/SC loops on MIPSr6+ Paul Burton
2019-10-01 21:53 ` [PATCH v2 03/36] MIPS: barrier: Add __SYNC() infrastructure Paul Burton
2019-10-01 21:53 ` [PATCH v2 04/36] MIPS: barrier: Clean up rmb() & wmb() definitions Paul Burton
2019-10-01 21:53 ` [PATCH v2 05/36] MIPS: barrier: Clean up __smp_mb() definition Paul Burton
2019-10-01 21:53 ` [PATCH v2 06/36] MIPS: barrier: Remove fast_mb() Octeon #ifdef'ery Paul Burton
2019-10-01 21:53 ` [PATCH v2 07/36] MIPS: barrier: Clean up __sync() definition Paul Burton
2019-10-01 21:53 ` [PATCH v2 08/36] MIPS: barrier: Clean up sync_ginv() Paul Burton
2019-10-01 21:53 ` [PATCH v2 09/36] MIPS: atomic: Fix whitespace in ATOMIC_OP macros Paul Burton
2019-10-01 21:53 ` [PATCH v2 10/36] MIPS: atomic: Handle !kernel_uses_llsc first Paul Burton
2019-10-01 21:53 ` [PATCH v2 11/36] MIPS: atomic: Use one macro to generate 32b & 64b functions Paul Burton
2019-10-01 21:53 ` [PATCH v2 12/36] MIPS: atomic: Emit Loongson3 sync workarounds within asm Paul Burton
2019-10-01 21:53 ` [PATCH v2 13/36] MIPS: atomic: Use _atomic barriers in atomic_sub_if_positive() Paul Burton
2019-10-01 21:53 ` [PATCH v2 14/36] MIPS: atomic: Unify 32b & 64b sub_if_positive Paul Burton
2019-10-01 21:53 ` [PATCH v2 15/36] MIPS: atomic: Deduplicate 32b & 64b read, set, xchg, cmpxchg Paul Burton
2019-10-01 21:53 ` [PATCH v2 16/36] MIPS: bitops: Handle !kernel_uses_llsc first Paul Burton
2019-10-01 21:53 ` Paul Burton [this message]
2019-10-01 21:53 ` [PATCH v2 18/36] MIPS: bitops: Use MIPS_ISA_REV, not #ifdefs Paul Burton
2019-10-01 21:53 ` [PATCH v2 19/36] MIPS: bitops: ins start position is always an immediate Paul Burton
2019-10-01 21:53 ` [PATCH v2 20/36] MIPS: bitops: Implement test_and_set_bit() in terms of _lock variant Paul Burton
2019-10-01 21:53 ` [PATCH v2 21/36] MIPS: bitops: Allow immediates in test_and_{set,clear,change}_bit Paul Burton
2019-10-01 21:53 ` [PATCH v2 22/36] MIPS: bitops: Use the BIT() macro Paul Burton
2019-10-01 21:53 ` [PATCH v2 23/36] MIPS: bitops: Avoid redundant zero-comparison for non-LLSC Paul Burton
2019-10-01 21:53 ` [PATCH v2 24/36] MIPS: bitops: Abstract LL/SC loops Paul Burton
2019-10-01 21:53 ` [PATCH v2 25/36] MIPS: bitops: Use BIT_WORD() & BITS_PER_LONG Paul Burton
2019-10-01 21:53 ` [PATCH v2 26/36] MIPS: bitops: Emit Loongson3 sync workarounds within asm Paul Burton
2019-10-01 21:53 ` [PATCH v2 27/36] MIPS: bitops: Use smp_mb__before_atomic in test_* ops Paul Burton
2019-10-01 21:53 ` [PATCH v2 28/36] MIPS: cmpxchg: Emit Loongson3 sync workarounds within asm Paul Burton
2019-10-01 21:53 ` [PATCH v2 30/36] MIPS: futex: " Paul Burton
2019-10-01 21:53 ` [PATCH v2 29/36] MIPS: cmpxchg: Omit redundant barriers for Loongson3 Paul Burton
2019-10-01 21:53 ` [PATCH v2 31/36] MIPS: syscall: Emit Loongson3 sync workarounds within asm Paul Burton
2019-10-01 21:53 ` [PATCH v2 32/36] MIPS: barrier: Remove loongson_llsc_mb() Paul Burton
2019-10-01 21:53 ` [PATCH v2 33/36] MIPS: barrier: Make __smp_mb__before_atomic() a no-op for Loongson3 Paul Burton
2019-10-01 21:53 ` [PATCH v2 34/36] MIPS: genex: Add Loongson3 LL/SC workaround to ejtag_debug_handler Paul Burton
2019-10-01 21:53 ` [PATCH v2 35/36] MIPS: genex: Don't reload address unnecessarily Paul Burton
2019-10-01 21:53 ` [PATCH v2 36/36] MIPS: Check Loongson3 LL/SC errata workaround correctness Paul Burton
2019-10-07 17:51 ` [PATCH v2 00/36] MIPS: barriers & atomics cleanups Paul Burton
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