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| author | Will Deacon <will.deacon@arm.com> | 2015-02-12 04:17:37 +0000 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2015-07-27 15:28:51 +0100 |
| commit | 084f903727e1c3a61d6bcdaeeed30bddc6d7f65a (patch) | |
| tree | 614b95211ba1f8b103ed8f8b9de13ee14a5fab8b /arch/arm64/lib | |
| parent | 81bb5c6420635dfd058c210bd342c29c95ccd145 (diff) | |
| download | op-kernel-dev-084f903727e1c3a61d6bcdaeeed30bddc6d7f65a.zip op-kernel-dev-084f903727e1c3a61d6bcdaeeed30bddc6d7f65a.tar.gz | |
arm64: bitops: patch in lse instructions when supported by the CPU
On CPUs which support the LSE atomic instructions introduced in ARMv8.1,
it makes sense to use them in preference to ll/sc sequences.
This patch introduces runtime patching of our bitops functions so that
LSE atomic instructions are used instead.
Reviewed-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/lib')
| -rw-r--r-- | arch/arm64/lib/bitops.S | 43 |
1 files changed, 24 insertions, 19 deletions
diff --git a/arch/arm64/lib/bitops.S b/arch/arm64/lib/bitops.S index 7dac371..bc18457 100644 --- a/arch/arm64/lib/bitops.S +++ b/arch/arm64/lib/bitops.S @@ -18,52 +18,57 @@ #include <linux/linkage.h> #include <asm/assembler.h> +#include <asm/lse.h> /* * x0: bits 5:0 bit offset * bits 31:6 word offset * x1: address */ - .macro bitop, name, instr + .macro bitop, name, llsc, lse ENTRY( \name ) and w3, w0, #63 // Get bit offset eor w0, w0, w3 // Clear low bits mov x2, #1 add x1, x1, x0, lsr #3 // Get word offset lsl x3, x2, x3 // Create mask -1: ldxr x2, [x1] - \instr x2, x2, x3 - stxr w0, x2, [x1] - cbnz w0, 1b + +alt_lse "1: ldxr x2, [x1]", "\lse x3, [x1]" +alt_lse " \llsc x2, x2, x3", "nop" +alt_lse " stxr w0, x2, [x1]", "nop" +alt_lse " cbnz w0, 1b", "nop" + ret ENDPROC(\name ) .endm - .macro testop, name, instr + .macro testop, name, llsc, lse ENTRY( \name ) and w3, w0, #63 // Get bit offset eor w0, w0, w3 // Clear low bits mov x2, #1 add x1, x1, x0, lsr #3 // Get word offset lsl x4, x2, x3 // Create mask -1: ldxr x2, [x1] - lsr x0, x2, x3 // Save old value of bit - \instr x2, x2, x4 // toggle bit - stlxr w5, x2, [x1] - cbnz w5, 1b - dmb ish + +alt_lse "1: ldxr x2, [x1]", "\lse x4, x2, [x1]" + lsr x0, x2, x3 +alt_lse " \llsc x2, x2, x4", "nop" +alt_lse " stlxr w5, x2, [x1]", "nop" +alt_lse " cbnz w5, 1b", "nop" +alt_lse " dmb ish", "nop" + and x0, x0, #1 -3: ret + ret ENDPROC(\name ) .endm /* * Atomic bit operations. */ - bitop change_bit, eor - bitop clear_bit, bic - bitop set_bit, orr + bitop change_bit, eor, steor + bitop clear_bit, bic, stclr + bitop set_bit, orr, stset - testop test_and_change_bit, eor - testop test_and_clear_bit, bic - testop test_and_set_bit, orr + testop test_and_change_bit, eor, ldeoral + testop test_and_clear_bit, bic, ldclral + testop test_and_set_bit, orr, ldsetal |
