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Diffstat (limited to 'pkg/safecopy/atomic_arm64.s')
| -rw-r--r-- | pkg/safecopy/atomic_arm64.s | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/pkg/safecopy/atomic_arm64.s b/pkg/safecopy/atomic_arm64.s new file mode 100644 index 000000000..d58ed71f7 --- /dev/null +++ b/pkg/safecopy/atomic_arm64.s @@ -0,0 +1,126 @@ +// Copyright 2014 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "textflag.h" + +// handleSwapUint32Fault returns the value stored in R1. Control is transferred +// to it when swapUint32 below receives SIGSEGV or SIGBUS, with the signal +// number stored in R1. +// +// It must have the same frame configuration as swapUint32 so that it can undo +// any potential call frame set up by the assembler. +TEXT handleSwapUint32Fault(SB), NOSPLIT, $0-24 + MOVW R1, sig+20(FP) + RET + +// See the corresponding doc in safecopy_unsafe.go +// +// The code is derived from Go source runtime/internal/atomic.Xchg. +// +//func swapUint32(ptr unsafe.Pointer, new uint32) (old uint32, sig int32) +TEXT ·swapUint32(SB), NOSPLIT, $0-24 + // Store 0 as the returned signal number. If we run to completion, + // this is the value the caller will see; if a signal is received, + // handleSwapUint32Fault will store a different value in this address. + MOVW $0, sig+20(FP) +again: + MOVD addr+0(FP), R0 + MOVW new+8(FP), R1 + LDAXRW (R0), R2 + STLXRW R1, (R0), R3 + CBNZ R3, again + MOVW R2, old+16(FP) + RET + +// handleSwapUint64Fault returns the value stored in R1. Control is transferred +// to it when swapUint64 below receives SIGSEGV or SIGBUS, with the signal +// number stored in R1. +// +// It must have the same frame configuration as swapUint64 so that it can undo +// any potential call frame set up by the assembler. +TEXT handleSwapUint64Fault(SB), NOSPLIT, $0-28 + MOVW R1, sig+24(FP) + RET + +// See the corresponding doc in safecopy_unsafe.go +// +// The code is derived from Go source runtime/internal/atomic.Xchg64. +// +//func swapUint64(ptr unsafe.Pointer, new uint64) (old uint64, sig int32) +TEXT ·swapUint64(SB), NOSPLIT, $0-28 + // Store 0 as the returned signal number. If we run to completion, + // this is the value the caller will see; if a signal is received, + // handleSwapUint64Fault will store a different value in this address. + MOVW $0, sig+24(FP) +again: + MOVD addr+0(FP), R0 + MOVD new+8(FP), R1 + LDAXR (R0), R2 + STLXR R1, (R0), R3 + CBNZ R3, again + MOVD R2, old+16(FP) + RET + +// handleCompareAndSwapUint32Fault returns the value stored in R1. Control is +// transferred to it when compareAndSwapUint32 below receives SIGSEGV or SIGBUS, +// with the signal number stored in R1. +// +// It must have the same frame configuration as compareAndSwapUint32 so that it +// can undo any potential call frame set up by the assembler. +TEXT handleCompareAndSwapUint32Fault(SB), NOSPLIT, $0-24 + MOVW R1, sig+20(FP) + RET + +// See the corresponding doc in safecopy_unsafe.go +// +// The code is derived from Go source runtime/internal/atomic.Cas. +// +//func compareAndSwapUint32(ptr unsafe.Pointer, old, new uint32) (prev uint32, sig int32) +TEXT ·compareAndSwapUint32(SB), NOSPLIT, $0-24 + // Store 0 as the returned signal number. If we run to completion, this is + // the value the caller will see; if a signal is received, + // handleCompareAndSwapUint32Fault will store a different value in this + // address. + MOVW $0, sig+20(FP) + + MOVD addr+0(FP), R0 + MOVW old+8(FP), R1 + MOVW new+12(FP), R2 +again: + LDAXRW (R0), R3 + CMPW R1, R3 + BNE done + STLXRW R2, (R0), R4 + CBNZ R4, again +done: + MOVW R3, prev+16(FP) + RET + +// handleLoadUint32Fault returns the value stored in DI. Control is transferred +// to it when LoadUint32 below receives SIGSEGV or SIGBUS, with the signal +// number stored in DI. +// +// It must have the same frame configuration as loadUint32 so that it can undo +// any potential call frame set up by the assembler. +TEXT handleLoadUint32Fault(SB), NOSPLIT, $0-16 + MOVW R1, sig+12(FP) + RET + +// loadUint32 atomically loads *addr and returns it. If a SIGSEGV or SIGBUS +// signal is received, the value returned is unspecified, and sig is the number +// of the signal that was received. +// +// Preconditions: addr must be aligned to a 4-byte boundary. +// +//func loadUint32(ptr unsafe.Pointer) (val uint32, sig int32) +TEXT ·loadUint32(SB), NOSPLIT, $0-16 + // Store 0 as the returned signal number. If we run to completion, + // this is the value the caller will see; if a signal is received, + // handleLoadUint32Fault will store a different value in this address. + MOVW $0, sig+12(FP) + + MOVD addr+0(FP), R0 + LDARW (R0), R1 + MOVW R1, val+8(FP) + RET |