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40 lines
756 B
ArmAsm
40 lines
756 B
ArmAsm
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build !gccgo
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#include "textflag.h"
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TEXT ·RewindAndSetgid(SB),NOSPLIT,$-8-0
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// Save link register
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MOVD R30, R9
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// Rewind stack pointer so anything that happens on the stack
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// will clobber the test pattern created by the caller
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ADD $(1024 * 8), RSP
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// Ask signaller to setgid
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MOVD $·Baton(SB), R0
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MOVD $1, R1
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storeloop:
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LDAXRW (R0), R2
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STLXRW R1, (R0), R3
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CBNZ R3, storeloop
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// Wait for setgid completion
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MOVW $0, R1
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MOVW $0, R2
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loop:
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LDAXRW (R0), R3
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CMPW R1, R3
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BNE loop
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STLXRW R2, (R0), R3
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CBNZ R3, loop
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// Restore stack
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SUB $(1024 * 8), RSP
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MOVD R9, R30
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RET
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