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https://github.com/golang/go
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1b49487692
To avoid allocation between entersyscall and exitsyscall in Plan 9, syscall error strings retrieved from the OS were being stored in a shared buffer for each M, leading to overwriting of error strings by subsequent syscalls, and potential confusion if exitsyscall switched to a different M. Instead, the error string is now retrieved to the G stack and then copied to a new allocated array after exitsyscall. A new test TestPlan9Syserr is provided to confirm the correction. Fixes #13770 Fixes #24921 Change-Id: I013c4a42baae80d03a5b61d828396527189f5551 Reviewed-on: https://go-review.googlesource.com/111195 Reviewed-by: David du Colombier <0intro@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: David du Colombier <0intro@gmail.com>
133 lines
3.2 KiB
ArmAsm
133 lines
3.2 KiB
ArmAsm
// Copyright 2009 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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#include "textflag.h"
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#include "funcdata.h"
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#define SYS_ERRSTR 41 /* from zsysnum_plan9.go */
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#define SYS_SEEK 39 /* from zsysnum_plan9.go */
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// System call support for plan9 on arm
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//func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err ErrorString)
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TEXT ·Syscall(SB),NOSPLIT,$144-32
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NO_LOCAL_POINTERS
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BL runtime·entersyscall(SB)
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MOVW $a1+4(FP), R0 // move syscall args
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MOVW $sysargs-144(SP), R1
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MOVM.IA (R0), [R2-R4]
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MOVM.IA [R2-R4], (R1)
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MOVW trap+0(FP), R0 // syscall num
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SWI $0
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MOVW $0, R2
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MOVW $r1+16(FP), R3
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MOVM.IA [R0,R2], (R3)
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CMP $-1, R0
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B.EQ syscallerr
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BL runtime·exitsyscall(SB)
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MOVW $·emptystring+0(SB), R2
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B syscallok
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syscallerr:
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MOVW $errbuf-128(SP), R2
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MOVW $128, R3
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MOVM.IA [R2,R3], (R1)
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MOVW $SYS_ERRSTR, R0
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SWI $0
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BL runtime·exitsyscall(SB)
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BL runtime·gostring(SB)
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MOVW $str-140(SP), R2
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syscallok:
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MOVW $err+24(FP), R1
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MOVM.IA (R2), [R3-R4]
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MOVM.IA [R3-R4], (R1)
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RET
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//func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err ErrorString)
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// Actually Syscall5 but the rest of the code expects it to be named Syscall6.
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TEXT ·Syscall6(SB),NOSPLIT,$144-44
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NO_LOCAL_POINTERS
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BL runtime·entersyscall(SB)
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MOVW $a1+4(FP), R0 // move syscall args
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MOVW $sysargs-144(SP), R1
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MOVM.IA (R0), [R2-R6]
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MOVM.IA [R2-R6], (R1)
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MOVW trap+0(FP), R0 // syscall num
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SWI $0
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MOVW $0, R2
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MOVW $r1+28(FP), R3
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MOVM.IA.W [R0,R2], (R3)
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CMP $-1, R0
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B.EQ syscall6err
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BL runtime·exitsyscall(SB)
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MOVW $·emptystring+0(SB), R2
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B syscall6ok
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syscall6err:
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MOVW $errbuf-128(SP), R2
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MOVW $128, R3
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MOVM.IA [R2,R3], (R1)
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MOVW $SYS_ERRSTR, R0
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SWI $0
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BL runtime·exitsyscall(SB)
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BL runtime·gostring(SB)
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MOVW $str-140(SP), R2
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syscall6ok:
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MOVW $err+36(FP), R1
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MOVM.IA (R2), [R3-R4]
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MOVM.IA [R3-R4], (R1)
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RET
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//func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
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TEXT ·RawSyscall(SB),NOSPLIT,$12-28
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MOVW $a1+4(FP), R0 // move syscall args
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MOVW $sysargs-12(SP), R1
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MOVM.IA (R0), [R2-R4]
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MOVM.IA [R2-R4], (R1)
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MOVW trap+0(FP), R0 // syscall num
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SWI $0
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MOVW R0, r1+16(FP)
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MOVW R0, r2+20(FP)
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MOVW R0, err+24(FP)
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RET
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//func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
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// Actually RawSyscall5 but the rest of the code expects it to be named RawSyscall6.
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TEXT ·RawSyscall6(SB),NOSPLIT,$20-40
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MOVW $a1+4(FP), R0 // move syscall args
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MOVW $sysargs-20(SP), R1
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MOVM.IA (R0), [R2-R6]
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MOVM.IA [R2-R6], (R1)
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MOVW trap+0(FP), R0 // syscall num
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SWI $0
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MOVW R0, r1+28(FP)
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MOVW R0, r2+32(FP)
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MOVW R0, err+36(FP)
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RET
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//func seek(placeholder uintptr, fd int, offset int64, whence int) (newoffset int64, err string)
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TEXT ·seek(SB),NOSPLIT,$20-36
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NO_LOCAL_POINTERS
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MOVW $newoffset_lo+20(FP), R6
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MOVW R6, sysargs-20(SP) // dest for return value
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MOVW $fd+4(FP), R0 // move syscall args
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MOVW $sysarg1-16(SP), R1
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MOVM.IA (R0), [R2-R5]
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MOVM.IA [R2-R5], (R1)
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MOVW $SYS_SEEK, R0 // syscall num
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SWI $0
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CMP $-1, R0
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B.EQ seekerr
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MOVW $·emptystring+0(SB), R2
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B seekok
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seekerr:
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MOVW R0, 0(R6)
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MOVW R0, 4(R6)
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BL ·errstr(SB)
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MOVW $ret-20(SP), R2
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seekok:
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MOVW $err+28(FP), R1
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MOVM.IA (R2), [R3-R4]
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MOVM.IA [R3-R4], (R1)
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RET
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