syscall: define Syscall6 in terms of RawSyscall6 on linux

This is an exact copy of CL 388478 after fixing #52472 in CL 401654.

For #51087
For #52472

Change-Id: I6c6bd7ddcab1512c682e6b44f61c7bcde97f5c58
Reviewed-on: https://go-review.googlesource.com/c/go/+/401655
Run-TryBot: Michael Pratt <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>

Author: prattmic

src/syscall/asm_linux_386.s

@@ -13,32 +13,6 @@
 // instead of the glibc-specific "CALL 0x10(GS)".
 #define INVOKE_SYSCALL	INT	$0x80
 
-// func Syscall6(trap uintptr, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr);
-TEXT ·Syscall6(SB),NOSPLIT,$0-40
-	CALL	runtime·entersyscall(SB)
-	MOVL	trap+0(FP), AX	// syscall entry
-	MOVL	a1+4(FP), BX
-	MOVL	a2+8(FP), CX
-	MOVL	a3+12(FP), DX
-	MOVL	a4+16(FP), SI
-	MOVL	a5+20(FP), DI
-	MOVL	a6+24(FP), BP
-	INVOKE_SYSCALL
-	CMPL	AX, $0xfffff001
-	JLS	ok6
-	MOVL	$-1, r1+28(FP)
-	MOVL	$0, r2+32(FP)
-	NEGL	AX
-	MOVL	AX, err+36(FP)
-	CALL	runtime·exitsyscall(SB)
-	RET
-ok6:
-	MOVL	AX, r1+28(FP)
-	MOVL	DX, r2+32(FP)
-	MOVL	$0, err+36(FP)
-	CALL	runtime·exitsyscall(SB)
-	RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-16
 	MOVL	trap+0(FP), AX	// syscall entry

src/syscall/asm_linux_amd64.s

@@ -11,32 +11,6 @@
 
 #define SYS_gettimeofday 96
 
-// func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
-TEXT ·Syscall6(SB),NOSPLIT,$0-80
-	CALL	runtime·entersyscall<ABIInternal>(SB)
-	MOVQ	a1+8(FP), DI
-	MOVQ	a2+16(FP), SI
-	MOVQ	a3+24(FP), DX
-	MOVQ	a4+32(FP), R10
-	MOVQ	a5+40(FP), R8
-	MOVQ	a6+48(FP), R9
-	MOVQ	trap+0(FP), AX	// syscall entry
-	SYSCALL
-	CMPQ	AX, $0xfffffffffffff001
-	JLS	ok6
-	MOVQ	$-1, r1+56(FP)
-	MOVQ	$0, r2+64(FP)
-	NEGQ	AX
-	MOVQ	AX, err+72(FP)
-	CALL	runtime·exitsyscall<ABIInternal>(SB)
-	RET
-ok6:
-	MOVQ	AX, r1+56(FP)
-	MOVQ	DX, r2+64(FP)
-	MOVQ	$0, err+72(FP)
-	CALL	runtime·exitsyscall<ABIInternal>(SB)
-	RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
 	MOVQ	a1+8(FP), DI

src/syscall/asm_linux_arm.s

@@ -9,37 +9,6 @@
 // System calls for arm, Linux
 //
 
-// func Syscall6(trap uintptr, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr);
-// Actually Syscall5 but the rest of the code expects it to be named Syscall6.
-TEXT ·Syscall6(SB),NOSPLIT,$0-40
-	BL	runtime·entersyscall(SB)
-	MOVW	trap+0(FP), R7	// syscall entry
-	MOVW	a1+4(FP), R0
-	MOVW	a2+8(FP), R1
-	MOVW	a3+12(FP), R2
-	MOVW	a4+16(FP), R3
-	MOVW	a5+20(FP), R4
-	MOVW	a6+24(FP), R5
-	SWI	$0
-	MOVW	$0xfffff001, R6
-	CMP	R6, R0
-	BLS	ok6
-	MOVW	$-1, R1
-	MOVW	R1, r1+28(FP)
-	MOVW	$0, R2
-	MOVW	R2, r2+32(FP)
-	RSB	$0, R0, R0
-	MOVW	R0, err+36(FP)
-	BL	runtime·exitsyscall(SB)
-	RET
-ok6:
-	MOVW	R0, r1+28(FP)
-	MOVW	R1, r2+32(FP)
-	MOVW	$0, R0
-	MOVW	R0, err+36(FP)
-	BL	runtime·exitsyscall(SB)
-	RET
-
 #define SYS__LLSEEK 140  /* from zsysnum_linux_arm.go */
 // func seek(fd int, offset int64, whence int) (newoffset int64, errno int)
 // Implemented in assembly to avoid allocation when

src/syscall/asm_linux_arm64.s

@@ -4,32 +4,6 @@
 
 #include "textflag.h"
 
-TEXT ·Syscall6(SB),NOSPLIT,$0-80
-	BL	runtime·entersyscall<ABIInternal>(SB)
-	MOVD	a1+8(FP), R0
-	MOVD	a2+16(FP), R1
-	MOVD	a3+24(FP), R2
-	MOVD	a4+32(FP), R3
-	MOVD	a5+40(FP), R4
-	MOVD	a6+48(FP), R5
-	MOVD	trap+0(FP), R8	// syscall entry
-	SVC
-	CMN	$4095, R0
-	BCC	ok
-	MOVD	$-1, R4
-	MOVD	R4, r1+56(FP)	// r1
-	MOVD	ZR, r2+64(FP)	// r2
-	NEG	R0, R0
-	MOVD	R0, err+72(FP)	// errno
-	BL	runtime·exitsyscall<ABIInternal>(SB)
-	RET
-ok:
-	MOVD	R0, r1+56(FP)	// r1
-	MOVD	R1, r2+64(FP)	// r2
-	MOVD	ZR, err+72(FP)	// errno
-	BL	runtime·exitsyscall<ABIInternal>(SB)
-	RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT,$0-32
 	MOVD	a1+8(FP), R0

src/syscall/asm_linux_mips64x.s

@@ -10,30 +10,6 @@
 // System calls for mips64, Linux
 //
 
-TEXT ·Syscall6(SB),NOSPLIT,$0-80
-	JAL	runtime·entersyscall(SB)
-	MOVV	a1+8(FP), R4
-	MOVV	a2+16(FP), R5
-	MOVV	a3+24(FP), R6
-	MOVV	a4+32(FP), R7
-	MOVV	a5+40(FP), R8
-	MOVV	a6+48(FP), R9
-	MOVV	trap+0(FP), R2	// syscall entry
-	SYSCALL
-	BEQ	R7, ok6
-	MOVV	$-1, R1
-	MOVV	R1, r1+56(FP)	// r1
-	MOVV	R0, r2+64(FP)	// r2
-	MOVV	R2, err+72(FP)	// errno
-	JAL	runtime·exitsyscall(SB)
-	RET
-ok6:
-	MOVV	R2, r1+56(FP)	// r1
-	MOVV	R3, r2+64(FP)	// r2
-	MOVV	R0, err+72(FP)	// errno
-	JAL	runtime·exitsyscall(SB)
-	RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
 	MOVV	a1+8(FP), R4

src/syscall/asm_linux_mipsx.s

@@ -11,36 +11,6 @@
 // System calls for mips, Linux
 //
 
-// func Syscall6(trap trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr);
-// 5th and 6th arg go at sp+16, sp+20.
-// Note that frame size of 20 means that 24 bytes gets reserved on stack.
-TEXT ·Syscall6(SB),NOSPLIT,$20-40
-	NO_LOCAL_POINTERS
-	JAL	runtime·entersyscall(SB)
-	MOVW	a1+4(FP), R4
-	MOVW	a2+8(FP), R5
-	MOVW	a3+12(FP), R6
-	MOVW	a4+16(FP), R7
-	MOVW	a5+20(FP), R8
-	MOVW	a6+24(FP), R9
-	MOVW	R8, 16(R29)
-	MOVW	R9, 20(R29)
-	MOVW	trap+0(FP), R2	// syscall entry
-	SYSCALL
-	BEQ	R7, ok6
-	MOVW	$-1, R1
-	MOVW	R1, r1+28(FP)	// r1
-	MOVW	R0, r2+32(FP)	// r2
-	MOVW	R2, err+36(FP)	// errno
-	JAL	runtime·exitsyscall(SB)
-	RET
-ok6:
-	MOVW	R2, r1+28(FP)	// r1
-	MOVW	R3, r2+32(FP)	// r2
-	MOVW	R0, err+36(FP)	// errno
-	JAL	runtime·exitsyscall(SB)
-	RET
-
 // func Syscall9(trap trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr);
 // Actually Syscall8 but the rest of the code expects it to be named Syscall9.
 TEXT ·Syscall9(SB),NOSPLIT,$28-52

src/syscall/asm_linux_ppc64x.s

@@ -10,30 +10,6 @@
 // System calls for ppc64, Linux
 //
 
-TEXT ·Syscall6(SB),NOSPLIT,$0-80
-	BL	runtime·entersyscall<ABIInternal>(SB)
-	MOVD	a1+8(FP), R3
-	MOVD	a2+16(FP), R4
-	MOVD	a3+24(FP), R5
-	MOVD	a4+32(FP), R6
-	MOVD	a5+40(FP), R7
-	MOVD	a6+48(FP), R8
-	MOVD	trap+0(FP), R9	// syscall entry
-	SYSCALL R9
-	BVC	ok6
-	MOVD	$-1, R4
-	MOVD	R4, r1+56(FP)	// r1
-	MOVD	R0, r2+64(FP)	// r2
-	MOVD	R3, err+72(FP)	// errno
-	BL	runtime·exitsyscall<ABIInternal>(SB)
-	RET
-ok6:
-	MOVD	R3, r1+56(FP)	// r1
-	MOVD	R0, r2+64(FP)	// r2
-	MOVD	R0, err+72(FP)	// errno
-	BL	runtime·exitsyscall<ABIInternal>(SB)
-	RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
 	MOVD	a1+8(FP), R3

src/syscall/asm_linux_riscv64.s

@@ -8,33 +8,6 @@
 // System calls for riscv64, Linux
 //
 
-// func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
-TEXT ·Syscall6(SB),NOSPLIT,$0-80
-	CALL	runtime·entersyscall(SB)
-	MOV	a1+8(FP), A0
-	MOV	a2+16(FP), A1
-	MOV	a3+24(FP), A2
-	MOV	a4+32(FP), A3
-	MOV	a5+40(FP), A4
-	MOV	a6+48(FP), A5
-	MOV	trap+0(FP), A7	// syscall entry
-	ECALL
-	MOV	$-4096, T0
-	BLTU	T0, A0, err
-	MOV	A0, r1+56(FP)	// r1
-	MOV	A1, r2+64(FP)	// r2
-	MOV	ZERO, err+72(FP)	// errno
-	CALL	runtime·exitsyscall(SB)
-	RET
-err:
-	MOV	$-1, T0
-	MOV	T0, r1+56(FP)	// r1
-	MOV	ZERO, r2+64(FP)	// r2
-	SUB	A0, ZERO, A0
-	MOV	A0, err+72(FP)	// errno
-	CALL	runtime·exitsyscall(SB)
-	RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
 	MOV	a1+8(FP), A0

src/syscall/asm_linux_s390x.s

@@ -8,32 +8,6 @@
 // System calls for s390x, Linux
 //
 
-// func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
-TEXT ·Syscall6(SB),NOSPLIT,$0-80
-	BL	runtime·entersyscall(SB)
-	MOVD	a1+8(FP), R2
-	MOVD	a2+16(FP), R3
-	MOVD	a3+24(FP), R4
-	MOVD	a4+32(FP), R5
-	MOVD	a5+40(FP), R6
-	MOVD	a6+48(FP), R7
-	MOVD	trap+0(FP), R1	// syscall entry
-	SYSCALL
-	MOVD	$0xfffffffffffff001, R8
-	CMPUBLT	R2, R8, ok6
-	MOVD	$-1, r1+56(FP)
-	MOVD	$0, r2+64(FP)
-	NEG	R2, R2
-	MOVD	R2, err+72(FP)	// errno
-	BL	runtime·exitsyscall(SB)
-	RET
-ok6:
-	MOVD	R2, r1+56(FP)
-	MOVD	R3, r2+64(FP)
-	MOVD	$0, err+72(FP)	// errno
-	BL	runtime·exitsyscall(SB)
-	RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
 	MOVD	$0, R2

src/syscall/syscall_linux.go

@@ -16,8 +16,6 @@ import (
 	"unsafe"
 )
 
-func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
-
 // N.B. RawSyscall6 is provided via linkname by runtime/internal/syscall.
 //
 // Errno is uintptr and thus compatible with the runtime/internal/syscall
@@ -80,6 +78,16 @@ func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
 	return
 }
 
+//go:uintptrkeepalive
+//go:nosplit
+//go:linkname Syscall6
+func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
+	runtime_entersyscall()
+	r1, r2, err = RawSyscall6(trap, a1, a2, a3, a4, a5, a6)
+	runtime_exitsyscall()
+	return
+}
+
 func rawSyscallNoError(trap, a1, a2, a3 uintptr) (r1, r2 uintptr)
 
 /*