syscall: make func Syscall use pointer maps from Go prototypes

Before, Syscall and friends were having their arguments
treated conservatively. Now they will use the Go prototype,
which will mean the arguments are not considered pointers
at all.

This is safe because of CL 139360044.

The fact that all these non-Solaris systems were using
conservative scanning of the Syscall arguments is why
the failure that prompted CL 139360044 was only
observed on Solaris, which does something completely different.
If we'd done this earlier, we'd have seen the Solaris
failure in more places.

LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/144730043

src/syscall/asm_darwin_386.s

@@ -16,6 +16,7 @@
 // Trap # in AX, args on stack above caller pc.
 
 TEXT	·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -40,6 +41,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -67,6 +69,7 @@ ok6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-52
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -97,6 +100,7 @@ ok9:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI
@@ -118,6 +122,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI

src/syscall/asm_darwin_amd64.s

@@ -6,6 +6,7 @@
 // so that go vet can check that they are correct.
 
 #include "textflag.h"
+#include "funcdata.h"
 
 //
 // System call support for AMD64, Darwin
@@ -16,6 +17,7 @@
 // Trap # in AX, args in DI SI DX, return in AX DX
 
 TEXT	·Syscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
@@ -40,6 +42,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
@@ -64,6 +67,7 @@ ok6:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX
@@ -85,6 +89,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX

src/syscall/asm_dragonfly_386.s

@@ -13,6 +13,7 @@
 // Trap # in AX, args on stack above caller pc.
 
 TEXT	·Syscall(SB),NOSPLIT,$0-32
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -37,6 +38,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-44
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -64,6 +66,7 @@ ok6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-56
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -94,6 +97,7 @@ ok9:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-32
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI
@@ -115,6 +119,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-44
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI

src/syscall/asm_dragonfly_amd64.s

@@ -14,6 +14,7 @@
 // Trap # in AX, args in DI SI DX, return in AX DX
 
 TEXT	·Syscall(SB),NOSPLIT,$0-64
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
@@ -37,6 +38,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-88
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
@@ -60,6 +62,7 @@ ok6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-112
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), AX
 	MOVQ	16(SP), DI
@@ -93,6 +96,7 @@ ok9:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-64
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX
@@ -113,6 +117,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-88
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX

src/syscall/asm_freebsd_386.s

@@ -16,6 +16,7 @@
 // Trap # in AX, args on stack above caller pc.
 
 TEXT	·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -40,6 +41,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -67,6 +69,7 @@ ok6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-52
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -97,6 +100,7 @@ ok9:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI
@@ -118,6 +122,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI

src/syscall/asm_freebsd_amd64.s

@@ -22,6 +22,7 @@
 // Trap # in AX, args in DI SI DX, return in AX DX
 
 TEXT	·Syscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
@@ -45,6 +46,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
@@ -68,6 +70,7 @@ ok6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-104
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), AX
 	MOVQ	16(SP), DI
@@ -101,6 +104,7 @@ ok9:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX
@@ -121,6 +125,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX

src/syscall/asm_freebsd_arm.s

@@ -13,6 +13,7 @@
 // func Syscall9(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, errno uintptr)
 
 TEXT	·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	BL runtime·entersyscall(SB)
 	MOVW 0(FP), R7 // syscall number
 	MOVW 4(FP), R0 // a1
@@ -35,6 +36,7 @@ error:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	BL runtime·entersyscall(SB)
 	MOVW 0(FP), R7 // syscall number
 	MOVW 4(FP), R0 // a1
@@ -61,6 +63,7 @@ error6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-52
+	GO_ARGS
 	BL runtime·entersyscall(SB)
 	MOVW 0(FP), R7 // syscall number
 	MOVW 4(FP), R0 // a1
@@ -87,6 +90,7 @@ error9:
 	RET
 
 TEXT	·RawSyscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	MOVW 0(FP), R7 // syscall number
 	MOVW 4(FP), R0 // a1
 	MOVW 8(FP), R1 // a2
@@ -106,6 +110,7 @@ errorr:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	MOVW 0(FP), R7 // syscall number
 	MOVW 4(FP), R0 // a1
 	MOVW 8(FP), R1 // a2

src/syscall/asm_linux_386.s

@@ -15,6 +15,7 @@
 // Trap # in AX, args in BX CX DX SI DI, return in AX
 
 TEXT	·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	MOVL	8(SP), BX
@@ -40,6 +41,7 @@ ok:
 
 // func Syscall6(trap uintptr, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr);
 TEXT	·Syscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	MOVL	8(SP), BX
@@ -66,6 +68,7 @@ ok6:
 
 // func RawSyscall(trap uintptr, a1, a2, a3 uintptr) (r1, r2, err uintptr);
 TEXT ·RawSyscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	MOVL	8(SP), BX
 	MOVL	12(SP), CX
@@ -88,6 +91,7 @@ ok1:
 
 // func RawSyscall6(trap uintptr, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr);
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	MOVL	8(SP), BX
 	MOVL	12(SP), CX

src/syscall/asm_linux_amd64.s

@@ -17,6 +17,7 @@
 // would pass 4th arg in CX, not R10.
 
 TEXT	·Syscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
@@ -42,6 +43,7 @@ ok:
 	RET
 
 TEXT ·Syscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
@@ -67,6 +69,7 @@ ok6:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX
@@ -89,6 +92,7 @@ ok1:
 	RET
 
 TEXT ·RawSyscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX

src/syscall/asm_linux_arm.s

@@ -13,6 +13,7 @@
 // func Syscall(syscall uintptr, a1, a2, a3 uintptr) (r1, r2, err uintptr);
 
 TEXT	·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	BL		runtime·entersyscall(SB)
 	MOVW	4(SP), R7
 	MOVW	8(SP), R0
@@ -44,6 +45,7 @@ ok:
 // 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
+	GO_ARGS
 	BL		runtime·entersyscall(SB)
 	MOVW	4(SP), R7	// syscall entry
 	MOVW	8(SP), R0
@@ -75,6 +77,7 @@ ok6:
 // func RawSyscall6(trap uintptr, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr);
 // Actually RawSyscall5 but the rest of the code expects it to be named RawSyscall6.
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	MOVW	4(SP), R7	// syscall entry
 	MOVW	8(SP), R0
 	MOVW	12(SP), R1
@@ -134,6 +137,7 @@ okseek:
 
 // func RawSyscall(trap uintptr, a1, a2, a3 uintptr) (r1, r2, err uintptr);
 TEXT ·RawSyscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	MOVW	4(SP), R7	// syscall entry
 	MOVW	8(SP), R0
 	MOVW	12(SP), R1

src/syscall/asm_nacl_386.s

@@ -16,6 +16,7 @@
 	MOVL $(0x10000 + ((code)<<5)), AX; JMP AX
 
 TEXT syscall·Syscall(SB),NOSPLIT,$12-28
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	trap+0(FP), AX
 	MOVL	a1+4(FP), BX

src/syscall/asm_nacl_amd64p32.s

@@ -16,6 +16,7 @@
 	MOVL $(0x10000 + ((code)<<5)), AX; JMP AX
 
 TEXT syscall·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	trap+0(FP), AX
 	MOVL	a1+4(FP), DI

src/syscall/asm_nacl_arm.s

@@ -16,6 +16,7 @@
 	MOVW $(0x10000 + ((code)<<5)), R8; B (R8)
 
 TEXT syscall·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	BL	runtime·entersyscall(SB)
 	MOVW	trap+0(FP), R8
 	MOVW	a1+4(FP), R0

src/syscall/asm_netbsd_386.s

@@ -16,6 +16,7 @@
 // Trap # in AX, args on stack above caller pc.
 
 TEXT	·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -40,6 +41,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -67,6 +69,7 @@ ok6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-52
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -97,6 +100,7 @@ ok9:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI
@@ -118,6 +122,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI

src/syscall/asm_netbsd_amd64.s

@@ -17,6 +17,7 @@
 // Trap # in AX, args in DI SI DX, return in AX DX
 
 TEXT	·Syscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), AX	// syscall entry
 	MOVQ	16(SP), DI
@@ -40,6 +41,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), AX	// syscall entry
 	MOVQ	16(SP), DI
@@ -63,6 +65,7 @@ ok6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-104
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), AX	// syscall entry
 	MOVQ	16(SP), DI
@@ -95,6 +98,7 @@ ok9:
 	RET
 
 TEXT	·RawSyscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX
@@ -115,6 +119,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX

src/syscall/asm_netbsd_arm.s

@@ -13,6 +13,7 @@
 // func Syscall9(trap int32, a1, a2, a3, a4, a5, a6, a7, a8, a9 int64) (r1, r2, err int32)
 
 TEXT	·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	BL runtime·entersyscall(SB)
 	MOVW 0(FP), R0 // sigcall num
 	MOVW 4(FP), R1 // a1
@@ -35,6 +36,7 @@ error:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	BL runtime·entersyscall(SB)
 	MOVW 0(FP), R0 // sigcall num
 	MOVW 4(FP), R1 // a1
@@ -60,6 +62,7 @@ error6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-52
+	GO_ARGS
 	BL runtime·entersyscall(SB)
 	MOVW 0(FP), R0 // sigcall num
 	MOVW 4(FP), R1 // a1
@@ -85,6 +88,7 @@ error9:
 	RET
 
 TEXT	·RawSyscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	MOVW 0(FP), R0 // sigcall num
 	MOVW 4(FP), R1 // a1
 	MOVW 8(FP), R2 // a2
@@ -104,6 +108,7 @@ errorr:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	MOVW 0(FP), R0 // sigcall num
 	MOVW 4(FP), R1 // a1
 	MOVW 8(FP), R2 // a2

src/syscall/asm_openbsd_386.s

@@ -16,6 +16,7 @@
 // Trap # in AX, args on stack above caller pc.
 
 TEXT	·Syscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -40,6 +41,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -67,6 +69,7 @@ ok6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-52
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -97,6 +100,7 @@ ok9:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI
@@ -118,6 +122,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI

src/syscall/asm_openbsd_amd64.s

@@ -17,6 +17,7 @@
 // Trap # in AX, args in DI SI DX, return in AX DX
 
 TEXT	·Syscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), AX	// syscall entry
 	MOVQ	16(SP), DI
@@ -40,6 +41,7 @@ ok:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), AX	// syscall entry
 	MOVQ	16(SP), DI
@@ -63,6 +65,7 @@ ok6:
 	RET
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-104
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), AX	// syscall entry
 	MOVQ	16(SP), DI
@@ -95,6 +98,7 @@ ok9:
 	RET
 
 TEXT	·RawSyscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX
@@ -115,6 +119,7 @@ ok1:
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	MOVQ	16(SP), DI
 	MOVQ	24(SP), SI
 	MOVQ	32(SP), DX

src/syscall/asm_plan9_386.s

@@ -18,6 +18,7 @@
 
 // Trap # in AX, args on stack above caller pc.
 TEXT	·Syscall(SB),NOSPLIT,$0-32
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -53,6 +54,7 @@ copyresult3:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-44
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
@@ -91,6 +93,7 @@ copyresult4:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-28
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI
@@ -106,6 +109,7 @@ TEXT ·RawSyscall(SB),NOSPLIT,$0-28
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
+	GO_ARGS
 	MOVL	4(SP), AX	// syscall entry
 	// slide args down on top of system call number
 	LEAL		8(SP), SI

src/syscall/asm_plan9_amd64.s

@@ -17,6 +17,7 @@
 //func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
 
 TEXT	·Syscall(SB),NOSPLIT,$0-64
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), BP	// syscall entry
 	// slide args down on top of system call number
@@ -52,6 +53,7 @@ copyresult3:
 	RET
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-88
+	GO_ARGS
 	CALL	runtime·entersyscall(SB)
 	MOVQ	8(SP), BP	// syscall entry
 	// slide args down on top of system call number
@@ -90,6 +92,7 @@ copyresult4:
 	RET
 
 TEXT ·RawSyscall(SB),NOSPLIT,$0-56
+	GO_ARGS
 	MOVQ	8(SP), BP	// syscall entry
 	// slide args down on top of system call number
 	LEAQ		16(SP), SI
@@ -105,6 +108,7 @@ TEXT ·RawSyscall(SB),NOSPLIT,$0-56
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-80
+	GO_ARGS
 	MOVQ	8(SP), BP	// syscall entry
 	// slide args down on top of system call number
 	LEAQ		16(SP), SI