syscall: define RawSyscall in terms of RawSyscall6 on linux

For #51087

Change-Id: I63e07638507328efe33dbf7dd5f8a8b78890e037
Reviewed-on: https://go-review.googlesource.com/c/go/+/388476
Run-TryBot: Michael Pratt <mpratt@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/syscall/asm_linux_386.s b/src/syscall/asm_linux_386.s
index a2b5efb2db2a1be839544e93f8df8530e606e219..546d27932d0335c3f107c80825ee2cccc6250be5 100644 (file)
--- a/src/syscall/asm_linux_386.s
+++ b/src/syscall/asm_linux_386.s
@@ -65,28 +65,6 @@ ok6:
        CALL    runtime·exitsyscall(SB)
        RET
 
-// func RawSyscall(trap uintptr, a1, a2, a3 uintptr) (r1, r2, err uintptr);
-TEXT ·RawSyscall(SB),NOSPLIT,$0-28
-       MOVL    trap+0(FP), AX  // syscall entry
-       MOVL    a1+4(FP), BX
-       MOVL    a2+8(FP), CX
-       MOVL    a3+12(FP), DX
-       MOVL    $0, SI
-       MOVL    $0, DI
-       INVOKE_SYSCALL
-       CMPL    AX, $0xfffff001
-       JLS     ok1
-       MOVL    $-1, r1+16(FP)
-       MOVL    $0, r2+20(FP)
-       NEGL    AX
-       MOVL    AX, err+24(FP)
-       RET
-ok1:
-       MOVL    AX, r1+16(FP)
-       MOVL    DX, r2+20(FP)
-       MOVL    $0, err+24(FP)
-       RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-16
        MOVL    trap+0(FP), AX  // syscall entry

diff --git a/src/syscall/asm_linux_amd64.s b/src/syscall/asm_linux_amd64.s
index a98125903ab0e43f4f13a2291178f38f6f045100..bd50b5ebfeff17dda6621b218f3d0095bc068bb6 100644 (file)
--- a/src/syscall/asm_linux_amd64.s
+++ b/src/syscall/asm_linux_amd64.s
@@ -64,26 +64,6 @@ ok6:
        CALL    runtime·exitsyscall<ABIInternal>(SB)
        RET
 
-// func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
-TEXT ·RawSyscall(SB),NOSPLIT,$0-56
-       MOVQ    a1+8(FP), DI
-       MOVQ    a2+16(FP), SI
-       MOVQ    a3+24(FP), DX
-       MOVQ    trap+0(FP), AX  // syscall entry
-       SYSCALL
-       CMPQ    AX, $0xfffffffffffff001
-       JLS     ok1
-       MOVQ    $-1, r1+32(FP)
-       MOVQ    $0, r2+40(FP)
-       NEGQ    AX
-       MOVQ    AX, err+48(FP)
-       RET
-ok1:
-       MOVQ    AX, r1+32(FP)
-       MOVQ    DX, r2+40(FP)
-       MOVQ    $0, err+48(FP)
-       RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
        MOVQ    a1+8(FP), DI

diff --git a/src/syscall/asm_linux_arm.s b/src/syscall/asm_linux_arm.s
index 50103172bac891b26f2170a4c030b18d78bea6f7..12986f801ec3a2ae53571be8fac341b4d9cd5893 100644 (file)
--- a/src/syscall/asm_linux_arm.s
+++ b/src/syscall/asm_linux_arm.s
@@ -102,30 +102,6 @@ okseek:
        BL      runtime·exitsyscall(SB)
        RET
 
-// func RawSyscall(trap uintptr, a1, a2, a3 uintptr) (r1, r2, err uintptr);
-TEXT ·RawSyscall(SB),NOSPLIT,$0-28
-       MOVW    trap+0(FP), R7  // syscall entry
-       MOVW    a1+4(FP), R0
-       MOVW    a2+8(FP), R1
-       MOVW    a3+12(FP), R2
-       SWI     $0
-       MOVW    $0xfffff001, R1
-       CMP     R1, R0
-       BLS     ok1
-       MOVW    $-1, R1
-       MOVW    R1, r1+16(FP)
-       MOVW    $0, R2
-       MOVW    R2, r2+20(FP)
-       RSB     $0, R0, R0
-       MOVW    R0, err+24(FP)
-       RET
-ok1:
-       MOVW    R0, r1+16(FP)
-       MOVW    $0, R0
-       MOVW    R0, r2+20(FP)
-       MOVW    R0, err+24(FP)
-       RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-16
        MOVW    trap+0(FP), R7  // syscall entry

diff --git a/src/syscall/asm_linux_arm64.s b/src/syscall/asm_linux_arm64.s
index c9c6bfab09c2b17d15cb72f7bc9920d9d9cf29d9..fc1466cc80cc9bfc7f66e8c37524ecffe7e89b82 100644 (file)
--- a/src/syscall/asm_linux_arm64.s
+++ b/src/syscall/asm_linux_arm64.s
@@ -57,29 +57,6 @@ ok:
        BL      runtime·exitsyscall<ABIInternal>(SB)
        RET
 
-TEXT ·RawSyscall(SB),NOSPLIT,$0-56
-       MOVD    a1+8(FP), R0
-       MOVD    a2+16(FP), R1
-       MOVD    a3+24(FP), R2
-       MOVD    $0, R3
-       MOVD    $0, R4
-       MOVD    $0, R5
-       MOVD    trap+0(FP), R8  // syscall entry
-       SVC
-       CMN     $4095, R0
-       BCC     ok
-       MOVD    $-1, R4
-       MOVD    R4, r1+32(FP)   // r1
-       MOVD    ZR, r2+40(FP)   // r2
-       NEG     R0, R0
-       MOVD    R0, err+48(FP)  // errno
-       RET
-ok:
-       MOVD    R0, r1+32(FP)   // r1
-       MOVD    R1, r2+40(FP)   // r2
-       MOVD    ZR, err+48(FP)  // errno
-       RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT,$0-32
        MOVD    a1+8(FP), R0

diff --git a/src/syscall/asm_linux_mips64x.s b/src/syscall/asm_linux_mips64x.s
index bc2f72c96517c1a1f1a791a630a05b146c62007a..b6f293471de6b798c6cca1205bf567ad4b65944b 100644 (file)
--- a/src/syscall/asm_linux_mips64x.s
+++ b/src/syscall/asm_linux_mips64x.s
@@ -59,27 +59,6 @@ ok6:
        JAL     runtime·exitsyscall(SB)
        RET
 
-TEXT ·RawSyscall(SB),NOSPLIT,$0-56
-       MOVV    a1+8(FP), R4
-       MOVV    a2+16(FP), R5
-       MOVV    a3+24(FP), R6
-       MOVV    R0, R7
-       MOVV    R0, R8
-       MOVV    R0, R9
-       MOVV    trap+0(FP), R2  // syscall entry
-       SYSCALL
-       BEQ     R7, ok1
-       MOVV    $-1, R1
-       MOVV    R1, r1+32(FP)   // r1
-       MOVV    R0, r2+40(FP)   // r2
-       MOVV    R2, err+48(FP)  // errno
-       RET
-ok1:
-       MOVV    R2, r1+32(FP)   // r1
-       MOVV    R3, r2+40(FP)   // r2
-       MOVV    R0, err+48(FP)  // errno
-       RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
        MOVV    a1+8(FP), R4

diff --git a/src/syscall/asm_linux_mipsx.s b/src/syscall/asm_linux_mipsx.s
index 04fad404a4702f95c653be9b9ea80410691966ce..041c353e794d6248ded8f226c957500ff6bc501f 100644 (file)
--- a/src/syscall/asm_linux_mipsx.s
+++ b/src/syscall/asm_linux_mipsx.s
@@ -97,24 +97,6 @@ ok9:
        JAL     runtime·exitsyscall(SB)
        RET
 
-TEXT ·RawSyscall(SB),NOSPLIT,$24-28
-       MOVW    a1+4(FP), R4
-       MOVW    a2+8(FP), R5
-       MOVW    a3+12(FP), R6
-       MOVW    trap+0(FP), R2  // syscall entry
-       SYSCALL
-       BEQ     R7, ok1
-       MOVW    $-1, R1
-       MOVW    R1, r1+16(FP)   // r1
-       MOVW    R0, r2+20(FP)   // r2
-       MOVW    R2, err+24(FP)  // errno
-       RET
-ok1:
-       MOVW    R2, r1+16(FP)   // r1
-       MOVW    R3, r2+20(FP)   // r2
-       MOVW    R0, err+24(FP)  // errno
-       RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-16
        MOVW    a1+4(FP), R4

diff --git a/src/syscall/asm_linux_ppc64x.s b/src/syscall/asm_linux_ppc64x.s
index 4c9c383ff00c9eb04ab1b496acaa0ad05ea950aa..b03d859ca229bfe08bdc6fee09ac45db83b7af52 100644 (file)
--- a/src/syscall/asm_linux_ppc64x.s
+++ b/src/syscall/asm_linux_ppc64x.s
@@ -59,27 +59,6 @@ ok6:
        BL      runtime·exitsyscall<ABIInternal>(SB)
        RET
 
-TEXT ·RawSyscall(SB),NOSPLIT,$0-56
-       MOVD    a1+8(FP), R3
-       MOVD    a2+16(FP), R4
-       MOVD    a3+24(FP), R5
-       MOVD    R0, R6
-       MOVD    R0, R7
-       MOVD    R0, R8
-       MOVD    trap+0(FP), R9  // syscall entry
-       SYSCALL R9
-       BVC     ok1
-       MOVD    $-1, R4
-       MOVD    R4, r1+32(FP)   // r1
-       MOVD    R0, r2+40(FP)   // r2
-       MOVD    R3, err+48(FP)  // errno
-       RET
-ok1:
-       MOVD    R3, r1+32(FP)   // r1
-       MOVD    R0, r2+40(FP)   // r2
-       MOVD    R0, err+48(FP)  // errno
-       RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
        MOVD    a1+8(FP), R3

diff --git a/src/syscall/asm_linux_riscv64.s b/src/syscall/asm_linux_riscv64.s
index c7e10039972cdc223e76b86f6de81255e451e479..f6b7d11c082d0672bfb71f7c3ec5b89ad3a52fff 100644 (file)
--- a/src/syscall/asm_linux_riscv64.s
+++ b/src/syscall/asm_linux_riscv64.s
@@ -59,27 +59,6 @@ err:
        CALL    runtime·exitsyscall(SB)
        RET
 
-// func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
-TEXT ·RawSyscall(SB),NOSPLIT,$0-56
-       MOV     a1+8(FP), A0
-       MOV     a2+16(FP), A1
-       MOV     a3+24(FP), A2
-       MOV     trap+0(FP), A7  // syscall entry
-       ECALL
-       MOV     $-4096, T0
-       BLTU    T0, A0, err
-       MOV     A0, r1+32(FP)   // r1
-       MOV     A1, r2+40(FP)   // r2
-       MOV     ZERO, err+48(FP)        // errno
-       RET
-err:
-       MOV     $-1, T0
-       MOV     T0, r1+32(FP)   // r1
-       MOV     ZERO, r2+40(FP) // r2
-       SUB     A0, ZERO, A0
-       MOV     A0, err+48(FP)  // errno
-       RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
        MOV     a1+8(FP), A0

diff --git a/src/syscall/asm_linux_s390x.s b/src/syscall/asm_linux_s390x.s
index 3fbda38b5c310531916bc7aeedbba3f9faf15ce5..0a4913779ad7d87367658334c06cf82241de4c28 100644 (file)
--- a/src/syscall/asm_linux_s390x.s
+++ b/src/syscall/asm_linux_s390x.s
@@ -60,29 +60,6 @@ ok6:
        BL      runtime·exitsyscall(SB)
        RET
 
-// func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
-TEXT ·RawSyscall(SB),NOSPLIT,$0-56
-       MOVD    a1+8(FP), R2
-       MOVD    a2+16(FP), R3
-       MOVD    a3+24(FP), R4
-       MOVD    $0, R5
-       MOVD    $0, R6
-       MOVD    $0, R7
-       MOVD    trap+0(FP), R1  // syscall entry
-       SYSCALL
-       MOVD    $0xfffffffffffff001, R8
-       CMPUBLT R2, R8, ok1
-       MOVD    $-1, r1+32(FP)
-       MOVD    $0, r2+40(FP)
-       NEG     R2, R2
-       MOVD    R2, err+48(FP)  // errno
-       RET
-ok1:
-       MOVD    R2, r1+32(FP)
-       MOVD    R3, r2+40(FP)
-       MOVD    $0, err+48(FP)  // errno
-       RET
-
 // func rawVforkSyscall(trap, a1 uintptr) (r1, err uintptr)
 TEXT ·rawVforkSyscall(SB),NOSPLIT|NOFRAME,$0-32
        MOVD    $0, R2

diff --git a/src/syscall/syscall_linux.go b/src/syscall/syscall_linux.go
index b0e2cdb682aa5b8d376b67113906db67b5d8641d..a9a8ecbefd34fa551ddff24ecb000dfaae5ed4ee 100644 (file)
--- a/src/syscall/syscall_linux.go
+++ b/src/syscall/syscall_linux.go
@@ -18,7 +18,6 @@ import (
 
 func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
 func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
-func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
 
 // N.B. RawSyscall6 is provided via linkname by runtime/internal/syscall.
 //
@@ -27,6 +26,27 @@ func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
 
 func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
 
+// N.B. For the Syscall functions below:
+//
+// //go:uintptrkeepalive because the uintptr argument may be converted pointers
+// that need to be kept alive in the caller (this is implied for RawSyscall6
+// since it has no body).
+//
+// //go:nosplit because stack copying does not account for uintptrkeepalive, so
+// the stack must not grow. Stack copying cannot blindly assume that all
+// uintptr arguments are pointers, because some values may look like pointers,
+// but not really be pointers, and adjusting their value would break the call.
+//
+// //go:linkname to ensure ABI wrappers are generated for external callers
+// (notably x/sys/unix assembly).
+
+//go:uintptrkeepalive
+//go:nosplit
+//go:linkname RawSyscall
+func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
+       return RawSyscall6(trap, a1, a2, a3, 0, 0, 0)
+}
+
 func rawSyscallNoError(trap, a1, a2, a3 uintptr) (r1, r2 uintptr)
 
 /*