internal/poll, syscall: convert writev to direct libc call on openbsd (except mips64)

Add and use a writev libc wrapper instead of using syscall(2).

Updates golang/go#36435

Change-Id: I3c67665388ac276d9ef36868e368e91efb92800e
Reviewed-on: https://go-review.googlesource.com/c/go/+/428776
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Joel Sing <joel@sing.id.au>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

11 files changed, 95 insertions, 4 deletions

diff --git a/src/internal/poll/fd_writev_darwin.go b/src/internal/poll/fd_writev_libc.go
index b5b8998df8..e427e62481 100644
--- a/src/internal/poll/fd_writev_darwin.go
+++ b/src/internal/poll/fd_writev_libc.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build darwin
+//go:build darwin || (openbsd && !mips64)
 
 package poll
 
@@ -11,7 +11,5 @@ import (
 	_ "unsafe" // for go:linkname
 )
 
-// Implemented in syscall/syscall_darwin.go.
-//
 //go:linkname writev syscall.writev
 func writev(fd int, iovecs []syscall.Iovec) (uintptr, error)
diff --git a/src/internal/poll/fd_writev_unix.go b/src/internal/poll/fd_writev_unix.go
index aa96d104c8..005638b06f 100644
--- a/src/internal/poll/fd_writev_unix.go
+++ b/src/internal/poll/fd_writev_unix.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build dragonfly || freebsd || linux || netbsd || openbsd
+//go:build dragonfly || freebsd || linux || netbsd || (openbsd && mips64)
 
 package poll
 
diff --git a/src/syscall/syscall_openbsd.go b/src/syscall/syscall_openbsd.go
index 75217344df..ba67ab1a57 100644
--- a/src/syscall/syscall_openbsd.go
+++ b/src/syscall/syscall_openbsd.go
@@ -209,6 +209,7 @@ func Getfsstat(buf []Statfs_t, flags int) (n int, err error) {
 //sys	Unlink(path string) (err error)
 //sys	Unmount(path string, flags int) (err error)
 //sys	write(fd int, p []byte) (n int, err error)
+//sys	writev(fd int, iovecs []Iovec) (n uintptr, err error)
 //sys	mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error)
 //sys	munmap(addr uintptr, length uintptr) (err error)
 //sys	utimensat(dirfd int, path string, times *[2]Timespec, flag int) (err error)
diff --git a/src/syscall/zsyscall_openbsd_386.go b/src/syscall/zsyscall_openbsd_386.go
index f7986d5ea5..b60af1743d 100644
--- a/src/syscall/zsyscall_openbsd_386.go
+++ b/src/syscall/zsyscall_openbsd_386.go
@@ -1610,6 +1610,27 @@ func libc_write_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func writev(fd int, iovecs []Iovec) (n uintptr, err error) {
+	var _p0 unsafe.Pointer
+	if len(iovecs) > 0 {
+		_p0 = unsafe.Pointer(&iovecs[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := syscall(abi.FuncPCABI0(libc_writev_trampoline), uintptr(fd), uintptr(_p0), uintptr(len(iovecs)))
+	n = uintptr(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_writev_trampoline()
+
+//go:cgo_import_dynamic libc_writev writev "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error) {
 	r0, _, e1 := syscall9(abi.FuncPCABI0(libc_mmap_trampoline), uintptr(addr), uintptr(length), uintptr(prot), uintptr(flag), uintptr(fd), uintptr(pos), uintptr(pos>>32), 0, 0)
 	ret = uintptr(r0)
diff --git a/src/syscall/zsyscall_openbsd_386.s b/src/syscall/zsyscall_openbsd_386.s
index e2c58625bb..a77d931e8a 100644
--- a/src/syscall/zsyscall_openbsd_386.s
+++ b/src/syscall/zsyscall_openbsd_386.s
@@ -201,6 +201,8 @@ TEXT ·libc_unmount_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unmount(SB)
 TEXT ·libc_write_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_write(SB)
+TEXT ·libc_writev_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_writev(SB)
 TEXT ·libc_mmap_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_mmap(SB)
 TEXT ·libc_munmap_trampoline(SB),NOSPLIT,$0-0
diff --git a/src/syscall/zsyscall_openbsd_amd64.go b/src/syscall/zsyscall_openbsd_amd64.go
index 605443d890..8b3e81e6bd 100644
--- a/src/syscall/zsyscall_openbsd_amd64.go
+++ b/src/syscall/zsyscall_openbsd_amd64.go
@@ -1610,6 +1610,27 @@ func libc_write_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func writev(fd int, iovecs []Iovec) (n uintptr, err error) {
+	var _p0 unsafe.Pointer
+	if len(iovecs) > 0 {
+		_p0 = unsafe.Pointer(&iovecs[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := syscallX(abi.FuncPCABI0(libc_writev_trampoline), uintptr(fd), uintptr(_p0), uintptr(len(iovecs)))
+	n = uintptr(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_writev_trampoline()
+
+//go:cgo_import_dynamic libc_writev writev "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error) {
 	r0, _, e1 := syscall6X(abi.FuncPCABI0(libc_mmap_trampoline), uintptr(addr), uintptr(length), uintptr(prot), uintptr(flag), uintptr(fd), uintptr(pos))
 	ret = uintptr(r0)
diff --git a/src/syscall/zsyscall_openbsd_amd64.s b/src/syscall/zsyscall_openbsd_amd64.s
index 964c9ed9e1..d13e9c0782 100644
--- a/src/syscall/zsyscall_openbsd_amd64.s
+++ b/src/syscall/zsyscall_openbsd_amd64.s
@@ -201,6 +201,8 @@ TEXT ·libc_unmount_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unmount(SB)
 TEXT ·libc_write_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_write(SB)
+TEXT ·libc_writev_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_writev(SB)
 TEXT ·libc_mmap_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_mmap(SB)
 TEXT ·libc_munmap_trampoline(SB),NOSPLIT,$0-0
diff --git a/src/syscall/zsyscall_openbsd_arm.go b/src/syscall/zsyscall_openbsd_arm.go
index 0f2312fbc4..42d57812b2 100644
--- a/src/syscall/zsyscall_openbsd_arm.go
+++ b/src/syscall/zsyscall_openbsd_arm.go
@@ -1610,6 +1610,27 @@ func libc_write_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func writev(fd int, iovecs []Iovec) (n uintptr, err error) {
+	var _p0 unsafe.Pointer
+	if len(iovecs) > 0 {
+		_p0 = unsafe.Pointer(&iovecs[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := syscall(abi.FuncPCABI0(libc_writev_trampoline), uintptr(fd), uintptr(_p0), uintptr(len(iovecs)))
+	n = uintptr(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_writev_trampoline()
+
+//go:cgo_import_dynamic libc_writev writev "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error) {
 	r0, _, e1 := syscall9(abi.FuncPCABI0(libc_mmap_trampoline), uintptr(addr), uintptr(length), uintptr(prot), uintptr(flag), uintptr(fd), 0, uintptr(pos), uintptr(pos>>32), 0)
 	ret = uintptr(r0)
diff --git a/src/syscall/zsyscall_openbsd_arm.s b/src/syscall/zsyscall_openbsd_arm.s
index 5975780edb..34ae794ee1 100644
--- a/src/syscall/zsyscall_openbsd_arm.s
+++ b/src/syscall/zsyscall_openbsd_arm.s
@@ -201,6 +201,8 @@ TEXT ·libc_unmount_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unmount(SB)
 TEXT ·libc_write_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_write(SB)
+TEXT ·libc_writev_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_writev(SB)
 TEXT ·libc_mmap_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_mmap(SB)
 TEXT ·libc_munmap_trampoline(SB),NOSPLIT,$0-0
diff --git a/src/syscall/zsyscall_openbsd_arm64.go b/src/syscall/zsyscall_openbsd_arm64.go
index 1367e2aba9..7a5a2c0c81 100644
--- a/src/syscall/zsyscall_openbsd_arm64.go
+++ b/src/syscall/zsyscall_openbsd_arm64.go
@@ -1610,6 +1610,27 @@ func libc_write_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func writev(fd int, iovecs []Iovec) (n uintptr, err error) {
+	var _p0 unsafe.Pointer
+	if len(iovecs) > 0 {
+		_p0 = unsafe.Pointer(&iovecs[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	r0, _, e1 := syscallX(abi.FuncPCABI0(libc_writev_trampoline), uintptr(fd), uintptr(_p0), uintptr(len(iovecs)))
+	n = uintptr(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_writev_trampoline()
+
+//go:cgo_import_dynamic libc_writev writev "libc.so"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error) {
 	r0, _, e1 := syscall6X(abi.FuncPCABI0(libc_mmap_trampoline), uintptr(addr), uintptr(length), uintptr(prot), uintptr(flag), uintptr(fd), uintptr(pos))
 	ret = uintptr(r0)
diff --git a/src/syscall/zsyscall_openbsd_arm64.s b/src/syscall/zsyscall_openbsd_arm64.s
index 2c4a0b0faf..20a79e433b 100644
--- a/src/syscall/zsyscall_openbsd_arm64.s
+++ b/src/syscall/zsyscall_openbsd_arm64.s
@@ -201,6 +201,8 @@ TEXT ·libc_unmount_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unmount(SB)
 TEXT ·libc_write_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_write(SB)
+TEXT ·libc_writev_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_writev(SB)
 TEXT ·libc_mmap_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_mmap(SB)
 TEXT ·libc_munmap_trampoline(SB),NOSPLIT,$0-0