unix: fix build for linux/386 and linux/arm

Because ARM ABI requires 64-bit argument to be passed in even
register pairs, to avoid wasting one register between fd and
advise in the usual fadvise64 syscall signature, linux/arm
has its own variation that reorders the argument so that the
arguments fit in six registers.

While we're at it, also fix build for linux/386.

Fixes golang/go#10294.

Change-Id: I322e2226619c5aa9c096a1d5cb7ae1e94fd4a5a1
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/8282Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

unix/syscall_linux.go

@@ -799,7 +799,6 @@ func Mount(source string, target string, fstype string, flags uintptr, data stri
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Exit(code int) = SYS_EXIT_GROUP
 //sys	Faccessat(dirfd int, path string, mode uint32, flags int) (err error)
-//sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
 //sys	Fallocate(fd int, mode uint32, off int64, len int64) (err error)
 //sys	Fchdir(fd int) (err error)
 //sys	Fchmod(fd int, mode uint32) (err error)

unix/syscall_linux_amd64.go

@@ -7,6 +7,7 @@ package unix
 import "syscall"
 
 //sys	Chown(path string, uid int, gid int) (err error)
+//sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
 //sys	Fchown(fd int, uid int, gid int) (err error)
 //sys	Fstat(fd int, stat *Stat_t) (err error)
 //sys	Fstatfs(fd int, buf *Statfs_t) (err error)

unix/syscall_linux_arm.go

@@ -86,9 +86,16 @@ func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 //sys   Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys   Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
 //sys	Truncate(path string, length int64) (err error) = SYS_TRUNCATE64
-//sys	Fadvise(fd int, advice int64, offset int64, length int) = SYS_FADVISE64
 //sys	Ftruncate(fd int, length int64) (err error) = SYS_FTRUNCATE64
 
+func Fadvise(fd int, offset int64, length int64, advice int) (err error) {
+	_, _, e1 := Syscall6(SYS_ARM_FADVISE64_64, uintptr(fd), uintptr(advice), uintptr(offset), uintptr(offset>>32), uintptr(length), uintptr(length>>32))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 //sys	mmap2(addr uintptr, length uintptr, prot int, flags int, fd int, pageOffset uintptr) (xaddr uintptr, err error)
 
 func Fstatfs(fd int, buf *Statfs_t) (err error) {

unix/zsyscall_linux_386.go

@@ -411,16 +411,6 @@ func Faccessat(dirfd int, path string, mode uint32, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Fadvise(fd int, offset int64, length int64, advice int) (err error) {
-	_, _, e1 := Syscall6(SYS_FADVISE64, uintptr(fd), uintptr(offset), uintptr(offset>>32), uintptr(length), uintptr(length>>32), uintptr(advice))
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Fallocate(fd int, mode uint32, off int64, len int64) (err error) {
 	_, _, e1 := Syscall6(SYS_FALLOCATE, uintptr(fd), uintptr(mode), uintptr(off), uintptr(off>>32), uintptr(len), uintptr(len>>32))
 	if e1 != 0 {

unix/zsyscall_linux_amd64.go

@@ -411,16 +411,6 @@ func Faccessat(dirfd int, path string, mode uint32, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Fadvise(fd int, offset int64, length int64, advice int) (err error) {
-	_, _, e1 := Syscall6(SYS_FADVISE64, uintptr(fd), uintptr(offset), uintptr(length), uintptr(advice), 0, 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Fallocate(fd int, mode uint32, off int64, len int64) (err error) {
 	_, _, e1 := Syscall6(SYS_FALLOCATE, uintptr(fd), uintptr(mode), uintptr(off), uintptr(len), 0, 0)
 	if e1 != 0 {
@@ -1419,6 +1409,16 @@ func Chown(path string, uid int, gid int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Fadvise(fd int, offset int64, length int64, advice int) (err error) {
+	_, _, e1 := Syscall6(SYS_FADVISE64, uintptr(fd), uintptr(offset), uintptr(length), uintptr(advice), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Fchown(fd int, uid int, gid int) (err error) {
 	_, _, e1 := Syscall(SYS_FCHOWN, uintptr(fd), uintptr(uid), uintptr(gid))
 	if e1 != 0 {

unix/zsyscall_linux_arm.go

@@ -411,16 +411,6 @@ func Faccessat(dirfd int, path string, mode uint32, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Fadvise(fd int, offset int64, length int64, advice int) (err error) {
-	_, _, e1 := Syscall9(SYS_FADVISE64, uintptr(fd), 0, uintptr(offset), uintptr(offset>>32), uintptr(length), uintptr(length>>32), uintptr(advice), 0, 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Fallocate(fd int, mode uint32, off int64, len int64) (err error) {
 	_, _, e1 := Syscall6(SYS_FALLOCATE, uintptr(fd), uintptr(mode), uintptr(off), uintptr(off>>32), uintptr(len), uintptr(len>>32))
 	if e1 != 0 {
@@ -1882,13 +1872,6 @@ func Truncate(path string, length int64) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Fadvise(fd int, advice int64, offset int64, length int) {
-	Syscall9(SYS_FADVISE64, uintptr(fd), 0, uintptr(advice), uintptr(advice>>32), uintptr(offset), uintptr(offset>>32), uintptr(length), 0, 0)
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Ftruncate(fd int, length int64) (err error) {
 	_, _, e1 := Syscall6(SYS_FTRUNCATE64, uintptr(fd), 0, uintptr(length), uintptr(length>>32), 0, 0)
 	if e1 != 0 {