runtime: move epoll syscalls to runtime/internal/syscall

This change moves Linux epoll's syscalls implementation to the
"runtime/internal/syscall" package. The intention in this CL was to
minimise behavioural changes but make the code more generalised. This
also will allow adding new syscalls (like epoll_pwait2) without the
need to implement assembly stubs for each arch.

It also drops epoll_create as not all architectures provide this call.
epoll_create1 was added to the kernel in version 2.6.27 and Go requires
Linux kernel version 2.6.32 or later since Go 1.18. So it is safe to
always use epoll_create1.

This is a resubmit as the previous CL 421994 was reverted due to test
failures after the merge with the master. The issue was fixed in
CL 438615

For #53824
For #51087

Change-Id: I1bd0f23a85b4f9b80178c5dd36fd3e95ff4f9648
Reviewed-on: https://go-review.googlesource.com/c/go/+/440115
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>

1 files changed, 4 insertions, 6 deletions

diff --git a/src/runtime/export_linux_test.go b/src/runtime/export_linux_test.go
index dea94a934c..a441c0efa2 100644
--- a/src/runtime/export_linux_test.go
+++ b/src/runtime/export_linux_test.go
@@ -6,19 +6,17 @@
 
 package runtime
 
-import "unsafe"
+import (
+	"runtime/internal/syscall"
+)
 
 const SiginfoMaxSize = _si_max_size
 const SigeventMaxSize = _sigev_max_size
 
+var Closeonexec = syscall.CloseOnExec
 var NewOSProc0 = newosproc0
 var Mincore = mincore
 var Add = add
 
-type EpollEvent epollevent
 type Siginfo siginfo
 type Sigevent sigevent
-
-func Epollctl(epfd, op, fd int32, ev unsafe.Pointer) int32 {
-	return epollctl(epfd, op, fd, (*epollevent)(ev))
-}