runtime: don't restore the alternate signal stack on ios

The alternative signal stack doesn't work on ios, so the setup of
the alternative stack was skipped. The corresponding unminitSignals
was effectively a no-op on ios until CL 70130. Skip unminitSignals
on ios to restore the previous behaviour.

For the ios builders.

Change-Id: I5692ca7f5997e6b9d10cc5f2383a5a37c42b133c
Reviewed-on: https://go-review.googlesource.com/70270
Run-TryBot: Elias Naur <elias.naur@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>

diff --git a/src/runtime/os_darwin.go b/src/runtime/os_darwin.go
index 635f71f126e3e142151d3a98db4ce51da204cad0..4ab5a7637366e6ba669941e623c3decbdbf35072 100644 (file)
--- a/src/runtime/os_darwin.go
+++ b/src/runtime/os_darwin.go
@@ -188,7 +188,11 @@ func minit() {
 // Called from dropm to undo the effect of an minit.
 //go:nosplit
 func unminit() {
-       unminitSignals()
+       // The alternate signal stack is buggy on arm and arm64.
+       // See minit.
+       if GOARCH != "arm" && GOARCH != "arm64" {
+               unminitSignals()
+       }
 }
 
 // Mach IPC, to get at semaphores