misc/cgo/test/issue9400: add arm64 implementation
Change-Id: I309e3df7608b9eef9339196fdc50dedf5f9439f4
Reviewed-on: https://go-review.googlesource.com/8451
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
diff --git a/misc/cgo/test/issue9400/asm_arm64.s b/misc/cgo/test/issue9400/asm_arm64.s
new file mode 100644
index 0000000..0c024e8
--- /dev/null
+++ b/misc/cgo/test/issue9400/asm_arm64.s
@@ -0,0 +1,33 @@
+#include "textflag.h"
+
+TEXT ·RewindAndSetgid(SB),NOSPLIT,$-8-0
+ // Save link register
+ MOVD R30, R9
+
+ // Rewind stack pointer so anything that happens on the stack
+ // will clobber the test pattern created by the caller
+ ADD $(1024 * 8), RSP
+
+ // Ask signaller to setgid
+ MOVD $·Baton(SB), R0
+ MOVD $1, R1
+storeloop:
+ LDAXRW (R0), R2
+ STLXRW R1, (R0), R3
+ CBNZ R3, storeloop
+
+ // Wait for setgid completion
+ MOVW $0, R1
+ MOVW $0, R2
+loop:
+ LDAXRW (R0), R3
+ CMPW R1, R3
+ BNE loop
+ STLXRW R2, (R0), R3
+ CBNZ R3, loop
+
+ // Restore stack
+ SUB $(1024 * 8), RSP
+
+ MOVD R9, R30
+ RET
