From 517226c2b1bfb00c93e14f7a597a63d3817ce3aa Mon Sep 17 00:00:00 2001
From: Frances Wingerter <fw@immunant.com>
Date: Thu, 3 Oct 2024 14:05:10 -0400
Subject: [PATCH] runtime: tag pointers to newly-allocated stacks

---
 runtime/libia2/init.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/runtime/libia2/init.c b/runtime/libia2/init.c
index 707efa649..db891d6b6 100644
--- a/runtime/libia2/init.c
+++ b/runtime/libia2/init.c
@@ -26,6 +26,10 @@ char *allocate_stack(int i) {
       exit(-1);
     }
   }
+#ifdef __aarch64__
+  /* Tag the allocated stack pointer so it is accessed with the right pkey */
+  stack = (char *)((uint64_t)stack | (uint64_t)i << 56);
+#endif
   /* Each stack frame start + 8 is initially 16-byte aligned. */
   return stack + STACK_SIZE - 8;
 }