From: John Baldwin <jhb@FreeBSD.org>
Date: Wed, 10 Aug 2022 19:14:16 +0000 (-0700)
Subject: Write memory capabilities atomically.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=36d1b3bff14b48cb2166e0bc27cf74c9c3bc3c25;p=thirdparty%2Fbinutils-gdb.git

Write memory capabilities atomically.

Use target_write_capability to write a capability atomically in
put_frame_register.
---

diff --git a/gdb/frame.c b/gdb/frame.c
index 44b3bd09463..bc3189e3dac 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -1399,15 +1399,21 @@ put_frame_register (struct frame_info *frame, int regnum,
     {
     case lval_memory:
       {
-	write_memory (addr, buf, register_size (gdbarch, regnum));
-
 	/* If this value is a capability, we need to handle the capability tag
-	   as well.  */
+	   as an atomic write.  */
 	if ((val_type->code () == TYPE_CODE_CAPABILITY
 	    || (val_type->code () == TYPE_CODE_PTR
 		&& TYPE_CAPABILITY (val_type)))
 	    && value_tagged (fromval))
-	  gdbarch_set_cap_tag_from_address (gdbarch, addr, value_tag (fromval));
+	  {
+	    gdb::byte_vector cap (register_size (gdbarch, regnum) + 1);
+
+	    cap[0] = value_tag (fromval) ? 1 : 0;
+	    memcpy (cap.data () + 1, buf, register_size (gdbarch, regnum));
+	    if (target_write_capability (addr, cap))
+	      break;
+	  }
+	write_memory (addr, buf, register_size (gdbarch, regnum));
 	break;
       }
     case lval_register: