diff --git a/lldb/docs/lldb-gdb-remote.txt b/lldb/docs/lldb-gdb-remote.txt
--- a/lldb/docs/lldb-gdb-remote.txt
+++ b/lldb/docs/lldb-gdb-remote.txt
@@ -1636,6 +1636,24 @@
 //                                  Example:
 //                                  thread-pcs:dec14,2cf872b0,2cf8681c,2d02d68c,2cf716a8;
 //
+//  "addressing_bits" unsigned optional  Specifies how many bits in addresses 
+//                                       are significant for addressing, base 
+//                                       10.  If bits 38..0 in a 64-bit 
+//                                       pointer are significant for 
+//                                       addressing, then the value is 39.  
+//                                       This is needed on e.g. AArch64
+//                                       v8.3 ABIs that use pointer 
+//                                       authentication in the high bits.
+//                                       This value is normally sent in the
+//                                       qHostInfo packet response, and if the
+//                                       value cannot change during the process
+//                                       lifetime, it does not need to be 
+//                                       duplicated here in the stop packet.
+//                                       For a firmware environment with early
+//                                       start code that may be changing the
+//                                       page table setup, a dynamically set
+//                                       value may be needed.
+//
 // BEST PRACTICES:
 //  Since register values can be supplied with this packet, it is often useful
 //  to return the PC, SP, FP, LR (if any), and FLAGS registers so that separate
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -2257,6 +2257,13 @@
         StreamString ostr;
         ostr.Printf("%" PRIu64 " %" PRIu64, pid_tid->first, pid_tid->second);
         description = std::string(ostr.GetString());
+      } else if (key.compare("addressing_bits") == 0) {
+        uint64_t addressing_bits;
+        if (!value.getAsInteger(0, addressing_bits)) {
+          addr_t address_mask = ~((1ULL << addressing_bits) - 1);
+          SetCodeAddressMask(address_mask);
+          SetDataAddressMask(address_mask);
+        }
       } else if (key.size() == 2 && ::isxdigit(key[0]) && ::isxdigit(key[1])) {
         uint32_t reg = UINT32_MAX;
         if (!key.getAsInteger(16, reg))