From 0a765c1a8e9c59f4cd0cdaf986291f957fe6ee90 Mon Sep 17 00:00:00 2001
From: John Baldwin <jhb@FreeBSD.org>
Date: Tue, 3 May 2022 16:05:10 -0700
Subject: [PATCH] Read the tpidr register from NT_ARM_TLS core dump notes on
 FreeBSD/Aarch64.

---
 gdb/aarch64-fbsd-tdep.c | 34 ++++++++++++++++++++++++++++++++++
 gdb/aarch64-fbsd-tdep.h |  3 +++
 2 files changed, 37 insertions(+)

diff --git a/gdb/aarch64-fbsd-tdep.c b/gdb/aarch64-fbsd-tdep.c
index 32f441892a8..ed1b84387f0 100644
--- a/gdb/aarch64-fbsd-tdep.c
+++ b/gdb/aarch64-fbsd-tdep.c
@@ -142,10 +142,42 @@ aarch64_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					   void *cb_data,
 					   const struct regcache *regcache)
 {
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
   cb (".reg", AARCH64_FBSD_SIZEOF_GREGSET, AARCH64_FBSD_SIZEOF_GREGSET,
       &aarch64_fbsd_gregset, NULL, cb_data);
   cb (".reg2", AARCH64_FBSD_SIZEOF_FPREGSET, AARCH64_FBSD_SIZEOF_FPREGSET,
       &aarch64_fbsd_fpregset, NULL, cb_data);
+
+  if (tdep->has_tls ())
+    {
+      const struct regcache_map_entry aarch64_fbsd_tls_regmap[] =
+	{
+	  { 1, tdep->tls_regnum, 8 },
+	  { 0 }
+	};
+
+      const struct regset aarch64_fbsd_tls_regset =
+	{
+	  aarch64_fbsd_tls_regmap,
+	  regcache_supply_regset, regcache_collect_regset
+	};
+
+      cb (".reg-aarch-tls", AARCH64_FBSD_SIZEOF_TLSREGSET,
+	  AARCH64_FBSD_SIZEOF_TLSREGSET, &aarch64_fbsd_tls_regset,
+	  "TLS register", cb_data);
+    }
+}
+
+/* Implement the "core_read_description" gdbarch method.  */
+
+static const struct target_desc *
+aarch64_fbsd_core_read_description (struct gdbarch *gdbarch,
+				    struct target_ops *target, bfd *abfd)
+{
+  asection *tls = bfd_get_section_by_name (abfd, ".reg-aarch-tls");
+
+  return aarch64_read_description (0, false, false, tls != nullptr);
 }
 
 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
@@ -168,6 +200,8 @@ aarch64_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 
   set_gdbarch_iterate_over_regset_sections
     (gdbarch, aarch64_fbsd_iterate_over_regset_sections);
+  set_gdbarch_core_read_description (gdbarch,
+				     aarch64_fbsd_core_read_description);
 }
 
 void _initialize_aarch64_fbsd_tdep ();
diff --git a/gdb/aarch64-fbsd-tdep.h b/gdb/aarch64-fbsd-tdep.h
index fc8fbee8843..7419ea6be03 100644
--- a/gdb/aarch64-fbsd-tdep.h
+++ b/gdb/aarch64-fbsd-tdep.h
@@ -32,6 +32,9 @@
    alignment.  */
 #define AARCH64_FBSD_SIZEOF_FPREGSET (33 * V_REGISTER_SIZE)
 
+/* The TLS regset consists of a single register.  */
+#define	AARCH64_FBSD_SIZEOF_TLSREGSET (X_REGISTER_SIZE)
+
 extern const struct regset aarch64_fbsd_gregset;
 extern const struct regset aarch64_fbsd_fpregset;
 
-- 
2.30.2