From 099fbce0accf209677e041fd9dc10bcb4a5eb578 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 tpidruro register from NT_ARM_TLS core dump notes on
 FreeBSD/arm.

---
 gdb/arm-fbsd-nat.c  |  2 +-
 gdb/arm-fbsd-tdep.c | 32 ++++++++++++++++++++++++++------
 gdb/arm-fbsd-tdep.h |  5 ++++-
 3 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/gdb/arm-fbsd-nat.c b/gdb/arm-fbsd-nat.c
index 3106d73cc3a..c32924de735 100644
--- a/gdb/arm-fbsd-nat.c
+++ b/gdb/arm-fbsd-nat.c
@@ -72,7 +72,7 @@ arm_fbsd_nat_target::read_description ()
 {
   const struct target_desc *desc;
 
-  desc = arm_fbsd_read_description_auxv (this);
+  desc = arm_fbsd_read_description_auxv (this, false);
   if (desc == NULL)
     desc = this->beneath ()->read_description ();
   return desc;
diff --git a/gdb/arm-fbsd-tdep.c b/gdb/arm-fbsd-tdep.c
index 06745a36186..a27dfb2fb4a 100644
--- a/gdb/arm-fbsd-tdep.c
+++ b/gdb/arm-fbsd-tdep.c
@@ -163,6 +163,24 @@ arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
   cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
       &arm_fbsd_gregset, NULL, cb_data);
 
+  if (tdep->tls_regnum > 0)
+    {
+      const struct regcache_map_entry arm_fbsd_tlsregmap[] =
+	{
+	  { 1, tdep->tls_regnum, 4 },
+	  { 0 }
+	};
+
+      const struct regset arm_fbsd_tlsregset =
+	{
+	  arm_fbsd_tlsregmap,
+	  regcache_supply_regset, regcache_collect_regset
+	};
+
+      cb (".reg-aarch-tls", ARM_FBSD_SIZEOF_TLSREGSET, ARM_FBSD_SIZEOF_TLSREGSET,
+	  &arm_fbsd_tlsregset, NULL, cb_data);
+    }
+
   /* While FreeBSD/arm cores do contain a NT_FPREGSET / ".reg2"
      register set, it is not populated with register values by the
      kernel but just contains all zeroes.  */
@@ -175,12 +193,12 @@ arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
    vector.  */
 
 const struct target_desc *
-arm_fbsd_read_description_auxv (struct target_ops *target)
+arm_fbsd_read_description_auxv (struct target_ops *target, bool tls)
 {
   CORE_ADDR arm_hwcap = 0;
 
   if (target_auxv_search (target, AT_FREEBSD_HWCAP, &arm_hwcap) != 1)
-    return nullptr;
+    return arm_read_description (ARM_FP_TYPE_NONE, tls);
 
   if (arm_hwcap & HWCAP_VFP)
     {
@@ -188,12 +206,12 @@ arm_fbsd_read_description_auxv (struct target_ops *target)
 	return aarch32_read_description ();
       else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPD32))
 	       == (HWCAP_VFPv3 | HWCAP_VFPD32))
-	return arm_read_description (ARM_FP_TYPE_VFPV3, false);
+	return arm_read_description (ARM_FP_TYPE_VFPV3, tls);
       else
-	return arm_read_description (ARM_FP_TYPE_VFPV2, false);
+	return arm_read_description (ARM_FP_TYPE_VFPV2, tls);
     }
 
-  return nullptr;
+  return arm_read_description (ARM_FP_TYPE_NONE, tls);
 }
 
 /* Implement the "core_read_description" gdbarch method.  */
@@ -203,7 +221,9 @@ arm_fbsd_core_read_description (struct gdbarch *gdbarch,
 				struct target_ops *target,
 				bfd *abfd)
 {
-  return arm_fbsd_read_description_auxv (target);
+  asection *tls = bfd_get_section_by_name (abfd, ".reg-aarch-tls");
+
+  return arm_fbsd_read_description_auxv (target, tls != nullptr);
 }
 
 /* Implement the 'init_osabi' method of struct gdb_osabi_handler.  */
diff --git a/gdb/arm-fbsd-tdep.h b/gdb/arm-fbsd-tdep.h
index 633dafad75d..193eb76df3c 100644
--- a/gdb/arm-fbsd-tdep.h
+++ b/gdb/arm-fbsd-tdep.h
@@ -26,6 +26,9 @@
    PC, and CPSR registers.  */
 #define ARM_FBSD_SIZEOF_GREGSET  (17 * 4)
 
+/* The TLS regset consists of a single register.  */
+#define	ARM_FBSD_SIZEOF_TLSREGSET	(4)
+
 /* The VFP regset consists of 32 D registers plus FPSCR, and the whole
    structure is padded to 64-bit alignment.  */
 #define	ARM_FBSD_SIZEOF_VFPREGSET	(33 * 8)
@@ -40,6 +43,6 @@ extern const struct regset arm_fbsd_vfpregset;
 #define	HWCAP_VFPD32		0x00080000
 
 extern const struct target_desc *
-arm_fbsd_read_description_auxv (struct target_ops *target);
+arm_fbsd_read_description_auxv (struct target_ops *target, bool tls);
 
 #endif /* ARM_FBSD_TDEP_H */
-- 
2.30.2