[PATCH v2 13/14] gdbserver: Read the tpidr register from NT_ARM_TLS on Linux.

[John Baldwin <jhb@FreeBSD.org>]

XXX: This currently assumes NT_ARM_TLS is always available rather than
doing a runtime test.
---
 gdbserver/linux-aarch64-ipa.cc   |  8 ++++----
 gdbserver/linux-aarch64-low.cc   | 28 +++++++++++++++++++++++++++-
 gdbserver/linux-aarch64-tdesc.cc | 11 ++++++-----
 gdbserver/linux-aarch64-tdesc.h  |  2 +-
 4 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/gdbserver/linux-aarch64-ipa.cc b/gdbserver/linux-aarch64-ipa.cc
index 296c63534d8..dc907d3ff88 100644
--- a/gdbserver/linux-aarch64-ipa.cc
+++ b/gdbserver/linux-aarch64-ipa.cc
@@ -147,12 +147,12 @@ get_raw_reg (const unsigned char *raw_regs, int regnum)
 
 /* Return target_desc to use for IPA, given the tdesc index passed by
    gdbserver.  Index is ignored, since we have only one tdesc
-   at the moment.  SVE, pauth and MTE not yet supported.  */
+   at the moment.  SVE, pauth, MTE and TLS not yet supported.  */
 
 const struct target_desc *
 get_ipa_tdesc (int idx)
 {
-  return aarch64_linux_read_description (0, false, false);
+  return aarch64_linux_read_description (0, false, false, false);
 }
 
 /* Allocate buffer for the jump pads.  The branch instruction has a reach
@@ -204,6 +204,6 @@ alloc_jump_pad_buffer (size_t size)
 void
 initialize_low_tracepoint (void)
 {
-  /* SVE, pauth and MTE not yet supported.  */
-  aarch64_linux_read_description (0, false, false);
+  /* SVE, pauth, MTE and TLS not yet supported.  */
+  aarch64_linux_read_description (0, false, false, false);
 }
diff --git a/gdbserver/linux-aarch64-low.cc b/gdbserver/linux-aarch64-low.cc
index 0091f998c63..b265f91a657 100644
--- a/gdbserver/linux-aarch64-low.cc
+++ b/gdbserver/linux-aarch64-low.cc
@@ -287,6 +287,22 @@ aarch64_store_mteregset (struct regcache *regcache, const void *buf)
   supply_register (regcache, mte_base, mte_regset);
 }
 
+/* Fill BUF with TLS register from the regcache.  */
+
+static void
+aarch64_fill_tlsregset (struct regcache *regcache, void *buf)
+{
+  collect_register (regcache, AARCH64_TPIDR_REGNUM, buf);
+}
+
+/* Store TLS register to regcache.  */
+
+static void
+aarch64_store_tlsregset (struct regcache *regcache, const void *buf)
+{
+  supply_register (regcache, AARCH64_TPIDR_REGNUM, buf);
+}
+
 bool
 aarch64_target::low_supports_breakpoints ()
 {
@@ -719,6 +735,10 @@ static struct regset_info aarch64_regsets[] =
   { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_ARM_TAGGED_ADDR_CTRL,
     0, OPTIONAL_REGS,
     aarch64_fill_mteregset, aarch64_store_mteregset },
+  /* TLS register.  */
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_ARM_TLS,
+    0, OPTIONAL_REGS,
+    aarch64_fill_tlsregset, aarch64_store_tlsregset },
   NULL_REGSET
 };
 
@@ -770,6 +790,10 @@ aarch64_adjust_register_sets (const struct aarch64_features &features)
 	  if (features.mte)
 	    regset->size = AARCH64_LINUX_SIZEOF_MTE;
 	  break;
+	case NT_ARM_TLS:
+	  if (features.tls)
+	    regset->size = AARCH64_TLS_REGS_SIZE;
+	  break;
 	default:
 	  gdb_assert_not_reached ("Unknown register set found.");
 	}
@@ -802,9 +826,11 @@ aarch64_target::low_arch_setup ()
       features.pauth = linux_get_hwcap (8) & AARCH64_HWCAP_PACA;
       /* A-profile MTE is 64-bit only.  */
       features.mte = linux_get_hwcap2 (8) & HWCAP2_MTE;
+      features.tls = true;
 
       current_process ()->tdesc
-	= aarch64_linux_read_description (vq, features.pauth, features.mte);
+	= aarch64_linux_read_description (vq, features.pauth, features.mte,
+					  features.tls);
 
       /* Adjust the register sets we should use for this particular set of
 	 features.  */
diff --git a/gdbserver/linux-aarch64-tdesc.cc b/gdbserver/linux-aarch64-tdesc.cc
index 14d6a4f80eb..be96612d571 100644
--- a/gdbserver/linux-aarch64-tdesc.cc
+++ b/gdbserver/linux-aarch64-tdesc.cc
@@ -27,22 +27,23 @@
 #include <inttypes.h>
 
 /* All possible aarch64 target descriptors.  */
-struct target_desc *tdesc_aarch64_list[AARCH64_MAX_SVE_VQ + 1][2/*pauth*/][2 /* mte */];
+struct target_desc *tdesc_aarch64_list[AARCH64_MAX_SVE_VQ + 1][2/*pauth*/][2 /* mte */][2 /* tls */];
 
 /* Create the aarch64 target description.  */
 
 const target_desc *
-aarch64_linux_read_description (uint64_t vq, bool pauth_p, bool mte_p)
+aarch64_linux_read_description (uint64_t vq, bool pauth_p, bool mte_p,
+				bool tls_p)
 {
   if (vq > AARCH64_MAX_SVE_VQ)
     error (_("VQ is %" PRIu64 ", maximum supported value is %d"), vq,
 	   AARCH64_MAX_SVE_VQ);
 
-  struct target_desc *tdesc = tdesc_aarch64_list[vq][pauth_p][mte_p];
+  struct target_desc *tdesc = tdesc_aarch64_list[vq][pauth_p][mte_p][tls_p];
 
   if (tdesc == NULL)
     {
-      tdesc = aarch64_create_target_description (vq, pauth_p, mte_p, false);
+      tdesc = aarch64_create_target_description (vq, pauth_p, mte_p, tls_p);
 
       static const char *expedite_regs_aarch64[] = { "x29", "sp", "pc", NULL };
       static const char *expedite_regs_aarch64_sve[] = { "x29", "sp", "pc",
@@ -53,7 +54,7 @@ aarch64_linux_read_description (uint64_t vq, bool pauth_p, bool mte_p)
       else
 	init_target_desc (tdesc, expedite_regs_aarch64_sve);
 
-      tdesc_aarch64_list[vq][pauth_p][mte_p] = tdesc;
+      tdesc_aarch64_list[vq][pauth_p][mte_p][tls_p] = tdesc;
     }
 
   return tdesc;
diff --git a/gdbserver/linux-aarch64-tdesc.h b/gdbserver/linux-aarch64-tdesc.h
index 66d6fa32f16..4ab658447a2 100644
--- a/gdbserver/linux-aarch64-tdesc.h
+++ b/gdbserver/linux-aarch64-tdesc.h
@@ -21,6 +21,6 @@
 #define GDBSERVER_LINUX_AARCH64_TDESC_H
 
 const target_desc * aarch64_linux_read_description (uint64_t vq, bool pauth_p,
-						    bool mte_p);
+						    bool mte_p, bool tls_p);
 
 #endif /* GDBSERVER_LINUX_AARCH64_TDESC_H */
-- 
2.34.1