AArch64: Add MTE CPU feature check support

This patch is a preparation for the next patches implementing MTE. It just adds
a HWCAP2 constant for MTE, creates a new generic arch/aarch64-mte-linux.h file
and includes that file in the source files that will use it.

gdb/ChangeLog:

2021-03-24  Luis Machado  <luis.machado@linaro.org>

	* Makefile.in (HFILES_NO_SRCDIR): Add arch/aarch64-mte-linux.h.
	* aarch64-linux-nat.c: Include arch/aarch64-mte-linux.h.
	* aarch64-linux-tdep.c: Likewise
	* arch/aarch64-mte-linux.h: New file.

gdbserver/ChangeLog:

2021-03-24  Luis Machado  <luis.machado@linaro.org>

	* linux-aarch64-low.cc: Include arch/aarch64-mte-linux.h.

5 files changed, 40 insertions, 0 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 0ea440d..a7d8902 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
 2021-03-24  Luis Machado  <luis.machado@linaro.org>
 
+	* Makefile.in (HFILES_NO_SRCDIR): Add arch/aarch64-mte-linux.h.
+	* aarch64-linux-nat.c: Include arch/aarch64-mte-linux.h.
+	* aarch64-linux-tdep.c: Likewise
+	* arch/aarch64-mte-linux.h: New file.
+
+2021-03-24  Luis Machado  <luis.machado@linaro.org>
+
 	* remote: Include gdbsupport/selftest.h.
 	(test_memory_tagging_functions): New function.
 	(_initialize_remote): Register test_memory_tagging_functions.
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index a6ca5a5..49202d4 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1474,6 +1474,7 @@ HFILES_NO_SRCDIR = \
 	arch/aarch32.h \
 	arch/aarch64.h \
 	arch/aarch64-insn.h \
+	arch/aarch64-mte-linux.h \
 	arch/arc.h \
 	arch/arm.h \
 	arch/i386.h \
diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c
index 0cae91b..424e616 100644
--- a/gdb/aarch64-linux-nat.c
+++ b/gdb/aarch64-linux-nat.c
@@ -50,6 +50,8 @@
 #include "gdb_proc_service.h"
 #include "arch-utils.h"
 
+#include "arch/aarch64-mte-linux.h"
+
 #ifndef TRAP_HWBKPT
 #define TRAP_HWBKPT 0x0004
 #endif
diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index d8476c9..a6044ea 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -45,6 +45,8 @@
 #include "record-full.h"
 #include "linux-record.h"
 
+#include "arch/aarch64-mte-linux.h"
+
 /* Signal frame handling.
 
       +------------+  ^
diff --git a/gdb/arch/aarch64-mte-linux.h b/gdb/arch/aarch64-mte-linux.h
new file mode 100644
index 0000000..629ed9c
--- /dev/null
+++ b/gdb/arch/aarch64-mte-linux.h
@@ -0,0 +1,28 @@
+/* Common Linux target-dependent definitions for AArch64 MTE
+
+   Copyright (C) 2021 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef ARCH_AARCH64_LINUX_H
+#define ARCH_AARCH64_LINUX_H
+
+/* Feature check for Memory Tagging Extension.  */
+#ifndef HWCAP2_MTE
+#define HWCAP2_MTE  (1 << 18)
+#endif
+
+#endif /* ARCH_AARCH64_LINUX_H */