AArch64: Add pointer authentication feature

Pointer Authentication is a new feature in AArch64 v8.3-a. When enabled in
the compiler, function return addresses will be mangled by the kernel.

Add register description xml and wire up to aarch64_linux_read_description.
This description includes the two pauth user registers.

Nothing yet uses the feature - that is added in later patches.

gdb/ChangeLog:

	* aarch64-linux-nat.c
	(aarch64_linux_nat_target::read_description): Add pauth param.
	* aarch64-linux-tdep.c
	(aarch64_linux_core_read_description): Likewise.
	* aarch64-tdep.c (struct target_desc): Add in pauth.
	(aarch64_read_description): Add pauth param.
	(aarch64_gdbarch_init): Likewise.
	* aarch64-tdep.h (aarch64_read_description): Likewise.
	* arch/aarch64.c (aarch64_create_target_description): Likewise.
	* arch/aarch64.h (aarch64_create_target_description): Likewise.
	* features/Makefile: Add new files.
	* features/aarch64-pauth.c: New file.
	* features/aarch64-pauth.xml: New file.

gdb/doc/ChangeLog:

	* gdb.texinfo: Describe pauth feature.

gdb/gdbserver/ChangeLog:

	* linux-aarch64-ipa.c (get_ipa_tdesc): Add pauth param.
	(initialize_low_tracepoint): Likewise.
	* linux-aarch64-low.c (aarch64_arch_setup): Likewise.
	* linux-aarch64-tdesc-selftest.c (aarch64_tdesc_test): Likewise.
	* linux-aarch64-tdesc.c (struct target_desc): Likewise.
	(aarch64_linux_read_description): Likewise.
	* linux-aarch64-tdesc.h (aarch64_linux_read_description): Likewise.

3 files changed, 30 insertions, 0 deletions

diff --git a/gdb/features/Makefile b/gdb/features/Makefile
index 3d84ca0..d0cd4f8 100644
--- a/gdb/features/Makefile
+++ b/gdb/features/Makefile
@@ -227,6 +227,7 @@ $(outdir)/%.dat: %.xml number-regs.xsl sort-regs.xsl gdbserver-regs.xsl
 
 FEATURE_XMLFILES = aarch64-core.xml \
 	aarch64-fpu.xml \
+	aarch64-pauth.xml \
 	i386/32bit-core.xml \
 	i386/32bit-sse.xml \
 	i386/32bit-linux.xml \
diff --git a/gdb/features/aarch64-pauth.c b/gdb/features/aarch64-pauth.c
new file mode 100644
index 0000000..e4b84ff
--- /dev/null
+++ b/gdb/features/aarch64-pauth.c
@@ -0,0 +1,16 @@
+/* THIS FILE IS GENERATED.  -*- buffer-read-only: t -*- vi:set ro:
+  Original: aarch64-pauth.xml */
+
+#include "common/tdesc.h"
+
+static int
+create_feature_aarch64_pauth (struct target_desc *result, long regnum)
+{
+  struct tdesc_feature *feature;
+
+  feature = tdesc_create_feature (result, "org.gnu.gdb.aarch64.pauth");
+  tdesc_create_reg (feature, "pauth_dmask", regnum++, 1, NULL, 64, "int");
+  tdesc_create_reg (feature, "pauth_cmask", regnum++, 1, NULL, 64, "int");
+
+  return regnum;
+}
diff --git a/gdb/features/aarch64-pauth.xml b/gdb/features/aarch64-pauth.xml
new file mode 100644
index 0000000..9c8987f
--- /dev/null
+++ b/gdb/features/aarch64-pauth.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2018 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.aarch64.pauth">
+  <reg name="pauth_dmask" bitsize="64"/>
+  <reg name="pauth_cmask" bitsize="64"/>
+</feature>
+