[Arm, 3/3] Add Execution and Data Prediction instructions for AArch32

This patch is part of the patch series to add support for ARMv8.5-A
extensions.

(https://developer.arm.com/products/architecture/cpu-architecture/a-profile/exploration-tools)

This patch adds the Execution and Data Prediction Restriction
instructions (that is, cfprctx, dvprxtc, cpprctx). These are all
aliases to MCR and are disassembled as such.

This instruction is retrospectively made optional for all versions of
the architecture from ARMv8.0 to ARMv8.4 and is mandatory from
ARMv8.5.  Hence adding a new +predres for older versions of the
architecture.

*** include/ChangeLog ***

2018-10-05  Sudakshina Das  <sudi.das@arm.com>

	* opcode/arm.h (ARM_EXT2_PREDRES): New.
	(ARM_ARCH_V8_5A): Add ARM_EXT2_PREDRES by default.

*** gas/ChangeLog ***

2018-10-05  Sudakshina Das  <sudi.das@arm.com>

	* config/tc-arm.c (arm_ext_predres): New.
	(insns): Add new cfprctx, dvprctx and cpprctx instructions.
	(arm_extensions): Add "predres".
	* doc/c-arm.texi: Document the above.
	* testsuite/gas/arm/predres-bad.d: New test.
	* testsuite/gas/arm/predres-bad.l: New test.
	* testsuite/gas/arm/predres.s: New test.
	* testsuite/gas/arm/predres1.d: New test.
	* testsuite/gas/arm/predres2.d: New test.

8 files changed, 63 insertions, 0 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 9bdeb22..9b6afa1 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,5 +1,17 @@
 2018-10-05  Sudakshina Das  <sudi.das@arm.com>
 
+	* config/tc-arm.c (arm_ext_predres): New.
+	(insns): Add new cfprctx, dvprctx and cpprctx instructions.
+	(arm_extensions): Add "predres".
+	* doc/c-arm.texi: Document the above.
+	* testsuite/gas/arm/predres-bad.d: New test.
+	* testsuite/gas/arm/predres-bad.l: New test.
+	* testsuite/gas/arm/predres.s: New test.
+	* testsuite/gas/arm/predres1.d: New test.
+	* testsuite/gas/arm/predres2.d: New test.
+
+2018-10-05  Sudakshina Das  <sudi.das@arm.com>
+
 	* config/tc-arm.c (arm_ext_sb): New.
 	(insns): Add new sb instruction.
 	(arm_extensions): Add "sb".
diff --git a/gas/config/tc-arm.c b/gas/config/tc-arm.c
index 1ecaa45..80fb0c3 100644
--- a/gas/config/tc-arm.c
+++ b/gas/config/tc-arm.c
@@ -258,6 +258,8 @@ static const arm_feature_set arm_ext_v8_3 =
   ARM_FEATURE_CORE_HIGH (ARM_EXT2_V8_3A);
 static const arm_feature_set arm_ext_sb =
   ARM_FEATURE_CORE_HIGH (ARM_EXT2_SB);
+static const arm_feature_set arm_ext_predres =
+  ARM_FEATURE_CORE_HIGH (ARM_EXT2_PREDRES);
 
 static const arm_feature_set arm_arch_any = ARM_ANY;
 #ifdef OBJ_ELF
@@ -21525,6 +21527,14 @@ static const struct asm_opcode insns[] =
 #define THUMB_VARIANT & arm_ext_sb
  TUF("sb", 57ff070, f3bf8f70, 0, (), noargs, noargs),
 
+#undef  ARM_VARIANT
+#define ARM_VARIANT   & arm_ext_predres
+#undef  THUMB_VARIANT
+#define THUMB_VARIANT & arm_ext_predres
+ CE("cfprctx", e070f93, 1, (RRnpc), rd),
+ CE("dvprctx", e070fb3, 1, (RRnpc), rd),
+ CE("cpprctx", e070ff3, 1, (RRnpc), rd),
+
  /* ARMv8-M instructions.  */
 #undef  ARM_VARIANT
 #define ARM_VARIANT NULL
@@ -26421,6 +26431,9 @@ static const struct arm_option_extension_value_table arm_extensions[] =
   ARM_EXT_OPT ("pan",	ARM_FEATURE_CORE_HIGH (ARM_EXT2_PAN),
 			ARM_FEATURE (ARM_EXT_V8, ARM_EXT2_PAN, 0),
 			ARM_FEATURE_CORE_HIGH (ARM_EXT2_V8A)),
+  ARM_EXT_OPT ("predres", ARM_FEATURE_CORE_HIGH (ARM_EXT2_PREDRES),
+			ARM_FEATURE_CORE_HIGH (ARM_EXT2_PREDRES),
+			ARM_ARCH_V8A),
   ARM_EXT_OPT ("ras",	ARM_FEATURE_CORE_HIGH (ARM_EXT2_RAS),
 			ARM_FEATURE (ARM_EXT_V8, ARM_EXT2_RAS, 0),
 			ARM_FEATURE_CORE_HIGH (ARM_EXT2_V8A)),
diff --git a/gas/doc/c-arm.texi b/gas/doc/c-arm.texi
index 18008c4..835777a 100644
--- a/gas/doc/c-arm.texi
+++ b/gas/doc/c-arm.texi
@@ -189,6 +189,8 @@ The following extensions are currently supported:
 @code{mp} (Multiprocessing Extensions for v7-A and v7-R
 architectures),
 @code{os} (Operating System for v6M architecture),
+@code{predres} (Execution and Data Prediction Restriction Instruction for
+v8-A architectures, added by default from v8.5-A),
 @code{sb} (Speculation Barrier Instruction for v8-A architectures, added by
 default from v8.5-A),
 @code{sec} (Security Extensions for v6K and v7-A architectures),
diff --git a/gas/testsuite/gas/arm/predres-bad.d b/gas/testsuite/gas/arm/predres-bad.d
new file mode 100644
index 0000000..8ddc8ee
--- /dev/null
+++ b/gas/testsuite/gas/arm/predres-bad.d
@@ -0,0 +1,4 @@
+#name: Error for Prediction Restriction instructions without +predres
+#source: predres.s
+#as: -march=armv8-a
+#error_output: predres-bad.l
diff --git a/gas/testsuite/gas/arm/predres-bad.l b/gas/testsuite/gas/arm/predres-bad.l
new file mode 100644
index 0000000..3f7efc6
--- /dev/null
+++ b/gas/testsuite/gas/arm/predres-bad.l
@@ -0,0 +1,4 @@
+[^:]*: Assembler messages:
+[^:]*:4: Error: selected processor does not support `cfprctx r1' in ARM mode
+[^:]*:5: Error: selected processor does not support `dvprctx r2' in ARM mode
+[^:]*:6: Error: selected processor does not support `cpprctx r3' in ARM mode
diff --git a/gas/testsuite/gas/arm/predres.s b/gas/testsuite/gas/arm/predres.s
new file mode 100644
index 0000000..6cfb1f1
--- /dev/null
+++ b/gas/testsuite/gas/arm/predres.s
@@ -0,0 +1,6 @@
+@ Test case to validate Prediction Restriction Instructions
+.section .text
+.syntax unified
+	cfprctx	r1
+	dvprctx	r2
+	cpprctx	r3
diff --git a/gas/testsuite/gas/arm/predres1.d b/gas/testsuite/gas/arm/predres1.d
new file mode 100644
index 0000000..b3a900a
--- /dev/null
+++ b/gas/testsuite/gas/arm/predres1.d
@@ -0,0 +1,11 @@
+#name: Execution and Data Prediction Restriction instructions
+#source: predres.s
+#as: -march=armv8.5-a
+#objdump: -dr --prefix-addresses --show-raw-insn
+
+.*: *file format .*arm.*
+
+Disassembly of section .text:
+.*> ee071f93 	mcr	15, 0, r1, cr7, cr3, \{4\}
+.*> ee072fb3 	mcr	15, 0, r2, cr7, cr3, \{5\}
+.*> ee073ff3 	mcr	15, 0, r3, cr7, cr3, \{7\}
diff --git a/gas/testsuite/gas/arm/predres2.d b/gas/testsuite/gas/arm/predres2.d
new file mode 100644
index 0000000..d17cf06
--- /dev/null
+++ b/gas/testsuite/gas/arm/predres2.d
@@ -0,0 +1,11 @@
+#name: Execution and Data Prediction Restriction instructions with +predres
+#source: predres.s
+#as: -march=armv8-a+predres
+#objdump: -dr --prefix-addresses --show-raw-insn
+
+.*: *file format .*arm.*
+
+Disassembly of section .text:
+.*> ee071f93 	mcr	15, 0, r1, cr7, cr3, \{4\}
+.*> ee072fb3 	mcr	15, 0, r2, cr7, cr3, \{5\}
+.*> ee073ff3 	mcr	15, 0, r3, cr7, cr3, \{7\}