[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.

gas/ChangeLog

@@ -1,3 +1,15 @@
+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.

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)),

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),

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

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

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

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\}

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\}

include/ChangeLog

@@ -1,3 +1,8 @@
+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.
+
 2018-10-05  Sudakshina Das  <sudi.das@arm.com>
 
 	* opcode/arm.h (ARM_EXT2_SB): New.

include/opcode/arm.h

@@ -70,6 +70,7 @@
 #define ARM_EXT2_FP16_FML 0x00000800	/* ARM V8.2A FP16-FML instructions.  */
 #define ARM_EXT2_V8_5A	 0x00001000	/* ARM V8.5A.  */
 #define ARM_EXT2_SB	 0x00002000	/* Speculation Barrier instruction.  */
+#define ARM_EXT2_PREDRES 0x00004000	/* Prediction Restriction insns.  */
 
 /* Co-processor space extensions.  */
 #define ARM_CEXT_XSCALE   0x00000001	/* Allow MIA etc.          */
@@ -297,7 +298,8 @@
 				     CRC_EXT_ARMV8 | FPU_NEON_EXT_RDMA \
 				     | FPU_NEON_EXT_DOTPROD)
 #define ARM_ARCH_V8_5A	ARM_FEATURE (ARM_AEXT_V8A,	\
-				     ARM_AEXT2_V8_5A | ARM_EXT2_SB,	\
+				     ARM_AEXT2_V8_5A | ARM_EXT2_SB	\
+				     | ARM_EXT2_PREDRES,		\
 				     CRC_EXT_ARMV8 | FPU_NEON_EXT_RDMA \
 				     | FPU_NEON_EXT_DOTPROD)
 #define ARM_ARCH_V8M_BASE ARM_FEATURE_CORE (ARM_AEXT_V8M_BASE, ARM_AEXT2_V8M)