aarch64: Add DSB instruction Armv8.7-a variant

This patch adds new variant (nXS) of DSB memory barrier instruction
available in Armv8.7-a. New nXS variant has different encoding in
comparison with pre Armv8.7-a DSB memory barrier variant thus new
instruction and new operand was added.

DSB memory nXS barrier variant specifies the limitation on the barrier
operation. Allowed values are:

	DSB SYnXS|#28
	DSB ISHnXS|#24
	DSB NSHnXS|#20
	DSB OSHnXS|#16

Please note that till now,  for barriers, barrier operation was encoded in
4-bit unsigned immediate CRm field (in the range 0 to 15).
For DSB memory nXS barrier variant, barrier operation is a 5-bit unsigned
assembly instruction immediate, encoded in instruction in two bits CRm<3:2>:

		CRm<3:2>  #imm
		  00       16
		  01       20
		  10       24
		  11       28

This patch extends current AArch64 barrier instructions with above mapping.

Notable patch changes include:
+ New DSB memory barrier variant encoding for Armv8.7-a.
+ New operand BARRIER_DSB_NXS for above instruction in order to
distinguish between existing and new DSB instruction flavour.
+ New set of DSB nXS barrier options.
+ New instruction inserter and extractor map between instruction
immediate 5-bit value and 2-bit CRm field of the instruction itself (see
FLD_CRm_dsb_nxs).
+ Regeneration of aarch64-[asm|dis|opc]-2.c files.
+ Test cases to cover new instruction assembling and disassembling.

For more details regarding DSB memory barrier instruction and its
Armv8.7-a flavour please refer to Arm A64 Instruction set documentation
for Armv8-A architecture profile, see document pages 132-133 of [0].

	[0]: https://developer.arm.com/docs/ddi0596/i

gas/ChangeLog:

2020-10-23  Przemyslaw Wirkus  <przemyslaw.wirkus@arm.com>

	* NEWS: Docs update.
	* config/tc-aarch64.c (parse_operands): Add
	AARCH64_OPND_BARRIER_DSB_NXS handler.
	(md_begin): Add content of aarch64_barrier_dsb_nxs_options to
	aarch64_barrier_opt_hsh hash.
	* testsuite/gas/aarch64/system-4-invalid.d: New test.
	* testsuite/gas/aarch64/system-4-invalid.l: New test.
	* testsuite/gas/aarch64/system-4-invalid.s: New test.
	* testsuite/gas/aarch64/system-4.d: New test.
	* testsuite/gas/aarch64/system-4.s: New test.

include/ChangeLog:

2020-10-23  Przemyslaw Wirkus  <przemyslaw.wirkus@arm.com>

	* opcode/aarch64.h (enum aarch64_opnd): New operand
	AARCH64_OPND_BARRIER_DSB_NXS.
	(aarch64_barrier_dsb_nxs_options): Declare DSB nXS options.

opcodes/ChangeLog:

2020-10-23  Przemyslaw Wirkus  <przemyslaw.wirkus@arm.com>

	* aarch64-asm.c (aarch64_ins_barrier_dsb_nxs): New inserter.
	* aarch64-asm.h (AARCH64_DECL_OPD_INSERTER): New inserter
	ins_barrier_dsb_nx.
	* aarch64-dis.c (aarch64_ext_barrier_dsb_nxs): New extractor.
	* aarch64-dis.h (AARCH64_DECL_OPD_EXTRACTOR): New extractor
	ext_barrier_dsb_nx.
	* aarch64-opc.c (aarch64_print_operand): New options table
	aarch64_barrier_dsb_nxs_options.
	* aarch64-opc.h (enum aarch64_field_kind): New field name FLD_CRm_dsb_nxs.
	* aarch64-tbl.h (struct aarch64_opcode): Define DSB nXS barrier
	Armv8.7-a instruction.
	* aarch64-asm-2.c: Regenerated.
	* aarch64-dis-2.c: Regenerated.
	* aarch64-opc-2.c: Regenerated.

1 files changed, 5 insertions, 0 deletions

diff --git a/opcodes/aarch64-tbl.h b/opcodes/aarch64-tbl.h
index 16d008d..119625a 100644
--- a/opcodes/aarch64-tbl.h
+++ b/opcodes/aarch64-tbl.h
@@ -2561,6 +2561,8 @@ static const aarch64_feature_set aarch64_feature_v8_r =
   { NAME, OPCODE, MASK, CLASS, 0, F32MM_SVE, OPS, QUALS, FLAGS, CONSTRAINTS, TIED, NULL }
 #define V8_R_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS) \
   { NAME, OPCODE, MASK, CLASS, 0, ARMV8_R, OPS, QUALS, FLAGS, 0, 0, NULL }
+#define V8_7_INSN(NAME,OPCODE,MASK,CLASS,OPS,QUALS,FLAGS) \
+  { NAME, OPCODE, MASK, CLASS, 0, ARMV8_7, OPS, QUALS, FLAGS, 0, 0, NULL }
 
 struct aarch64_opcode aarch64_opcode_table[] =
 {
@@ -3853,6 +3855,7 @@ struct aarch64_opcode aarch64_opcode_table[] =
   CORE_INSN ("tsb", 0xd503225f, 0xffffffff, ic_system, 0, OP1 (BARRIER_PSB), {}, F_ALIAS),
   CORE_INSN ("clrex", 0xd503305f, 0xfffff0ff, ic_system, 0, OP1 (UIMM4), {}, F_OPD0_OPT | F_DEFAULT (0xF)),
   CORE_INSN ("dsb", 0xd503309f, 0xfffff0ff, ic_system, 0, OP1 (BARRIER), {}, F_HAS_ALIAS),
+  V8_7_INSN ("dsb", 0xd503323f, 0xfffff3ff, ic_system, OP1 (BARRIER_DSB_NXS), {}, F_HAS_ALIAS),
   V8_R_INSN ("dfb", 0xd5033c9f, 0xffffffff, ic_system, OP0 (), {}, F_ALIAS),
   CORE_INSN ("ssbb", 0xd503309f, 0xffffffff, ic_system, 0, OP0 (), {}, F_ALIAS),
   CORE_INSN ("pssbb", 0xd503349f, 0xffffffff, ic_system, 0, OP0 (), {}, F_ALIAS),
@@ -5323,6 +5326,8 @@ struct aarch64_opcode aarch64_opcode_table[] =
       "a Speculation Restriction option name (RCTX)")			\
     Y(SYSTEM, barrier, "BARRIER", 0, F(),				\
       "a barrier option name")						\
+    Y(SYSTEM, barrier_dsb_nxs, "BARRIER_DSB_NXS", 0, F(),				\
+      "the DSB nXS option qualifier name SY, ISH, NSH, OSH or an optional 5-bit unsigned immediate")	\
     Y(SYSTEM, barrier, "BARRIER_ISB", 0, F(),				\
       "the ISB option name SY or an optional 4-bit unsigned immediate")	\
     Y(SYSTEM, prfop, "PRFOP", 0, F(),					\