[RFC PATCH v2] RISC-V: Add Zawrs ISA extension support

[Christoph Muellner]

From: Christoph Müllner <christoph.muellner@vrull.eu>

This patch adds support for the Zawrs ISA extension
("wrs.nto" and "wrs.sto" instructions).

The specification can be found here:
https://github.com/riscv/riscv-zawrs/blob/main/zawrs.adoc

Note, that the Zawrs extension is not frozen or ratified yet.
Therefore this patch is an RFC and not intended to get merged.

Changes since v1:
* Adjustments according to a specification change

Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
---
 bfd/elfxx-riscv.c                  |  5 +++++
 gas/testsuite/gas/riscv/zawrs-32.d | 11 +++++++++++
 gas/testsuite/gas/riscv/zawrs.d    | 11 +++++++++++
 gas/testsuite/gas/riscv/zawrs.s    |  3 +++
 include/opcode/riscv-opc.h         |  8 ++++++++
 include/opcode/riscv.h             |  1 +
 opcodes/riscv-opc.c                |  4 ++++
 7 files changed, 43 insertions(+)
 create mode 100644 gas/testsuite/gas/riscv/zawrs-32.d
 create mode 100644 gas/testsuite/gas/riscv/zawrs.d
 create mode 100644 gas/testsuite/gas/riscv/zawrs.s

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index f920e0ce9ff..597bdb0ee5e 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1226,6 +1226,7 @@ static struct riscv_supported_ext riscv_supported_std_z_ext[] =
   {"zvl16384b",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zvl32768b",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zvl65536b",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  {"zawrs",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {NULL, 0, 0, 0, 0}
 };
 
@@ -2294,6 +2295,8 @@ riscv_multi_subset_supports (riscv_parse_subset_t *rps,
     {
     case INSN_CLASS_I:
       return riscv_subset_supports (rps, "i");
+    case INSN_CLASS_ZAWRS:
+      return riscv_subset_supports (rps, "zawrs");
     case INSN_CLASS_ZICBOM:
       return riscv_subset_supports (rps, "zicbom");
     case INSN_CLASS_ZICBOP:
@@ -2410,6 +2413,8 @@ riscv_multi_subset_supports_ext (riscv_parse_subset_t *rps,
     {
     case INSN_CLASS_I:
       return "i";
+    case INSN_CLASS_ZAWRS:
+      return "zawrs";
     case INSN_CLASS_ZICSR:
       return "zicsr";
     case INSN_CLASS_ZIFENCEI:
diff --git a/gas/testsuite/gas/riscv/zawrs-32.d b/gas/testsuite/gas/riscv/zawrs-32.d
new file mode 100644
index 00000000000..32e3a07fb3a
--- /dev/null
+++ b/gas/testsuite/gas/riscv/zawrs-32.d
@@ -0,0 +1,11 @@
+#as: -march=rv32i_zawrs
+#source: zawrs.s
+#objdump: -dr
+
+.*:[ 	]+file format .*
+
+Disassembly of section .text:
+
+0+000 <target>:
+[ 	]+[0-9a-f]+:[ 	]+00d00073[ 	]+wrs.nto
+[ 	]+[0-9a-f]+:[ 	]+01d00073[ 	]+wrs.sto
diff --git a/gas/testsuite/gas/riscv/zawrs.d b/gas/testsuite/gas/riscv/zawrs.d
new file mode 100644
index 00000000000..9fe44f7e359
--- /dev/null
+++ b/gas/testsuite/gas/riscv/zawrs.d
@@ -0,0 +1,11 @@
+#as: -march=rv64i_zawrs
+#source: zawrs.s
+#objdump: -dr
+
+.*:[ 	]+file format .*
+
+Disassembly of section .text:
+
+0+000 <target>:
+[ 	]+[0-9a-f]+:[ 	]+00d00073[ 	]+wrs.nto
+[ 	]+[0-9a-f]+:[ 	]+01d00073[ 	]+wrs.sto
diff --git a/gas/testsuite/gas/riscv/zawrs.s b/gas/testsuite/gas/riscv/zawrs.s
new file mode 100644
index 00000000000..138b7b5ca77
--- /dev/null
+++ b/gas/testsuite/gas/riscv/zawrs.s
@@ -0,0 +1,3 @@
+target:
+	wrs.nto
+	wrs.sto
diff --git a/include/opcode/riscv-opc.h b/include/opcode/riscv-opc.h
index 207215b79fc..bc80a1624a6 100644
--- a/include/opcode/riscv-opc.h
+++ b/include/opcode/riscv-opc.h
@@ -2113,6 +2113,11 @@
 #define MASK_CBO_INVAL 0xfff07fff
 #define MATCH_CBO_ZERO 0x40200f
 #define MASK_CBO_ZERO 0xfff07fff
+/* Zawrs intructions.  */
+#define MATCH_WRS_NTO 0x00d00073
+#define MASK_WRS_NTO 0xffffffff
+#define MATCH_WRS_STO 0x01d00073
+#define MASK_WRS_STO 0xffffffff
 /* Unprivileged Counter/Timers CSR addresses.  */
 #define CSR_CYCLE 0xc00
 #define CSR_TIME 0xc01
@@ -2795,6 +2800,9 @@ DECLARE_INSN(cbo_clean, MATCH_CBO_CLEAN, MASK_CBO_CLEAN);
 DECLARE_INSN(cbo_flush, MATCH_CBO_FLUSH, MASK_CBO_FLUSH);
 DECLARE_INSN(cbo_inval, MATCH_CBO_INVAL, MASK_CBO_INVAL);
 DECLARE_INSN(cbo_zero, MATCH_CBO_ZERO, MASK_CBO_ZERO);
+/* Zawrs instructions.  */
+DECLARE_INSN(wrs_nto, MATCH_WRS_NTO, MASK_WRS_NTO)
+DECLARE_INSN(wrs_sto, MATCH_WRS_STO, MASK_WRS_STO)
 #endif /* DECLARE_INSN */
 #ifdef DECLARE_CSR
 /* Unprivileged Counter/Timers CSRs.  */
diff --git a/include/opcode/riscv.h b/include/opcode/riscv.h
index 808f05f3d7a..a65b47740b8 100644
--- a/include/opcode/riscv.h
+++ b/include/opcode/riscv.h
@@ -396,6 +396,7 @@ enum riscv_insn_class
   INSN_CLASS_ZICBOP,
   INSN_CLASS_ZICBOZ,
   INSN_CLASS_H,
+  INSN_CLASS_ZAWRS,
 };
 
 /* This structure holds information for a particular instruction.  */
diff --git a/opcodes/riscv-opc.c b/opcodes/riscv-opc.c
index d5cedbe176c..1f80f090bb2 100644
--- a/opcodes/riscv-opc.c
+++ b/opcodes/riscv-opc.c
@@ -915,6 +915,10 @@ const struct riscv_opcode riscv_opcodes[] =
 {"sfence.vma", 0, INSN_CLASS_I,    "s,t",      MATCH_SFENCE_VMA, MASK_SFENCE_VMA, match_opcode, 0 },
 {"wfi",        0, INSN_CLASS_I,    "",         MATCH_WFI, MASK_WFI, match_opcode, 0 },
 
+/* Zawrs instructions.  */
+{"wrs.nto",    0, INSN_CLASS_ZAWRS, "", MATCH_WRS_NTO, MASK_WRS_NTO, match_opcode, 0 },
+{"wrs.sto",    0, INSN_CLASS_ZAWRS, "", MATCH_WRS_STO, MASK_WRS_STO, match_opcode, 0 },
+
 /* Zicbom and Zicboz instructions.  */
 {"cbo.clean",  0, INSN_CLASS_ZICBOM, "0(s)", MATCH_CBO_CLEAN, MASK_CBO_CLEAN, match_opcode, 0 },
 {"cbo.flush",  0, INSN_CLASS_ZICBOM, "0(s)", MATCH_CBO_FLUSH, MASK_CBO_FLUSH, match_opcode, 0 },
-- 
2.35.3