RISC-V: Add T-Head SYNC vendor extension

T-Head has a range of vendor-specific instructions.
Therefore it makes sense to group them into smaller chunks
in form of vendor extensions.

This patch adds the XTheadSync extension, a collection of
T-Head-specific multi-processor synchronization instructions.
The 'th' prefix and the "XTheadSync" extension are documented in a PR
for the RISC-V toolchain conventions ([1]).

[1] https://github.com/riscv-non-isa/riscv-toolchain-conventions/pull/19

Co-developed-by: Lifang Xia <lifang_xia@linux.alibaba.com>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>

1 files changed, 5 insertions, 0 deletions

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index 82891f3..ed516c2 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1225,6 +1225,7 @@ static struct riscv_supported_ext riscv_supported_std_zxm_ext[] =
 static struct riscv_supported_ext riscv_supported_vendor_x_ext[] =
 {
   {"xtheadcmo",		ISA_SPEC_CLASS_DRAFT,	1, 0, 0 },
+  {"xtheadsync",	ISA_SPEC_CLASS_DRAFT,	1, 0, 0 },
   {NULL, 0, 0, 0, 0}
 };
 
@@ -2389,6 +2390,8 @@ riscv_multi_subset_supports (riscv_parse_subset_t *rps,
       return riscv_subset_supports (rps, "h");
     case INSN_CLASS_XTHEADCMO:
       return riscv_subset_supports (rps, "xtheadcmo");
+    case INSN_CLASS_XTHEADSYNC:
+      return riscv_subset_supports (rps, "xtheadsync");
     default:
       rps->error_handler
         (_("internal: unreachable INSN_CLASS_*"));
@@ -2518,6 +2521,8 @@ riscv_multi_subset_supports_ext (riscv_parse_subset_t *rps,
       return _("h");
     case INSN_CLASS_XTHEADCMO:
       return "xtheadcmo";
+    case INSN_CLASS_XTHEADSYNC:
+      return "xtheadsync";
     default:
       rps->error_handler
         (_("internal: unreachable INSN_CLASS_*"));