RISC-V: Make ELF `priv-spec' overridable

`priv-spec' disassembler option only allowed a privileged specification
matching the one that is specified on the ELF attributes.  This commit
removes this restriction (making privileged specification for the
disassembler overridable) for programs which uses future privileged
specification than the toolchain (e.g. OpenSBI).

opcodes/ChangeLog:

	* riscv-dis.c (init_riscv_dis_state_for_arch_and_options):
	Use `priv_spec' instead of `default_priv_spec'.
	(print_insn_args): Likewise.
	(set_default_riscv_dis_options): Add initialization.
	(riscv_get_disassembler): Likewise.
	(parse_riscv_dis_option): Make ELF `priv-spec' overridable.
	(parse_riscv_dis_options): Track custom `priv-spec' option.

opcodes/riscv-dis.c

@@ -84,6 +84,12 @@ static bool is_numeric = false;
 /* Reset when either arch or option is changed.  */
 static bool is_init_csr = false;
 
+/* Current privileged specification version.  */
+static enum riscv_spec_class priv_spec = PRIV_SPEC_CLASS_NONE;
+
+/* If set, a custom privileged specification is specified.  */
+static bool is_custom_priv_spec = false;
+
 
 /* Initialization (for arch and options).  */
 
@@ -102,25 +108,25 @@ static void
 init_riscv_dis_state_for_arch_and_options (void)
 {
   static bool init = false;
-  static enum riscv_spec_class prev_default_priv_spec;
+  static enum riscv_spec_class prev_priv_spec;
   if (!init)
     {
       set_default_riscv_dis_options ();
       build_riscv_opcodes_hash_table ();
       init = true;
       /* Save initial options.  */
-      prev_default_priv_spec = default_priv_spec;
+      prev_priv_spec = priv_spec;
     }
   riscv_gpr_names = is_numeric ? riscv_gpr_names_numeric : riscv_gpr_names_abi;
   riscv_fpr_names = is_numeric ? riscv_fpr_names_numeric : riscv_fpr_names_abi;
   /* If arch has Zfinx extension, use GPR to disassemble.  */
   if (riscv_subset_supports (&riscv_rps_dis, "zfinx"))
     riscv_fpr_names = riscv_gpr_names;
   /* Reset CSR hashtable if either `arch' or `priv-spec' option changes.  */
-  if (is_arch_changed || prev_default_priv_spec != default_priv_spec)
+  if (is_arch_changed || prev_priv_spec != priv_spec)
     is_init_csr = false;
   /* Save previous options and mark them "unchanged".  */
-  prev_default_priv_spec = default_priv_spec;
+  prev_priv_spec = priv_spec;
   is_arch_changed = false;
 }
 
@@ -129,6 +135,7 @@ set_default_riscv_dis_options (void)
 {
   no_aliases = false;
   is_numeric = false;
+  is_custom_priv_spec = false;
 }
 
 /* Update current architecture string
@@ -206,22 +213,13 @@ parse_riscv_dis_option (const char *option)
   value = equal + 1;
   if (strcmp (option, "priv-spec") == 0)
     {
-      enum riscv_spec_class priv_spec = PRIV_SPEC_CLASS_NONE;
-      const char *name = NULL;
-
-      RISCV_GET_PRIV_SPEC_CLASS (value, priv_spec);
-      if (priv_spec == PRIV_SPEC_CLASS_NONE)
+      is_custom_priv_spec = true;
+      enum riscv_spec_class priv_spec_new = PRIV_SPEC_CLASS_NONE;
+      RISCV_GET_PRIV_SPEC_CLASS (value, priv_spec_new);
+      if (priv_spec_new == PRIV_SPEC_CLASS_NONE)
 	opcodes_error_handler (_("unknown privileged spec set by %s=%s"),
 			       option, value);
-      else if (default_priv_spec == PRIV_SPEC_CLASS_NONE)
-	default_priv_spec = priv_spec;
-      else if (default_priv_spec != priv_spec)
-	{
-	  RISCV_GET_PRIV_SPEC_NAME (name, default_priv_spec);
-	  opcodes_error_handler (_("mis-matched privilege spec set by %s=%s, "
-				   "the elf privilege attribute is %s"),
-				 option, value, name);
-	}
+      priv_spec = priv_spec_new;
     }
   else
     {
@@ -234,6 +232,7 @@ static void
 parse_riscv_dis_options (const char *opts_in)
 {
   char *opts = xstrdup (opts_in), *opt = opts, *opt_end = opts;
+  bool prev_is_custom_priv_spec = is_custom_priv_spec;
 
   set_default_riscv_dis_options ();
 
@@ -245,6 +244,8 @@ parse_riscv_dis_options (const char *opts_in)
     }
 
   free (opts);
+  if (prev_is_custom_priv_spec && !is_custom_priv_spec)
+    priv_spec = default_priv_spec;
 }
 
 /* Print one argument from an array.  */
@@ -610,15 +611,15 @@ print_insn_args (const char *oparg, insn_t l, bfd_vma pc, disassemble_info *info
 		  riscv_csr_hash[i] = NULL;
 
 		/* Set to the newest privileged version.  */
-		if (default_priv_spec == PRIV_SPEC_CLASS_NONE)
-		  default_priv_spec = PRIV_SPEC_CLASS_DRAFT - 1;
+		if (priv_spec == PRIV_SPEC_CLASS_NONE)
+		  priv_spec = PRIV_SPEC_CLASS_DRAFT - 1;
 
 #define DECLARE_CSR(name, num, class, define_version, abort_version)	\
 		if (riscv_csr_hash[num] == NULL 			\
 		    && ((define_version == PRIV_SPEC_CLASS_NONE 	\
 			 && abort_version == PRIV_SPEC_CLASS_NONE)	\
-			|| (default_priv_spec >= define_version 	\
-			    && default_priv_spec < abort_version)))	\
+			|| (priv_spec >= define_version 	\
+			    && priv_spec < abort_version)))	\
 		  riscv_csr_hash[num] = #name;
 #define DECLARE_CSR_ALIAS(name, num, class, define_version, abort_version) \
 		DECLARE_CSR (name, num, class, define_version, abort_version)
@@ -1156,6 +1157,8 @@ riscv_get_disassembler (bfd *abfd)
 
   if (update_riscv_dis_default_arch (default_arch_next))
     update_riscv_dis_current_arch (default_arch_next);
+  if (!is_custom_priv_spec)
+    priv_spec = default_priv_spec;
   init_riscv_dis_state_for_arch_and_options ();
   return print_insn_riscv;
 }