c18n: Add CHERI-RISC-V workaround for lack of memarg ABI

libexec/rtld-elf/rtld_c18n.c

@@ -343,6 +343,17 @@ compart_id_allocate(const char *lib)
 		if (string_base_search(&comparts.data[i].libs, lib) != -1)
 			return (i);
 
+#ifdef __riscv
+	/*
+	 * XXX: All compartments have the same compartment ID on CHERI-RISC-V to
+	 * work around the lack of bounded memory and variadic arguments.
+	 */
+	lib = "[grand]";
+	for (i = RTLD_COMPART_ID; i < comparts.size; ++i)
+		if (string_base_search(&comparts.data[i].libs, lib) != -1)
+			return (i);
+#endif
+
 	com = add_comparts_data(lib);
 	string_base_push(&com->libs, lib);
 
@@ -571,8 +582,14 @@ tramp_should_include(const Obj_Entry *reqobj, const struct tramp_data *data)
 	if (reqobj == NULL)
 		return (true);
 
+#ifndef __riscv
+	/*
+	 * XXX: All compartments have the same compartment ID on CHERI-RISC-V to
+	 * work around the lack of bounded memory and variadic arguments.
+	 */
 	if (reqobj->compart_id == data->defobj->compart_id)
 		return (false);
+#endif
 
 	if (string_base_search(&comparts.data[reqobj->compart_id].trusts, sym)
 	    != -1)

libexec/rtld-elf/rtld_c18n_policy.txt

@@ -1,13 +1,5 @@
 Version 1
 
-compartment [TCB]
-	libc.so.7
-	libthr.so.3
-	libsys.so.7
-
-compartment [libunwind]
-	libgcc_s.so.1
-
 caller *
 trust
 	memset
@@ -46,25 +38,3 @@ trust
 	unw_getcontext
 	_rtld_thread_start
 	_rtld_sighandler
-
-callee [RTLD]
-export to [TCB]
-	_rtld_thread_start_init
-	_rtld_thread_start
-	_rtld_thr_exit
-	_rtld_sighandler_init
-	_rtld_sighandler
-	_rtld_siginvoke
-	_rtld_sigaction
-
-callee [RTLD]
-export to [TCB]
-export to [libunwind]
-	c18n_get_trusted_stk
-	c18n_unwind_trusted_stk
-
-callee [RTLD]
-export to [libunwind]
-	c18n_is_enabled
-	c18n_is_tramp
-	c18n_pop_trusted_stk