configure: Add --enable-boot-machine in BBL

If --enable-boot-machine is passed, BBL disables VM and runs the payload in machine mode.
This is useful for payloads (e.g. RTOSes or other OSes) that want to run
only in machine mode while still relying on bbl/pk for system calls and emulation

bbl/bbl.ac

@@ -18,3 +18,8 @@ AC_ARG_WITH([payload], AS_HELP_STRING([--with-payload], [Set ELF payload for bbl
 AC_ARG_WITH([logo], AS_HELP_STRING([--with-logo], [Specify a better logo]),
   [AC_SUBST([BBL_LOGO_FILE], $with_logo, [Logo for bbl])],
   [AC_SUBST([BBL_LOGO_FILE], [riscv_logo.txt], [Logo for bbl])])
+
+AC_ARG_ENABLE([boot-machine], AS_HELP_STRING([--enable-boot-machine], [Run payload in machine mode]))
+AS_IF([test "x$enable_boot_machine" == "xyes"], [
+  AC_DEFINE([BBL_BOOT_MACHINE],,[Define to run payload in machine mode])
+])

config.h.in

@@ -1,5 +1,8 @@
 /* config.h.in.  Generated from configure.ac by autoheader.  */
 
+/* Define to run payload in machine mode */
+#undef BBL_BOOT_MACHINE
+
 /* Define if subproject MCPPBS_SPROJ_NORM is enabled */
 #undef BBL_ENABLED
 

configure

@@ -677,6 +677,7 @@ enable_vm
 enable_logo
 with_payload
 with_logo
+enable_boot_machine
 enable_fp_emulation
 '
       ac_precious_vars='build_alias
@@ -1325,6 +1326,7 @@ Optional Features:
                           Enable all optional subprojects
   --disable-vm            Disable virtual memory
   --enable-logo           Enable boot logo
+  --enable-boot-machine   Run payload in machine mode
   --disable-fp-emulation  Disable floating-point emulation
 
 Optional Packages:
@@ -4272,6 +4274,19 @@ else
 fi
 
 
+# Check whether --enable-boot-machine was given.
+if test "${enable_boot_machine+set}" = set; then :
+  enableval=$enable_boot_machine;
+fi
+
+if test "x$enable_boot_machine" == "xyes"; then :
+
+
+$as_echo "#define BBL_BOOT_MACHINE /**/" >>confdefs.h
+
+
+fi
+