MPFS: Use NuttX SBI for Kernel mode

arch/risc-v/src/mpfs/mpfs_shead.S

@@ -39,7 +39,11 @@
   .extern __trap_vec
 
   .section .start, "ax"
+#ifdef CONFIG_NUTTSBI
+  .global __start_s
+#else
   .global __start
+#endif
 
 /****************************************************************************
  * Name: __start
@@ -52,8 +56,11 @@
  *
  ****************************************************************************/
 
+#ifdef CONFIG_NUTTSBI
+__start_s:
+#else
 __start:
-
+#endif
   /* Disable all interrupts in sie */
 
   csrw sie, zero

boards/risc-v/mpfs/icicle/configs/knsh/defconfig

@@ -77,6 +77,9 @@ CONFIG_NSH_ARCHINIT=y
 CONFIG_NSH_FILE_APPS=y
 CONFIG_NSH_LINELEN=160
 CONFIG_NSH_STRERROR=y
+CONFIG_NUTTSBI=y
+CONFIG_NUTTSBI_MTIMECMP_BASE=0x02004000
+CONFIG_NUTTSBI_MTIME_BASE=0x0200bff8
 CONFIG_PREALLOC_TIMERS=4
 CONFIG_PSEUDOFS_SOFTLINKS=y
 CONFIG_RAM_SIZE=2097152

boards/risc-v/mpfs/icicle/scripts/ld-kernel.script

@@ -73,6 +73,13 @@ SECTIONS
 
     _eronly = ABSOLUTE(.);
 
+    /* No init section */
+
+    .noinit (NOLOAD) : ALIGN(4) {
+        *(.noinit)
+        *(.noinit.*)
+    } > ksram
+
     .data : ALIGN(4) {
         _sdata = ABSOLUTE(.);
         *(.data .data.*)