updates linker script for rtl env

bare-metal-bsp/env/rtl/link.lds

@@ -118,6 +118,7 @@ SECTIONS
 
   .data          :
   {
+    __DATA_BEGIN__ = .;
     *(.data .data.*)
     *(.gnu.linkonce.d.*)
   } >ram AT>flash :ram_init
@@ -134,6 +135,7 @@ SECTIONS
 
   .sdata          :
   {
+    __SDATA_BEGIN__ = .;
     *(.sdata .sdata.*)
     *(.gnu.linkonce.s.*)
   } >ram AT>flash :ram_init
@@ -155,6 +157,8 @@ SECTIONS
   } >ram AT>ram :ram
 
   . = ALIGN(8);
+  __BSS_END__ = .;
+  __global_pointer$ = MIN(__SDATA_BEGIN__ + 0x800,  MAX(__DATA_BEGIN__ + 0x800, __BSS_END__ - 0x800));
   PROVIDE( _end = . );
   PROVIDE( end = . );
 
@@ -165,6 +169,7 @@ SECTIONS
     PROVIDE( _sp = . );
   } >ram AT>ram :ram
 
-  PROVIDE( tohost = 0x00018000 );
+  #PROVIDE( tohost = 0x00018000 );
+  PROVIDE( tohost = 0xfffffff0 );
   PROVIDE( fromhost = 0xfffffff8 );
 }