diff options
Diffstat (limited to 'bsps/m68k/mvme167/start/bspclean.c')
-rw-r--r-- | bsps/m68k/mvme167/start/bspclean.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/bsps/m68k/mvme167/start/bspclean.c b/bsps/m68k/mvme167/start/bspclean.c new file mode 100644 index 0000000000..2dd980fdb4 --- /dev/null +++ b/bsps/m68k/mvme167/start/bspclean.c @@ -0,0 +1,70 @@ +/** + * @file + * + * These routines return control to 167Bug after a normal exit from the + * application. + */ + +/* + * COPYRIGHT (c) 1989-2012. + * On-Line Applications Research Corporation (OAR). + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.org/license/LICENSE. + * + * Modifications of respective RTEMS files: + * Copyright (c) 1998, National Research Council of Canada + */ + +#include <bsp.h> +#include <bsp/bootcard.h> +#include <page_table.h> + +extern void start( void ); +extern void page_table_teardown( void ); + +/** + * @brief bsp_return_to_monitor_trap + * + * Switch the VBR back to ROM and make a .RETURN syscall to return control to + * 167 Bug. If 167Bug ever returns, restart the application. + */ +static void bsp_return_to_monitor_trap( void ) +{ + register volatile void *start_addr; + + page_table_teardown(); + + lcsr->intr_ena = 0; /* disable interrupts */ + m68k_set_vbr(0xFFE00000); /* restore 167Bug vectors */ + __asm__ volatile( "trap #15\n\t" /* trap to 167Bug */ + ".short 0x63" ); /* return to 167Bug (.RETURN) */ + + /* restart program */ + start_addr = start; + __asm__ volatile( "jmp %0@" : "=a" (start_addr) : "0" (start_addr) ); +} + +/* + * This code was copied from other MC680x0 MVME BSPs. + * Our guess is that someone was concerned about the CPU no longer being in + * supervisor mode when they got here. This function forces the CPU back to + * supervisor mode so the VBR may be changed. It places the address of the + * function that makes a 167Bug .RETURN syscall in the trap 13 entry in the + * exception vector, and then issues a trap 13 call. It is also possible that + * the code was copied from some other OS that does run tasks in user mode. + * In any case, it appears to be a bit of paranoia, and could lead to + * problems if 167Bug is invoked before we get to switch the VBR back to + * 167Bug because trap 13 is documented as being reserved for the internal + * use of the debugger. + */ +void bsp_fatal_extension( + rtems_fatal_source source, + bool always_set_to_false, + rtems_fatal_code error +) +{ + M68Kvec[ 45 ] = bsp_return_to_monitor_trap; + __asm__ volatile( "trap #13" ); +} |