2009-05-05 Michael Walle <michael@walle.cc>

* shared/gdbstub/README, shared/gdbstub/gdb_if.h,
	shared/gdbstub/lm32-debug.S, shared/gdbstub/lm32-stub.c: New files.

c/src/lib/libbsp/lm32/ChangeLog

@@ -1,3 +1,8 @@
+2009-05-05	Michael Walle <michael@walle.cc>
+
+	* shared/gdbstub/README, shared/gdbstub/gdb_if.h,
+	shared/gdbstub/lm32-debug.S, shared/gdbstub/lm32-stub.c: New files.
+
 2009-04-28	Chris Johns <chrisj@rtems.org>
 
 	* shared/start/start.S: Update for boot_card command line change.

c/src/lib/libbsp/lm32/shared/gdbstub/README

@@ -0,0 +1,86 @@
+#
+#  $Id$
+#
+
+This is a thread-aware gdb stub for the lm32 architecture. It has to be
+linked with the application, which should be debugged. The application has
+to call 'lm32_gdb_stub_install' to setup the stub.
+   The stub remaps _all_ h/w exceptions to an own code (lm32-debug.S), which
+saves all the registers, calls the gdb stub and restores the registers again.
+   The interrupt exceptions gets handled in a special way. Because we remapped
+this exception, we need to do
+ - the same as the original one (in cpu_asm.S),
+ - and, as we might use an ISR for breaking into a running application with
+   gdb, we need to save all registers as well. To be backward compatible
+   the missing callee saved registers gets appended to CPU_Interrupt_frame.
+   There is a mapping in 'gdb_handle_break' for that.
+
+To use this gdb stub, your bsp has to provide the following functions:
+ - void gdb_put_debug_char(char c)
+   Puts the given charater c to the debug console output. The function can
+   block until the character can be written to the output buffer.
+
+ - char gdb_get_debug_char(void)
+   Returns the character in the input buffer of the debug console. If no one
+   is availabe, the function must block.
+
+ - void gdb_console_init()
+   This function can be used to initialize the debug console. Additionally,
+   it should set up the ISR for the debug console to call the function
+   'gdb_handle_break', which is provided by the gdb stub and enable the
+   interrupt for a break symbol on the debug serial port. If no ISR is
+   provided, you won't be able to interrupt a running application.
+
+ - void gdb_ack_irq()
+   If an ISR is used, this function is used to acknowledge the interrupt.
+
+NOTE: the stub don't skip a hardcoded 'break' in the code. So you have to
+   set the PC an instruction further in the debugger (set $pc += 4).
+
+NOTE2: make sure you have the following CFLAGS set:
+     -mbarrel-shift-enabled -mmultiply-enabled -mdivide-enabled 
+     -msign-extend-enabled
+   Without the hardware support, it is done in software. Unfortunately, the
+   stub also uses some shifts and multiplies. If you step through your code,
+   there will be a chance that a breakpoint is set to one of that functions,
+   which then causes an endless loop.
+
+
+EXAMPLES
+
+  char gdb_get_debug_char(void)
+  {
+    /* Wait until there is a byte in RXTX */
+    while (!(uartread(LM32_UART_LSR) & LM32_UART_LSR_DR));
+
+    return (char) uartread(LM32_UART_RBR);
+  }
+
+  void gdb_put_debug_char(char c)
+  {
+    /* Wait until RXTX is empty. */
+    while (!(uartread(LM32_UART_LSR) & LM32_UART_LSR_THRE));
+    uartwrite(LM32_UART_RBR, c);
+  }
+
+  extern void gdb_handle_break(
+    rtems_vector_number vector,
+    CPU_Interrupt_frame *frame
+  );
+  void gdb_console_init()
+  {
+    rtems_isr_entry old;
+
+    /* enable interrupts */
+    uartwrite(LM32_UART_IER, 1);
+
+    rtems_interrupt_catch((rtems_isr_entry) gdb_handle_break, DEBUG_UART_IRQ,
+      &old);
+    lm32_interrupt_unmask(1 << DEBUG_UART_IRQ);
+  }
+
+  void gdb_ack_irq()
+  {
+    lm32_interrupt_ack(1 << DEBUG_UART_IRQ);
+  }
+

c/src/lib/libbsp/lm32/shared/gdbstub/gdb_if.h

@@ -0,0 +1,112 @@
+/*
+ * gdb_if.h - definition of the interface between the stub and gdb
+ *
+ *                   THIS SOFTWARE IS NOT COPYRIGHTED
+ *
+ *  The following software is offered for use in the public domain.
+ *  There is no warranty with regard to this software or its performance
+ *  and the user must accept the software "AS IS" with all faults.
+ *
+ *  THE CONTRIBUTORS DISCLAIM ANY WARRANTIES, EXPRESS OR IMPLIED, WITH
+ *  REGARD TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ *  $Id$
+ */
+
+#ifndef _GDB_IF_H
+#define _GDB_IF_H
+
+/* Max number of threads in qM response */
+#define QM_MAX_THREADS (20)
+
+struct rtems_gdb_stub_thread_info {
+  char display[256];
+  char name[256];
+  char more_display[256];
+};
+
+/*
+ *  Prototypes
+ */
+
+int parse_zbreak(const char *in, int *type, unsigned char **addr, int *len);
+
+char* mem2hstr(char *buf, const unsigned char *mem, int count);
+int   hstr2mem(unsigned char *mem, const char *buf, int count);
+void  set_mem_err(void);
+unsigned char get_byte(const unsigned char *ptr);
+void  set_byte(unsigned char *ptr, int val);
+char* thread2vhstr(char *buf, int thread);
+char* thread2fhstr(char *buf, int thread);
+const char* fhstr2thread(const char *buf, int *thread);
+const char* vhstr2thread(const char *buf, int *thread);
+char* int2fhstr(char *buf, int val);
+char* int2vhstr(char *buf, int vali);
+const char* fhstr2int(const char *buf, int *ival);
+const char* vhstr2int(const char *buf, int *ival);
+int   hstr2byte(const char *buf, int *bval);
+int   hstr2nibble(const char *buf, int *nibble);
+
+Thread_Control *rtems_gdb_index_to_stub_id(int);
+int rtems_gdb_stub_thread_support_ok(void);
+int rtems_gdb_stub_get_current_thread(void);
+int rtems_gdb_stub_get_next_thread(int);
+int rtems_gdb_stub_get_offsets(
+  unsigned char **text_addr,
+  unsigned char **data_addr,
+  unsigned char **bss_addr
+);
+int rtems_gdb_stub_get_thread_regs(
+  int thread,
+  unsigned int *registers
+);
+int rtems_gdb_stub_set_thread_regs(
+  int thread,
+  unsigned int *registers
+);
+void rtems_gdb_process_query(
+  char *inbuffer,
+  char *outbuffer,
+  int   do_threads,
+  int   thread
+);
+
+/* Exception IDs */
+#define LM32_EXCEPTION_RESET                  0x0
+#define LM32_EXCEPTION_INST_BREAKPOINT        0x1
+#define LM32_EXCEPTION_INST_BUS_ERROR         0x2
+#define LM32_EXCEPTION_DATA_BREAKPOINT        0x3
+#define LM32_EXCEPTION_DATA_BUS_ERROR         0x4
+#define LM32_EXCEPTION_DIVIDE_BY_ZERO         0x5
+#define LM32_EXCEPTION_INTERRUPT              0x6
+#define LM32_EXCEPTION_SYSTEM_CALL            0x7
+
+/* Breakpoint instruction */
+#define LM32_BREAK                            0xac000002UL
+
+/* This numbering must be consistant with GDBs numbering in gdb/lm32-tdep.c */
+enum lm32_regnames {
+  LM32_REG_R0, LM32_REG_R1, LM32_REG_R2, LM32_REG_R3, LM32_REG_R4, LM32_REG_R5,
+  LM32_REG_R6, LM32_REG_R7, LM32_REG_R8, LM32_REG_R9, LM32_REG_R10,
+  LM32_REG_R11, LM32_REG_R12, LM32_REG_R13, LM32_REG_R14, LM32_REG_R15,
+  LM32_REG_R16, LM32_REG_R17, LM32_REG_R18, LM32_REG_R19, LM32_REG_R20,
+  LM32_REG_R21, LM32_REG_R22, LM32_REG_R23, LM32_REG_R24, LM32_REG_R25,
+  LM32_REG_GP, LM32_REG_FP, LM32_REG_SP, LM32_REG_RA, LM32_REG_EA, LM32_REG_BA,
+  LM32_REG_PC, LM32_REG_EID, LM32_REG_EBA, LM32_REG_DEBA, LM32_REG_IE, NUM_REGS
+};
+
+/* keep this in sync with the debug isr handler in lm32-debug.S */
+enum lm32_int_regnames {
+  LM32_INT_REG_R1, LM32_INT_REG_R2, LM32_INT_REG_R3, LM32_INT_REG_R4,
+  LM32_INT_REG_R5, LM32_INT_REG_R6, LM32_INT_REG_R7, LM32_INT_REG_R8,
+  LM32_INT_REG_R9, LM32_INT_REG_R10, LM32_INT_REG_RA, LM32_INT_REG_EA,
+  LM32_INT_REG_BA, LM32_INT_REG_R11, LM32_INT_REG_R12, LM32_INT_REG_R13,
+  LM32_INT_REG_R14, LM32_INT_REG_R15, LM32_INT_REG_R16, LM32_INT_REG_R17,
+  LM32_INT_REG_R18, LM32_INT_REG_R19, LM32_INT_REG_R20, LM32_INT_REG_R21,
+  LM32_INT_REG_R22, LM32_INT_REG_R23, LM32_INT_REG_R24, LM32_INT_REG_R25,
+  LM32_INT_REG_GP, LM32_INT_REG_FP, LM32_INT_REG_SP, LM32_INT_REG_PC,
+  LM32_INT_REG_EID, LM32_INT_REG_EBA, LM32_INT_REG_DEBA, LM32_INT_REG_IE,
+};
+
+#endif /* _GDB_IF_H */