kgdb.c
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- /*!**************************************************************************
- *!
- *! FILE NAME : kgdb.c
- *!
- *! DESCRIPTION: Implementation of the gdb stub with respect to ETRAX 100.
- *! It is a mix of arch/m68k/kernel/kgdb.c and cris_stub.c.
- *!
- *!---------------------------------------------------------------------------
- *! HISTORY
- *!
- *! DATE NAME CHANGES
- *! ---- ---- -------
- *! Apr 26 1999 Hendrik Ruijter Initial version.
- *! May 6 1999 Hendrik Ruijter Removed call to strlen in libc and removed
- *! struct assignment as it generates calls to
- *! memcpy in libc.
- *! Jun 17 1999 Hendrik Ruijter Added gdb 4.18 support. 'X', 'qC' and 'qL'.
- *! Jul 21 1999 Bjorn Wesen eLinux port
- *!
- *! $Log: kgdb.c,v $
- *! Revision 1.6 2001/10/09 13:10:03 matsfg
- *! Added $ on registers and removed some underscores
- *!
- *! Revision 1.5 2001/04/17 13:58:39 orjanf
- *! * Renamed CONFIG_KGDB to CONFIG_ETRAX_KGDB.
- *!
- *! Revision 1.4 2001/02/23 13:45:19 bjornw
- *! config.h check
- *!
- *! Revision 1.3 2001/01/31 18:08:23 orjanf
- *! Removed kgdb_handle_breakpoint from being the break 8 handler.
- *!
- *! Revision 1.2 2001/01/12 14:22:25 orjanf
- *! Updated kernel debugging support to work with ETRAX 100LX.
- *!
- *! Revision 1.1 2000/07/10 16:25:21 bjornw
- *! Initial revision
- *!
- *! Revision 1.1.1.1 1999/12/03 14:57:31 bjornw
- *! * Initial version of arch/cris, the latest CRIS architecture with an MMU.
- *! Mostly copied from arch/etrax100 with appropriate renames of files.
- *! The mm/ subdir is copied from arch/i386.
- *! This does not compile yet at all.
- *!
- *!
- *! Revision 1.4 1999/07/22 17:25:25 bjornw
- *! Dont wait for + in putpacket if we havent hit the initial breakpoint yet. Added a kgdb_init function which sets up the break and irq vectors.
- *!
- *! Revision 1.3 1999/07/21 19:51:18 bjornw
- *! Check if the interrupting char is a ctrl-C, ignore otherwise.
- *!
- *! Revision 1.2 1999/07/21 18:09:39 bjornw
- *! Ported to eLinux architecture, and added some kgdb documentation.
- *!
- *!
- *!---------------------------------------------------------------------------
- *!
- *! $Id: kgdb.c,v 1.6 2001/10/09 13:10:03 matsfg Exp $
- *!
- *! (C) Copyright 1999, Axis Communications AB, LUND, SWEDEN
- *!
- *!**************************************************************************/
- /* @(#) cris_stub.c 1.3 06/17/99 */
- /*
- * kgdb usage notes:
- * -----------------
- *
- * If you select CONFIG_ETRAX_KGDB in the configuration, the kernel will be
- * built with different gcc flags: "-g" is added to get debug infos, and
- * "-fomit-frame-pointer" is omitted to make debugging easier. Since the
- * resulting kernel will be quite big (approx. > 7 MB), it will be stripped
- * before compresion. Such a kernel will behave just as usually, except if
- * given a "debug=<device>" command line option. (Only serial devices are
- * allowed for <device>, i.e. no printers or the like; possible values are
- * machine depedend and are the same as for the usual debug device, the one
- * for logging kernel messages.) If that option is given and the device can be
- * initialized, the kernel will connect to the remote gdb in trap_init(). The
- * serial parameters are fixed to 8N1 and 115200 bps, for easyness of
- * implementation.
- *
- * To start a debugging session, start that gdb with the debugging kernel
- * image (the one with the symbols, vmlinux.debug) named on the command line.
- * This file will be used by gdb to get symbol and debugging infos about the
- * kernel. Next, select remote debug mode by
- * target remote <device>
- * where <device> is the name of the serial device over which the debugged
- * machine is connected. Maybe you have to adjust the baud rate by
- * set remotebaud <rate>
- * or also other parameters with stty:
- * shell stty ... </dev/...
- * If the kernel to debug has already booted, it waited for gdb and now
- * connects, and you'll see a breakpoint being reported. If the kernel isn't
- * running yet, start it now. The order of gdb and the kernel doesn't matter.
- * Another thing worth knowing about in the getting-started phase is how to
- * debug the remote protocol itself. This is activated with
- * set remotedebug 1
- * gdb will then print out each packet sent or received. You'll also get some
- * messages about the gdb stub on the console of the debugged machine.
- *
- * If all that works, you can use lots of the usual debugging techniques on
- * the kernel, e.g. inspecting and changing variables/memory, setting
- * breakpoints, single stepping and so on. It's also possible to interrupt the
- * debugged kernel by pressing C-c in gdb. Have fun! :-)
- *
- * The gdb stub is entered (and thus the remote gdb gets control) in the
- * following situations:
- *
- * - If breakpoint() is called. This is just after kgdb initialization, or if
- * a breakpoint() call has been put somewhere into the kernel source.
- * (Breakpoints can of course also be set the usual way in gdb.)
- * In eLinux, we call breakpoint() in init/main.c after IRQ initialization.
- *
- * - If there is a kernel exception, i.e. bad_super_trap() or die_if_kernel()
- * are entered. All the CPU exceptions are mapped to (more or less..., see
- * the hard_trap_info array below) appropriate signal, which are reported
- * to gdb. die_if_kernel() is usually called after some kind of access
- * error and thus is reported as SIGSEGV.
- *
- * - When panic() is called. This is reported as SIGABRT.
- *
- * - If C-c is received over the serial line, which is treated as
- * SIGINT.
- *
- * Of course, all these signals are just faked for gdb, since there is no
- * signal concept as such for the kernel. It also isn't possible --obviously--
- * to set signal handlers from inside gdb, or restart the kernel with a
- * signal.
- *
- * Current limitations:
- *
- * - While the kernel is stopped, interrupts are disabled for safety reasons
- * (i.e., variables not changing magically or the like). But this also
- * means that the clock isn't running anymore, and that interrupts from the
- * hardware may get lost/not be served in time. This can cause some device
- * errors...
- *
- * - When single-stepping, only one instruction of the current thread is
- * executed, but interrupts are allowed for that time and will be serviced
- * if pending. Be prepared for that.
- *
- * - All debugging happens in kernel virtual address space. There's no way to
- * access physical memory not mapped in kernel space, or to access user
- * space. A way to work around this is using get_user_long & Co. in gdb
- * expressions, but only for the current process.
- *
- * - Interrupting the kernel only works if interrupts are currently allowed,
- * and the interrupt of the serial line isn't blocked by some other means
- * (IPL too high, disabled, ...)
- *
- * - The gdb stub is currently not reentrant, i.e. errors that happen therein
- * (e.g. accesing invalid memory) may not be caught correctly. This could
- * be removed in future by introducing a stack of struct registers.
- *
- */
- /*
- * To enable debugger support, two things need to happen. One, a
- * call to kgdb_init() is necessary in order to allow any breakpoints
- * or error conditions to be properly intercepted and reported to gdb.
- * Two, a breakpoint needs to be generated to begin communication. This
- * is most easily accomplished by a call to breakpoint().
- *
- * The following gdb commands are supported:
- *
- * command function Return value
- *
- * g return the value of the CPU registers hex data or ENN
- * G set the value of the CPU registers OK or ENN
- *
- * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN
- * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN
- *
- * c Resume at current address SNN ( signal NN)
- * cAA..AA Continue at address AA..AA SNN
- *
- * s Step one instruction SNN
- * sAA..AA Step one instruction from AA..AA SNN
- *
- * k kill
- *
- * ? What was the last sigval ? SNN (signal NN)
- *
- * bBB..BB Set baud rate to BB..BB OK or BNN, then sets
- * baud rate
- *
- * All commands and responses are sent with a packet which includes a
- * checksum. A packet consists of
- *
- * $<packet info>#<checksum>.
- *
- * where
- * <packet info> :: <characters representing the command or response>
- * <checksum> :: < two hex digits computed as modulo 256 sum of <packetinfo>>
- *
- * When a packet is received, it is first acknowledged with either '+' or '-'.
- * '+' indicates a successful transfer. '-' indicates a failed transfer.
- *
- * Example:
- *
- * Host: Reply:
- * $m0,10#2a +$00010203040506070809101112131415#42
- *
- */
- #include <linux/string.h>
- #include <linux/signal.h>
- #include <linux/kernel.h>
- #include <linux/delay.h>
- #include <linux/linkage.h>
- #include <asm/setup.h>
- #include <asm/ptrace.h>
- #include <asm/svinto.h>
- #include <asm/irq.h>
- static int kgdb_started = 0;
- /********************************* Register image ****************************/
- /* Use the order of registers as defined in "AXIS ETRAX CRIS Programmer's
- Reference", p. 1-1, with the additional register definitions of the
- ETRAX 100LX in cris-opc.h.
- There are 16 general 32-bit registers, R0-R15, where R14 is the stack
- pointer, SP, and R15 is the program counter, PC.
- There are 16 special registers, P0-P15, where three of the unimplemented
- registers, P0, P4 and P8, are reserved as zero-registers. A read from
- any of these registers returns zero and a write has no effect. */
- typedef
- struct register_image
- {
- /* Offset */
- unsigned int r0; /* 0x00 */
- unsigned int r1; /* 0x04 */
- unsigned int r2; /* 0x08 */
- unsigned int r3; /* 0x0C */
- unsigned int r4; /* 0x10 */
- unsigned int r5; /* 0x14 */
- unsigned int r6; /* 0x18 */
- unsigned int r7; /* 0x1C */
- unsigned int r8; /* 0x20 Frame pointer */
- unsigned int r9; /* 0x24 */
- unsigned int r10; /* 0x28 */
- unsigned int r11; /* 0x2C */
- unsigned int r12; /* 0x30 */
- unsigned int r13; /* 0x34 */
- unsigned int sp; /* 0x38 Stack pointer */
- unsigned int pc; /* 0x3C Program counter */
- unsigned char p0; /* 0x40 8-bit zero-register */
- unsigned char vr; /* 0x41 Version register */
- unsigned short p4; /* 0x42 16-bit zero-register */
- unsigned short ccr; /* 0x44 Condition code register */
-
- unsigned int mof; /* 0x46 Multiply overflow register */
-
- unsigned int p8; /* 0x4A 32-bit zero-register */
- unsigned int ibr; /* 0x4E Interrupt base register */
- unsigned int irp; /* 0x52 Interrupt return pointer */
- unsigned int srp; /* 0x56 Subroutine return pointer */
- unsigned int bar; /* 0x5A Breakpoint address register */
- unsigned int dccr; /* 0x5E Double condition code register */
- unsigned int brp; /* 0x62 Breakpoint return pointer (pc in caller) */
- unsigned int usp; /* 0x66 User mode stack pointer */
- } registers;
- /************** Prototypes for local library functions ***********************/
- /* Copy of strcpy from libc. */
- static char *gdb_cris_strcpy (char *s1, const char *s2);
- /* Copy of strlen from libc. */
- static int gdb_cris_strlen (const char *s);
- /* Copy of memchr from libc. */
- static void *gdb_cris_memchr (const void *s, int c, int n);
- /* Copy of strtol from libc. Does only support base 16. */
- static int gdb_cris_strtol (const char *s, char **endptr, int base);
- /********************** Prototypes for local functions. **********************/
- /* Copy the content of a register image into another. The size n is
- the size of the register image. Due to struct assignment generation of
- memcpy in libc. */
- static void copy_registers (registers *dptr, registers *sptr, int n);
- /* Copy the stored registers from the stack. Put the register contents
- of thread thread_id in the struct reg. */
- static void copy_registers_from_stack (int thread_id, registers *reg);
- /* Copy the registers to the stack. Put the register contents of thread
- thread_id from struct reg to the stack. */
- static void copy_registers_to_stack (int thread_id, registers *reg);
- /* Write a value to a specified register regno in the register image
- of the current thread. */
- static int write_register (int regno, char *val);
- /* Write a value to a specified register in the stack of a thread other
- than the current thread. */
- static write_stack_register (int thread_id, int regno, char *valptr);
- /* Read a value from a specified register in the register image. Returns the
- status of the read operation. The register value is returned in valptr. */
- static int read_register (char regno, unsigned int *valptr);
- /* Serial port, reads one character. ETRAX 100 specific. from debugport.c */
- int getDebugChar (void);
- /* Serial port, writes one character. ETRAX 100 specific. from debugport.c */
- void putDebugChar (int val);
- void enableDebugIRQ (void);
- /* Returns the character equivalent of a nibble, bit 7, 6, 5, and 4 of a byte,
- represented by int x. */
- static char highhex (int x);
- /* Returns the character equivalent of a nibble, bit 3, 2, 1, and 0 of a byte,
- represented by int x. */
- static char lowhex (int x);
- /* Returns the integer equivalent of a hexadecimal character. */
- static int hex (char ch);
- /* Convert the memory, pointed to by mem into hexadecimal representation.
- Put the result in buf, and return a pointer to the last character
- in buf (null). */
- static char *mem2hex (char *buf, unsigned char *mem, int count);
- /* Convert the array, in hexadecimal representation, pointed to by buf into
- binary representation. Put the result in mem, and return a pointer to
- the character after the last byte written. */
- static unsigned char *hex2mem (unsigned char *mem, char *buf, int count);
- /* Put the content of the array, in binary representation, pointed to by buf
- into memory pointed to by mem, and return a pointer to
- the character after the last byte written. */
- static unsigned char *bin2mem (unsigned char *mem, unsigned char *buf, int count);
- /* Await the sequence $<data>#<checksum> and store <data> in the array buffer
- returned. */
- static void getpacket (char *buffer);
- /* Send $<data>#<checksum> from the <data> in the array buffer. */
- static void putpacket (char *buffer);
- /* Build and send a response packet in order to inform the host the
- stub is stopped. */
- static void stub_is_stopped (int sigval);
- /* All expected commands are sent from remote.c. Send a response according
- to the description in remote.c. */
- static void handle_exception (int sigval);
- /* Performs a complete re-start from scratch. ETRAX specific. */
- static void kill_restart (void);
- /******************** Prototypes for global functions. ***********************/
- /* The string str is prepended with the GDB printout token and sent. */
- void putDebugString (const unsigned char *str, int length); /* used by etrax100ser.c */
- /* The hook for both static (compiled) and dynamic breakpoints set by GDB.
- ETRAX 100 specific. */
- void handle_breakpoint (void); /* used by irq.c */
- /* The hook for an interrupt generated by GDB. ETRAX 100 specific. */
- void handle_interrupt (void); /* used by irq.c */
- /* A static breakpoint to be used at startup. */
- void breakpoint (void); /* called by init/main.c */
- /* From osys_int.c, executing_task contains the number of the current
- executing task in osys. Does not know of object-oriented threads. */
- extern unsigned char executing_task;
- /* The number of characters used for a 64 bit thread identifier. */
- #define HEXCHARS_IN_THREAD_ID 16
- /* Avoid warning as the internal_stack is not used in the C-code. */
- #define USEDVAR(name) { if (name) { ; } }
- #define USEDFUN(name) { void (*pf)(void) = (void *)name; USEDVAR(pf) }
- /********************************** Packet I/O ******************************/
- /* BUFMAX defines the maximum number of characters in
- inbound/outbound buffers */
- #define BUFMAX 512
- /* Run-length encoding maximum length. Send 64 at most. */
- #define RUNLENMAX 64
- /* Definition of all valid hexadecimal characters */
- static const char hexchars[] = "0123456789abcdef";
- /* The inbound/outbound buffers used in packet I/O */
- static char remcomInBuffer[BUFMAX];
- static char remcomOutBuffer[BUFMAX];
- /* Error and warning messages. */
- enum error_type
- {
- SUCCESS, E01, E02, E03, E04, E05, E06, E07
- };
- static char *error_message[] =
- {
- "",
- "E01 Set current or general thread - H[c,g] - internal error.",
- "E02 Change register content - P - cannot change read-only register.",
- "E03 Thread is not alive.", /* T, not used. */
- "E04 The command is not supported - [s,C,S,!,R,d,r] - internal error.",
- "E05 Change register content - P - the register is not implemented..",
- "E06 Change memory content - M - internal error.",
- "E07 Change register content - P - the register is not stored on the stack"
- };
- /********************************* Register image ****************************/
- /* Use the order of registers as defined in "AXIS ETRAX CRIS Programmer's
- Reference", p. 1-1, with the additional register definitions of the
- ETRAX 100LX in cris-opc.h.
- There are 16 general 32-bit registers, R0-R15, where R14 is the stack
- pointer, SP, and R15 is the program counter, PC.
- There are 16 special registers, P0-P15, where three of the unimplemented
- registers, P0, P4 and P8, are reserved as zero-registers. A read from
- any of these registers returns zero and a write has no effect. */
- enum register_name
- {
- R0, R1, R2, R3,
- R4, R5, R6, R7,
- R8, R9, R10, R11,
- R12, R13, SP, PC,
- P0, VR, P2, P3,
- P4, CCR, P6, MOF,
- P8, IBR, IRP, SRP,
- BAR, DCCR, BRP, USP
- };
- /* The register sizes of the registers in register_name. An unimplemented register
- is designated by size 0 in this array. */
- static int register_size[] =
- {
- 4, 4, 4, 4,
- 4, 4, 4, 4,
- 4, 4, 4, 4,
- 4, 4, 4, 4,
- 1, 1, 0, 0,
- 2, 2, 0, 4,
- 4, 4, 4, 4,
- 4, 4, 4, 4
- };
- /* Contains the register image of the executing thread in the assembler
- part of the code in order to avoid horrible addressing modes. */
- static registers reg;
- /* FIXME: Should this be used? Delete otherwise. */
- /* Contains the assumed consistency state of the register image. Uses the
- enum error_type for state information. */
- static int consistency_status = SUCCESS;
- /********************************** Handle exceptions ************************/
- /* The variable reg contains the register image associated with the
- current_thread_c variable. It is a complete register image created at
- entry. The reg_g contains a register image of a task where the general
- registers are taken from the stack and all special registers are taken
- from the executing task. It is associated with current_thread_g and used
- in order to provide access mainly for 'g', 'G' and 'P'.
- */
- /* Need two task id pointers in order to handle Hct and Hgt commands. */
- static int current_thread_c = 0;
- static int current_thread_g = 0;
- /* Need two register images in order to handle Hct and Hgt commands. The
- variable reg_g is in addition to reg above. */
- static registers reg_g;
- /********************************** Breakpoint *******************************/
- /* Use an internal stack in the breakpoint and interrupt response routines */
- #define INTERNAL_STACK_SIZE 1024
- static char internal_stack[INTERNAL_STACK_SIZE];
- /* Due to the breakpoint return pointer, a state variable is needed to keep
- track of whether it is a static (compiled) or dynamic (gdb-invoked)
- breakpoint to be handled. A static breakpoint uses the content of register
- BRP as it is whereas a dynamic breakpoint requires subtraction with 2
- in order to execute the instruction. The first breakpoint is static. */
- static unsigned char is_dyn_brkp = 0;
- /********************************* String library ****************************/
- /* Single-step over library functions creates trap loops. */
- /* Copy char s2[] to s1[]. */
- static char*
- gdb_cris_strcpy (char *s1, const char *s2)
- {
- char *s = s1;
-
- for (s = s1; (*s++ = *s2++) != ' '; )
- ;
- return (s1);
- }
- /* Find length of s[]. */
- static int
- gdb_cris_strlen (const char *s)
- {
- const char *sc;
-
- for (sc = s; *sc != ' '; sc++)
- ;
- return (sc - s);
- }
- /* Find first occurrence of c in s[n]. */
- static void*
- gdb_cris_memchr (const void *s, int c, int n)
- {
- const unsigned char uc = c;
- const unsigned char *su;
-
- for (su = s; 0 < n; ++su, --n)
- if (*su == uc)
- return ((void *)su);
- return (NULL);
- }
- /******************************* Standard library ****************************/
- /* Single-step over library functions creates trap loops. */
- /* Convert string to long. */
- static int
- gdb_cris_strtol (const char *s, char **endptr, int base)
- {
- char *s1;
- char *sd;
- int x = 0;
-
- for (s1 = (char*)s; (sd = gdb_cris_memchr(hexchars, *s1, base)) != NULL; ++s1)
- x = x * base + (sd - hexchars);
-
- if (endptr)
- {
- /* Unconverted suffix is stored in endptr unless endptr is NULL. */
- *endptr = s1;
- }
-
- return x;
- }
- int
- double_this(int x)
- {
- return 2 * x;
- }
- /********************************* Register image ****************************/
- /* Copy the content of a register image into another. The size n is
- the size of the register image. Due to struct assignment generation of
- memcpy in libc. */
- static void
- copy_registers (registers *dptr, registers *sptr, int n)
- {
- unsigned char *dreg;
- unsigned char *sreg;
-
- for (dreg = (unsigned char*)dptr, sreg = (unsigned char*)sptr; n > 0; n--)
- *dreg++ = *sreg++;
- }
- #ifdef PROCESS_SUPPORT
- /* Copy the stored registers from the stack. Put the register contents
- of thread thread_id in the struct reg. */
- static void
- copy_registers_from_stack (int thread_id, registers *regptr)
- {
- int j;
- stack_registers *s = (stack_registers *)stack_list[thread_id];
- unsigned int *d = (unsigned int *)regptr;
-
- for (j = 13; j >= 0; j--)
- *d++ = s->r[j];
- regptr->sp = (unsigned int)stack_list[thread_id];
- regptr->pc = s->pc;
- regptr->dccr = s->dccr;
- regptr->srp = s->srp;
- }
- /* Copy the registers to the stack. Put the register contents of thread
- thread_id from struct reg to the stack. */
- static void
- copy_registers_to_stack (int thread_id, registers *regptr)
- {
- int i;
- stack_registers *d = (stack_registers *)stack_list[thread_id];
- unsigned int *s = (unsigned int *)regptr;
-
- for (i = 0; i < 14; i++) {
- d->r[i] = *s++;
- }
- d->pc = regptr->pc;
- d->dccr = regptr->dccr;
- d->srp = regptr->srp;
- }
- #endif
- /* Write a value to a specified register in the register image of the current
- thread. Returns status code SUCCESS, E02 or E05. */
- static int
- write_register (int regno, char *val)
- {
- int status = SUCCESS;
- registers *current_reg = ®
- if (regno >= R0 && regno <= PC) {
- /* 32-bit register with simple offset. */
- hex2mem ((unsigned char *)current_reg + regno * sizeof(unsigned int),
- val, sizeof(unsigned int));
- }
- else if (regno == P0 || regno == VR || regno == P4 || regno == P8) {
- /* Do not support read-only registers. */
- status = E02;
- }
- else if (regno == CCR) {
- /* 16 bit register with complex offset. (P4 is read-only, P6 is not implemented,
- and P7 (MOF) is 32 bits in ETRAX 100LX. */
- hex2mem ((unsigned char *)&(current_reg->ccr) + (regno-CCR) * sizeof(unsigned short),
- val, sizeof(unsigned short));
- }
- else if (regno >= MOF && regno <= USP) {
- /* 32 bit register with complex offset. (P8 has been taken care of.) */
- hex2mem ((unsigned char *)&(current_reg->ibr) + (regno-IBR) * sizeof(unsigned int),
- val, sizeof(unsigned int));
- }
- else {
- /* Do not support nonexisting or unimplemented registers (P2, P3, and P6). */
- status = E05;
- }
- return status;
- }
- #ifdef PROCESS_SUPPORT
- /* Write a value to a specified register in the stack of a thread other
- than the current thread. Returns status code SUCCESS or E07. */
- static int
- write_stack_register (int thread_id, int regno, char *valptr)
- {
- int status = SUCCESS;
- stack_registers *d = (stack_registers *)stack_list[thread_id];
- unsigned int val;
-
- hex2mem ((unsigned char *)&val, valptr, sizeof(unsigned int));
- if (regno >= R0 && regno < SP) {
- d->r[regno] = val;
- }
- else if (regno == SP) {
- stack_list[thread_id] = val;
- }
- else if (regno == PC) {
- d->pc = val;
- }
- else if (regno == SRP) {
- d->srp = val;
- }
- else if (regno == DCCR) {
- d->dccr = val;
- }
- else {
- /* Do not support registers in the current thread. */
- status = E07;
- }
- return status;
- }
- #endif
- /* Read a value from a specified register in the register image. Returns the
- value in the register or -1 for non-implemented registers.
- Should check consistency_status after a call which may be E05 after changes
- in the implementation. */
- static int
- read_register (char regno, unsigned int *valptr)
- {
- registers *current_reg = ®
- if (regno >= R0 && regno <= PC) {
- /* 32-bit register with simple offset. */
- *valptr = *(unsigned int *)((char *)current_reg + regno * sizeof(unsigned int));
- return SUCCESS;
- }
- else if (regno == P0 || regno == VR) {
- /* 8 bit register with complex offset. */
- *valptr = (unsigned int)(*(unsigned char *)
- ((char *)&(current_reg->p0) + (regno-P0) * sizeof(char)));
- return SUCCESS;
- }
- else if (regno == P4 || regno == CCR) {
- /* 16 bit register with complex offset. */
- *valptr = (unsigned int)(*(unsigned short *)
- ((char *)&(current_reg->p4) + (regno-P4) * sizeof(unsigned short)));
- return SUCCESS;
- }
- else if (regno >= MOF && regno <= USP) {
- /* 32 bit register with complex offset. */
- *valptr = *(unsigned int *)((char *)&(current_reg->p8)
- + (regno-P8) * sizeof(unsigned int));
- return SUCCESS;
- }
- else {
- /* Do not support nonexisting or unimplemented registers (P2, P3, and P6). */
- consistency_status = E05;
- return E05;
- }
- }
- /********************************** Packet I/O ******************************/
- /* Returns the character equivalent of a nibble, bit 7, 6, 5, and 4 of a byte,
- represented by int x. */
- static inline char
- highhex(int x)
- {
- return hexchars[(x >> 4) & 0xf];
- }
- /* Returns the character equivalent of a nibble, bit 3, 2, 1, and 0 of a byte,
- represented by int x. */
- static inline char
- lowhex(int x)
- {
- return hexchars[x & 0xf];
- }
- /* Returns the integer equivalent of a hexadecimal character. */
- static int
- hex (char ch)
- {
- if ((ch >= 'a') && (ch <= 'f'))
- return (ch - 'a' + 10);
- if ((ch >= '0') && (ch <= '9'))
- return (ch - '0');
- if ((ch >= 'A') && (ch <= 'F'))
- return (ch - 'A' + 10);
- return (-1);
- }
- /* Convert the memory, pointed to by mem into hexadecimal representation.
- Put the result in buf, and return a pointer to the last character
- in buf (null). */
- static int do_printk = 0;
- static char *
- mem2hex(char *buf, unsigned char *mem, int count)
- {
- int i;
- int ch;
-
- if (mem == NULL) {
- /* Bogus read from m0. FIXME: What constitutes a valid address? */
- for (i = 0; i < count; i++) {
- *buf++ = '0';
- *buf++ = '0';
- }
- } else {
- /* Valid mem address. */
- for (i = 0; i < count; i++) {
- ch = *mem++;
- *buf++ = highhex (ch);
- *buf++ = lowhex (ch);
- }
- }
-
- /* Terminate properly. */
- *buf = ' ';
- return (buf);
- }
- /* Convert the array, in hexadecimal representation, pointed to by buf into
- binary representation. Put the result in mem, and return a pointer to
- the character after the last byte written. */
- static unsigned char*
- hex2mem (unsigned char *mem, char *buf, int count)
- {
- int i;
- unsigned char ch;
- for (i = 0; i < count; i++) {
- ch = hex (*buf++) << 4;
- ch = ch + hex (*buf++);
- *mem++ = ch;
- }
- return (mem);
- }
- /* Put the content of the array, in binary representation, pointed to by buf
- into memory pointed to by mem, and return a pointer to the character after
- the last byte written.
- Gdb will escape $, #, and the escape char (0x7d). */
- static unsigned char*
- bin2mem (unsigned char *mem, unsigned char *buf, int count)
- {
- int i;
- unsigned char *next;
- for (i = 0; i < count; i++) {
- /* Check for any escaped characters. Be paranoid and
- only unescape chars that should be escaped. */
- if (*buf == 0x7d) {
- next = buf + 1;
- if (*next == 0x3 || *next == 0x4 || *next == 0x5D) /* #, $, ESC */
- {
- buf++;
- *buf += 0x20;
- }
- }
- *mem++ = *buf++;
- }
- return (mem);
- }
- /* Await the sequence $<data>#<checksum> and store <data> in the array buffer
- returned. */
- static void
- getpacket (char *buffer)
- {
- unsigned char checksum;
- unsigned char xmitcsum;
- int i;
- int count;
- char ch;
- do {
- while ((ch = getDebugChar ()) != '$')
- /* Wait for the start character $ and ignore all other characters */;
- checksum = 0;
- xmitcsum = -1;
- count = 0;
- /* Read until a # or the end of the buffer is reached */
- while (count < BUFMAX) {
- ch = getDebugChar ();
- if (ch == '#')
- break;
- checksum = checksum + ch;
- buffer[count] = ch;
- count = count + 1;
- }
- buffer[count] = ' ';
-
- if (ch == '#') {
- xmitcsum = hex (getDebugChar ()) << 4;
- xmitcsum += hex (getDebugChar ());
- if (checksum != xmitcsum) {
- /* Wrong checksum */
- putDebugChar ('-');
- }
- else {
- /* Correct checksum */
- putDebugChar ('+');
- /* If sequence characters are received, reply with them */
- if (buffer[2] == ':') {
- putDebugChar (buffer[0]);
- putDebugChar (buffer[1]);
- /* Remove the sequence characters from the buffer */
- count = gdb_cris_strlen (buffer);
- for (i = 3; i <= count; i++)
- buffer[i - 3] = buffer[i];
- }
- }
- }
- } while (checksum != xmitcsum);
- }
- /* Send $<data>#<checksum> from the <data> in the array buffer. */
- static void
- putpacket(char *buffer)
- {
- int checksum;
- int runlen;
- int encode;
-
- do {
- char *src = buffer;
- putDebugChar ('$');
- checksum = 0;
- while (*src) {
- /* Do run length encoding */
- putDebugChar (*src);
- checksum += *src;
- runlen = 0;
- while (runlen < RUNLENMAX && *src == src[runlen]) {
- runlen++;
- }
- if (runlen > 3) {
- /* Got a useful amount */
- putDebugChar ('*');
- checksum += '*';
- encode = runlen + ' ' - 4;
- putDebugChar (encode);
- checksum += encode;
- src += runlen;
- }
- else {
- src++;
- }
- }
- putDebugChar ('#');
- putDebugChar (highhex (checksum));
- putDebugChar (lowhex (checksum));
- } while(kgdb_started && (getDebugChar() != '+'));
- }
- /* The string str is prepended with the GDB printout token and sent. Required
- in traditional implementations. */
- void
- putDebugString (const unsigned char *str, int length)
- {
- remcomOutBuffer[0] = 'O';
- mem2hex(&remcomOutBuffer[1], (unsigned char *)str, length);
- putpacket(remcomOutBuffer);
- }
- /********************************** Handle exceptions ************************/
- /* Build and send a response packet in order to inform the host the
- stub is stopped. TAAn...:r...;n...:r...;n...:r...;
- AA = signal number
- n... = register number (hex)
- r... = register contents
- n... = `thread'
- r... = thread process ID. This is a hex integer.
- n... = other string not starting with valid hex digit.
- gdb should ignore this n,r pair and go on to the next.
- This way we can extend the protocol. */
- static void
- stub_is_stopped(int sigval)
- {
- char *ptr = remcomOutBuffer;
- int regno;
- unsigned int reg_cont;
- int status;
-
- /* Send trap type (converted to signal) */
- *ptr++ = 'T';
- *ptr++ = highhex (sigval);
- *ptr++ = lowhex (sigval);
- /* Send register contents. We probably only need to send the
- * PC, frame pointer and stack pointer here. Other registers will be
- * explicitely asked for. But for now, send all.
- */
-
- for (regno = R0; regno <= USP; regno++) {
- /* Store n...:r...; for the registers in the buffer. */
- status = read_register (regno, ®_cont);
-
- if (status == SUCCESS) {
-
- *ptr++ = highhex (regno);
- *ptr++ = lowhex (regno);
- *ptr++ = ':';
- ptr = mem2hex(ptr, (unsigned char *)®_cont,
- register_size[regno]);
- *ptr++ = ';';
- }
-
- }
- #ifdef PROCESS_SUPPORT
- /* Store the registers of the executing thread. Assume that both step,
- continue, and register content requests are with respect to this
- thread. The executing task is from the operating system scheduler. */
- current_thread_c = executing_task;
- current_thread_g = executing_task;
- /* A struct assignment translates into a libc memcpy call. Avoid
- all libc functions in order to prevent recursive break points. */
- copy_registers (®_g, ®, sizeof(registers));
- /* Store thread:r...; with the executing task TID. */
- gdb_cris_strcpy (&remcomOutBuffer[pos], "thread:");
- pos += gdb_cris_strlen ("thread:");
- remcomOutBuffer[pos++] = highhex (executing_task);
- remcomOutBuffer[pos++] = lowhex (executing_task);
- gdb_cris_strcpy (&remcomOutBuffer[pos], ";");
- #endif
- /* null-terminate and send it off */
- *ptr = 0;
- putpacket (remcomOutBuffer);
- }
- /* All expected commands are sent from remote.c. Send a response according
- to the description in remote.c. */
- static void
- handle_exception (int sigval)
- {
- /* Avoid warning of not used. */
- USEDFUN(handle_exception);
- USEDVAR(internal_stack[0]);
- /* Send response. */
- stub_is_stopped (sigval);
- for (;;) {
- remcomOutBuffer[0] = ' ';
- getpacket (remcomInBuffer);
- switch (remcomInBuffer[0]) {
- case 'g':
- /* Read registers: g
- Success: Each byte of register data is described by two hex digits.
- Registers are in the internal order for GDB, and the bytes
- in a register are in the same order the machine uses.
- Failure: void. */
-
- {
- #ifdef PROCESS_SUPPORT
- /* Use the special register content in the executing thread. */
- copy_registers (®_g, ®, sizeof(registers));
- /* Replace the content available on the stack. */
- if (current_thread_g != executing_task) {
- copy_registers_from_stack (current_thread_g, ®_g);
- }
- mem2hex ((unsigned char *)remcomOutBuffer, (unsigned char *)®_g, sizeof(registers));
- #else
- mem2hex(remcomOutBuffer, (char *)®, sizeof(registers));
- #endif
- }
- break;
-
- case 'G':
- /* Write registers. GXX..XX
- Each byte of register data is described by two hex digits.
- Success: OK
- Failure: void. */
- #ifdef PROCESS_SUPPORT
- hex2mem ((unsigned char *)®_g, &remcomInBuffer[1], sizeof(registers));
- if (current_thread_g == executing_task) {
- copy_registers (®, ®_g, sizeof(registers));
- }
- else {
- copy_registers_to_stack(current_thread_g, ®_g);
- }
- #else
- hex2mem((char *)®, &remcomInBuffer[1], sizeof(registers));
- #endif
- gdb_cris_strcpy (remcomOutBuffer, "OK");
- break;
-
- case 'P':
- /* Write register. Pn...=r...
- Write register n..., hex value without 0x, with value r...,
- which contains a hex value without 0x and two hex digits
- for each byte in the register (target byte order). P1f=11223344 means
- set register 31 to 44332211.
- Success: OK
- Failure: E02, E05 */
- {
- char *suffix;
- int regno = gdb_cris_strtol (&remcomInBuffer[1], &suffix, 16);
- int status;
- #ifdef PROCESS_SUPPORT
- if (current_thread_g =! executing_task)
- status = write_stack_register (current_thread_g, regno, suffix+1);
- else
- #endif
- status = write_register (regno, suffix+1);
- switch (status) {
- case E02:
- /* Do not support read-only registers. */
- gdb_cris_strcpy (remcomOutBuffer, error_message[E02]);
- break;
- case E05:
- /* Do not support non-existing registers. */
- gdb_cris_strcpy (remcomOutBuffer, error_message[E05]);
- break;
- case E07:
- /* Do not support non-existing registers on the stack. */
- gdb_cris_strcpy (remcomOutBuffer, error_message[E07]);
- break;
- default:
- /* Valid register number. */
- gdb_cris_strcpy (remcomOutBuffer, "OK");
- break;
- }
- }
- break;
-
- case 'm':
- /* Read from memory. mAA..AA,LLLL
- AA..AA is the address and LLLL is the length.
- Success: XX..XX is the memory content. Can be fewer bytes than
- requested if only part of the data may be read. m6000120a,6c means
- retrieve 108 byte from base address 6000120a.
- Failure: void. */
- {
- char *suffix;
- unsigned char *addr = (unsigned char *)gdb_cris_strtol(&remcomInBuffer[1],
- &suffix, 16); int length = gdb_cris_strtol(suffix+1, 0, 16);
-
- mem2hex(remcomOutBuffer, addr, length);
- }
- break;
-
- case 'X':
- /* Write to memory. XAA..AA,LLLL:XX..XX
- AA..AA is the start address, LLLL is the number of bytes, and
- XX..XX is the binary data.
- Success: OK
- Failure: void. */
- case 'M':
- /* Write to memory. MAA..AA,LLLL:XX..XX
- AA..AA is the start address, LLLL is the number of bytes, and
- XX..XX is the hexadecimal data.
- Success: OK
- Failure: void. */
- {
- char *lenptr;
- char *dataptr;
- unsigned char *addr = (unsigned char *)gdb_cris_strtol(&remcomInBuffer[1],
- &lenptr, 16);
- int length = gdb_cris_strtol(lenptr+1, &dataptr, 16);
- if (*lenptr == ',' && *dataptr == ':') {
- if (remcomInBuffer[0] == 'M') {
- hex2mem(addr, dataptr + 1, length);
- }
- else /* X */ {
- bin2mem(addr, dataptr + 1, length);
- }
- gdb_cris_strcpy (remcomOutBuffer, "OK");
- }
- else {
- gdb_cris_strcpy (remcomOutBuffer, error_message[E06]);
- }
- }
- break;
-
- case 'c':
- /* Continue execution. cAA..AA
- AA..AA is the address where execution is resumed. If AA..AA is
- omitted, resume at the present address.
- Success: return to the executing thread.
- Failure: will never know. */
- if (remcomInBuffer[1] != ' ') {
- reg.pc = gdb_cris_strtol (&remcomInBuffer[1], 0, 16);
- }
- enableDebugIRQ();
- return;
-
- case 's':
- /* Step. sAA..AA
- AA..AA is the address where execution is resumed. If AA..AA is
- omitted, resume at the present address. Success: return to the
- executing thread. Failure: will never know.
-
- Should never be invoked. The single-step is implemented on
- the host side. If ever invoked, it is an internal error E04. */
- gdb_cris_strcpy (remcomOutBuffer, error_message[E04]);
- putpacket (remcomOutBuffer);
- return;
-
- case '?':
- /* The last signal which caused a stop. ?
- Success: SAA, where AA is the signal number.
- Failure: void. */
- remcomOutBuffer[0] = 'S';
- remcomOutBuffer[1] = highhex (sigval);
- remcomOutBuffer[2] = lowhex (sigval);
- remcomOutBuffer[3] = 0;
- break;
-
- case 'D':
- /* Detach from host. D
- Success: OK, and return to the executing thread.
- Failure: will never know */
- putpacket ("OK");
- return;
-
- case 'k':
- case 'r':
- /* kill request or reset request.
- Success: restart of target.
- Failure: will never know. */
- kill_restart ();
- break;
-
- case 'C':
- case 'S':
- case '!':
- case 'R':
- case 'd':
- /* Continue with signal sig. Csig;AA..AA
- Step with signal sig. Ssig;AA..AA
- Use the extended remote protocol. !
- Restart the target system. R0
- Toggle debug flag. d
- Search backwards. tAA:PP,MM
- Not supported: E04 */
- gdb_cris_strcpy (remcomOutBuffer, error_message[E04]);
- break;
- #ifdef PROCESS_SUPPORT
- case 'T':
- /* Thread alive. TXX
- Is thread XX alive?
- Success: OK, thread XX is alive.
- Failure: E03, thread XX is dead. */
- {
- int thread_id = (int)gdb_cris_strtol (&remcomInBuffer[1], 0, 16);
- /* Cannot tell whether it is alive or not. */
- if (thread_id >= 0 && thread_id < number_of_tasks)
- gdb_cris_strcpy (remcomOutBuffer, "OK");
- }
- break;
-
- case 'H':
- /* Set thread for subsequent operations: Hct
- c = 'c' for thread used in step and continue;
- t can be -1 for all threads.
- c = 'g' for thread used in other operations.
- t = 0 means pick any thread.
- Success: OK
- Failure: E01 */
- {
- int thread_id = gdb_cris_strtol (&remcomInBuffer[2], 0, 16);
- if (remcomInBuffer[1] == 'c') {
- /* c = 'c' for thread used in step and continue */
- /* Do not change current_thread_c here. It would create a mess in
- the scheduler. */
- gdb_cris_strcpy (remcomOutBuffer, "OK");
- }
- else if (remcomInBuffer[1] == 'g') {
- /* c = 'g' for thread used in other operations.
- t = 0 means pick any thread. Impossible since the scheduler does
- not allow that. */
- if (thread_id >= 0 && thread_id < number_of_tasks) {
- current_thread_g = thread_id;
- gdb_cris_strcpy (remcomOutBuffer, "OK");
- }
- else {
- /* Not expected - send an error message. */
- gdb_cris_strcpy (remcomOutBuffer, error_message[E01]);
- }
- }
- else {
- /* Not expected - send an error message. */
- gdb_cris_strcpy (remcomOutBuffer, error_message[E01]);
- }
- }
- break;
-
- case 'q':
- case 'Q':
- /* Query of general interest. qXXXX
- Set general value XXXX. QXXXX=yyyy */
- {
- int pos;
- int nextpos;
- int thread_id;
-
- switch (remcomInBuffer[1]) {
- case 'C':
- /* Identify the remote current thread. */
- gdb_cris_strcpy (&remcomOutBuffer[0], "QC");
- remcomOutBuffer[2] = highhex (current_thread_c);
- remcomOutBuffer[3] = lowhex (current_thread_c);
- remcomOutBuffer[4] = ' ';
- break;
- case 'L':
- gdb_cris_strcpy (&remcomOutBuffer[0], "QM");
- /* Reply with number of threads. */
- if (os_is_started()) {
- remcomOutBuffer[2] = highhex (number_of_tasks);
- remcomOutBuffer[3] = lowhex (number_of_tasks);
- }
- else {
- remcomOutBuffer[2] = highhex (0);
- remcomOutBuffer[3] = lowhex (1);
- }
- /* Done with the reply. */
- remcomOutBuffer[4] = lowhex (1);
- pos = 5;
- /* Expects the argument thread id. */
- for (; pos < (5 + HEXCHARS_IN_THREAD_ID); pos++)
- remcomOutBuffer[pos] = remcomInBuffer[pos];
- /* Reply with the thread identifiers. */
- if (os_is_started()) {
- /* Store the thread identifiers of all tasks. */
- for (thread_id = 0; thread_id < number_of_tasks; thread_id++) {
- nextpos = pos + HEXCHARS_IN_THREAD_ID - 1;
- for (; pos < nextpos; pos ++)
- remcomOutBuffer[pos] = lowhex (0);
- remcomOutBuffer[pos++] = lowhex (thread_id);
- }
- }
- else {
- /* Store the thread identifier of the boot task. */
- nextpos = pos + HEXCHARS_IN_THREAD_ID - 1;
- for (; pos < nextpos; pos ++)
- remcomOutBuffer[pos] = lowhex (0);
- remcomOutBuffer[pos++] = lowhex (current_thread_c);
- }
- remcomOutBuffer[pos] = ' ';
- break;
- default:
- /* Not supported: "" */
- /* Request information about section offsets: qOffsets. */
- remcomOutBuffer[0] = 0;
- break;
- }
- }
- break;
- #endif /* PROCESS_SUPPORT */
-
- default:
- /* The stub should ignore other request and send an empty
- response ($#<checksum>). This way we can extend the protocol and GDB
- can tell whether the stub it is talking to uses the old or the new. */
- remcomOutBuffer[0] = 0;
- break;
- }
- putpacket(remcomOutBuffer);
- }
- }
- /* The jump is to the address 0x00000002. Performs a complete re-start
- from scratch. */
- static void
- kill_restart ()
- {
- __asm__ volatile ("jump 2");
- }
- /********************************** Breakpoint *******************************/
- /* The hook for both a static (compiled) and a dynamic breakpoint set by GDB.
- An internal stack is used by the stub. The register image of the caller is
- stored in the structure register_image.
- Interactive communication with the host is handled by handle_exception and
- finally the register image is restored. */
- void kgdb_handle_breakpoint(void);
- asm ("
- .global kgdb_handle_breakpoint
- kgdb_handle_breakpoint:
- ;;
- ;; Response to the break-instruction
- ;;
- ;; Create a register image of the caller
- ;;
- move $dccr,[reg+0x5E] ; Save the flags in DCCR before disable interrupts
- di ; Disable interrupts
- move.d $r0,[reg] ; Save R0
- move.d $r1,[reg+0x04] ; Save R1
- move.d $r2,[reg+0x08] ; Save R2
- move.d $r3,[reg+0x0C] ; Save R3
- move.d $r4,[reg+0x10] ; Save R4
- move.d $r5,[reg+0x14] ; Save R5
- move.d $r6,[reg+0x18] ; Save R6
- move.d $r7,[reg+0x1C] ; Save R7
- move.d $r8,[reg+0x20] ; Save R8
- move.d $r9,[reg+0x24] ; Save R9
- move.d $r10,[reg+0x28] ; Save R10
- move.d $r11,[reg+0x2C] ; Save R11
- move.d $r12,[reg+0x30] ; Save R12
- move.d $r13,[reg+0x34] ; Save R13
- move.d $sp,[reg+0x38] ; Save SP (R14)
- ;; Due to the old assembler-versions BRP might not be recognized
- .word 0xE670 ; move brp,$r0
- subq 2,$r0 ; Set to address of previous instruction.
- move.d $r0,[reg+0x3c] ; Save the address in PC (R15)
- clear.b [reg+0x40] ; Clear P0
- move $vr,[reg+0x41] ; Save special register P1
- clear.w [reg+0x42] ; Clear P4
- move $ccr,[reg+0x44] ; Save special register CCR
- move $mof,[reg+0x46] ; P7
- clear.d [reg+0x4A] ; Clear P8
- move $ibr,[reg+0x4E] ; P9,
- move $irp,[reg+0x52] ; P10,
- move $srp,[reg+0x56] ; P11,
- move $dtp0,[reg+0x5A] ; P12, register BAR, assembler might not know BAR
- ; P13, register DCCR already saved
- ;; Due to the old assembler-versions BRP might not be recognized
- .word 0xE670 ; move brp,r0
- ;; Static (compiled) breakpoints must return to the next instruction in order
- ;; to avoid infinite loops. Dynamic (gdb-invoked) must restore the instruction
- ;; in order to execute it when execution is continued.
- test.b [is_dyn_brkp] ; Is this a dynamic breakpoint?
- beq is_static ; No, a static breakpoint
- nop
- subq 2,$r0 ; rerun the instruction the break replaced
- is_static:
- moveq 1,$r1
- move.b $r1,[is_dyn_brkp] ; Set the state variable to dynamic breakpoint
- move.d $r0,[reg+0x62] ; Save the return address in BRP
- move $usp,[reg+0x66] ; USP
- ;;
- ;; Handle the communication
- ;;
- move.d internal_stack+1020,$sp ; Use the internal stack which grows upward
- moveq 5,$r10 ; SIGTRAP
- jsr handle_exception ; Interactive routine
- ;;
- ;; Return to the caller
- ;;
- move.d [reg],$r0 ; Restore R0
- move.d [reg+0x04],$r1 ; Restore R1
- move.d [reg+0x08],$r2 ; Restore R2
- move.d [reg+0x0C],$r3 ; Restore R3
- move.d [reg+0x10],$r4 ; Restore R4
- move.d [reg+0x14],$r5 ; Restore R5
- move.d [reg+0x18],$r6 ; Restore R6
- move.d [reg+0x1C],$r7 ; Restore R7
- move.d [reg+0x20],$r8 ; Restore R8
- move.d [reg+0x24],$r9 ; Restore R9
- move.d [reg+0x28],$r10 ; Restore R10
- move.d [reg+0x2C],$r11 ; Restore R11
- move.d [reg+0x30],$r12 ; Restore R12
- move.d [reg+0x34],$r13 ; Restore R13
- ;;
- ;; FIXME: Which registers should be restored?
- ;;
- move.d [reg+0x38],$sp ; Restore SP (R14)
- move [reg+0x56],$srp ; Restore the subroutine return pointer.
- move [reg+0x5E],$dccr ; Restore DCCR
- move [reg+0x66],$usp ; Restore USP
- jump [reg+0x62] ; A jump to the content in register BRP works.
- nop ;
- ");
- /* The hook for an interrupt generated by GDB. An internal stack is used
- by the stub. The register image of the caller is stored in the structure
- register_image. Interactive communication with the host is handled by
- handle_exception and finally the register image is restored. Due to the
- old assembler which does not recognise the break instruction and the
- breakpoint return pointer hex-code is used. */
- void kgdb_handle_serial(void);
- asm ("
- .global kgdb_handle_serial
- kgdb_handle_serial:
- ;;
- ;; Response to a serial interrupt
- ;;
- move $dccr,[reg+0x5E] ; Save the flags in DCCR
- di ; Disable interrupts
- move.d $r0,[reg] ; Save R0
- move.d $r1,[reg+0x04] ; Save R1
- move.d $r2,[reg+0x08] ; Save R2
- move.d $r3,[reg+0x0C] ; Save R3
- move.d $r4,[reg+0x10] ; Save R4
- move.d $r5,[reg+0x14] ; Save R5
- move.d $r6,[reg+0x18] ; Save R6
- move.d $r7,[reg+0x1C] ; Save R7
- move.d $r8,[reg+0x20] ; Save R8
- move.d $r9,[reg+0x24] ; Save R9
- move.d $r10,[reg+0x28] ; Save R10
- move.d $r11,[reg+0x2C] ; Save R11
- move.d $r12,[reg+0x30] ; Save R12
- move.d $r13,[reg+0x34] ; Save R13
- move.d $sp,[reg+0x38] ; Save SP (R14)
- move $irp,[reg+0x3c] ; Save the address in PC (R15)
- clear.b [reg+0x40] ; Clear P0
- move $vr,[reg+0x41] ; Save special register P1,
- clear.w [reg+0x42] ; Clear P4
- move $ccr,[reg+0x44] ; Save special register CCR
- move $mof,[reg+0x46] ; P7
- clear.d [reg+0x4A] ; Clear P8
- move $ibr,[reg+0x4E] ; P9,
- move $irp,[reg+0x52] ; P10,
- move $srp,[reg+0x56] ; P11,
- move $dtp0,[reg+0x5A] ; P12, register BAR, assembler might not know BAR
- ; P13, register DCCR already saved
- ;; Due to the old assembler-versions BRP might not be recognized
- .word 0xE670 ; move brp,r0
- move.d $r0,[reg+0x62] ; Save the return address in BRP
- move $usp,[reg+0x66] ; USP
- ;; get the serial character (from debugport.c) and check if its a ctrl-c
- jsr getDebugChar
- cmp.b 3, $r10
- bne goback
- nop
- ;;
- ;; Handle the communication
- ;;
- move.d internal_stack+1020,$sp ; Use the internal stack
- moveq 2,$r10 ; SIGINT
- jsr handle_exception ; Interactive routine
- goback:
- ;;
- ;; Return to the caller
- ;;
- move.d [reg],$r0 ; Restore R0
- move.d [reg+0x04],$r1 ; Restore R1
- move.d [reg+0x08],$r2 ; Restore R2
- move.d [reg+0x0C],$r3 ; Restore R3
- move.d [reg+0x10],$r4 ; Restore R4
- move.d [reg+0x14],$r5 ; Restore R5
- move.d [reg+0x18],$r6 ; Restore R6
- move.d [reg+0x1C],$r7 ; Restore R7
- move.d [reg+0x20],$r8 ; Restore R8
- move.d [reg+0x24],$r9 ; Restore R9
- move.d [reg+0x28],$r10 ; Restore R10
- move.d [reg+0x2C],$r11 ; Restore R11
- move.d [reg+0x30],$r12 ; Restore R12
- move.d [reg+0x34],$r13 ; Restore R13
- ;;
- ;; FIXME: Which registers should be restored?
- ;;
- move.d [reg+0x38],$sp ; Restore SP (R14)
- move [reg+0x56],$srp ; Restore the subroutine return pointer.
- move [reg+0x5E],$dccr ; Restore DCCR
- move [reg+0x66],$usp ; Restore USP
- reti ; Return from the interrupt routine
- nop
- ");
- /* Use this static breakpoint in the start-up only. */
- void
- breakpoint(void)
- {
- kgdb_started = 1;
- is_dyn_brkp = 0; /* This is a static, not a dynamic breakpoint. */
- __asm__ volatile ("break 8"); /* Jump to handle_breakpoint. */
- }
- /* initialize kgdb. doesn't break into the debugger, but sets up irq and ports */
- void
- kgdb_init(void)
- {
- /* could initialize debug port as well but it's done in head.S already... */
- /* breakpoint handler is now set in irq.c */
- set_int_vector(8, kgdb_handle_serial, 0);
-
- enableDebugIRQ();
- }
- /****************************** End of file **********************************/