1 // SPDX-License-Identifier: GPL-2.0
2 /*!**************************************************************************
6 *! DESCRIPTION: Implementation of the gdb stub with respect to ETRAX 100.
7 *! It is a mix of arch/m68k/kernel/kgdb.c and cris_stub.c.
9 *!---------------------------------------------------------------------------
14 *! Apr 26 1999 Hendrik Ruijter Initial version.
15 *! May 6 1999 Hendrik Ruijter Removed call to strlen in libc and removed
16 *! struct assignment as it generates calls to
18 *! Jun 17 1999 Hendrik Ruijter Added gdb 4.18 support. 'X', 'qC' and 'qL'.
19 *! Jul 21 1999 Bjorn Wesen eLinux port
21 *!---------------------------------------------------------------------------
23 *! (C) Copyright 1999, Axis Communications AB, LUND, SWEDEN
25 *!**************************************************************************/
26 /* @(#) cris_stub.c 1.3 06/17/99 */
32 * If you select CONFIG_ETRAX_KGDB in the configuration, the kernel will be
33 * built with different gcc flags: "-g" is added to get debug infos, and
34 * "-fomit-frame-pointer" is omitted to make debugging easier. Since the
35 * resulting kernel will be quite big (approx. > 7 MB), it will be stripped
36 * before compresion. Such a kernel will behave just as usually, except if
37 * given a "debug=<device>" command line option. (Only serial devices are
38 * allowed for <device>, i.e. no printers or the like; possible values are
39 * machine depedend and are the same as for the usual debug device, the one
40 * for logging kernel messages.) If that option is given and the device can be
41 * initialized, the kernel will connect to the remote gdb in trap_init(). The
42 * serial parameters are fixed to 8N1 and 115200 bps, for easyness of
45 * To start a debugging session, start that gdb with the debugging kernel
46 * image (the one with the symbols, vmlinux.debug) named on the command line.
47 * This file will be used by gdb to get symbol and debugging infos about the
48 * kernel. Next, select remote debug mode by
49 * target remote <device>
50 * where <device> is the name of the serial device over which the debugged
51 * machine is connected. Maybe you have to adjust the baud rate by
52 * set remotebaud <rate>
53 * or also other parameters with stty:
54 * shell stty ... </dev/...
55 * If the kernel to debug has already booted, it waited for gdb and now
56 * connects, and you'll see a breakpoint being reported. If the kernel isn't
57 * running yet, start it now. The order of gdb and the kernel doesn't matter.
58 * Another thing worth knowing about in the getting-started phase is how to
59 * debug the remote protocol itself. This is activated with
61 * gdb will then print out each packet sent or received. You'll also get some
62 * messages about the gdb stub on the console of the debugged machine.
64 * If all that works, you can use lots of the usual debugging techniques on
65 * the kernel, e.g. inspecting and changing variables/memory, setting
66 * breakpoints, single stepping and so on. It's also possible to interrupt the
67 * debugged kernel by pressing C-c in gdb. Have fun! :-)
69 * The gdb stub is entered (and thus the remote gdb gets control) in the
70 * following situations:
72 * - If breakpoint() is called. This is just after kgdb initialization, or if
73 * a breakpoint() call has been put somewhere into the kernel source.
74 * (Breakpoints can of course also be set the usual way in gdb.)
75 * In eLinux, we call breakpoint() in init/main.c after IRQ initialization.
77 * - If there is a kernel exception, i.e. bad_super_trap() or die_if_kernel()
78 * are entered. All the CPU exceptions are mapped to (more or less..., see
79 * the hard_trap_info array below) appropriate signal, which are reported
80 * to gdb. die_if_kernel() is usually called after some kind of access
81 * error and thus is reported as SIGSEGV.
83 * - When panic() is called. This is reported as SIGABRT.
85 * - If C-c is received over the serial line, which is treated as
88 * Of course, all these signals are just faked for gdb, since there is no
89 * signal concept as such for the kernel. It also isn't possible --obviously--
90 * to set signal handlers from inside gdb, or restart the kernel with a
93 * Current limitations:
95 * - While the kernel is stopped, interrupts are disabled for safety reasons
96 * (i.e., variables not changing magically or the like). But this also
97 * means that the clock isn't running anymore, and that interrupts from the
98 * hardware may get lost/not be served in time. This can cause some device
101 * - When single-stepping, only one instruction of the current thread is
102 * executed, but interrupts are allowed for that time and will be serviced
103 * if pending. Be prepared for that.
105 * - All debugging happens in kernel virtual address space. There's no way to
106 * access physical memory not mapped in kernel space, or to access user
107 * space. A way to work around this is using get_user_long & Co. in gdb
108 * expressions, but only for the current process.
110 * - Interrupting the kernel only works if interrupts are currently allowed,
111 * and the interrupt of the serial line isn't blocked by some other means
112 * (IPL too high, disabled, ...)
114 * - The gdb stub is currently not reentrant, i.e. errors that happen therein
115 * (e.g. accessing invalid memory) may not be caught correctly. This could
116 * be removed in future by introducing a stack of struct registers.
121 * To enable debugger support, two things need to happen. One, a
122 * call to kgdb_init() is necessary in order to allow any breakpoints
123 * or error conditions to be properly intercepted and reported to gdb.
124 * Two, a breakpoint needs to be generated to begin communication. This
125 * is most easily accomplished by a call to breakpoint().
127 * The following gdb commands are supported:
129 * command function Return value
131 * g return the value of the CPU registers hex data or ENN
132 * G set the value of the CPU registers OK or ENN
134 * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN
135 * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN
137 * c Resume at current address SNN ( signal NN)
138 * cAA..AA Continue at address AA..AA SNN
140 * s Step one instruction SNN
141 * sAA..AA Step one instruction from AA..AA SNN
145 * ? What was the last sigval ? SNN (signal NN)
147 * bBB..BB Set baud rate to BB..BB OK or BNN, then sets
150 * All commands and responses are sent with a packet which includes a
151 * checksum. A packet consists of
153 * $<packet info>#<checksum>.
156 * <packet info> :: <characters representing the command or response>
157 * <checksum> :: < two hex digits computed as modulo 256 sum of <packetinfo>>
159 * When a packet is received, it is first acknowledged with either '+' or '-'.
160 * '+' indicates a successful transfer. '-' indicates a failed transfer.
165 * $m0,10#2a +$00010203040506070809101112131415#42
170 #include <linux/string.h>
171 #include <linux/signal.h>
172 #include <linux/kernel.h>
173 #include <linux/delay.h>
174 #include <linux/linkage.h>
175 #include <linux/reboot.h>
177 #include <asm/setup.h>
178 #include <asm/ptrace.h>
180 #include <arch/svinto.h>
183 static int kgdb_started = 0;
185 /********************************* Register image ****************************/
186 /* Use the order of registers as defined in "AXIS ETRAX CRIS Programmer's
187 Reference", p. 1-1, with the additional register definitions of the
188 ETRAX 100LX in cris-opc.h.
189 There are 16 general 32-bit registers, R0-R15, where R14 is the stack
190 pointer, SP, and R15 is the program counter, PC.
191 There are 16 special registers, P0-P15, where three of the unimplemented
192 registers, P0, P4 and P8, are reserved as zero-registers. A read from
193 any of these registers returns zero and a write has no effect. */
196 struct register_image
199 unsigned int r0; /* 0x00 */
200 unsigned int r1; /* 0x04 */
201 unsigned int r2; /* 0x08 */
202 unsigned int r3; /* 0x0C */
203 unsigned int r4; /* 0x10 */
204 unsigned int r5; /* 0x14 */
205 unsigned int r6; /* 0x18 */
206 unsigned int r7; /* 0x1C */
207 unsigned int r8; /* 0x20 Frame pointer */
208 unsigned int r9; /* 0x24 */
209 unsigned int r10; /* 0x28 */
210 unsigned int r11; /* 0x2C */
211 unsigned int r12; /* 0x30 */
212 unsigned int r13; /* 0x34 */
213 unsigned int sp; /* 0x38 Stack pointer */
214 unsigned int pc; /* 0x3C Program counter */
216 unsigned char p0; /* 0x40 8-bit zero-register */
217 unsigned char vr; /* 0x41 Version register */
219 unsigned short p4; /* 0x42 16-bit zero-register */
220 unsigned short ccr; /* 0x44 Condition code register */
222 unsigned int mof; /* 0x46 Multiply overflow register */
224 unsigned int p8; /* 0x4A 32-bit zero-register */
225 unsigned int ibr; /* 0x4E Interrupt base register */
226 unsigned int irp; /* 0x52 Interrupt return pointer */
227 unsigned int srp; /* 0x56 Subroutine return pointer */
228 unsigned int bar; /* 0x5A Breakpoint address register */
229 unsigned int dccr; /* 0x5E Double condition code register */
230 unsigned int brp; /* 0x62 Breakpoint return pointer (pc in caller) */
231 unsigned int usp; /* 0x66 User mode stack pointer */
234 /* Serial port, reads one character. ETRAX 100 specific. from debugport.c */
235 int getDebugChar (void);
237 /* Serial port, writes one character. ETRAX 100 specific. from debugport.c */
238 void putDebugChar (int val);
240 void enableDebugIRQ (void);
242 /******************** Prototypes for global functions. ***********************/
244 /* The string str is prepended with the GDB printout token and sent. */
245 void putDebugString (const unsigned char *str, int length); /* used by etrax100ser.c */
247 /* The hook for both static (compiled) and dynamic breakpoints set by GDB.
248 ETRAX 100 specific. */
249 void handle_breakpoint (void); /* used by irq.c */
251 /* The hook for an interrupt generated by GDB. ETRAX 100 specific. */
252 void handle_interrupt (void); /* used by irq.c */
254 /* A static breakpoint to be used at startup. */
255 void breakpoint (void); /* called by init/main.c */
257 /* From osys_int.c, executing_task contains the number of the current
258 executing task in osys. Does not know of object-oriented threads. */
259 extern unsigned char executing_task;
261 /* The number of characters used for a 64 bit thread identifier. */
262 #define HEXCHARS_IN_THREAD_ID 16
264 /********************************** Packet I/O ******************************/
265 /* BUFMAX defines the maximum number of characters in
266 inbound/outbound buffers */
269 /* Run-length encoding maximum length. Send 64 at most. */
272 /* The inbound/outbound buffers used in packet I/O */
273 static char remcomInBuffer[BUFMAX];
274 static char remcomOutBuffer[BUFMAX];
276 /* Error and warning messages. */
279 SUCCESS, E01, E02, E03, E04, E05, E06, E07, E08
281 static char *error_message[] =
284 "E01 Set current or general thread - H[c,g] - internal error.",
285 "E02 Change register content - P - cannot change read-only register.",
286 "E03 Thread is not alive.", /* T, not used. */
287 "E04 The command is not supported - [s,C,S,!,R,d,r] - internal error.",
288 "E05 Change register content - P - the register is not implemented..",
289 "E06 Change memory content - M - internal error.",
290 "E07 Change register content - P - the register is not stored on the stack",
291 "E08 Invalid parameter"
293 /********************************* Register image ****************************/
294 /* Use the order of registers as defined in "AXIS ETRAX CRIS Programmer's
295 Reference", p. 1-1, with the additional register definitions of the
296 ETRAX 100LX in cris-opc.h.
297 There are 16 general 32-bit registers, R0-R15, where R14 is the stack
298 pointer, SP, and R15 is the program counter, PC.
299 There are 16 special registers, P0-P15, where three of the unimplemented
300 registers, P0, P4 and P8, are reserved as zero-registers. A read from
301 any of these registers returns zero and a write has no effect. */
314 /* The register sizes of the registers in register_name. An unimplemented register
315 is designated by size 0 in this array. */
316 static int register_size[] =
328 /* Contains the register image of the executing thread in the assembler
329 part of the code in order to avoid horrible addressing modes. */
332 /* FIXME: Should this be used? Delete otherwise. */
333 /* Contains the assumed consistency state of the register image. Uses the
334 enum error_type for state information. */
335 static int consistency_status = SUCCESS;
337 /********************************** Handle exceptions ************************/
338 /* The variable cris_reg contains the register image associated with the
339 current_thread_c variable. It is a complete register image created at
340 entry. The reg_g contains a register image of a task where the general
341 registers are taken from the stack and all special registers are taken
342 from the executing task. It is associated with current_thread_g and used
343 in order to provide access mainly for 'g', 'G' and 'P'.
346 /********************************** Breakpoint *******************************/
347 /* Use an internal stack in the breakpoint and interrupt response routines */
348 #define INTERNAL_STACK_SIZE 1024
349 char internal_stack[INTERNAL_STACK_SIZE];
351 /* Due to the breakpoint return pointer, a state variable is needed to keep
352 track of whether it is a static (compiled) or dynamic (gdb-invoked)
353 breakpoint to be handled. A static breakpoint uses the content of register
354 BRP as it is whereas a dynamic breakpoint requires subtraction with 2
355 in order to execute the instruction. The first breakpoint is static. */
356 static unsigned char __used is_dyn_brkp;
358 /********************************* String library ****************************/
359 /* Single-step over library functions creates trap loops. */
361 /* Copy char s2[] to s1[]. */
363 gdb_cris_strcpy (char *s1, const char *s2)
367 for (s = s1; (*s++ = *s2++) != '\0'; )
372 /* Find length of s[]. */
374 gdb_cris_strlen (const char *s)
378 for (sc = s; *sc != '\0'; sc++)
383 /* Find first occurrence of c in s[n]. */
385 gdb_cris_memchr (const void *s, int c, int n)
387 const unsigned char uc = c;
388 const unsigned char *su;
390 for (su = s; 0 < n; ++su, --n)
395 /******************************* Standard library ****************************/
396 /* Single-step over library functions creates trap loops. */
397 /* Convert string to long. */
399 gdb_cris_strtol (const char *s, char **endptr, int base)
405 for (s1 = (char*)s; (sd = gdb_cris_memchr(hex_asc, *s1, base)) != NULL; ++s1)
406 x = x * base + (sd - hex_asc);
410 /* Unconverted suffix is stored in endptr unless endptr is NULL. */
417 /********************************** Packet I/O ******************************/
419 /* Convert the memory, pointed to by mem into hexadecimal representation.
420 Put the result in buf, and return a pointer to the last character
424 mem2hex(char *buf, unsigned char *mem, int count)
430 /* Bogus read from m0. FIXME: What constitutes a valid address? */
431 for (i = 0; i < count; i++) {
436 /* Valid mem address. */
437 for (i = 0; i < count; i++) {
439 buf = hex_byte_pack(buf, ch);
443 /* Terminate properly. */
448 /* Put the content of the array, in binary representation, pointed to by buf
449 into memory pointed to by mem, and return a pointer to the character after
450 the last byte written.
451 Gdb will escape $, #, and the escape char (0x7d). */
452 static unsigned char*
453 bin2mem (unsigned char *mem, unsigned char *buf, int count)
457 for (i = 0; i < count; i++) {
458 /* Check for any escaped characters. Be paranoid and
459 only unescape chars that should be escaped. */
462 if (*next == 0x3 || *next == 0x4 || *next == 0x5D) /* #, $, ESC */
473 /* Await the sequence $<data>#<checksum> and store <data> in the array buffer
476 getpacket (char *buffer)
478 unsigned char checksum;
479 unsigned char xmitcsum;
484 while ((ch = getDebugChar ()) != '$')
485 /* Wait for the start character $ and ignore all other characters */;
489 /* Read until a # or the end of the buffer is reached */
490 while (count < BUFMAX - 1) {
491 ch = getDebugChar ();
494 checksum = checksum + ch;
498 buffer[count] = '\0';
501 xmitcsum = hex_to_bin(getDebugChar()) << 4;
502 xmitcsum += hex_to_bin(getDebugChar());
503 if (checksum != xmitcsum) {
508 /* Correct checksum */
510 /* If sequence characters are received, reply with them */
511 if (buffer[2] == ':') {
512 putDebugChar (buffer[0]);
513 putDebugChar (buffer[1]);
514 /* Remove the sequence characters from the buffer */
515 count = gdb_cris_strlen (buffer);
516 for (i = 3; i <= count; i++)
517 buffer[i - 3] = buffer[i];
521 } while (checksum != xmitcsum);
524 /* Send $<data>#<checksum> from the <data> in the array buffer. */
527 putpacket(char *buffer)
538 /* Do run length encoding */
542 while (runlen < RUNLENMAX && *src == src[runlen]) {
546 /* Got a useful amount */
549 encode = runlen + ' ' - 4;
550 putDebugChar (encode);
559 putDebugChar(hex_asc_hi(checksum));
560 putDebugChar(hex_asc_lo(checksum));
561 } while(kgdb_started && (getDebugChar() != '+'));
564 /* The string str is prepended with the GDB printout token and sent. Required
565 in traditional implementations. */
567 putDebugString (const unsigned char *str, int length)
569 remcomOutBuffer[0] = 'O';
570 mem2hex(&remcomOutBuffer[1], (unsigned char *)str, length);
571 putpacket(remcomOutBuffer);
574 /********************************* Register image ****************************/
575 /* Write a value to a specified register in the register image of the current
576 thread. Returns status code SUCCESS, E02, E05 or E08. */
578 write_register (int regno, char *val)
580 int status = SUCCESS;
581 registers *current_reg = &cris_reg;
583 if (regno >= R0 && regno <= PC) {
584 /* 32-bit register with simple offset. */
585 if (hex2bin((unsigned char *)current_reg + regno * sizeof(unsigned int),
586 val, sizeof(unsigned int)))
589 else if (regno == P0 || regno == VR || regno == P4 || regno == P8) {
590 /* Do not support read-only registers. */
593 else if (regno == CCR) {
594 /* 16 bit register with complex offset. (P4 is read-only, P6 is not implemented,
595 and P7 (MOF) is 32 bits in ETRAX 100LX. */
596 if (hex2bin((unsigned char *)&(current_reg->ccr) + (regno-CCR) * sizeof(unsigned short),
597 val, sizeof(unsigned short)))
600 else if (regno >= MOF && regno <= USP) {
601 /* 32 bit register with complex offset. (P8 has been taken care of.) */
602 if (hex2bin((unsigned char *)&(current_reg->ibr) + (regno-IBR) * sizeof(unsigned int),
603 val, sizeof(unsigned int)))
607 /* Do not support nonexisting or unimplemented registers (P2, P3, and P6). */
613 /* Read a value from a specified register in the register image. Returns the
614 value in the register or -1 for non-implemented registers.
615 Should check consistency_status after a call which may be E05 after changes
616 in the implementation. */
618 read_register (char regno, unsigned int *valptr)
620 registers *current_reg = &cris_reg;
622 if (regno >= R0 && regno <= PC) {
623 /* 32-bit register with simple offset. */
624 *valptr = *(unsigned int *)((char *)current_reg + regno * sizeof(unsigned int));
627 else if (regno == P0 || regno == VR) {
628 /* 8 bit register with complex offset. */
629 *valptr = (unsigned int)(*(unsigned char *)
630 ((char *)&(current_reg->p0) + (regno-P0) * sizeof(char)));
633 else if (regno == P4 || regno == CCR) {
634 /* 16 bit register with complex offset. */
635 *valptr = (unsigned int)(*(unsigned short *)
636 ((char *)&(current_reg->p4) + (regno-P4) * sizeof(unsigned short)));
639 else if (regno >= MOF && regno <= USP) {
640 /* 32 bit register with complex offset. */
641 *valptr = *(unsigned int *)((char *)&(current_reg->p8)
642 + (regno-P8) * sizeof(unsigned int));
646 /* Do not support nonexisting or unimplemented registers (P2, P3, and P6). */
647 consistency_status = E05;
652 /********************************** Handle exceptions ************************/
653 /* Build and send a response packet in order to inform the host the
654 stub is stopped. TAAn...:r...;n...:r...;n...:r...;
656 n... = register number (hex)
657 r... = register contents
659 r... = thread process ID. This is a hex integer.
660 n... = other string not starting with valid hex digit.
661 gdb should ignore this n,r pair and go on to the next.
662 This way we can extend the protocol. */
664 stub_is_stopped(int sigval)
666 char *ptr = remcomOutBuffer;
669 unsigned int reg_cont;
672 /* Send trap type (converted to signal) */
675 ptr = hex_byte_pack(ptr, sigval);
677 /* Send register contents. We probably only need to send the
678 * PC, frame pointer and stack pointer here. Other registers will be
679 * explicitly asked for. But for now, send all.
682 for (regno = R0; regno <= USP; regno++) {
683 /* Store n...:r...; for the registers in the buffer. */
685 status = read_register (regno, ®_cont);
687 if (status == SUCCESS) {
688 ptr = hex_byte_pack(ptr, regno);
691 ptr = mem2hex(ptr, (unsigned char *)®_cont,
692 register_size[regno]);
698 /* null-terminate and send it off */
702 putpacket (remcomOutBuffer);
705 /* Performs a complete re-start from scratch. */
712 /* All expected commands are sent from remote.c. Send a response according
713 to the description in remote.c. */
715 handle_exception (int sigval)
719 stub_is_stopped (sigval);
722 remcomOutBuffer[0] = '\0';
723 getpacket (remcomInBuffer);
724 switch (remcomInBuffer[0]) {
727 Success: Each byte of register data is described by two hex digits.
728 Registers are in the internal order for GDB, and the bytes
729 in a register are in the same order the machine uses.
732 mem2hex(remcomOutBuffer, (char *)&cris_reg, sizeof(registers));
736 /* Write registers. GXX..XX
737 Each byte of register data is described by two hex digits.
740 if (hex2bin((char *)&cris_reg, &remcomInBuffer[1], sizeof(registers)))
741 gdb_cris_strcpy (remcomOutBuffer, error_message[E08]);
743 gdb_cris_strcpy (remcomOutBuffer, "OK");
747 /* Write register. Pn...=r...
748 Write register n..., hex value without 0x, with value r...,
749 which contains a hex value without 0x and two hex digits
750 for each byte in the register (target byte order). P1f=11223344 means
751 set register 31 to 44332211.
753 Failure: E02, E05, E08 */
756 int regno = gdb_cris_strtol (&remcomInBuffer[1], &suffix, 16);
758 status = write_register (regno, suffix+1);
762 /* Do not support read-only registers. */
763 gdb_cris_strcpy (remcomOutBuffer, error_message[E02]);
766 /* Do not support non-existing registers. */
767 gdb_cris_strcpy (remcomOutBuffer, error_message[E05]);
770 /* Do not support non-existing registers on the stack. */
771 gdb_cris_strcpy (remcomOutBuffer, error_message[E07]);
774 /* Invalid parameter. */
775 gdb_cris_strcpy (remcomOutBuffer, error_message[E08]);
778 /* Valid register number. */
779 gdb_cris_strcpy (remcomOutBuffer, "OK");
786 /* Read from memory. mAA..AA,LLLL
787 AA..AA is the address and LLLL is the length.
788 Success: XX..XX is the memory content. Can be fewer bytes than
789 requested if only part of the data may be read. m6000120a,6c means
790 retrieve 108 byte from base address 6000120a.
794 unsigned char *addr = (unsigned char *)gdb_cris_strtol(&remcomInBuffer[1],
795 &suffix, 16); int length = gdb_cris_strtol(suffix+1, 0, 16);
797 mem2hex(remcomOutBuffer, addr, length);
802 /* Write to memory. XAA..AA,LLLL:XX..XX
803 AA..AA is the start address, LLLL is the number of bytes, and
804 XX..XX is the binary data.
808 /* Write to memory. MAA..AA,LLLL:XX..XX
809 AA..AA is the start address, LLLL is the number of bytes, and
810 XX..XX is the hexadecimal data.
816 unsigned char *addr = (unsigned char *)gdb_cris_strtol(&remcomInBuffer[1],
818 int length = gdb_cris_strtol(lenptr+1, &dataptr, 16);
819 if (*lenptr == ',' && *dataptr == ':') {
820 if (remcomInBuffer[0] == 'M') {
821 if (hex2bin(addr, dataptr + 1, length))
822 gdb_cris_strcpy (remcomOutBuffer, error_message[E08]);
824 gdb_cris_strcpy (remcomOutBuffer, "OK");
826 bin2mem(addr, dataptr + 1, length);
827 gdb_cris_strcpy (remcomOutBuffer, "OK");
830 gdb_cris_strcpy (remcomOutBuffer, error_message[E06]);
836 /* Continue execution. cAA..AA
837 AA..AA is the address where execution is resumed. If AA..AA is
838 omitted, resume at the present address.
839 Success: return to the executing thread.
840 Failure: will never know. */
841 if (remcomInBuffer[1] != '\0') {
842 cris_reg.pc = gdb_cris_strtol (&remcomInBuffer[1], 0, 16);
849 AA..AA is the address where execution is resumed. If AA..AA is
850 omitted, resume at the present address. Success: return to the
851 executing thread. Failure: will never know.
853 Should never be invoked. The single-step is implemented on
854 the host side. If ever invoked, it is an internal error E04. */
855 gdb_cris_strcpy (remcomOutBuffer, error_message[E04]);
856 putpacket (remcomOutBuffer);
860 /* The last signal which caused a stop. ?
861 Success: SAA, where AA is the signal number.
863 remcomOutBuffer[0] = 'S';
864 remcomOutBuffer[1] = hex_asc_hi(sigval);
865 remcomOutBuffer[2] = hex_asc_lo(sigval);
866 remcomOutBuffer[3] = 0;
870 /* Detach from host. D
871 Success: OK, and return to the executing thread.
872 Failure: will never know */
878 /* kill request or reset request.
879 Success: restart of target.
880 Failure: will never know. */
889 /* Continue with signal sig. Csig;AA..AA
890 Step with signal sig. Ssig;AA..AA
891 Use the extended remote protocol. !
892 Restart the target system. R0
894 Search backwards. tAA:PP,MM
895 Not supported: E04 */
896 gdb_cris_strcpy (remcomOutBuffer, error_message[E04]);
900 /* The stub should ignore other request and send an empty
901 response ($#<checksum>). This way we can extend the protocol and GDB
902 can tell whether the stub it is talking to uses the old or the new. */
903 remcomOutBuffer[0] = 0;
906 putpacket(remcomOutBuffer);
910 /********************************** Breakpoint *******************************/
911 /* The hook for both a static (compiled) and a dynamic breakpoint set by GDB.
912 An internal stack is used by the stub. The register image of the caller is
913 stored in the structure register_image.
914 Interactive communication with the host is handled by handle_exception and
915 finally the register image is restored. */
917 void kgdb_handle_breakpoint(void);
920 " .global kgdb_handle_breakpoint\n"
921 "kgdb_handle_breakpoint:\n"
923 ";; Response to the break-instruction\n"
925 ";; Create a register image of the caller\n"
927 " move $dccr,[cris_reg+0x5E] ; Save the flags in DCCR before disable interrupts\n"
928 " di ; Disable interrupts\n"
929 " move.d $r0,[cris_reg] ; Save R0\n"
930 " move.d $r1,[cris_reg+0x04] ; Save R1\n"
931 " move.d $r2,[cris_reg+0x08] ; Save R2\n"
932 " move.d $r3,[cris_reg+0x0C] ; Save R3\n"
933 " move.d $r4,[cris_reg+0x10] ; Save R4\n"
934 " move.d $r5,[cris_reg+0x14] ; Save R5\n"
935 " move.d $r6,[cris_reg+0x18] ; Save R6\n"
936 " move.d $r7,[cris_reg+0x1C] ; Save R7\n"
937 " move.d $r8,[cris_reg+0x20] ; Save R8\n"
938 " move.d $r9,[cris_reg+0x24] ; Save R9\n"
939 " move.d $r10,[cris_reg+0x28] ; Save R10\n"
940 " move.d $r11,[cris_reg+0x2C] ; Save R11\n"
941 " move.d $r12,[cris_reg+0x30] ; Save R12\n"
942 " move.d $r13,[cris_reg+0x34] ; Save R13\n"
943 " move.d $sp,[cris_reg+0x38] ; Save SP (R14)\n"
944 ";; Due to the old assembler-versions BRP might not be recognized\n"
945 " .word 0xE670 ; move brp,$r0\n"
946 " subq 2,$r0 ; Set to address of previous instruction.\n"
947 " move.d $r0,[cris_reg+0x3c] ; Save the address in PC (R15)\n"
948 " clear.b [cris_reg+0x40] ; Clear P0\n"
949 " move $vr,[cris_reg+0x41] ; Save special register P1\n"
950 " clear.w [cris_reg+0x42] ; Clear P4\n"
951 " move $ccr,[cris_reg+0x44] ; Save special register CCR\n"
952 " move $mof,[cris_reg+0x46] ; P7\n"
953 " clear.d [cris_reg+0x4A] ; Clear P8\n"
954 " move $ibr,[cris_reg+0x4E] ; P9,\n"
955 " move $irp,[cris_reg+0x52] ; P10,\n"
956 " move $srp,[cris_reg+0x56] ; P11,\n"
957 " move $bar,[cris_reg+0x5A] ; P12,\n"
958 " ; P13, register DCCR already saved\n"
959 ";; Due to the old assembler-versions BRP might not be recognized\n"
960 " .word 0xE670 ; move brp,r0\n"
961 ";; Static (compiled) breakpoints must return to the next instruction in order\n"
962 ";; to avoid infinite loops. Dynamic (gdb-invoked) must restore the instruction\n"
963 ";; in order to execute it when execution is continued.\n"
964 " test.b [is_dyn_brkp] ; Is this a dynamic breakpoint?\n"
965 " beq is_static ; No, a static breakpoint\n"
967 " subq 2,$r0 ; rerun the instruction the break replaced\n"
970 " move.b $r1,[is_dyn_brkp] ; Set the state variable to dynamic breakpoint\n"
971 " move.d $r0,[cris_reg+0x62] ; Save the return address in BRP\n"
972 " move $usp,[cris_reg+0x66] ; USP\n"
974 ";; Handle the communication\n"
976 " move.d internal_stack+1020,$sp ; Use the internal stack which grows upward\n"
977 " moveq 5,$r10 ; SIGTRAP\n"
978 " jsr handle_exception ; Interactive routine\n"
980 ";; Return to the caller\n"
982 " move.d [cris_reg],$r0 ; Restore R0\n"
983 " move.d [cris_reg+0x04],$r1 ; Restore R1\n"
984 " move.d [cris_reg+0x08],$r2 ; Restore R2\n"
985 " move.d [cris_reg+0x0C],$r3 ; Restore R3\n"
986 " move.d [cris_reg+0x10],$r4 ; Restore R4\n"
987 " move.d [cris_reg+0x14],$r5 ; Restore R5\n"
988 " move.d [cris_reg+0x18],$r6 ; Restore R6\n"
989 " move.d [cris_reg+0x1C],$r7 ; Restore R7\n"
990 " move.d [cris_reg+0x20],$r8 ; Restore R8\n"
991 " move.d [cris_reg+0x24],$r9 ; Restore R9\n"
992 " move.d [cris_reg+0x28],$r10 ; Restore R10\n"
993 " move.d [cris_reg+0x2C],$r11 ; Restore R11\n"
994 " move.d [cris_reg+0x30],$r12 ; Restore R12\n"
995 " move.d [cris_reg+0x34],$r13 ; Restore R13\n"
997 ";; FIXME: Which registers should be restored?\n"
999 " move.d [cris_reg+0x38],$sp ; Restore SP (R14)\n"
1000 " move [cris_reg+0x56],$srp ; Restore the subroutine return pointer.\n"
1001 " move [cris_reg+0x5E],$dccr ; Restore DCCR\n"
1002 " move [cris_reg+0x66],$usp ; Restore USP\n"
1003 " jump [cris_reg+0x62] ; A jump to the content in register BRP works.\n"
1007 /* The hook for an interrupt generated by GDB. An internal stack is used
1008 by the stub. The register image of the caller is stored in the structure
1009 register_image. Interactive communication with the host is handled by
1010 handle_exception and finally the register image is restored. Due to the
1011 old assembler which does not recognise the break instruction and the
1012 breakpoint return pointer hex-code is used. */
1014 void kgdb_handle_serial(void);
1017 " .global kgdb_handle_serial\n"
1018 "kgdb_handle_serial:\n"
1020 ";; Response to a serial interrupt\n"
1023 " move $dccr,[cris_reg+0x5E] ; Save the flags in DCCR\n"
1024 " di ; Disable interrupts\n"
1025 " move.d $r0,[cris_reg] ; Save R0\n"
1026 " move.d $r1,[cris_reg+0x04] ; Save R1\n"
1027 " move.d $r2,[cris_reg+0x08] ; Save R2\n"
1028 " move.d $r3,[cris_reg+0x0C] ; Save R3\n"
1029 " move.d $r4,[cris_reg+0x10] ; Save R4\n"
1030 " move.d $r5,[cris_reg+0x14] ; Save R5\n"
1031 " move.d $r6,[cris_reg+0x18] ; Save R6\n"
1032 " move.d $r7,[cris_reg+0x1C] ; Save R7\n"
1033 " move.d $r8,[cris_reg+0x20] ; Save R8\n"
1034 " move.d $r9,[cris_reg+0x24] ; Save R9\n"
1035 " move.d $r10,[cris_reg+0x28] ; Save R10\n"
1036 " move.d $r11,[cris_reg+0x2C] ; Save R11\n"
1037 " move.d $r12,[cris_reg+0x30] ; Save R12\n"
1038 " move.d $r13,[cris_reg+0x34] ; Save R13\n"
1039 " move.d $sp,[cris_reg+0x38] ; Save SP (R14)\n"
1040 " move $irp,[cris_reg+0x3c] ; Save the address in PC (R15)\n"
1041 " clear.b [cris_reg+0x40] ; Clear P0\n"
1042 " move $vr,[cris_reg+0x41] ; Save special register P1,\n"
1043 " clear.w [cris_reg+0x42] ; Clear P4\n"
1044 " move $ccr,[cris_reg+0x44] ; Save special register CCR\n"
1045 " move $mof,[cris_reg+0x46] ; P7\n"
1046 " clear.d [cris_reg+0x4A] ; Clear P8\n"
1047 " move $ibr,[cris_reg+0x4E] ; P9,\n"
1048 " move $irp,[cris_reg+0x52] ; P10,\n"
1049 " move $srp,[cris_reg+0x56] ; P11,\n"
1050 " move $bar,[cris_reg+0x5A] ; P12,\n"
1051 " ; P13, register DCCR already saved\n"
1052 ";; Due to the old assembler-versions BRP might not be recognized\n"
1053 " .word 0xE670 ; move brp,r0\n"
1054 " move.d $r0,[cris_reg+0x62] ; Save the return address in BRP\n"
1055 " move $usp,[cris_reg+0x66] ; USP\n"
1057 ";; get the serial character (from debugport.c) and check if it is a ctrl-c\n"
1059 " jsr getDebugChar\n"
1064 " move.d [cris_reg+0x5E], $r10 ; Get DCCR\n"
1065 " btstq 8, $r10 ; Test the U-flag.\n"
1070 ";; Handle the communication\n"
1072 " move.d internal_stack+1020,$sp ; Use the internal stack\n"
1073 " moveq 2,$r10 ; SIGINT\n"
1074 " jsr handle_exception ; Interactive routine\n"
1078 ";; Return to the caller\n"
1080 " move.d [cris_reg],$r0 ; Restore R0\n"
1081 " move.d [cris_reg+0x04],$r1 ; Restore R1\n"
1082 " move.d [cris_reg+0x08],$r2 ; Restore R2\n"
1083 " move.d [cris_reg+0x0C],$r3 ; Restore R3\n"
1084 " move.d [cris_reg+0x10],$r4 ; Restore R4\n"
1085 " move.d [cris_reg+0x14],$r5 ; Restore R5\n"
1086 " move.d [cris_reg+0x18],$r6 ; Restore R6\n"
1087 " move.d [cris_reg+0x1C],$r7 ; Restore R7\n"
1088 " move.d [cris_reg+0x20],$r8 ; Restore R8\n"
1089 " move.d [cris_reg+0x24],$r9 ; Restore R9\n"
1090 " move.d [cris_reg+0x28],$r10 ; Restore R10\n"
1091 " move.d [cris_reg+0x2C],$r11 ; Restore R11\n"
1092 " move.d [cris_reg+0x30],$r12 ; Restore R12\n"
1093 " move.d [cris_reg+0x34],$r13 ; Restore R13\n"
1095 ";; FIXME: Which registers should be restored?\n"
1097 " move.d [cris_reg+0x38],$sp ; Restore SP (R14)\n"
1098 " move [cris_reg+0x56],$srp ; Restore the subroutine return pointer.\n"
1099 " move [cris_reg+0x5E],$dccr ; Restore DCCR\n"
1100 " move [cris_reg+0x66],$usp ; Restore USP\n"
1101 " reti ; Return from the interrupt routine\n"
1105 /* Use this static breakpoint in the start-up only. */
1111 is_dyn_brkp = 0; /* This is a static, not a dynamic breakpoint. */
1112 __asm__ volatile ("break 8"); /* Jump to handle_breakpoint. */
1115 /* initialize kgdb. doesn't break into the debugger, but sets up irq and ports */
1120 /* could initialize debug port as well but it's done in head.S already... */
1122 /* breakpoint handler is now set in irq.c */
1123 set_int_vector(8, kgdb_handle_serial);
1128 /****************************** End of file **********************************/