1 /* Remote target communications for serial-line targets in custom GDB protocol
2 Copyright 1988, 1991, 1992 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
20 /* Remote communication protocol.
21 All values are encoded in ascii hex digits.
26 reply XX....X Each byte of register data
27 is described by two hex digits.
28 Registers are in the internal order
29 for GDB, and the bytes in a register
30 are in the same order the machine uses.
33 write regs GXX..XX Each byte of register data
34 is described by two hex digits.
38 read mem mAA..AA,LLLL AA..AA is address, LLLL is length.
39 reply XX..XX XX..XX is mem contents
42 write mem MAA..AA,LLLL:XX..XX
44 LLLL is number of bytes,
49 cont cAA..AA AA..AA is address to resume
51 resume at same address.
53 step sAA..AA AA..AA is address to resume
55 resume at same address.
57 last signal ? Reply the current reason for stopping.
58 This is the same reply as is generated
59 for step or cont : SAA where AA is the
62 There is no immediate reply to step or cont.
63 The reply comes when the machine stops.
64 It is SAA AA is the "signal number"
66 or... TAAPPPPPPPPFFFFFFFF
67 where AA is the signal number,
68 PPPPPPPP is the PC (PC_REGNUM), and
69 FFFFFFFF is the frame ptr (FP_REGNUM).
84 #if !defined(DONT_USE_REMOTE)
86 #include <sys/types.h>
91 /* Prototypes for local functions */
94 remote_write_bytes
PARAMS ((CORE_ADDR
, char *, int));
97 remote_read_bytes
PARAMS ((CORE_ADDR
, char *, int));
100 remote_files_info
PARAMS ((struct target_ops
*));
103 remote_xfer_memory
PARAMS ((CORE_ADDR
, char *, int, int, struct target_ops
*));
106 remote_prepare_to_store
PARAMS ((void));
109 remote_fetch_registers
PARAMS ((int));
112 remote_resume
PARAMS ((int, int));
115 remote_open
PARAMS ((char *, int));
118 remote_close
PARAMS ((int));
121 remote_store_registers
PARAMS ((int));
124 getpkt
PARAMS ((char *));
127 putpkt
PARAMS ((char *));
130 remote_send
PARAMS ((char *));
133 readchar
PARAMS ((void));
136 remote_wait
PARAMS ((WAITTYPE
*));
139 tohex
PARAMS ((int));
142 fromhex
PARAMS ((int));
145 remote_detach
PARAMS ((char *, int));
148 extern struct target_ops remote_ops
; /* Forward decl */
150 static int kiodebug
= 0;
151 static int timeout
= 5;
157 /* Descriptor for I/O to remote machine. Initialize it to -1 so that
158 remote_open knows that we don't have a file open when the program
160 int remote_desc
= -1;
164 /* Maximum number of bytes to read/write at once. The value here
165 is chosen to fill up a packet (the headers account for the 32). */
166 #define MAXBUFBYTES ((PBUFSIZ-32)/2)
168 /* Round up PBUFSIZ to hold all the registers, at least. */
169 #if REGISTER_BYTES > MAXBUFBYTES
171 #define PBUFSIZ (REGISTER_BYTES * 2 + 32)
174 /* Called when SIGALRM signal sent due to alarm() timeout. */
181 printf ("remote_timer called\n");
187 /* Clean up connection to a remote debugger. */
191 remote_close (quitting
)
194 if (remote_desc
>= 0)
199 /* Translate baud rates from integers to damn B_codes. Unix should
200 have outgrown this crap years ago, but even POSIX wouldn't buck it. */
211 static struct {int rate
, damn_b
;} baudtab
[] = {
237 for (i
= 0; baudtab
[i
].rate
!= -1; i
++)
238 if (rate
== baudtab
[i
].rate
) return baudtab
[i
].damn_b
;
239 return B38400
; /* Random */
242 /* Open a connection to a remote debugger.
243 NAME is the filename used for communication. */
246 remote_open (name
, from_tty
)
251 int a_rate
, b_rate
= 0;
252 int baudrate_set
= 0;
256 "To open a remote debug connection, you need to specify what serial\n\
257 device is attached to the remote system (e.g. /dev/ttya).");
259 target_preopen (from_tty
);
267 remote_desc
= open (name
, O_RDWR
);
269 perror_with_name (name
);
273 if (1 != sscanf (baud_rate
, "%d ", &a_rate
))
275 b_rate
= damn_b (a_rate
);
280 ioctl (remote_desc
, TIOCGETP
, &sg
);
282 sg
.c_cc
[VMIN
] = 0; /* read with timeout. */
283 sg
.c_cc
[VTIME
] = timeout
* 10;
284 sg
.c_lflag
&= ~(ICANON
| ECHO
);
285 sg
.c_cflag
&= ~PARENB
; /* No parity */
286 sg
.c_cflag
|= CS8
; /* 8-bit path */
288 sg
.c_cflag
= (sg
.c_cflag
& ~CBAUD
) | b_rate
;
290 sg
.sg_flags
|= RAW
| ANYP
;
291 sg
.sg_flags
&= ~ECHO
;
294 sg
.sg_ispeed
= b_rate
;
295 sg
.sg_ospeed
= b_rate
;
298 ioctl (remote_desc
, TIOCSETP
, &sg
);
301 printf ("Remote debugging using %s\n", name
);
302 push_target (&remote_ops
); /* Switch to using remote target now */
305 #ifndef NO_SIGINTERRUPT
306 /* Cause SIGALRM's to make reads fail. */
307 if (siginterrupt (SIGALRM
, 1) != 0)
308 perror ("remote_open: error in siginterrupt");
311 /* Set up read timeout timer. */
312 if ((void (*)()) signal (SIGALRM
, remote_timer
) == (void (*)()) -1)
313 perror ("remote_open: error in signal");
316 /* Ack any packet which the remote side has already sent. */
317 write (remote_desc
, "+\r", 2);
318 putpkt ("?"); /* initiate a query from remote machine */
320 start_remote (); /* Initialize gdb process mechanisms */
324 takes a program previously attached to and detaches it.
325 We better not have left any breakpoints
326 in the program or it'll die when it hits one.
327 Close the open connection to the remote debugger.
328 Use this when you want to detach and do something else
332 remote_detach (args
, from_tty
)
337 error ("Argument given to \"detach\" when remotely debugging.");
341 printf ("Ending remote debugging.\n");
344 /* Convert hex digit A to a number. */
350 if (a
>= '0' && a
<= '9')
352 else if (a
>= 'a' && a
<= 'f')
355 error ("Reply contains invalid hex digit");
359 /* Convert number NIB to a hex digit. */
371 /* Tell the remote machine to resume. */
374 remote_resume (step
, siggnal
)
380 error ("Can't send signals to a remote system. Try `handle %d ignore'.",
387 strcpy (buf
, step
? "s": "c");
392 /* Send ^C to target to halt it. Target will respond, and send us a
395 void remote_interrupt(signo
)
400 printf ("remote_interrupt called\n");
402 write (remote_desc
, "\003", 1); /* Send a ^C */
406 /* Wait until the remote machine stops, then return,
407 storing status in STATUS just as `wait' would.
408 Returns "pid" (though it's not clear what, if anything, that
409 means in the case of this target). */
415 unsigned char buf
[PBUFSIZ
];
419 char regs
[REGISTER_RAW_SIZE (PC_REGNUM
) + REGISTER_RAW_SIZE (FP_REGNUM
)];
421 WSETEXIT ((*status
), 0);
423 ofunc
= (void (*)()) signal (SIGINT
, remote_interrupt
);
424 getpkt ((char *) buf
);
425 signal (SIGINT
, ofunc
);
428 error ("Remote failure reply: %s", buf
);
431 /* Expedited reply, containing Signal, PC, and FP. */
432 p
= &buf
[3]; /* after Txx */
433 for (i
= 0; i
< sizeof (regs
); i
++)
435 if (p
[0] == 0 || p
[1] == 0)
436 error ("Remote reply is too short: %s", buf
);
437 regs
[i
] = fromhex (p
[0]) * 16 + fromhex (p
[1]);
440 supply_register (PC_REGNUM
, ®s
[0]);
441 supply_register (FP_REGNUM
, ®s
[REGISTER_RAW_SIZE (PC_REGNUM
)]);
443 else if (buf
[0] != 'S')
444 error ("Invalid remote reply: %s", buf
);
446 WSETSTOP ((*status
), (((fromhex (buf
[1])) << 4) + (fromhex (buf
[2]))));
451 /* Read the remote registers into the block REGS. */
452 /* Currently we just read all the registers, so we don't use regno. */
455 remote_fetch_registers (regno
)
461 char regs
[REGISTER_BYTES
];
466 /* Reply describes registers byte by byte, each byte encoded as two
467 hex characters. Suck them all up, then supply them to the
468 register cacheing/storage mechanism. */
471 for (i
= 0; i
< REGISTER_BYTES
; i
++)
473 if (p
[0] == 0 || p
[1] == 0)
474 error ("Remote reply is too short: %s", buf
);
475 regs
[i
] = fromhex (p
[0]) * 16 + fromhex (p
[1]);
478 for (i
= 0; i
< NUM_REGS
; i
++)
479 supply_register (i
, ®s
[REGISTER_BYTE(i
)]);
482 /* Prepare to store registers. Since we send them all, we have to
483 read out the ones we don't want to change first. */
486 remote_prepare_to_store ()
488 remote_fetch_registers (-1);
491 /* Store the remote registers from the contents of the block REGISTERS.
492 FIXME, eventually just store one register if that's all that is needed. */
496 remote_store_registers (regno
)
505 /* Command describes registers byte by byte,
506 each byte encoded as two hex characters. */
509 for (i
= 0; i
< REGISTER_BYTES
; i
++)
511 *p
++ = tohex ((registers
[i
] >> 4) & 0xf);
512 *p
++ = tohex (registers
[i
] & 0xf);
520 /* Read a word from remote address ADDR and return it.
521 This goes through the data cache. */
524 remote_fetch_word (addr
)
529 extern CORE_ADDR text_start
, text_end
;
531 if (addr
>= text_start
&& addr
< text_end
)
534 xfer_core_file (addr
, &buffer
, sizeof (int));
538 return dcache_fetch (addr
);
541 /* Write a word WORD into remote address ADDR.
542 This goes through the data cache. */
545 remote_store_word (addr
, word
)
549 dcache_poke (addr
, word
);
553 /* Write memory data directly to the remote machine.
554 This does not inform the data cache; the data cache uses this.
555 MEMADDR is the address in the remote memory space.
556 MYADDR is the address of the buffer in our space.
557 LEN is the number of bytes. */
560 remote_write_bytes (memaddr
, myaddr
, len
)
569 if (len
> PBUFSIZ
/ 2 - 20)
572 sprintf (buf
, "M%x,%x:", memaddr
, len
);
574 /* We send target system values byte by byte, in increasing byte addresses,
575 each byte encoded as two hex characters. */
577 p
= buf
+ strlen (buf
);
578 for (i
= 0; i
< len
; i
++)
580 *p
++ = tohex ((myaddr
[i
] >> 4) & 0xf);
581 *p
++ = tohex (myaddr
[i
] & 0xf);
588 /* Read memory data directly from the remote machine.
589 This does not use the data cache; the data cache uses this.
590 MEMADDR is the address in the remote memory space.
591 MYADDR is the address of the buffer in our space.
592 LEN is the number of bytes. */
595 remote_read_bytes (memaddr
, myaddr
, len
)
604 if (len
> PBUFSIZ
/ 2 - 1)
607 sprintf (buf
, "m%x,%x", memaddr
, len
);
610 /* Reply describes memory byte by byte,
611 each byte encoded as two hex characters. */
614 for (i
= 0; i
< len
; i
++)
616 if (p
[0] == 0 || p
[1] == 0)
617 error ("Remote reply is too short: %s", buf
);
618 myaddr
[i
] = fromhex (p
[0]) * 16 + fromhex (p
[1]);
623 /* Read or write LEN bytes from inferior memory at MEMADDR, transferring
624 to or from debugger address MYADDR. Write to inferior if SHOULD_WRITE is
625 nonzero. Returns length of data written or read; 0 for error. */
629 remote_xfer_memory(memaddr
, myaddr
, len
, should_write
, target
)
634 struct target_ops
*target
; /* ignored */
640 if (len
> MAXBUFBYTES
)
641 xfersize
= MAXBUFBYTES
;
646 remote_write_bytes(memaddr
, myaddr
, xfersize
);
648 remote_read_bytes (memaddr
, myaddr
, xfersize
);
653 return origlen
; /* no error possible */
657 remote_files_info (ignore
)
658 struct target_ops
*ignore
;
660 printf ("Debugging a target over a serial line.\n");
665 A debug packet whose contents are <data>
666 is encapsulated for transmission in the form:
668 $ <data> # CSUM1 CSUM2
670 <data> must be ASCII alphanumeric and cannot include characters
673 CSUM1 and CSUM2 are ascii hex representation of an 8-bit
674 checksum of <data>, the most significant nibble is sent first.
675 the hex digits 0-9,a-f are used.
677 Receiver responds with:
679 + - if CSUM is correct and ready for next packet
680 - - if CSUM is incorrect
684 /* Read a single character from the remote end.
685 (If supported, we actually read many characters and buffer them up.) */
690 static int inbuf_index
, inbuf_count
;
691 #define INBUFSIZE PBUFSIZ
692 static char inbuf
[INBUFSIZE
];
694 if (inbuf_index
>= inbuf_count
)
696 /* Time to do another read... */
699 inbuf
[0] = 0; /* Just in case */
701 /* termio does the timeout for us. */
702 inbuf_count
= read (remote_desc
, inbuf
, INBUFSIZE
);
705 inbuf_count
= read (remote_desc
, inbuf
, INBUFSIZE
);
710 /* Just return the next character from the buffer. */
711 return inbuf
[inbuf_index
++] & 0x7f;
714 /* Send the command in BUF to the remote machine,
715 and read the reply into BUF.
716 Report an error if we get an error reply. */
727 error ("Remote failure reply: %s", buf
);
730 /* Send a packet to the remote machine, with error checking.
731 The data of the packet is in BUF. */
738 unsigned char csum
= 0;
740 int cnt
= strlen (buf
);
744 /* Copy the packet into buffer BUF2, encapsulating it
745 and giving it a checksum. */
747 if (cnt
> sizeof(buf2
) - 5) /* Prosanity check */
753 for (i
= 0; i
< cnt
; i
++)
759 *p
++ = tohex ((csum
>> 4) & 0xf);
760 *p
++ = tohex (csum
& 0xf);
762 /* Send it over and over until we get a positive ack. */
768 printf ("Sending packet: %s...", buf2
); fflush(stdout
);
770 write (remote_desc
, buf2
, p
- buf2
);
772 /* read until either a timeout occurs (\0) or '+' is read */
779 printf ("%02X%c ", ch
&0xFF, ch
);
781 } while ((ch
!= '+') && (ch
!= '\0'));
785 /* Read a packet from the remote machine, with error checking,
786 and store it in BUF. BUF is expected to be of size PBUFSIZ. */
795 unsigned char c1
, c2
;
797 #define MAX_RETRIES 10
800 /* Sorry, this will cause all hell to break loose, i.e. we'll end
801 up in the command loop with an inferior, but (at least if this
802 happens in remote_wait or some such place) without a current_frame,
803 having set up prev_* in wait_for_inferior, etc.
805 If it is necessary to have such an "emergency exit", seems like
806 the only plausible thing to do is to say the inferior died, and
807 make the user reattach if they want to. Perhaps with a prompt
808 asking for confirmation. */
810 /* allow immediate quit while reading from device, it could be hung */
816 /* Force csum to be zero here because of possible error retry. */
819 while ((c
= readchar()) != '$');
827 if (bp
>= buf
+PBUFSIZ
-1)
830 printf_filtered ("Remote packet too long: %s\n", buf
);
838 c1
= fromhex (readchar ());
839 c2
= fromhex (readchar ());
840 if ((csum
& 0xff) == (c1
<< 4) + c2
)
842 printf_filtered ("Bad checksum, sentsum=0x%x, csum=0x%x, buf=%s\n",
843 (c1
<< 4) + c2
, csum
& 0xff, buf
);
845 /* Try the whole thing again. */
847 if (++retries
< MAX_RETRIES
)
849 write (remote_desc
, "-", 1);
853 printf ("Ignoring packet error, continuing...\n");
862 write (remote_desc
, "+", 1);
865 fprintf (stderr
,"Packet received: %s\n", buf
);
868 /* The data cache leads to incorrect results because it doesn't know about
869 volatile variables, thus making it impossible to debug functions which
870 use hardware registers. Therefore it is #if 0'd out. Effect on
871 performance is some, for backtraces of functions with a few
872 arguments each. For functions with many arguments, the stack
873 frames don't fit in the cache blocks, which makes the cache less
874 helpful. Disabling the cache is a big performance win for fetching
875 large structures, because the cache code fetched data in 16-byte
878 /* The data cache records all the data read from the remote machine
879 since the last time it stopped.
881 Each cache block holds 16 bytes of data
882 starting at a multiple-of-16 address. */
884 #define DCACHE_SIZE 64 /* Number of cache blocks */
886 struct dcache_block
{
887 struct dcache_block
*next
, *last
;
888 unsigned int addr
; /* Address for which data is recorded. */
892 struct dcache_block dcache_free
, dcache_valid
;
894 /* Free all the data cache blocks, thus discarding all cached data. */
899 register struct dcache_block
*db
;
901 while ((db
= dcache_valid
.next
) != &dcache_valid
)
904 insque (db
, &dcache_free
);
909 * If addr is present in the dcache, return the address of the block
913 struct dcache_block
*
916 register struct dcache_block
*db
;
921 /* Search all cache blocks for one that is at this address. */
922 db
= dcache_valid
.next
;
923 while (db
!= &dcache_valid
)
925 if ((addr
& 0xfffffff0) == db
->addr
)
932 /* Return the int data at address ADDR in dcache block DC. */
935 dcache_value (db
, addr
)
936 struct dcache_block
*db
;
941 return (db
->data
[(addr
>>2)&3]);
944 /* Get a free cache block, put it on the valid list,
945 and return its address. The caller should store into the block
946 the address and data that it describes. */
948 struct dcache_block
*
951 register struct dcache_block
*db
;
953 if ((db
= dcache_free
.next
) == &dcache_free
)
954 /* If we can't get one from the free list, take last valid */
955 db
= dcache_valid
.last
;
958 insque (db
, &dcache_valid
);
962 /* Return the contents of the word at address ADDR in the remote machine,
963 using the data cache. */
969 register struct dcache_block
*db
;
971 db
= dcache_hit (addr
);
974 db
= dcache_alloc ();
975 remote_read_bytes (addr
& ~0xf, db
->data
, 16);
976 db
->addr
= addr
& ~0xf;
978 return (dcache_value (db
, addr
));
981 /* Write the word at ADDR both in the data cache and in the remote machine. */
983 dcache_poke (addr
, data
)
987 register struct dcache_block
*db
;
989 /* First make sure the word is IN the cache. DB is its cache block. */
990 db
= dcache_hit (addr
);
993 db
= dcache_alloc ();
994 remote_read_bytes (addr
& ~0xf, db
->data
, 16);
995 db
->addr
= addr
& ~0xf;
998 /* Modify the word in the cache. */
999 db
->data
[(addr
>>2)&3] = data
;
1001 /* Send the changed word. */
1002 remote_write_bytes (addr
, &data
, 4);
1005 /* Initialize the data cache. */
1010 register struct dcache_block
*db
;
1012 db
= (struct dcache_block
*) xmalloc (sizeof (struct dcache_block
) *
1014 dcache_free
.next
= dcache_free
.last
= &dcache_free
;
1015 dcache_valid
.next
= dcache_valid
.last
= &dcache_valid
;
1016 for (i
=0;i
<DCACHE_SIZE
;i
++,db
++)
1017 insque (db
, &dcache_free
);
1021 /* Define the target subroutine names */
1023 struct target_ops remote_ops
= {
1024 "remote", /* to_shortname */
1025 "Remote serial target in gdb-specific protocol", /* to_longname */
1026 "Use a remote computer via a serial line, using a gdb-specific protocol.\n\
1027 Specify the serial device it is connected to (e.g. /dev/ttya).", /* to_doc */
1028 remote_open
, /* to_open */
1029 remote_close
, /* to_close */
1030 NULL
, /* to_attach */
1031 remote_detach
, /* to_detach */
1032 remote_resume
, /* to_resume */
1033 remote_wait
, /* to_wait */
1034 remote_fetch_registers
, /* to_fetch_registers */
1035 remote_store_registers
, /* to_store_registers */
1036 remote_prepare_to_store
, /* to_prepare_to_store */
1037 NULL
, /* to_convert_to_virtual */
1038 NULL
, /* to_convert_from_virtual */
1039 remote_xfer_memory
, /* to_xfer_memory */
1040 remote_files_info
, /* to_files_info */
1041 NULL
, /* to_insert_breakpoint */
1042 NULL
, /* to_remove_breakpoint */
1043 NULL
, /* to_terminal_init */
1044 NULL
, /* to_terminal_inferior */
1045 NULL
, /* to_terminal_ours_for_output */
1046 NULL
, /* to_terminal_ours */
1047 NULL
, /* to_terminal_info */
1050 NULL
, /* to_lookup_symbol */
1051 NULL
, /* to_create_inferior */
1052 NULL
, /* to_mourn_inferior */
1053 process_stratum
, /* to_stratum */
1055 1, /* to_has_all_memory */
1056 1, /* to_has_memory */
1057 1, /* to_has_stack */
1058 1, /* to_has_registers */
1059 1, /* to_has_execution */
1060 NULL
, /* sections */
1061 NULL
, /* sections_end */
1062 OPS_MAGIC
/* to_magic */
1066 _initialize_remote ()
1068 add_target (&remote_ops
);
1071 add_set_cmd ("remotedebug", no_class
, var_boolean
, (char *)&kiodebug
,
1072 "Set debugging of remote serial I/O.\n\
1073 When enabled, each packet sent or received with the remote target\n\
1074 is displayed.", &setlist
),
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