/* Memory-access and commands for inferior process, for GDB. Copyright (C) 1988-1991 Free Software Foundation, Inc. This file is part of GDB. GDB is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 1, or (at your option) any later version. GDB is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GDB; see the file COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ /* Remote communication protocol. All values are encoded in ascii hex digits. Request Packet read registers g reply XX....X 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. or ENN for an error. write regs GXX..XX Each byte of register data is described by two hex digits. reply OK for success ENN for an error read mem mAA..AA,LLLL AA..AA is address, LLLL is length. reply XX..XX XX..XX is mem contents or ENN NN is errno write mem MAA..AA,LLLL:XX..XX AA..AA is address, LLLL is number of bytes, XX..XX is data reply OK for success ENN for an error cont cAA..AA AA..AA is address to resume If AA..AA is omitted, resume at same address. step sAA..AA AA..AA is address to resume If AA..AA is omitted, resume at same address. last signal ? Reply the current reason for stopping. This is the same reply as is generated for step or cont : SAA where AA is the signal number. There is no immediate reply to step or cont. The reply comes when the machine stops. It is SAA AA is the "signal number" kill req k */ #include #include #include #include "defs.h" #include "param.h" #include "frame.h" #include "inferior.h" #include "target.h" #include "wait.h" #include "terminal.h" #ifdef USG #include #endif #include extern void add_syms_addr_command (); extern struct value *call_function_by_hand(); extern void start_remote (); extern struct target_ops remote_ops; /* Forward decl */ static int kiodebug; static int timeout = 5; #if 0 int icache; #endif /* Descriptor for I/O to remote machine. Initialize it to -1 so that remote_open knows that we don't have a file open when the program starts. */ int remote_desc = -1; #define PBUFSIZ 400 /* Maximum number of bytes to read/write at once. The value here is chosen to fill up a packet (the headers account for the 32). */ #define MAXBUFBYTES ((PBUFSIZ-32)/2) static void remote_send (); static void putpkt (); static void getpkt (); #if 0 static void dcache_flush (); #endif /* Called when SIGALRM signal sent due to alarm() timeout. */ #ifndef HAVE_TERMIO void remote_timer () { if (kiodebug) printf ("remote_timer called\n"); alarm (timeout); } #endif /* Initialize remote connection */ void remote_start() { } /* Clean up connection to a remote debugger. */ /* ARGSUSED */ void remote_close (quitting) int quitting; { if (remote_desc >= 0) close (remote_desc); remote_desc = -1; } /* Open a connection to a remote debugger. NAME is the filename used for communication. */ void remote_open (name, from_tty) char *name; int from_tty; { TERMINAL sg; if (name == 0) error ( "To open a remote debug connection, you need to specify what serial\n\ device is attached to the remote system (e.g. /dev/ttya)."); target_preopen (from_tty); remote_close (0); #if 0 dcache_init (); #endif remote_desc = open (name, O_RDWR); if (remote_desc < 0) perror_with_name (name); ioctl (remote_desc, TIOCGETP, &sg); #ifdef HAVE_TERMIO sg.c_cc[VMIN] = 0; /* read with timeout. */ sg.c_cc[VTIME] = timeout * 10; sg.c_lflag &= ~(ICANON | ECHO); #else sg.sg_flags = RAW; #endif ioctl (remote_desc, TIOCSETP, &sg); if (from_tty) printf ("Remote debugging using %s\n", name); push_target (&remote_ops); /* Switch to using remote target now */ #ifndef HAVE_TERMIO #ifndef NO_SIGINTERRUPT /* Cause SIGALRM's to make reads fail. */ if (siginterrupt (SIGALRM, 1) != 0) perror ("remote_open: error in siginterrupt"); #endif /* Set up read timeout timer. */ if ((void (*)()) signal (SIGALRM, remote_timer) == (void (*)()) -1) perror ("remote_open: error in signal"); #endif /* Ack any packet which the remote side has already sent. */ write (remote_desc, "+", 1); putpkt ("?"); /* initiate a query from remote machine */ start_remote (); /* Initialize gdb process mechanisms */ } /* remote_detach() takes a program previously attached to and detaches it. We better not have left any breakpoints in the program or it'll die when it hits one. Close the open connection to the remote debugger. Use this when you want to detach and do something else with your gdb. */ static void remote_detach (args, from_tty) char *args; int from_tty; { if (args) error ("Argument given to \"detach\" when remotely debugging."); pop_target (); if (from_tty) printf ("Ending remote debugging.\n"); } /* Convert hex digit A to a number. */ static int fromhex (a) int a; { if (a >= '0' && a <= '9') return a - '0'; else if (a >= 'a' && a <= 'f') return a - 'a' + 10; else error ("Reply contains invalid hex digit"); return -1; } /* Convert number NIB to a hex digit. */ static int tohex (nib) int nib; { if (nib < 10) return '0'+nib; else return 'a'+nib-10; } /* Tell the remote machine to resume. */ void remote_resume (step, siggnal) int step, siggnal; { char buf[PBUFSIZ]; if (siggnal) error ("Can't send signals to a remote system."); #if 0 dcache_flush (); #endif strcpy (buf, step ? "s": "c"); putpkt (buf); } /* Wait until the remote machine stops, then return, storing status in STATUS just as `wait' would. Returns "pid" (though it's not clear what, if anything, that means in the case of this target). */ int remote_wait (status) WAITTYPE *status; { unsigned char buf[PBUFSIZ]; WSETEXIT ((*status), 0); getpkt (buf); if (buf[0] == 'E') error ("Remote failure reply: %s", buf); if (buf[0] != 'S') error ("Invalid remote reply: %s", buf); WSETSTOP ((*status), (((fromhex (buf[1])) << 4) + (fromhex (buf[2])))); return 0; } /* Read the remote registers into the block REGS. */ /* Currently we just read all the registers, so we don't use regno. */ /* ARGSUSED */ void remote_fetch_registers (regno) int regno; { char buf[PBUFSIZ]; int i; char *p; char regs[REGISTER_BYTES]; sprintf (buf, "g"); remote_send (buf); /* Reply describes registers byte by byte, each byte encoded as two hex characters. Suck them all up, then supply them to the register cacheing/storage mechanism. */ p = buf; for (i = 0; i < REGISTER_BYTES; i++) { if (p[0] == 0 || p[1] == 0) error ("Remote reply is too short: %s", buf); regs[i] = fromhex (p[0]) * 16 + fromhex (p[1]); p += 2; } for (i = 0; i < NUM_REGS; i++) supply_register (i, ®s[REGISTER_BYTE(i)]); } /* Prepare to store registers. Since we send them all, we have to read out the ones we don't want to change first. */ void remote_prepare_to_store () { remote_fetch_registers (-1); } /* Store the remote registers from the contents of the block REGISTERS. FIXME, eventually just store one register if that's all that is needed. */ /* ARGSUSED */ int remote_store_registers (regno) int regno; { char buf[PBUFSIZ]; int i; char *p; buf[0] = 'G'; /* Command describes registers byte by byte, each byte encoded as two hex characters. */ p = buf + 1; for (i = 0; i < REGISTER_BYTES; i++) { *p++ = tohex ((registers[i] >> 4) & 0xf); *p++ = tohex (registers[i] & 0xf); } *p = '\0'; remote_send (buf); return 0; } #if 0 /* Read a word from remote address ADDR and return it. This goes through the data cache. */ int remote_fetch_word (addr) CORE_ADDR addr; { if (icache) { extern CORE_ADDR text_start, text_end; if (addr >= text_start && addr < text_end) { int buffer; xfer_core_file (addr, &buffer, sizeof (int)); return buffer; } } return dcache_fetch (addr); } /* Write a word WORD into remote address ADDR. This goes through the data cache. */ void remote_store_word (addr, word) CORE_ADDR addr; int word; { dcache_poke (addr, word); } #endif /* 0 */ /* Write memory data directly to the remote machine. This does not inform the data cache; the data cache uses this. MEMADDR is the address in the remote memory space. MYADDR is the address of the buffer in our space. LEN is the number of bytes. */ void remote_write_bytes (memaddr, myaddr, len) CORE_ADDR memaddr; char *myaddr; int len; { char buf[PBUFSIZ]; int i; char *p; if (len > PBUFSIZ / 2 - 20) abort (); sprintf (buf, "M%x,%x:", memaddr, len); /* Command describes registers byte by byte, each byte encoded as two hex characters. */ p = buf + strlen (buf); for (i = 0; i < len; i++) { *p++ = tohex ((myaddr[i] >> 4) & 0xf); *p++ = tohex (myaddr[i] & 0xf); } *p = '\0'; remote_send (buf); } /* Read memory data directly from the remote machine. This does not use the data cache; the data cache uses this. MEMADDR is the address in the remote memory space. MYADDR is the address of the buffer in our space. LEN is the number of bytes. */ void remote_read_bytes (memaddr, myaddr, len) CORE_ADDR memaddr; char *myaddr; int len; { char buf[PBUFSIZ]; int i; char *p; if (len > PBUFSIZ / 2 - 1) abort (); sprintf (buf, "m%x,%x", memaddr, len); remote_send (buf); /* Reply describes registers byte by byte, each byte encoded as two hex characters. */ p = buf; for (i = 0; i < len; i++) { if (p[0] == 0 || p[1] == 0) error ("Remote reply is too short: %s", buf); myaddr[i] = fromhex (p[0]) * 16 + fromhex (p[1]); p += 2; } } /* Read or write LEN bytes from inferior memory at MEMADDR, transferring to or from debugger address MYADDR. Write to inferior if SHOULD_WRITE is nonzero. Returns length of data written or read; 0 for error. */ int remote_xfer_inferior_memory(memaddr, myaddr, len, should_write) CORE_ADDR memaddr; char *myaddr; int len; int should_write; { int origlen = len; int xfersize; while (len > 0) { if (len > MAXBUFBYTES) xfersize = MAXBUFBYTES; else xfersize = len; if (should_write) remote_write_bytes(memaddr, myaddr, xfersize); else remote_read_bytes (memaddr, myaddr, xfersize); memaddr += xfersize; myaddr += xfersize; len -= xfersize; } return origlen; /* no error possible */ } void remote_files_info () { printf ("remote files info missing here. FIXME.\n"); } /* A debug packet whose contents are is encapsulated for transmission in the form: $ # CSUM1 CSUM2 must be ASCII alphanumeric and cannot include characters '$' or '#' CSUM1 and CSUM2 are ascii hex representation of an 8-bit checksum of , the most significant nibble is sent first. the hex digits 0-9,a-f are used. Receiver responds with: + - if CSUM is correct and ready for next packet - - if CSUM is incorrect */ static int readchar () { char buf; buf = '\0'; #ifdef HAVE_TERMIO /* termio does the timeout for us. */ read (remote_desc, &buf, 1); #else alarm (timeout); read (remote_desc, &buf, 1); alarm (0); #endif return buf & 0x7f; } /* Send the command in BUF to the remote machine, and read the reply into BUF. Report an error if we get an error reply. */ static void remote_send (buf) char *buf; { putpkt (buf); getpkt (buf); if (buf[0] == 'E') error ("Remote failure reply: %s", buf); } /* Send a packet to the remote machine, with error checking. The data of the packet is in BUF. */ static void putpkt (buf) char *buf; { int i; unsigned char csum = 0; char buf2[500]; int cnt = strlen (buf); char ch; char *p; /* Copy the packet into buffer BUF2, encapsulating it and giving it a checksum. */ p = buf2; *p++ = '$'; for (i = 0; i < cnt; i++) { csum += buf[i]; *p++ = buf[i]; } *p++ = '#'; *p++ = tohex ((csum >> 4) & 0xf); *p++ = tohex (csum & 0xf); /* Send it over and over until we get a positive ack. */ do { if (kiodebug) { *p = '\0'; printf ("Sending packet: %s (%s)\n", buf2, buf); } write (remote_desc, buf2, p - buf2); /* read until either a timeout occurs (\0) or '+' is read */ do { ch = readchar (); } while ((ch != '+') && (ch != '\0')); } while (ch != '+'); } /* Read a packet from the remote machine, with error checking, and store it in BUF. */ static void getpkt (buf) char *buf; { char *bp; unsigned char csum; int c; unsigned char c1, c2; #if 0 /* Sorry, this will cause all hell to break loose, i.e. we'll end up in the command loop with an inferior, but (at least if this happens in remote_wait or some such place) without a current_frame, having set up prev_* in wait_for_inferior, etc. If it is necessary to have such an "emergency exit", seems like the only plausible thing to do is to say the inferior died, and make the user reattach if they want to. Perhaps with a prompt asking for confirmation. */ /* allow immediate quit while reading from device, it could be hung */ immediate_quit++; #endif /* 0 */ while (1) { /* Force csum to be zero here because of possible error retry. */ csum = 0; while ((c = readchar()) != '$'); bp = buf; while (1) { c = readchar (); if (c == '#') break; *bp++ = c; csum += c; } *bp = 0; c1 = fromhex (readchar ()); c2 = fromhex (readchar ()); if ((csum & 0xff) == (c1 << 4) + c2) break; printf ("Bad checksum, sentsum=0x%x, csum=0x%x, buf=%s\n", (c1 << 4) + c2, csum & 0xff, buf); write (remote_desc, "-", 1); } #if 0 immediate_quit--; #endif write (remote_desc, "+", 1); if (kiodebug) fprintf (stderr,"Packet received :%s\n", buf); } /* The data cache leads to incorrect results because it doesn't know about volatile variables, thus making it impossible to debug functions which use hardware registers. Therefore it is #if 0'd out. Effect on performance is some, for backtraces of functions with a few arguments each. For functions with many arguments, the stack frames don't fit in the cache blocks, which makes the cache less helpful. Disabling the cache is a big performance win for fetching large structures, because the cache code fetched data in 16-byte chunks. */ #if 0 /* The data cache records all the data read from the remote machine since the last time it stopped. Each cache block holds 16 bytes of data starting at a multiple-of-16 address. */ #define DCACHE_SIZE 64 /* Number of cache blocks */ struct dcache_block { struct dcache_block *next, *last; unsigned int addr; /* Address for which data is recorded. */ int data[4]; }; struct dcache_block dcache_free, dcache_valid; /* Free all the data cache blocks, thus discarding all cached data. */ static void dcache_flush () { register struct dcache_block *db; while ((db = dcache_valid.next) != &dcache_valid) { remque (db); insque (db, &dcache_free); } } /* * If addr is present in the dcache, return the address of the block * containing it. */ struct dcache_block * dcache_hit (addr) { register struct dcache_block *db; if (addr & 3) abort (); /* Search all cache blocks for one that is at this address. */ db = dcache_valid.next; while (db != &dcache_valid) { if ((addr & 0xfffffff0) == db->addr) return db; db = db->next; } return NULL; } /* Return the int data at address ADDR in dcache block DC. */ int dcache_value (db, addr) struct dcache_block *db; unsigned int addr; { if (addr & 3) abort (); return (db->data[(addr>>2)&3]); } /* Get a free cache block, put it on the valid list, and return its address. The caller should store into the block the address and data that it describes. */ struct dcache_block * dcache_alloc () { register struct dcache_block *db; if ((db = dcache_free.next) == &dcache_free) /* If we can't get one from the free list, take last valid */ db = dcache_valid.last; remque (db); insque (db, &dcache_valid); return (db); } /* Return the contents of the word at address ADDR in the remote machine, using the data cache. */ int dcache_fetch (addr) CORE_ADDR addr; { register struct dcache_block *db; db = dcache_hit (addr); if (db == 0) { db = dcache_alloc (); remote_read_bytes (addr & ~0xf, db->data, 16); db->addr = addr & ~0xf; } return (dcache_value (db, addr)); } /* Write the word at ADDR both in the data cache and in the remote machine. */ dcache_poke (addr, data) CORE_ADDR addr; int data; { register struct dcache_block *db; /* First make sure the word is IN the cache. DB is its cache block. */ db = dcache_hit (addr); if (db == 0) { db = dcache_alloc (); remote_read_bytes (addr & ~0xf, db->data, 16); db->addr = addr & ~0xf; } /* Modify the word in the cache. */ db->data[(addr>>2)&3] = data; /* Send the changed word. */ remote_write_bytes (addr, &data, 4); } /* Initialize the data cache. */ dcache_init () { register i; register struct dcache_block *db; db = (struct dcache_block *) xmalloc (sizeof (struct dcache_block) * DCACHE_SIZE); dcache_free.next = dcache_free.last = &dcache_free; dcache_valid.next = dcache_valid.last = &dcache_valid; for (i=0;i