/* * GDB stub. * * Migarte form linux to rt-thread by Wzyy2 * Original edition : KGDB stub * * File : gdb_stub.c * This file is part of RT-Thread RTOS * COPYRIGHT (C) 2006, RT-Thread Develop Team * * The license and distribution terms for this file may be * found in the file LICENSE in this distribution or at * http://www.rt-thread.org/license/LICENSE * * Change Logs: * Date Author Notes * 2014-07-04 Wzyy2 first version * * This file incorporates work covered by the following copyright and * permission notice: * * KGDB stub. * * Maintainer: Jason Wessel * * Copyright (C) 2000-2001 VERITAS Software Corporation. * Copyright (C) 2002-2004 Timesys Corporation * Copyright (C) 2003-2004 Amit S. Kale * Copyright (C) 2004 Pavel Machek * Copyright (C) 2004-2006 Tom Rini * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. * Copyright (C) 2005-2008 Wind River Systems, Inc. * Copyright (C) 2007 MontaVista Software, Inc. * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar * * Contributors at various stages not listed above: * Jason Wessel ( jason.wessel@windriver.com ) * George Anzinger * Anurekh Saxena (anurekh.saxena@timesys.com) * Lake Stevens Instrument Division (Glenn Engel) * Jim Kingdon, Cygnus Support. * * Original KGDB stub: David Grothe , * Tigran Aivazian * * This file is licensed under the terms of the GNU General Public License * version 2. This program is licensed "as is" without any warranty of any * kind, whether express or implied. */ #include #include #include #include "gdb_stub.h" struct gdb_state { int signo; int pass_exception; }gs; /** * gdb_connected - Is a host GDB connected to us? */ int gdb_connected; /* * Holds information about breakpoints in a kernel. These breakpoints are * added and removed by gdb. */ #if RT_GDB_HAVE_SWBP static struct gdb_bkpt gdb_break[GDB_MAX_BREAKPOINTS] = { [0 ... GDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } }; #endif /* Storage for the registers, in GDB format. */ static unsigned long gdb_regs[(NUMREGBYTES + sizeof(unsigned long) - 1) / sizeof(unsigned long)]; char remcom_in_buffer[BUFMAX]; char remcom_out_buffer[BUFMAX]; static const char hexchars[] = "0123456789abcdef"; //to call that there has been an error void* volatile gdb_mem_fault_handler = (void *)0; static long probe_kernel_write(void *dst, void *src, size_t size) { int i = 0; char *dst_ptr = (char *)dst; char *src_ptr = (char *)src; gdb_mem_fault_handler = &&err; for (i = 0; i= '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; } static char tohex(char c) { return hexchars[c & 15]; } /* * Copy the binary array pointed to by buf into mem. Fix $, #, and * 0x7d escaped with 0x7d. Return a pointer to the character after * the last byte written. */ int gdb_ebin2mem(char *buf, char *mem, int count) { int err = 0; char c; while (count-- > 0) { c = *buf++; if (c == 0x7d) c = *buf++ ^ 0x20; err = probe_kernel_write(mem, &c, 1); if (err) break; mem++; } return err; } /* * Convert the hex array pointed to by buf into binary to be placed in mem. * Return a pointer to the character AFTER the last byte written. * May return an error. */ int gdb_hex2mem(char *buf, char *mem, int count) { char *tmp_raw; char *tmp_hex; tmp_raw = buf + count * 2; tmp_hex = tmp_raw - 1; while (tmp_hex >= buf) { tmp_raw--; *tmp_raw = hex(*tmp_hex--); *tmp_raw |= hex(*tmp_hex--) << 4; } return probe_kernel_write(mem, tmp_raw, count); } /* * Convert the memory pointed to by mem into hex, placing result in buf. * Return a pointer to the last char put in buf (null). May return an error. */ int gdb_mem2hex(char *mem, char *buf, int count) { char *tmp = mem; char ch; gdb_mem_fault_handler = &&err; while (count > 0) { ch = *(tmp++); *(buf++) = tohex((ch >> 4) & 0xf); *(buf++) = tohex(ch & 0xf); count--; } *buf = 0; gdb_mem_fault_handler = (void *)0; return 0; err: gdb_mem_fault_handler = (void *)0; return -1; } /* * While we find nice hex chars, build a long_val. * Return number of chars processed. */ int gdb_hex2long(char **ptr, unsigned long *long_val) { int hex_val; int num = 0; int negate = 0; *long_val = 0; if (**ptr == '-') { negate = 1; (*ptr)++; } while (**ptr) { hex_val = hex(**ptr); if (hex_val < 0) break; *long_val = (*long_val << 4) | hex_val; num++; (*ptr)++; } if (negate) *long_val = -*long_val; return num; } /* Write memory due to an 'M' or 'X' packet. */ static int write_mem_msg(int binary) { char *ptr = &remcom_in_buffer[1]; unsigned long addr; unsigned long length; int err; if (gdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && gdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { #ifdef GDB_DATA_ACCESS //accesses to areas not backed can cause error if (gdb_permit_data_access(addr, length)) return -1; #endif if (binary) err = gdb_ebin2mem(ptr, (char *)addr, length); else err = gdb_hex2mem(ptr, (char *)addr, length); if (err) return err; #ifdef RT_GDB_ICACHE if (CACHE_FLUSH_IS_SAFE) gdb_flush_icache_range(addr, addr + length); #endif return 0; } return -1; } /* * Send the packet in buffer. * Check for gdb connection if asked for. */ static void put_packet(char *buffer) { unsigned char checksum; int count; char ch; /* * $#. */ while (1) { gdb_io_ops.write_char('$'); checksum = 0; count = 0; while ((ch = buffer[count])) { gdb_io_ops.write_char(ch); checksum += ch; count++; } gdb_io_ops.write_char('#'); gdb_io_ops.write_char(tohex((checksum >> 4) & 0xf)); gdb_io_ops.write_char(tohex(checksum & 0xf)); /* Now see what we get in reply. */ ch = gdb_io_ops.read_char(); /* If we get an ACK, we are done. */ if (ch == '+') return; /* * If we get the start of another packet, this means * that GDB is attempting to reconnect. We will NAK * the packet being sent, and stop trying to send this * packet. */ if (ch == '$') { gdb_io_ops.write_char('-'); if (gdb_io_ops.flush) gdb_io_ops.flush(); return; } } } /* scan for the sequence $# */ static void get_packet(char *buffer) { unsigned char checksum; unsigned char xmitcsum; int count; char ch; do { /* * Spin and wait around for the start character, ignore all * other characters: */ while ((ch = (gdb_io_ops.read_char())) != '$') /* nothing */; gdb_connected = 1; checksum = 0; xmitcsum = -1; count = 0; /* * now, read until a # or end of buffer is found: */ while (count < (BUFMAX - 1)) { ch = gdb_io_ops.read_char(); if (ch == '#') break; checksum = checksum + ch; buffer[count] = ch; count = count + 1; } buffer[count] = 0; if (ch == '#') { xmitcsum = hex(gdb_io_ops.read_char()) << 4; xmitcsum += hex(gdb_io_ops.read_char()); if (checksum != xmitcsum) /* failed checksum */ gdb_io_ops.write_char('-'); else /* successful transfer */ gdb_io_ops.write_char('+'); if (gdb_io_ops.flush) gdb_io_ops.flush(); } } while (checksum != xmitcsum); } static void error_packet(char *pkt, int error) { error = -error; pkt[0] = 'E'; pkt[1] = tohex((error / 10)); pkt[2] = tohex((error % 10)); pkt[3] = '\0'; } #if RT_GDB_HAVE_SWBP static int gdb_arch_set_breakpoint(unsigned long addr, char *saved_instr) { int err; err = probe_kernel_write((void *)saved_instr, (void *)addr, BREAK_INSTR_SIZE); if (err) return err; return probe_kernel_write((void *)addr, (void *)arch_gdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); } static int gdb_arch_remove_breakpoint(unsigned long addr, char *bundle) { return probe_kernel_write((void *)addr, (void *)bundle, BREAK_INSTR_SIZE); } static int gdb_validate_break_address(unsigned long addr) { char tmp_variable[BREAK_INSTR_SIZE]; int err; /* Validate setting the breakpoint and then removing it. In the * remove fails, the kernel needs to emit a bad message because we * are deep trouble not being able to put things back the way we * found them. */ err = gdb_arch_set_breakpoint(addr, tmp_variable); if (err) return err; err = gdb_arch_remove_breakpoint(addr, tmp_variable); if (err) rt_kprintf("GDB: Critical breakpoint error,memory destroyed at: %08x \n", addr); return err; } /* * Some architectures need cache flushes when we set/clear a * breakpoint: */ static void gdb_flush_swbreak_addr(unsigned long addr) { if (!CACHE_FLUSH_IS_SAFE) return; /* Force flush instruction cache if it was outside the mm */ gdb_flush_icache_range(addr, addr + BREAK_INSTR_SIZE); } /* * SW breakpoint management: */ static int gdb_activate_sw_breakpoints(void) { unsigned long addr; int error = 0; int i; for (i = 0; i < GDB_MAX_BREAKPOINTS; i++) { if (gdb_break[i].state != BP_SET) continue; addr = gdb_break[i].bpt_addr; error = gdb_arch_set_breakpoint(addr, (char *)(gdb_break[i].saved_instr)); if (error) return error; gdb_flush_swbreak_addr(addr); gdb_break[i].state = BP_ACTIVE; } return 0; } int gdb_set_sw_break(unsigned long addr) { int err = gdb_validate_break_address(addr); int breakno = -1; int i; if (err) return err; for (i = 0; i < GDB_MAX_BREAKPOINTS; i++) { if ((gdb_break[i].state == BP_SET) && (gdb_break[i].bpt_addr == addr)) return -1; } for (i = 0; i < GDB_MAX_BREAKPOINTS; i++) { if (gdb_break[i].state == BP_REMOVED) { breakno = i; break; } } if (breakno == -1) { for (i = 0; i < GDB_MAX_BREAKPOINTS; i++) { if (gdb_break[i].state == BP_UNDEFINED) { breakno = i; break; } } } if (breakno == -1) return -1; gdb_break[breakno].state = BP_SET; gdb_break[breakno].type = BP_BREAKPOINT; gdb_break[breakno].bpt_addr = addr; return 0; } static int gdb_deactivate_sw_breakpoints(void) { unsigned long addr; int error = 0; int i; for (i = 0; i < GDB_MAX_BREAKPOINTS; i++) { if (gdb_break[i].state != BP_ACTIVE) continue; addr = gdb_break[i].bpt_addr; error = gdb_arch_remove_breakpoint(addr, (char *)(gdb_break[i].saved_instr)); if (error) return error; gdb_flush_swbreak_addr(addr); gdb_break[i].state = BP_SET; } return 0; } int gdb_remove_sw_break(unsigned long addr) { int i; for (i = 0; i < GDB_MAX_BREAKPOINTS; i++) { if ((gdb_break[i].state == BP_SET) && (gdb_break[i].bpt_addr == addr)) { gdb_break[i].state = BP_REMOVED; return 0; } } return -1; } int gdb_isremovedbreak(unsigned long addr) { int i; for (i = 0; i < GDB_MAX_BREAKPOINTS; i++) { if ((gdb_break[i].state == BP_REMOVED) && (gdb_break[i].bpt_addr == addr)) return 1; } return 0; } #endif static int remove_all_break() { #if RT_GDB_HAVE_SWBP unsigned long addr; int error=0; int i; /* Clear memory breakpoints. */ for (i = 0; i < GDB_MAX_BREAKPOINTS; i++) { if (gdb_break[i].state != BP_ACTIVE) goto setundefined; addr = gdb_break[i].bpt_addr; error = gdb_arch_remove_breakpoint(addr, (char *)gdb_break[i].saved_instr); if (error) rt_kprintf("GDB: breakpoint remove failed: %lx\n", addr); setundefined: gdb_break[i].state = BP_UNDEFINED; } #endif #if RT_GDB_HAVE_HWBP /* Clear hardware breakpoints. */ arch_gdb_ops.remove_all_hw_break(); #endif return 0; } static char gdbmsgbuf[BUFMAX + 1]; static void gdb_msg_write(const char *s, int len) { char *bufptr; int wcount; int i; /* 'O'utput */ gdbmsgbuf[0] = 'O'; /* Fill and send buffers... */ while (len > 0) { bufptr = gdbmsgbuf + 1; /* Calculate how many this time */ if ((len << 1) > (BUFMAX - 2)) wcount = (BUFMAX - 2) >> 1; else wcount = len; /* Pack in hex chars */ for (i = 0; i < wcount; i++) { *(bufptr++) = tohex((s[i] >> 4) & 0xf); *(bufptr++) = tohex(s[i] & 0xf); } *bufptr = '\0'; /* Move up */ s += wcount; len -= wcount; /* Write packet */ put_packet(gdbmsgbuf); } } /* * Return true if there is a valid gdb I/O module. Also if no * debugger is attached a message can be printed to the console about * waiting for the debugger to attach. * * The print_wait argument is only to be true when called from inside * the core gdb_handle_exception, because it will wait for the * debugger to attach. */ static int gdb_io_ready(int print_wait) { if (!gdb_dev) return 0; if (gdb_connected) return 1; if (print_wait) rt_kprintf("GDB: Waiting for remote debugger\n"); return 1; } /* Handle the '?' status packets */ static void gdb_cmd_status(struct gdb_state *gs) { /* * We know that this packet is only sent * during initial connect. So to be safe, * we clear out our breakpoints now in case * GDB is reconnecting. */ remove_all_break(); remcom_out_buffer[0] = 'S'; remcom_out_buffer[1] = tohex((gs->signo >> 4) &0xf); remcom_out_buffer[2] = tohex(gs->signo & 0xf); remcom_out_buffer[3] = 0; } /* Handle the 'm' memory read bytes */ static void gdb_cmd_memread(struct gdb_state *gs) { char *ptr = &remcom_in_buffer[1]; unsigned long length; unsigned long addr; int err; if (gdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && gdb_hex2long(&ptr, &length) > 0) { #ifdef GDB_DATA_ACCESS //accesses to areas not backed can cause error if (gdb_permit_data_access(addr, length)) return ; #endif err = gdb_mem2hex((char *)addr, remcom_out_buffer, length); if (err) error_packet(remcom_out_buffer, err); } else { error_packet(remcom_out_buffer, -1); } } /* Handle the 'M' memory write bytes */ static void gdb_cmd_memwrite(struct gdb_state *gs) { int err = write_mem_msg(0); if (err) error_packet(remcom_out_buffer, err); else strcpy(remcom_out_buffer, "OK"); } /* Handle the 'X' memory binary write bytes */ static void gdb_cmd_binwrite(struct gdb_state *gs) { int err = write_mem_msg(1); if (err) error_packet(remcom_out_buffer, err); else strcpy(remcom_out_buffer, "OK"); } /* Handle the 'q' query packets */ static void gdb_cmd_query(struct gdb_state *gs) { /* nothing,because we have no thread support */ } /* Handle the 'g' or 'p' get registers request */ static void gdb_cmd_getregs(struct gdb_state *gs) { char len = sizeof(long); gdb_get_register((unsigned long *)gdb_regs); /*get one registers*/ if (remcom_in_buffer[0] == 'p'){ char *p = &remcom_in_buffer[1]; unsigned long regno = 0; if (gdb_hex2long(&p, ®no)){ gdb_mem2hex(((char *)gdb_regs) + regno * len, remcom_out_buffer, len); return; } else { strcpy(remcom_out_buffer, "INVALID"); return; } } gdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); } /* Handle the 'G' or 'P' set registers request */ static void gdb_cmd_setregs(struct gdb_state *gs) { char len = sizeof(long); /*set one registers*/ if (remcom_in_buffer[0] == 'P'){ char *p = &remcom_in_buffer[1]; unsigned long regno = 0; if (gdb_hex2long(&p, ®no) && *p++ == '='){ gdb_get_register((unsigned long *)gdb_regs); gdb_hex2mem(p, ((char *)gdb_regs) + regno * len, len); gdb_put_register(gdb_regs); strcpy(remcom_out_buffer, "OK"); } return; } gdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); gdb_put_register(gdb_regs); strcpy(remcom_out_buffer, "OK"); } /* Handle the 'D' or 'k', detach or kill packets */ static void gdb_cmd_detachkill(struct gdb_state *gs) { int error; /* The detach case */ if (remcom_in_buffer[0] == 'D') { error = remove_all_break(); if (error < 0) { error_packet(remcom_out_buffer, error); } else { strcpy(remcom_out_buffer, "OK"); gdb_connected = 0; } put_packet(remcom_out_buffer); } else { /* * Assume the kill case, with no exit code checking, * trying to force detach the debugger: */ remove_all_break(); gdb_connected = 0; } } /* Handle the 'z' or 'Z' breakpoint remove or set packets */ static void gdb_cmd_break(struct gdb_state *gs) { /* * Since GDB-5.3, it's been drafted that '0' is a software * breakpoint, '1' is a hardware breakpoint, so let's do that. */ char *bpt_type = &remcom_in_buffer[1]; char *ptr = &remcom_in_buffer[2]; unsigned long addr; unsigned long length; int error = 0; if (arch_gdb_ops.set_hw_breakpoint && *bpt_type >= '1') { /* Unsupported */ if (*bpt_type > '4') return; } /* * Test if this is a hardware breakpoint, and * if we support it: */ if (*bpt_type == '1' && !(arch_gdb_ops.flags)) { /* Unsupported. */ return; } if (*(ptr++) != ',') { error_packet(remcom_out_buffer, -1); return; } if (!gdb_hex2long(&ptr, &addr)) { error_packet(remcom_out_buffer, -1); return; } if (*(ptr++) != ',' || !gdb_hex2long(&ptr, &length)) { error_packet(remcom_out_buffer, -1); return; } #if RT_GDB_HAVE_SWBP if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') error = gdb_set_sw_break(addr); else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') error = gdb_remove_sw_break(addr); #else if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') error = arch_gdb_ops.set_hw_breakpoint(addr, (int)length, BP_HARDWARE_BREAKPOINT); else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') error = arch_gdb_ops.remove_hw_breakpoint(addr, (int) length, BP_HARDWARE_BREAKPOINT); #endif else if (remcom_in_buffer[0] == 'Z') error = arch_gdb_ops.set_hw_breakpoint(addr, (int)length, *bpt_type - '0'); else if (remcom_in_buffer[0] == 'z') error = arch_gdb_ops.remove_hw_breakpoint(addr, (int) length, *bpt_type - '0'); if (error == 0) strcpy(remcom_out_buffer, "OK"); else error_packet(remcom_out_buffer, error); } /* Handle the 'C' signal / exception passing packets */ static int gdb_cmd_exception_pass(struct gdb_state *gs) { /* C09 == pass exception * C15 == detach gdb, pass exception */ if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { gs->pass_exception = 1; remcom_in_buffer[0] = 'c'; } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { gs->pass_exception = 1; remcom_in_buffer[0] = 'D'; remove_all_break(); gdb_connected = 0; return 1; } else { error_packet(remcom_out_buffer, -1); return 0; } /* Indicate fall through */ return -1; } /*more about packet in https://www.sourceware.org/gdb/current/onlinedocs/gdb/Packets.html#Packets*/ static int process_packet(char *pkt) { int status = 0; int tmp; status = gdb_arch_handle_exception(remcom_in_buffer, remcom_out_buffer); remcom_out_buffer[0] = 0; switch (pkt[0]) { case '?':/* gdbserial status */ gdb_cmd_status(&gs); break; case 'q':/* query command */ gdb_cmd_query(&gs); break; case 'p': /* return the value of a single CPU register */ case 'g': /* return the value of the CPU registers */ gdb_cmd_getregs(&gs); break; case 'P': /* set the value of a single CPU registers - return OK */ case 'G': /* set the value of the CPU registers - return OK */ gdb_cmd_setregs(&gs); break; case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ gdb_cmd_memread(&gs); break; case 'X':/* XAA..AA,LLLL: Write LLLL escaped binary bytes at address AA.AA*/ gdb_cmd_binwrite(&gs); break; case 'M':/* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ gdb_cmd_memwrite(&gs); break; case 'D': /* Debugger detach */ case 'k': /* Debugger detach via kill */ gdb_cmd_detachkill(&gs); break; case 'C':/* Exception passing */ tmp = gdb_cmd_exception_pass(&gs); if (tmp > 0) process_packet(remcom_in_buffer); if (tmp == 0) break; case 'z':/* Break point remove */ case 'Z':/* Break point set */ gdb_cmd_break(&gs); break; case 'H':/* task related */ break; case 'T':/* Query thread status */ break; case 'b': /* bBB... Set baud rate to BB... */ break; case 's': /* sAA..AA step form address AA..AA (optional) */ case 'c': /* cAA..AA Continue at address AA..AA (optional) */ #if RT_GDB_HAVE_SWBP gdb_activate_sw_breakpoints(); #endif break; } if (!status) return -1; exit: put_packet(remcom_out_buffer); return 0; } /* * This function does all command procesing for interfacing to gdb. */ int gdb_process_exception() { int status; do { get_packet(remcom_in_buffer); status = process_packet(remcom_in_buffer); } while (status == 0); if (status < 0) return 0; else return 1; } int gdb_handle_exception(int signo, void *regs) { int error; gs.signo = signo; if (!gdb_io_ready(1)) { error = 1; return error; /* No I/O connection, so resume the system */ } #if RT_GDB_HAVE_SWBP gdb_deactivate_sw_breakpoints(); #endif gdb_set_register(regs); /* Clear the out buffer. */ memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); if (gdb_connected) { char *ptr; gdb_io_ops.write_char('\n'); /* Reply to host that an exception has occurred */ ptr = remcom_out_buffer; *ptr++ = 'T'; *ptr++ = tohex((gs.signo >> 4) &0xf); *ptr++ = tohex(gs.signo & 0xf); /*ptr += strlen(strcpy(ptr, "thread:"));*/ /**ptr++ = ';';*/ put_packet(remcom_out_buffer); } gs.pass_exception = 0; while (gdb_process_exception()); error = gs.pass_exception; return error; } void gdb_console_write(const char *s, unsigned count) { /* If we're debugging, or GDB has not connected, don't try * and print. */ if (!gdb_connected) return; gdb_msg_write(s, count); }