diff options
| -rw-r--r-- | Makefrag.am | 9 | ||||
| -rw-r--r-- | configfrag.ac | 11 | ||||
| -rw-r--r-- | i386/Makefrag.am | 6 | ||||
| -rw-r--r-- | i386/i386/gdb-stub.c | 936 | ||||
| -rw-r--r-- | i386/i386/locore.S | 17 | ||||
| -rw-r--r-- | kern/bootstrap.c | 18 | ||||
| -rw-r--r-- | kern/debug.c | 2 | ||||
| -rw-r--r-- | kern/gdb.c | 37 | ||||
| -rw-r--r-- | kern/startup.c | 4 |
9 files changed, 1035 insertions, 5 deletions
diff --git a/Makefrag.am b/Makefrag.am index b9d96c5d..5393513f 100644 --- a/Makefrag.am +++ b/Makefrag.am @@ -72,6 +72,14 @@ libkernel_a_SOURCES += \ AM_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls endif +# +# GDB stub +# + +if enable_gdb_stub +libkernel_a_SOURCES += \ + kern/gdb.c +endif # # IPC implementation. @@ -329,7 +337,6 @@ libkernel_a_SOURCES += \ device/kmsg.h endif - # # Version number. # diff --git a/configfrag.ac b/configfrag.ac index 5df6239d..3e5fea3f 100644 --- a/configfrag.ac +++ b/configfrag.ac @@ -135,6 +135,17 @@ AC_ARG_ENABLE([kmsg], AM_CONDITIONAL([enable_kmsg], [false]) [fi] + +AC_ARG_ENABLE([gdb-stub], + AS_HELP_STRING([--enable-gdb-stub], [enable the use of the GDB stub])) +[if [ x"$enable_gdb_stub" = xyes ]; then] + AC_DEFINE([MACH_GDB_STUB], [1], [Use GDB stub?]) + AM_CONDITIONAL([enable_gdb_stub], [true]) +[else] + AM_CONDITIONAL([enable_gdb_stub], [false]) +[fi] + + # # Set up `SYSTYPE/SYSTYPE' and `SYSTYPE/include/mach/SYSTYPE' links. # diff --git a/i386/Makefrag.am b/i386/Makefrag.am index 4dd6a9f6..05fe4adf 100644 --- a/i386/Makefrag.am +++ b/i386/Makefrag.am @@ -184,6 +184,12 @@ libkernel_a_SOURCES += \ i386/i386/_setjmp.S endif +# +# GDB stub stupport +if enable_gdb_stub +libkernel_a_SOURCES += \ + i386/i386/gdb-stub.c +endif # # Files from the generic sources that we want. diff --git a/i386/i386/gdb-stub.c b/i386/i386/gdb-stub.c new file mode 100644 index 00000000..d77b5acd --- /dev/null +++ b/i386/i386/gdb-stub.c @@ -0,0 +1,936 @@ +/**************************************************************************** + + THIS SOFTWARE IS NOT COPYRIGHTED + + HP offers the following for use in the public domain. HP makes no + warranty with regard to the software or it's performance and the + user accepts the software "AS IS" with all faults. + + HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD + TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES + OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. + +****************************************************************************/ + +/**************************************************************************** + * Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $ + * + * Module name: remcom.c $ + * Revision: 1.34 $ + * Date: 91/03/09 12:29:49 $ + * Contributor: Lake Stevens Instrument Division$ + * + * Description: low level support for gdb debugger. $ + * + * Considerations: only works on target hardware $ + * + * Written by: Glenn Engel $ + * ModuleState: Experimental $ + * + * NOTES: See Below $ + * + * Modified for 386 by Jim Kingdon, Cygnus Support. + * + * To enable debugger support, two things need to happen. One, a + * call to set_debug_traps() 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(). Breakpoint() + * simulates a breakpoint by executing a trap #1. + * + * The external function exceptionHandler() is + * used to attach a specific handler to a specific 386 vector number. + * It should use the same privilege level it runs at. It should + * install it as an interrupt gate so that interrupts are masked + * while the handler runs. + * + * Because gdb will sometimes write to the stack area to execute function + * calls, this program cannot rely on using the supervisor stack so it + * uses it's own stack area reserved in the int array remcomStack. + * + ************* + * + * 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) + * + * 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 <string.h> + +/************************************************************************ + * + * external low-level support routines + */ + +extern void putDebugChar(); /* write a single character */ +extern int getDebugChar(); /* read and return a single char */ +extern void exceptionHandler(); /* assign an exception handler */ + +/************************************************************************/ +/* BUFMAX defines the maximum number of characters in inbound/outbound buffers*/ +/* at least NUMREGBYTES*2 are needed for register packets */ +#define BUFMAX 400 + +static char initialized; /* boolean flag. != 0 means we've been initialized */ + +int remote_debug; +/* debug > 0 prints ill-formed commands in valid packets & checksum errors */ + +static const char hexchars[]="0123456789abcdef"; + +/* Number of registers. */ +#define NUMREGS 16 + +/* Number of bytes of registers. */ +#define NUMREGBYTES (NUMREGS * 4) + +enum regnames {EAX, ECX, EDX, EBX, ESP, EBP, ESI, EDI, + PC /* also known as eip */, + PS /* also known as eflags */, + CS, SS, DS, ES, FS, GS}; + +/* + * these should not be static cuz they can be used outside this module + */ +int registers[NUMREGS]; + +#define STACKSIZE 10000 +int remcomStack[STACKSIZE/sizeof(int)]; +static int* stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1]; + +/*************************** ASSEMBLY CODE MACROS *************************/ +/* */ + +extern void +return_to_prog (); + +/* Restore the program's registers (including the stack pointer, which + means we get the right stack and don't have to worry about popping our + return address and any stack frames and so on) and return. */ +asm(".text"); +asm(".globl return_to_prog"); +asm("return_to_prog:"); +asm(" movw registers+44, %ss"); +asm(" movl registers+16, %esp"); +asm(" movl registers+4, %ecx"); +asm(" movl registers+8, %edx"); +asm(" movl registers+12, %ebx"); +asm(" movl registers+20, %ebp"); +asm(" movl registers+24, %esi"); +asm(" movl registers+28, %edi"); +asm(" movw registers+48, %ds"); +asm(" movw registers+52, %es"); +asm(" movw registers+56, %fs"); +asm(" movw registers+60, %gs"); +asm(" movl registers+36, %eax"); +asm(" pushl %eax"); /* saved eflags */ +asm(" movl registers+40, %eax"); +asm(" pushl %eax"); /* saved cs */ +asm(" movl registers+32, %eax"); +asm(" pushl %eax"); /* saved eip */ +asm(" movl registers, %eax"); +/* use iret to restore pc and flags together so + that trace flag works right. */ +asm(" iret"); + +/* Changed to int 1 from 3 since this is kernel land, + not userland debugging ... */ +#define BREAKPOINT() asm(" int $1"); + +/* Put the error code here just in case the user cares. */ +int gdb_i386errcode; +/* Likewise, the vector number here (since GDB only gets the signal + number through the usual means, and that's not very specific). */ +int gdb_i386vector = -1; + +/* GDB stores segment registers in 32-bit words (that's just the way + m-i386v.h is written). So zero the appropriate areas in registers. */ +#define SAVE_REGISTERS1() \ + asm ("movl %eax, registers"); \ + asm ("movl %ecx, registers+4"); \ + asm ("movl %edx, registers+8"); \ + asm ("movl %ebx, registers+12"); \ + asm ("movl %ebp, registers+20"); \ + asm ("movl %esi, registers+24"); \ + asm ("movl %edi, registers+28"); \ + asm ("movw $0, %ax"); \ + asm ("movw %ds, registers+48"); \ + asm ("movw %ax, registers+50"); \ + asm ("movw %es, registers+52"); \ + asm ("movw %ax, registers+54"); \ + asm ("movw %fs, registers+56"); \ + asm ("movw %ax, registers+58"); \ + asm ("movw %gs, registers+60"); \ + asm ("movw %ax, registers+62"); +#define SAVE_ERRCODE() \ + asm ("popl %ebx"); \ + asm ("movl %ebx, gdb_i386errcode"); +#define SAVE_REGISTERS2() \ + asm ("popl %ebx"); /* old eip */ \ + asm ("movl %ebx, registers+32"); \ + asm ("popl %ebx"); /* old cs */ \ + asm ("movl %ebx, registers+40"); \ + asm ("movw %ax, registers+42"); \ + asm ("popl %ebx"); /* old eflags */ \ + asm ("movl %ebx, registers+36"); \ + /* Now that we've done the pops, we can save the stack pointer."); */ \ + asm ("movw %ss, registers+44"); \ + asm ("movw %ax, registers+46"); \ + asm ("movl %esp, registers+16"); + +/* See if mem_fault_routine is set, if so just IRET to that address. */ +#define CHECK_FAULT() \ + asm ("cmpl $0, mem_fault_routine"); \ + asm ("jne mem_fault"); + +asm (".text"); +asm ("mem_fault:"); +/* OK to clobber temp registers; we're just going to end up in set_mem_err. */ +/* Pop error code from the stack and save it. */ +asm (" popl %eax"); +asm (" movl %eax, gdb_i386errcode"); + +asm (" popl %eax"); /* eip */ +/* We don't want to return there, we want to return to the function + pointed to by mem_fault_routine instead. */ +asm (" movl mem_fault_routine, %eax"); +asm (" popl %ecx"); /* cs (low 16 bits; junk in hi 16 bits). */ +asm (" popl %edx"); /* eflags */ + +/* Remove this stack frame; when we do the iret, we will be going to + the start of a function, so we want the stack to look just like it + would after a "call" instruction. */ +asm (" leave"); + +/* Push the stuff that iret wants. */ +asm (" pushl %edx"); /* eflags */ +asm (" pushl %ecx"); /* cs */ +asm (" pushl %eax"); /* eip */ + +/* Zero mem_fault_routine. */ +asm (" movl $0, %eax"); +asm (" movl %eax, mem_fault_routine"); + +asm ("iret"); + +#define CALL_HOOK() asm("call _remcomHandler"); + +/* This function is called when a i386 exception occurs. It saves + * all the cpu regs in the _registers array, munges the stack a bit, + * and invokes an exception handler (remcom_handler). + * + * stack on entry: stack on exit: + * old eflags vector number + * old cs (zero-filled to 32 bits) + * old eip + * + */ +extern void _catchException3(); +asm(".text"); +asm(".globl __catchException3"); +asm("__catchException3:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $3"); +CALL_HOOK(); + +/* Same thing for exception 1. */ +extern void _catchException1(); +asm(".text"); +asm(".globl __catchException1"); +asm("__catchException1:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $1"); +CALL_HOOK(); + +/* Same thing for exception 0. */ +extern void _catchException0(); +asm(".text"); +asm(".globl __catchException0"); +asm("__catchException0:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $0"); +CALL_HOOK(); + +/* Same thing for exception 4. */ +extern void _catchException4(); +asm(".text"); +asm(".globl __catchException4"); +asm("__catchException4:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $4"); +CALL_HOOK(); + +/* Same thing for exception 5. */ +extern void _catchException5(); +asm(".text"); +asm(".globl __catchException5"); +asm("__catchException5:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $5"); +CALL_HOOK(); + +/* Same thing for exception 6. */ +extern void _catchException6(); +asm(".text"); +asm(".globl __catchException6"); +asm("__catchException6:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $6"); +CALL_HOOK(); + +/* Same thing for exception 7. */ +extern void _catchException7(); +asm(".text"); +asm(".globl __catchException7"); +asm("__catchException7:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $7"); +CALL_HOOK(); + +/* Same thing for exception 8. */ +extern void _catchException8(); +asm(".text"); +asm(".globl __catchException8"); +asm("__catchException8:"); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $8"); +CALL_HOOK(); + +/* Same thing for exception 9. */ +extern void _catchException9(); +asm(".text"); +asm(".globl __catchException9"); +asm("__catchException9:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $9"); +CALL_HOOK(); + +/* Same thing for exception 10. */ +extern void _catchException10(); +asm(".text"); +asm(".globl __catchException10"); +asm("__catchException10:"); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $10"); +CALL_HOOK(); + +/* Same thing for exception 12. */ +extern void _catchException12(); +asm(".text"); +asm(".globl __catchException12"); +asm("__catchException12:"); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $12"); +CALL_HOOK(); + +/* Same thing for exception 16. */ +extern void _catchException16(); +asm(".text"); +asm(".globl __catchException16"); +asm("__catchException16:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $16"); +CALL_HOOK(); + +/* For 13, 11, and 14 we have to deal with the CHECK_FAULT stuff. */ + +/* Same thing for exception 13. */ +extern void _catchException13 (); +asm (".text"); +asm (".globl __catchException13"); +asm ("__catchException13:"); +CHECK_FAULT(); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $13"); +CALL_HOOK(); + +/* Same thing for exception 11. */ +extern void _catchException11 (); +asm (".text"); +asm (".globl __catchException11"); +asm ("__catchException11:"); +CHECK_FAULT(); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $11"); +CALL_HOOK(); + +/* Same thing for exception 14. */ +extern void _catchException14 (); +asm (".text"); +asm (".globl __catchException14"); +asm ("__catchException14:"); +CHECK_FAULT(); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $14"); +CALL_HOOK(); + +/* + * remcomHandler is a front end for handle_exception. It moves the + * stack pointer into an area reserved for debugger use. + */ +asm("_remcomHandler:"); +asm(" popl %eax"); /* pop off return address */ +asm(" popl %eax"); /* get the exception number */ +asm(" movl stackPtr, %esp"); /* move to remcom stack area */ +asm(" pushl %eax"); /* push exception onto stack */ +asm(" call handle_exception"); /* this never returns */ + +void +_returnFromException () +{ + return_to_prog (); +} + +int +hex (ch) + 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); +} + +static char remcomInBuffer[BUFMAX]; +static char remcomOutBuffer[BUFMAX]; + +/* scan for the sequence $<data>#<checksum> */ + +unsigned char * +getpacket (void) +{ + unsigned char *buffer = &remcomInBuffer[0]; + unsigned char checksum; + unsigned char xmitcsum; + int count; + char ch; + + while (1) + { + /* wait around for the start character, ignore all other characters */ + while ((ch = getDebugChar ()) != '$') + ; + + retry: + checksum = 0; + xmitcsum = -1; + count = 0; + + /* now, read until a # or end of buffer is found */ + while (count < BUFMAX - 1) + { + ch = getDebugChar (); + if (ch == '$') + goto retry; + if (ch == '#') + break; + checksum = checksum + ch; + buffer[count] = ch; + count = count + 1; + } + buffer[count] = 0; + + if (ch == '#') + { + ch = getDebugChar (); + xmitcsum = hex (ch) << 4; + ch = getDebugChar (); + xmitcsum += hex (ch); + + if (checksum != xmitcsum) + { + if (remote_debug) + { + printf ("bad checksum. My count = 0x%x, sent=0x%x. buf=%s\n", + checksum, xmitcsum, buffer); + } + putDebugChar ('-'); /* failed checksum */ + } + else + { + putDebugChar ('+'); /* successful transfer */ + + /* if a sequence char is present, reply the sequence ID */ + if (buffer[2] == ':') + { + putDebugChar (buffer[0]); + putDebugChar (buffer[1]); + + return &buffer[3]; + } + + return &buffer[0]; + } + } + } +} + +/* send the packet in buffer. */ + +void +putpacket (unsigned char *buffer) +{ + unsigned char checksum; + int count; + char ch; + + /* $<packet info>#<checksum>. */ + do + { + putDebugChar ('$'); + checksum = 0; + count = 0; + + while (ch = buffer[count]) + { + putDebugChar (ch); + checksum += ch; + count += 1; + } + + putDebugChar ('#'); + putDebugChar (hexchars[checksum >> 4]); + putDebugChar (hexchars[checksum % 16]); + + } + while (getDebugChar () != '+'); +} + +void +debug_error (format, parm) + char *format; + char *parm; +{ + if (remote_debug) + printf (format, parm); +} + +/* Address of a routine to RTE to if we get a memory fault. */ +static void (*volatile mem_fault_routine) () = NULL; + +/* Indicate to caller of mem2hex or hex2mem that there has been an + error. */ +static volatile int mem_err = 0; + +void +set_mem_err (void) +{ + mem_err = 1; +} + +/* These are separate functions so that they are so short and sweet + that the compiler won't save any registers (if there is a fault + to mem_fault, they won't get restored, so there better not be any + saved). */ +int +get_char (char *addr) +{ + return *addr; +} + +void +set_char (char *addr, int val) +{ + *addr = val; +} + +/* convert the memory pointed to by mem into hex, placing result in buf */ +/* return a pointer to the last char put in buf (null) */ +/* If MAY_FAULT is non-zero, then we should set mem_err in response to + a fault; if zero treat a fault like any other fault in the stub. */ +char * +mem2hex (mem, buf, count, may_fault) + char *mem; + char *buf; + int count; + int may_fault; +{ + int i; + unsigned char ch; + + if (may_fault) + mem_fault_routine = set_mem_err; + for (i = 0; i < count; i++) + { + ch = get_char (mem++); + if (may_fault && mem_err) + return (buf); + *buf++ = hexchars[ch >> 4]; + *buf++ = hexchars[ch % 16]; + } + *buf = 0; + if (may_fault) + mem_fault_routine = NULL; + return (buf); +} + +/* 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 */ +char * +hex2mem (buf, mem, count, may_fault) + char *buf; + char *mem; + int count; + int may_fault; +{ + int i; + unsigned char ch; + + if (may_fault) + mem_fault_routine = set_mem_err; + for (i = 0; i < count; i++) + { + ch = hex (*buf++) << 4; + ch = ch + hex (*buf++); + set_char (mem++, ch); + if (may_fault && mem_err) + return (mem); + } + if (may_fault) + mem_fault_routine = NULL; + return (mem); +} + +/* this function takes the 386 exception vector and attempts to + translate this number into a unix compatible signal value */ +int +computeSignal (int exceptionVector) +{ + int sigval; + switch (exceptionVector) + { + case 0: + sigval = 8; + break; /* divide by zero */ + case 1: + sigval = 5; + break; /* debug exception */ + case 3: + sigval = 5; + break; /* breakpoint */ + case 4: + sigval = 16; + break; /* into instruction (overflow) */ + case 5: + sigval = 16; + break; /* bound instruction */ + case 6: + sigval = 4; + break; /* Invalid opcode */ + case 7: + sigval = 8; + break; /* coprocessor not available */ + case 8: + sigval = 7; + break; /* double fault */ + case 9: + sigval = 11; + break; /* coprocessor segment overrun */ + case 10: + sigval = 11; + break; /* Invalid TSS */ + case 11: + sigval = 11; + break; /* Segment not present */ + case 12: + sigval = 11; + break; /* stack exception */ + case 13: + sigval = 11; + break; /* general protection */ + case 14: + sigval = 11; + break; /* page fault */ + case 16: + sigval = 7; + break; /* coprocessor error */ + default: + sigval = 7; /* "software generated" */ + } + return (sigval); +} + +/**********************************************/ +/* WHILE WE FIND NICE HEX CHARS, BUILD AN INT */ +/* RETURN NUMBER OF CHARS PROCESSED */ +/**********************************************/ +int +hexToInt (char **ptr, int *intValue) +{ + int numChars = 0; + int hexValue; + + *intValue = 0; + + while (**ptr) + { + hexValue = hex (**ptr); + if (hexValue >= 0) + { + *intValue = (*intValue << 4) | hexValue; + numChars++; + } + else + break; + + (*ptr)++; + } + + return (numChars); +} + +/* + * This function does all command procesing for interfacing to gdb. + */ +void +handle_exception (int exceptionVector) +{ + int sigval, stepping; + int addr, length; + char *ptr; + int newPC; + + gdb_i386vector = exceptionVector; + + if (remote_debug) + { + printf ("vector=%d, sr=0x%x, pc=0x%x\n", + exceptionVector, registers[PS], registers[PC]); + } + + /* reply to host that an exception has occurred */ + sigval = computeSignal (exceptionVector); + + ptr = remcomOutBuffer; + + *ptr++ = 'T'; /* notify gdb with signo, PC, FP and SP */ + *ptr++ = hexchars[sigval >> 4]; + *ptr++ = hexchars[sigval & 0xf]; + + *ptr++ = hexchars[ESP]; + *ptr++ = ':'; + ptr = mem2hex((char *)®isters[ESP], ptr, 4, 0); /* SP */ + *ptr++ = ';'; + + *ptr++ = hexchars[EBP]; + *ptr++ = ':'; + ptr = mem2hex((char *)®isters[EBP], ptr, 4, 0); /* FP */ + *ptr++ = ';'; + + *ptr++ = hexchars[PC]; + *ptr++ = ':'; + ptr = mem2hex((char *)®isters[PC], ptr, 4, 0); /* PC */ + *ptr++ = ';'; + + *ptr = '\0'; + + putpacket (remcomOutBuffer); + + stepping = 0; + + while (1 == 1) + { + remcomOutBuffer[0] = 0; + ptr = getpacket (); + + switch (*ptr++) + { + case '?': + remcomOutBuffer[0] = 'S'; + remcomOutBuffer[1] = hexchars[sigval >> 4]; + remcomOutBuffer[2] = hexchars[sigval % 16]; + remcomOutBuffer[3] = 0; + break; + case 'd': + remote_debug = !(remote_debug); /* toggle debug flag */ + break; + case 'g': /* return the value of the CPU registers */ + mem2hex ((char *) registers, remcomOutBuffer, NUMREGBYTES, 0); + break; + case 'G': /* set the value of the CPU registers - return OK */ + hex2mem (ptr, (char *) registers, NUMREGBYTES, 0); + strcpy (remcomOutBuffer, "OK"); + break; + case 'P': /* set the value of a single CPU register - return OK */ + { + int regno; + + if (hexToInt (&ptr, ®no) && *ptr++ == '=') + if (regno >= 0 && regno < NUMREGS) + { + hex2mem (ptr, (char *) ®isters[regno], 4, 0); + strcpy (remcomOutBuffer, "OK"); + break; + } + + strcpy (remcomOutBuffer, "E01"); + break; + } + + /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ + case 'm': + /* TRY TO READ %x,%x. IF SUCCEED, SET PTR = 0 */ + if (hexToInt (&ptr, &addr)) + if (*(ptr++) == ',') + if (hexToInt (&ptr, &length)) + { + ptr = 0; + mem_err = 0; + mem2hex ((char *) addr, remcomOutBuffer, length, 1); + if (mem_err) + { + strcpy (remcomOutBuffer, "E03"); + debug_error ("memory fault"); + } + } + + if (ptr) + { + strcpy (remcomOutBuffer, "E01"); + } + break; + + /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ + case 'M': + /* TRY TO READ '%x,%x:'. IF SUCCEED, SET PTR = 0 */ + if (hexToInt (&ptr, &addr)) + if (*(ptr++) == ',') + if (hexToInt (&ptr, &length)) + if (*(ptr++) == ':') + { + mem_err = 0; + hex2mem (ptr, (char *) addr, length, 1); + + if (mem_err) + { + strcpy (remcomOutBuffer, "E03"); + debug_error ("memory fault"); + } + else + { + strcpy (remcomOutBuffer, "OK"); + } + + ptr = 0; + } + if (ptr) + { + strcpy (remcomOutBuffer, "E02"); + } + break; + + /* cAA..AA Continue at address AA..AA(optional) */ + /* sAA..AA Step one instruction from AA..AA(optional) */ + case 's': + stepping = 1; + case 'c': + /* try to read optional parameter, pc unchanged if no parm */ + if (hexToInt (&ptr, &addr)) + registers[PC] = addr; + + newPC = registers[PC]; + + /* clear the trace bit */ + registers[PS] &= 0xfffffeff; + + /* set the trace bit if we're stepping */ + if (stepping) + registers[PS] |= 0x100; + + _returnFromException (); /* this is a jump */ + break; + + /* kill the program */ + case 'k': /* do nothing */ +#if 0 + /* Huh? This doesn't look like "nothing". + m68k-stub.c and sparc-stub.c don't have it. */ + BREAKPOINT (); +#endif + break; + } /* switch */ + + /* reply to the request */ + putpacket (remcomOutBuffer); + } +} + +/* this function is used to set up exception handlers for tracing and + breakpoints */ +void +set_debug_traps (void) +{ + stackPtr = &remcomStack[STACKSIZE / sizeof (int) - 1]; + + initialized = 1; +} + +/* This function will generate a breakpoint exception. It is used at the + beginning of a program to sync up with a debugger and can be used + otherwise as a quick means to stop program execution and "break" into + the debugger. */ + +void +breakpoint (void) +{ + if (initialized) + BREAKPOINT (); +} diff --git a/i386/i386/locore.S b/i386/i386/locore.S index cfda86f0..a44be04d 100644 --- a/i386/i386/locore.S +++ b/i386/i386/locore.S @@ -423,8 +423,18 @@ ENTRY(t_debug) /* wants them */ addl $8,%esp /* remove eip/cs */ jmp syscall_entry_2 /* continue system call entry */ - -0: pushl $0 /* otherwise: */ + +0: +#ifdef MACH_GDB_STUB +/* + * The GDB stub should enter here if its being used alone + * and not called through kdb. The reason is that we don't + * want our backtrace to have all this overhead on it. The stub + * will use iret as it exits + */ + jmp __catchException1 +#endif + pushl $0 /* otherwise: */ pushl $(T_DEBUG) /* handle as normal */ jmp EXT(alltraps) /* debug fault */ @@ -539,7 +549,7 @@ _kret_iret: * Trap from kernel mode. No need to switch stacks. */ trap_from_kernel: -#if MACH_KDB || MACH_TTD +#if MACH_KDB || MACH_TTD || MACH_GDB_STUB movl %esp,%ebx /* save current stack */ cmpl EXT(int_stack_high),%esp /* on an interrupt stack? */ @@ -616,6 +626,7 @@ ENTRY(call_continuation) movl $(n),%eax ;\ jmp EXT(all_intrs) + .data 2 DATA(int_entry_table) .text diff --git a/kern/bootstrap.c b/kern/bootstrap.c index 50388ade..0a8dcedb 100644 --- a/kern/bootstrap.c +++ b/kern/bootstrap.c @@ -57,6 +57,11 @@ #include <ddb/db_sym.h> #endif +#if MACH_GDB_STUB +extern void set_debug_traps(); +extern void breakpoint(); +#endif + #if OSKIT_MACH #include <stddef.h> #include <oskit/machine/base_multiboot.h> @@ -125,8 +130,19 @@ void bootstrap_create(void) #else /* MACH_XEN */ struct multiboot_module *bmods = ((struct multiboot_module *) phystokv(boot_info.mods_addr)); - #endif /* MACH_XEN */ + +#ifdef MACH_GDB_STUB + /* + * FIXME: Change this so its only + * run if -d is passed to mach + */ + + printf("Waiting for debugger connection on com0\n"); + breakpoint(); + printf("Back from GDB\n"); +#endif /* MACH_GDB_STUB */ + if (!(boot_info.flags & MULTIBOOT_MODS) || (boot_info.mods_count == 0)) panic ("No bootstrap code loaded with the kernel!"); diff --git a/kern/debug.c b/kern/debug.c index fd392d21..faa03565 100644 --- a/kern/debug.c +++ b/kern/debug.c @@ -167,6 +167,8 @@ panic(const char *s, ...) #if MACH_KDB Debugger("panic"); +#elif MACH_GDB_STUB + breakpoint(); #else # ifdef MACH_HYP hyp_crash(); diff --git a/kern/gdb.c b/kern/gdb.c new file mode 100644 index 00000000..250bf8d8 --- /dev/null +++ b/kern/gdb.c @@ -0,0 +1,37 @@ +/* + * Mach Kernel - GDB Stub Code + * Copyright (c) 2007 Free Software Foundation + */ + +#include <mach/std_types.h> +#include <sys/types.h> + +/** + * We don't have a header file for the com + * functions, so extern them here, and talk + * about on bug-hurd about making the header + */ + +extern int comcnputc(dev_t dev, int c); +extern int comcngetc(dev_t dev, int wait); + +/** + * putDebugChar puts a character over the serial port + * for the GDB stub. Its prototyped in stub-i386.c + */ + +void putDebugChar(int character) +{ + comcnputc(0, character); +} + +/** + * getDebugChar gets a character over the serial port + * for the GDB stub. Its prototyped in stub-i386.c. + * It uses + */ + +int getDebugChar() +{ + return comcngetc(0, 10); +} diff --git a/kern/startup.c b/kern/startup.c index 30cff5c0..de21ca4a 100644 --- a/kern/startup.c +++ b/kern/startup.c @@ -125,6 +125,10 @@ void setup_main(void) init_timers(); init_timeout(); +#ifdef MACH_GDB_STUB + set_debug_traps(); +#endif + #if XPR_DEBUG xprbootstrap(); #endif /* XPR_DEBUG */ |