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Diffstat (limited to 'arch/cris/arch-v10/kernel/kgdb.c')
| -rw-r--r-- | arch/cris/arch-v10/kernel/kgdb.c | 1144 |
1 files changed, 1144 insertions, 0 deletions
diff --git a/arch/cris/arch-v10/kernel/kgdb.c b/arch/cris/arch-v10/kernel/kgdb.c new file mode 100644 index 000000000..22d846bfc --- /dev/null +++ b/arch/cris/arch-v10/kernel/kgdb.c @@ -0,0 +1,1144 @@ +/*!************************************************************************** +*! +*! FILE NAME : kgdb.c +*! +*! DESCRIPTION: Implementation of the gdb stub with respect to ETRAX 100. +*! It is a mix of arch/m68k/kernel/kgdb.c and cris_stub.c. +*! +*!--------------------------------------------------------------------------- +*! HISTORY +*! +*! DATE NAME CHANGES +*! ---- ---- ------- +*! Apr 26 1999 Hendrik Ruijter Initial version. +*! May 6 1999 Hendrik Ruijter Removed call to strlen in libc and removed +*! struct assignment as it generates calls to +*! memcpy in libc. +*! Jun 17 1999 Hendrik Ruijter Added gdb 4.18 support. 'X', 'qC' and 'qL'. +*! Jul 21 1999 Bjorn Wesen eLinux port +*! +*!--------------------------------------------------------------------------- +*! +*! (C) Copyright 1999, Axis Communications AB, LUND, SWEDEN +*! +*!**************************************************************************/ +/* @(#) cris_stub.c 1.3 06/17/99 */ + +/* + * kgdb usage notes: + * ----------------- + * + * If you select CONFIG_ETRAX_KGDB in the configuration, the kernel will be + * built with different gcc flags: "-g" is added to get debug infos, and + * "-fomit-frame-pointer" is omitted to make debugging easier. Since the + * resulting kernel will be quite big (approx. > 7 MB), it will be stripped + * before compresion. Such a kernel will behave just as usually, except if + * given a "debug=<device>" command line option. (Only serial devices are + * allowed for <device>, i.e. no printers or the like; possible values are + * machine depedend and are the same as for the usual debug device, the one + * for logging kernel messages.) If that option is given and the device can be + * initialized, the kernel will connect to the remote gdb in trap_init(). The + * serial parameters are fixed to 8N1 and 115200 bps, for easyness of + * implementation. + * + * To start a debugging session, start that gdb with the debugging kernel + * image (the one with the symbols, vmlinux.debug) named on the command line. + * This file will be used by gdb to get symbol and debugging infos about the + * kernel. Next, select remote debug mode by + * target remote <device> + * where <device> is the name of the serial device over which the debugged + * machine is connected. Maybe you have to adjust the baud rate by + * set remotebaud <rate> + * or also other parameters with stty: + * shell stty ... </dev/... + * If the kernel to debug has already booted, it waited for gdb and now + * connects, and you'll see a breakpoint being reported. If the kernel isn't + * running yet, start it now. The order of gdb and the kernel doesn't matter. + * Another thing worth knowing about in the getting-started phase is how to + * debug the remote protocol itself. This is activated with + * set remotedebug 1 + * gdb will then print out each packet sent or received. You'll also get some + * messages about the gdb stub on the console of the debugged machine. + * + * If all that works, you can use lots of the usual debugging techniques on + * the kernel, e.g. inspecting and changing variables/memory, setting + * breakpoints, single stepping and so on. It's also possible to interrupt the + * debugged kernel by pressing C-c in gdb. Have fun! :-) + * + * The gdb stub is entered (and thus the remote gdb gets control) in the + * following situations: + * + * - If breakpoint() is called. This is just after kgdb initialization, or if + * a breakpoint() call has been put somewhere into the kernel source. + * (Breakpoints can of course also be set the usual way in gdb.) + * In eLinux, we call breakpoint() in init/main.c after IRQ initialization. + * + * - If there is a kernel exception, i.e. bad_super_trap() or die_if_kernel() + * are entered. All the CPU exceptions are mapped to (more or less..., see + * the hard_trap_info array below) appropriate signal, which are reported + * to gdb. die_if_kernel() is usually called after some kind of access + * error and thus is reported as SIGSEGV. + * + * - When panic() is called. This is reported as SIGABRT. + * + * - If C-c is received over the serial line, which is treated as + * SIGINT. + * + * Of course, all these signals are just faked for gdb, since there is no + * signal concept as such for the kernel. It also isn't possible --obviously-- + * to set signal handlers from inside gdb, or restart the kernel with a + * signal. + * + * Current limitations: + * + * - While the kernel is stopped, interrupts are disabled for safety reasons + * (i.e., variables not changing magically or the like). But this also + * means that the clock isn't running anymore, and that interrupts from the + * hardware may get lost/not be served in time. This can cause some device + * errors... + * + * - When single-stepping, only one instruction of the current thread is + * executed, but interrupts are allowed for that time and will be serviced + * if pending. Be prepared for that. + * + * - All debugging happens in kernel virtual address space. There's no way to + * access physical memory not mapped in kernel space, or to access user + * space. A way to work around this is using get_user_long & Co. in gdb + * expressions, but only for the current process. + * + * - Interrupting the kernel only works if interrupts are currently allowed, + * and the interrupt of the serial line isn't blocked by some other means + * (IPL too high, disabled, ...) + * + * - The gdb stub is currently not reentrant, i.e. errors that happen therein + * (e.g. accessing invalid memory) may not be caught correctly. This could + * be removed in future by introducing a stack of struct registers. + * + */ + +/* + * To enable debugger support, two things need to happen. One, a + * call to kgdb_init() 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(). + * + * 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) + * + * bBB..BB Set baud rate to BB..BB OK or BNN, then sets + * baud rate + * + * 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 <linux/string.h> +#include <linux/signal.h> +#include <linux/kernel.h> +#include <linux/delay.h> +#include <linux/linkage.h> +#include <linux/reboot.h> + +#include <asm/setup.h> +#include <asm/ptrace.h> + +#include <arch/svinto.h> +#include <asm/irq.h> + +static int kgdb_started = 0; + +/********************************* Register image ****************************/ +/* Use the order of registers as defined in "AXIS ETRAX CRIS Programmer's + Reference", p. 1-1, with the additional register definitions of the + ETRAX 100LX in cris-opc.h. + There are 16 general 32-bit registers, R0-R15, where R14 is the stack + pointer, SP, and R15 is the program counter, PC. + There are 16 special registers, P0-P15, where three of the unimplemented + registers, P0, P4 and P8, are reserved as zero-registers. A read from + any of these registers returns zero and a write has no effect. */ + +typedef +struct register_image +{ + /* Offset */ + unsigned int r0; /* 0x00 */ + unsigned int r1; /* 0x04 */ + unsigned int r2; /* 0x08 */ + unsigned int r3; /* 0x0C */ + unsigned int r4; /* 0x10 */ + unsigned int r5; /* 0x14 */ + unsigned int r6; /* 0x18 */ + unsigned int r7; /* 0x1C */ + unsigned int r8; /* 0x20 Frame pointer */ + unsigned int r9; /* 0x24 */ + unsigned int r10; /* 0x28 */ + unsigned int r11; /* 0x2C */ + unsigned int r12; /* 0x30 */ + unsigned int r13; /* 0x34 */ + unsigned int sp; /* 0x38 Stack pointer */ + unsigned int pc; /* 0x3C Program counter */ + + unsigned char p0; /* 0x40 8-bit zero-register */ + unsigned char vr; /* 0x41 Version register */ + + unsigned short p4; /* 0x42 16-bit zero-register */ + unsigned short ccr; /* 0x44 Condition code register */ + + unsigned int mof; /* 0x46 Multiply overflow register */ + + unsigned int p8; /* 0x4A 32-bit zero-register */ + unsigned int ibr; /* 0x4E Interrupt base register */ + unsigned int irp; /* 0x52 Interrupt return pointer */ + unsigned int srp; /* 0x56 Subroutine return pointer */ + unsigned int bar; /* 0x5A Breakpoint address register */ + unsigned int dccr; /* 0x5E Double condition code register */ + unsigned int brp; /* 0x62 Breakpoint return pointer (pc in caller) */ + unsigned int usp; /* 0x66 User mode stack pointer */ +} registers; + +/* Serial port, reads one character. ETRAX 100 specific. from debugport.c */ +int getDebugChar (void); + +/* Serial port, writes one character. ETRAX 100 specific. from debugport.c */ +void putDebugChar (int val); + +void enableDebugIRQ (void); + +/******************** Prototypes for global functions. ***********************/ + +/* The string str is prepended with the GDB printout token and sent. */ +void putDebugString (const unsigned char *str, int length); /* used by etrax100ser.c */ + +/* The hook for both static (compiled) and dynamic breakpoints set by GDB. + ETRAX 100 specific. */ +void handle_breakpoint (void); /* used by irq.c */ + +/* The hook for an interrupt generated by GDB. ETRAX 100 specific. */ +void handle_interrupt (void); /* used by irq.c */ + +/* A static breakpoint to be used at startup. */ +void breakpoint (void); /* called by init/main.c */ + +/* From osys_int.c, executing_task contains the number of the current + executing task in osys. Does not know of object-oriented threads. */ +extern unsigned char executing_task; + +/* The number of characters used for a 64 bit thread identifier. */ +#define HEXCHARS_IN_THREAD_ID 16 + +/********************************** Packet I/O ******************************/ +/* BUFMAX defines the maximum number of characters in + inbound/outbound buffers */ +#define BUFMAX 512 + +/* Run-length encoding maximum length. Send 64 at most. */ +#define RUNLENMAX 64 + +/* The inbound/outbound buffers used in packet I/O */ +static char remcomInBuffer[BUFMAX]; +static char remcomOutBuffer[BUFMAX]; + +/* Error and warning messages. */ +enum error_type +{ + SUCCESS, E01, E02, E03, E04, E05, E06, E07 +}; +static char *error_message[] = +{ + "", + "E01 Set current or general thread - H[c,g] - internal error.", + "E02 Change register content - P - cannot change read-only register.", + "E03 Thread is not alive.", /* T, not used. */ + "E04 The command is not supported - [s,C,S,!,R,d,r] - internal error.", + "E05 Change register content - P - the register is not implemented..", + "E06 Change memory content - M - internal error.", + "E07 Change register content - P - the register is not stored on the stack" +}; +/********************************* Register image ****************************/ +/* Use the order of registers as defined in "AXIS ETRAX CRIS Programmer's + Reference", p. 1-1, with the additional register definitions of the + ETRAX 100LX in cris-opc.h. + There are 16 general 32-bit registers, R0-R15, where R14 is the stack + pointer, SP, and R15 is the program counter, PC. + There are 16 special registers, P0-P15, where three of the unimplemented + registers, P0, P4 and P8, are reserved as zero-registers. A read from + any of these registers returns zero and a write has no effect. */ +enum register_name +{ + R0, R1, R2, R3, + R4, R5, R6, R7, + R8, R9, R10, R11, + R12, R13, SP, PC, + P0, VR, P2, P3, + P4, CCR, P6, MOF, + P8, IBR, IRP, SRP, + BAR, DCCR, BRP, USP +}; + +/* The register sizes of the registers in register_name. An unimplemented register + is designated by size 0 in this array. */ +static int register_size[] = +{ + 4, 4, 4, 4, + 4, 4, 4, 4, + 4, 4, 4, 4, + 4, 4, 4, 4, + 1, 1, 0, 0, + 2, 2, 0, 4, + 4, 4, 4, 4, + 4, 4, 4, 4 +}; + +/* Contains the register image of the executing thread in the assembler + part of the code in order to avoid horrible addressing modes. */ +registers cris_reg; + +/* FIXME: Should this be used? Delete otherwise. */ +/* Contains the assumed consistency state of the register image. Uses the + enum error_type for state information. */ +static int consistency_status = SUCCESS; + +/********************************** Handle exceptions ************************/ +/* The variable cris_reg contains the register image associated with the + current_thread_c variable. It is a complete register image created at + entry. The reg_g contains a register image of a task where the general + registers are taken from the stack and all special registers are taken + from the executing task. It is associated with current_thread_g and used + in order to provide access mainly for 'g', 'G' and 'P'. +*/ + +/********************************** Breakpoint *******************************/ +/* Use an internal stack in the breakpoint and interrupt response routines */ +#define INTERNAL_STACK_SIZE 1024 +char internal_stack[INTERNAL_STACK_SIZE]; + +/* Due to the breakpoint return pointer, a state variable is needed to keep + track of whether it is a static (compiled) or dynamic (gdb-invoked) + breakpoint to be handled. A static breakpoint uses the content of register + BRP as it is whereas a dynamic breakpoint requires subtraction with 2 + in order to execute the instruction. The first breakpoint is static. */ +static unsigned char is_dyn_brkp = 0; + +/********************************* String library ****************************/ +/* Single-step over library functions creates trap loops. */ + +/* Copy char s2[] to s1[]. */ +static char* +gdb_cris_strcpy (char *s1, const char *s2) +{ + char *s = s1; + + for (s = s1; (*s++ = *s2++) != '\0'; ) + ; + return (s1); +} + +/* Find length of s[]. */ +static int +gdb_cris_strlen (const char *s) +{ + const char *sc; + + for (sc = s; *sc != '\0'; sc++) + ; + return (sc - s); +} + +/* Find first occurrence of c in s[n]. */ +static void* +gdb_cris_memchr (const void *s, int c, int n) +{ + const unsigned char uc = c; + const unsigned char *su; + + for (su = s; 0 < n; ++su, --n) + if (*su == uc) + return ((void *)su); + return (NULL); +} +/******************************* Standard library ****************************/ +/* Single-step over library functions creates trap loops. */ +/* Convert string to long. */ +static int +gdb_cris_strtol (const char *s, char **endptr, int base) +{ + char *s1; + char *sd; + int x = 0; + + for (s1 = (char*)s; (sd = gdb_cris_memchr(hex_asc, *s1, base)) != NULL; ++s1) + x = x * base + (sd - hex_asc); + + if (endptr) + { + /* Unconverted suffix is stored in endptr unless endptr is NULL. */ + *endptr = s1; + } + + return x; +} + +/********************************** Packet I/O ******************************/ +/* Returns the integer equivalent of a hexadecimal character. */ +static int +hex (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); +} + +/* Convert the memory, pointed to by mem into hexadecimal representation. + Put the result in buf, and return a pointer to the last character + in buf (null). */ + +static char * +mem2hex(char *buf, unsigned char *mem, int count) +{ + int i; + int ch; + + if (mem == NULL) { + /* Bogus read from m0. FIXME: What constitutes a valid address? */ + for (i = 0; i < count; i++) { + *buf++ = '0'; + *buf++ = '0'; + } + } else { + /* Valid mem address. */ + for (i = 0; i < count; i++) { + ch = *mem++; + buf = hex_byte_pack(buf, ch); + } + } + + /* Terminate properly. */ + *buf = '\0'; + return (buf); +} + +/* Convert the array, in hexadecimal representation, pointed to by buf into + binary representation. Put the result in mem, and return a pointer to + the character after the last byte written. */ +static unsigned char* +hex2mem (unsigned char *mem, char *buf, int count) +{ + int i; + unsigned char ch; + for (i = 0; i < count; i++) { + ch = hex (*buf++) << 4; + ch = ch + hex (*buf++); + *mem++ = ch; + } + return (mem); +} + +/* Put the content of the array, in binary representation, pointed to by buf + into memory pointed to by mem, and return a pointer to the character after + the last byte written. + Gdb will escape $, #, and the escape char (0x7d). */ +static unsigned char* +bin2mem (unsigned char *mem, unsigned char *buf, int count) +{ + int i; + unsigned char *next; + for (i = 0; i < count; i++) { + /* Check for any escaped characters. Be paranoid and + only unescape chars that should be escaped. */ + if (*buf == 0x7d) { + next = buf + 1; + if (*next == 0x3 || *next == 0x4 || *next == 0x5D) /* #, $, ESC */ + { + buf++; + *buf += 0x20; + } + } + *mem++ = *buf++; + } + return (mem); +} + +/* Await the sequence $<data>#<checksum> and store <data> in the array buffer + returned. */ +static void +getpacket (char *buffer) +{ + unsigned char checksum; + unsigned char xmitcsum; + int i; + int count; + char ch; + do { + while ((ch = getDebugChar ()) != '$') + /* Wait for the start character $ and ignore all other characters */; + checksum = 0; + xmitcsum = -1; + count = 0; + /* Read until a # or the end of the buffer is reached */ + while (count < BUFMAX - 1) { + ch = getDebugChar (); + if (ch == '#') + break; + checksum = checksum + ch; + buffer[count] = ch; + count = count + 1; + } + buffer[count] = '\0'; + + if (ch == '#') { + xmitcsum = hex (getDebugChar ()) << 4; + xmitcsum += hex (getDebugChar ()); + if (checksum != xmitcsum) { + /* Wrong checksum */ + putDebugChar ('-'); + } + else { + /* Correct checksum */ + putDebugChar ('+'); + /* If sequence characters are received, reply with them */ + if (buffer[2] == ':') { + putDebugChar (buffer[0]); + putDebugChar (buffer[1]); + /* Remove the sequence characters from the buffer */ + count = gdb_cris_strlen (buffer); + for (i = 3; i <= count; i++) + buffer[i - 3] = buffer[i]; + } + } + } + } while (checksum != xmitcsum); +} + +/* Send $<data>#<checksum> from the <data> in the array buffer. */ + +static void +putpacket(char *buffer) +{ + int checksum; + int runlen; + int encode; + + do { + char *src = buffer; + putDebugChar ('$'); + checksum = 0; + while (*src) { + /* Do run length encoding */ + putDebugChar (*src); + checksum += *src; + runlen = 0; + while (runlen < RUNLENMAX && *src == src[runlen]) { + runlen++; + } + if (runlen > 3) { + /* Got a useful amount */ + putDebugChar ('*'); + checksum += '*'; + encode = runlen + ' ' - 4; + putDebugChar (encode); + checksum += encode; + src += runlen; + } + else { + src++; + } + } + putDebugChar('#'); + putDebugChar(hex_asc_hi(checksum)); + putDebugChar(hex_asc_lo(checksum)); + } while(kgdb_started && (getDebugChar() != '+')); +} + +/* The string str is prepended with the GDB printout token and sent. Required + in traditional implementations. */ +void +putDebugString (const unsigned char *str, int length) +{ + remcomOutBuffer[0] = 'O'; + mem2hex(&remcomOutBuffer[1], (unsigned char *)str, length); + putpacket(remcomOutBuffer); +} + +/********************************* Register image ****************************/ +/* Write a value to a specified register in the register image of the current + thread. Returns status code SUCCESS, E02 or E05. */ +static int +write_register (int regno, char *val) +{ + int status = SUCCESS; + registers *current_reg = &cris_reg; + + if (regno >= R0 && regno <= PC) { + /* 32-bit register with simple offset. */ + hex2mem ((unsigned char *)current_reg + regno * sizeof(unsigned int), + val, sizeof(unsigned int)); + } + else if (regno == P0 || regno == VR || regno == P4 || regno == P8) { + /* Do not support read-only registers. */ + status = E02; + } + else if (regno == CCR) { + /* 16 bit register with complex offset. (P4 is read-only, P6 is not implemented, + and P7 (MOF) is 32 bits in ETRAX 100LX. */ + hex2mem ((unsigned char *)&(current_reg->ccr) + (regno-CCR) * sizeof(unsigned short), + val, sizeof(unsigned short)); + } + else if (regno >= MOF && regno <= USP) { + /* 32 bit register with complex offset. (P8 has been taken care of.) */ + hex2mem ((unsigned char *)&(current_reg->ibr) + (regno-IBR) * sizeof(unsigned int), + val, sizeof(unsigned int)); + } + else { + /* Do not support nonexisting or unimplemented registers (P2, P3, and P6). */ + status = E05; + } + return status; +} + +/* Read a value from a specified register in the register image. Returns the + value in the register or -1 for non-implemented registers. + Should check consistency_status after a call which may be E05 after changes + in the implementation. */ +static int +read_register (char regno, unsigned int *valptr) +{ + registers *current_reg = &cris_reg; + + if (regno >= R0 && regno <= PC) { + /* 32-bit register with simple offset. */ + *valptr = *(unsigned int *)((char *)current_reg + regno * sizeof(unsigned int)); + return SUCCESS; + } + else if (regno == P0 || regno == VR) { + /* 8 bit register with complex offset. */ + *valptr = (unsigned int)(*(unsigned char *) + ((char *)&(current_reg->p0) + (regno-P0) * sizeof(char))); + return SUCCESS; + } + else if (regno == P4 || regno == CCR) { + /* 16 bit register with complex offset. */ + *valptr = (unsigned int)(*(unsigned short *) + ((char *)&(current_reg->p4) + (regno-P4) * sizeof(unsigned short))); + return SUCCESS; + } + else if (regno >= MOF && regno <= USP) { + /* 32 bit register with complex offset. */ + *valptr = *(unsigned int *)((char *)&(current_reg->p8) + + (regno-P8) * sizeof(unsigned int)); + return SUCCESS; + } + else { + /* Do not support nonexisting or unimplemented registers (P2, P3, and P6). */ + consistency_status = E05; + return E05; + } +} + +/********************************** Handle exceptions ************************/ +/* Build and send a response packet in order to inform the host the + stub is stopped. TAAn...:r...;n...:r...;n...:r...; + AA = signal number + n... = register number (hex) + r... = register contents + n... = `thread' + r... = thread process ID. This is a hex integer. + n... = other string not starting with valid hex digit. + gdb should ignore this n,r pair and go on to the next. + This way we can extend the protocol. */ +static void +stub_is_stopped(int sigval) +{ + char *ptr = remcomOutBuffer; + int regno; + + unsigned int reg_cont; + int status; + + /* Send trap type (converted to signal) */ + + *ptr++ = 'T'; + ptr = hex_byte_pack(ptr, sigval); + + /* Send register contents. We probably only need to send the + * PC, frame pointer and stack pointer here. Other registers will be + * explicitly asked for. But for now, send all. + */ + + for (regno = R0; regno <= USP; regno++) { + /* Store n...:r...; for the registers in the buffer. */ + + status = read_register (regno, ®_cont); + + if (status == SUCCESS) { + ptr = hex_byte_pack(ptr, regno); + *ptr++ = ':'; + + ptr = mem2hex(ptr, (unsigned char *)®_cont, + register_size[regno]); + *ptr++ = ';'; + } + + } + + /* null-terminate and send it off */ + + *ptr = 0; + + putpacket (remcomOutBuffer); +} + +/* Performs a complete re-start from scratch. */ +static void +kill_restart (void) +{ + machine_restart(""); +} + +/* All expected commands are sent from remote.c. Send a response according + to the description in remote.c. */ +void +handle_exception (int sigval) +{ + /* Send response. */ + + stub_is_stopped (sigval); + + for (;;) { + remcomOutBuffer[0] = '\0'; + getpacket (remcomInBuffer); + switch (remcomInBuffer[0]) { + case 'g': + /* Read registers: g + Success: 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. + Failure: void. */ + + mem2hex(remcomOutBuffer, (char *)&cris_reg, sizeof(registers)); + break; + + case 'G': + /* Write registers. GXX..XX + Each byte of register data is described by two hex digits. + Success: OK + Failure: void. */ + hex2mem((char *)&cris_reg, &remcomInBuffer[1], sizeof(registers)); + gdb_cris_strcpy (remcomOutBuffer, "OK"); + break; + + case 'P': + /* Write register. Pn...=r... + Write register n..., hex value without 0x, with value r..., + which contains a hex value without 0x and two hex digits + for each byte in the register (target byte order). P1f=11223344 means + set register 31 to 44332211. + Success: OK + Failure: E02, E05 */ + { + char *suffix; + int regno = gdb_cris_strtol (&remcomInBuffer[1], &suffix, 16); + int status; + status = write_register (regno, suffix+1); + + switch (status) { + case E02: + /* Do not support read-only registers. */ + gdb_cris_strcpy (remcomOutBuffer, error_message[E02]); + break; + case E05: + /* Do not support non-existing registers. */ + gdb_cris_strcpy (remcomOutBuffer, error_message[E05]); + break; + case E07: + /* Do not support non-existing registers on the stack. */ + gdb_cris_strcpy (remcomOutBuffer, error_message[E07]); + break; + default: + /* Valid register number. */ + gdb_cris_strcpy (remcomOutBuffer, "OK"); + break; + } + } + break; + + case 'm': + /* Read from memory. mAA..AA,LLLL + AA..AA is the address and LLLL is the length. + Success: XX..XX is the memory content. Can be fewer bytes than + requested if only part of the data may be read. m6000120a,6c means + retrieve 108 byte from base address 6000120a. + Failure: void. */ + { + char *suffix; + unsigned char *addr = (unsigned char *)gdb_cris_strtol(&remcomInBuffer[1], + &suffix, 16); int length = gdb_cris_strtol(suffix+1, 0, 16); + + mem2hex(remcomOutBuffer, addr, length); + } + break; + + case 'X': + /* Write to memory. XAA..AA,LLLL:XX..XX + AA..AA is the start address, LLLL is the number of bytes, and + XX..XX is the binary data. + Success: OK + Failure: void. */ + case 'M': + /* Write to memory. MAA..AA,LLLL:XX..XX + AA..AA is the start address, LLLL is the number of bytes, and + XX..XX is the hexadecimal data. + Success: OK + Failure: void. */ + { + char *lenptr; + char *dataptr; + unsigned char *addr = (unsigned char *)gdb_cris_strtol(&remcomInBuffer[1], + &lenptr, 16); + int length = gdb_cris_strtol(lenptr+1, &dataptr, 16); + if (*lenptr == ',' && *dataptr == ':') { + if (remcomInBuffer[0] == 'M') { + hex2mem(addr, dataptr + 1, length); + } + else /* X */ { + bin2mem(addr, dataptr + 1, length); + } + gdb_cris_strcpy (remcomOutBuffer, "OK"); + } + else { + gdb_cris_strcpy (remcomOutBuffer, error_message[E06]); + } + } + break; + + case 'c': + /* Continue execution. cAA..AA + AA..AA is the address where execution is resumed. If AA..AA is + omitted, resume at the present address. + Success: return to the executing thread. + Failure: will never know. */ + if (remcomInBuffer[1] != '\0') { + cris_reg.pc = gdb_cris_strtol (&remcomInBuffer[1], 0, 16); + } + enableDebugIRQ(); + return; + + case 's': + /* Step. sAA..AA + AA..AA is the address where execution is resumed. If AA..AA is + omitted, resume at the present address. Success: return to the + executing thread. Failure: will never know. + + Should never be invoked. The single-step is implemented on + the host side. If ever invoked, it is an internal error E04. */ + gdb_cris_strcpy (remcomOutBuffer, error_message[E04]); + putpacket (remcomOutBuffer); + return; + + case '?': + /* The last signal which caused a stop. ? + Success: SAA, where AA is the signal number. + Failure: void. */ + remcomOutBuffer[0] = 'S'; + remcomOutBuffer[1] = hex_asc_hi(sigval); + remcomOutBuffer[2] = hex_asc_lo(sigval); + remcomOutBuffer[3] = 0; + break; + + case 'D': + /* Detach from host. D + Success: OK, and return to the executing thread. + Failure: will never know */ + putpacket ("OK"); + return; + + case 'k': + case 'r': + /* kill request or reset request. + Success: restart of target. + Failure: will never know. */ + kill_restart (); + break; + + case 'C': + case 'S': + case '!': + case 'R': + case 'd': + /* Continue with signal sig. Csig;AA..AA + Step with signal sig. Ssig;AA..AA + Use the extended remote protocol. ! + Restart the target system. R0 + Toggle debug flag. d + Search backwards. tAA:PP,MM + Not supported: E04 */ + gdb_cris_strcpy (remcomOutBuffer, error_message[E04]); + break; + + default: + /* The stub should ignore other request and send an empty + response ($#<checksum>). This way we can extend the protocol and GDB + can tell whether the stub it is talking to uses the old or the new. */ + remcomOutBuffer[0] = 0; + break; + } + putpacket(remcomOutBuffer); + } +} + +/********************************** Breakpoint *******************************/ +/* The hook for both a static (compiled) and a dynamic breakpoint set by GDB. + An internal stack is used by the stub. The register image of the caller is + stored in the structure register_image. + Interactive communication with the host is handled by handle_exception and + finally the register image is restored. */ + +void kgdb_handle_breakpoint(void); + +asm ("\n" +" .global kgdb_handle_breakpoint\n" +"kgdb_handle_breakpoint:\n" +";;\n" +";; Response to the break-instruction\n" +";;\n" +";; Create a register image of the caller\n" +";;\n" +" move $dccr,[cris_reg+0x5E] ; Save the flags in DCCR before disable interrupts\n" +" di ; Disable interrupts\n" +" move.d $r0,[cris_reg] ; Save R0\n" +" move.d $r1,[cris_reg+0x04] ; Save R1\n" +" move.d $r2,[cris_reg+0x08] ; Save R2\n" +" move.d $r3,[cris_reg+0x0C] ; Save R3\n" +" move.d $r4,[cris_reg+0x10] ; Save R4\n" +" move.d $r5,[cris_reg+0x14] ; Save R5\n" +" move.d $r6,[cris_reg+0x18] ; Save R6\n" +" move.d $r7,[cris_reg+0x1C] ; Save R7\n" +" move.d $r8,[cris_reg+0x20] ; Save R8\n" +" move.d $r9,[cris_reg+0x24] ; Save R9\n" +" move.d $r10,[cris_reg+0x28] ; Save R10\n" +" move.d $r11,[cris_reg+0x2C] ; Save R11\n" +" move.d $r12,[cris_reg+0x30] ; Save R12\n" +" move.d $r13,[cris_reg+0x34] ; Save R13\n" +" move.d $sp,[cris_reg+0x38] ; Save SP (R14)\n" +";; Due to the old assembler-versions BRP might not be recognized\n" +" .word 0xE670 ; move brp,$r0\n" +" subq 2,$r0 ; Set to address of previous instruction.\n" +" move.d $r0,[cris_reg+0x3c] ; Save the address in PC (R15)\n" +" clear.b [cris_reg+0x40] ; Clear P0\n" +" move $vr,[cris_reg+0x41] ; Save special register P1\n" +" clear.w [cris_reg+0x42] ; Clear P4\n" +" move $ccr,[cris_reg+0x44] ; Save special register CCR\n" +" move $mof,[cris_reg+0x46] ; P7\n" +" clear.d [cris_reg+0x4A] ; Clear P8\n" +" move $ibr,[cris_reg+0x4E] ; P9,\n" +" move $irp,[cris_reg+0x52] ; P10,\n" +" move $srp,[cris_reg+0x56] ; P11,\n" +" move $dtp0,[cris_reg+0x5A] ; P12, register BAR, assembler might not know BAR\n" +" ; P13, register DCCR already saved\n" +";; Due to the old assembler-versions BRP might not be recognized\n" +" .word 0xE670 ; move brp,r0\n" +";; Static (compiled) breakpoints must return to the next instruction in order\n" +";; to avoid infinite loops. Dynamic (gdb-invoked) must restore the instruction\n" +";; in order to execute it when execution is continued.\n" +" test.b [is_dyn_brkp] ; Is this a dynamic breakpoint?\n" +" beq is_static ; No, a static breakpoint\n" +" nop\n" +" subq 2,$r0 ; rerun the instruction the break replaced\n" +"is_static:\n" +" moveq 1,$r1\n" +" move.b $r1,[is_dyn_brkp] ; Set the state variable to dynamic breakpoint\n" +" move.d $r0,[cris_reg+0x62] ; Save the return address in BRP\n" +" move $usp,[cris_reg+0x66] ; USP\n" +";;\n" +";; Handle the communication\n" +";;\n" +" move.d internal_stack+1020,$sp ; Use the internal stack which grows upward\n" +" moveq 5,$r10 ; SIGTRAP\n" +" jsr handle_exception ; Interactive routine\n" +";;\n" +";; Return to the caller\n" +";;\n" +" move.d [cris_reg],$r0 ; Restore R0\n" +" move.d [cris_reg+0x04],$r1 ; Restore R1\n" +" move.d [cris_reg+0x08],$r2 ; Restore R2\n" +" move.d [cris_reg+0x0C],$r3 ; Restore R3\n" +" move.d [cris_reg+0x10],$r4 ; Restore R4\n" +" move.d [cris_reg+0x14],$r5 ; Restore R5\n" +" move.d [cris_reg+0x18],$r6 ; Restore R6\n" +" move.d [cris_reg+0x1C],$r7 ; Restore R7\n" +" move.d [cris_reg+0x20],$r8 ; Restore R8\n" +" move.d [cris_reg+0x24],$r9 ; Restore R9\n" +" move.d [cris_reg+0x28],$r10 ; Restore R10\n" +" move.d [cris_reg+0x2C],$r11 ; Restore R11\n" +" move.d [cris_reg+0x30],$r12 ; Restore R12\n" +" move.d [cris_reg+0x34],$r13 ; Restore R13\n" +";;\n" +";; FIXME: Which registers should be restored?\n" +";;\n" +" move.d [cris_reg+0x38],$sp ; Restore SP (R14)\n" +" move [cris_reg+0x56],$srp ; Restore the subroutine return pointer.\n" +" move [cris_reg+0x5E],$dccr ; Restore DCCR\n" +" move [cris_reg+0x66],$usp ; Restore USP\n" +" jump [cris_reg+0x62] ; A jump to the content in register BRP works.\n" +" nop ;\n" +"\n"); + +/* The hook for an interrupt generated by GDB. An internal stack is used + by the stub. The register image of the caller is stored in the structure + register_image. Interactive communication with the host is handled by + handle_exception and finally the register image is restored. Due to the + old assembler which does not recognise the break instruction and the + breakpoint return pointer hex-code is used. */ + +void kgdb_handle_serial(void); + +asm ("\n" +" .global kgdb_handle_serial\n" +"kgdb_handle_serial:\n" +";;\n" +";; Response to a serial interrupt\n" +";;\n" +"\n" +" move $dccr,[cris_reg+0x5E] ; Save the flags in DCCR\n" +" di ; Disable interrupts\n" +" move.d $r0,[cris_reg] ; Save R0\n" +" move.d $r1,[cris_reg+0x04] ; Save R1\n" +" move.d $r2,[cris_reg+0x08] ; Save R2\n" +" move.d $r3,[cris_reg+0x0C] ; Save R3\n" +" move.d $r4,[cris_reg+0x10] ; Save R4\n" +" move.d $r5,[cris_reg+0x14] ; Save R5\n" +" move.d $r6,[cris_reg+0x18] ; Save R6\n" +" move.d $r7,[cris_reg+0x1C] ; Save R7\n" +" move.d $r8,[cris_reg+0x20] ; Save R8\n" +" move.d $r9,[cris_reg+0x24] ; Save R9\n" +" move.d $r10,[cris_reg+0x28] ; Save R10\n" +" move.d $r11,[cris_reg+0x2C] ; Save R11\n" +" move.d $r12,[cris_reg+0x30] ; Save R12\n" +" move.d $r13,[cris_reg+0x34] ; Save R13\n" +" move.d $sp,[cris_reg+0x38] ; Save SP (R14)\n" +" move $irp,[cris_reg+0x3c] ; Save the address in PC (R15)\n" +" clear.b [cris_reg+0x40] ; Clear P0\n" +" move $vr,[cris_reg+0x41] ; Save special register P1,\n" +" clear.w [cris_reg+0x42] ; Clear P4\n" +" move $ccr,[cris_reg+0x44] ; Save special register CCR\n" +" move $mof,[cris_reg+0x46] ; P7\n" +" clear.d [cris_reg+0x4A] ; Clear P8\n" +" move $ibr,[cris_reg+0x4E] ; P9,\n" +" move $irp,[cris_reg+0x52] ; P10,\n" +" move $srp,[cris_reg+0x56] ; P11,\n" +" move $dtp0,[cris_reg+0x5A] ; P12, register BAR, assembler might not know BAR\n" +" ; P13, register DCCR already saved\n" +";; Due to the old assembler-versions BRP might not be recognized\n" +" .word 0xE670 ; move brp,r0\n" +" move.d $r0,[cris_reg+0x62] ; Save the return address in BRP\n" +" move $usp,[cris_reg+0x66] ; USP\n" +"\n" +";; get the serial character (from debugport.c) and check if it is a ctrl-c\n" +"\n" +" jsr getDebugChar\n" +" cmp.b 3, $r10\n" +" bne goback\n" +" nop\n" +"\n" +" move.d [cris_reg+0x5E], $r10 ; Get DCCR\n" +" btstq 8, $r10 ; Test the U-flag.\n" +" bmi goback\n" +" nop\n" +"\n" +";;\n" +";; Handle the communication\n" +";;\n" +" move.d internal_stack+1020,$sp ; Use the internal stack\n" +" moveq 2,$r10 ; SIGINT\n" +" jsr handle_exception ; Interactive routine\n" +"\n" +"goback:\n" +";;\n" +";; Return to the caller\n" +";;\n" +" move.d [cris_reg],$r0 ; Restore R0\n" +" move.d [cris_reg+0x04],$r1 ; Restore R1\n" +" move.d [cris_reg+0x08],$r2 ; Restore R2\n" +" move.d [cris_reg+0x0C],$r3 ; Restore R3\n" +" move.d [cris_reg+0x10],$r4 ; Restore R4\n" +" move.d [cris_reg+0x14],$r5 ; Restore R5\n" +" move.d [cris_reg+0x18],$r6 ; Restore R6\n" +" move.d [cris_reg+0x1C],$r7 ; Restore R7\n" +" move.d [cris_reg+0x20],$r8 ; Restore R8\n" +" move.d [cris_reg+0x24],$r9 ; Restore R9\n" +" move.d [cris_reg+0x28],$r10 ; Restore R10\n" +" move.d [cris_reg+0x2C],$r11 ; Restore R11\n" +" move.d [cris_reg+0x30],$r12 ; Restore R12\n" +" move.d [cris_reg+0x34],$r13 ; Restore R13\n" +";;\n" +";; FIXME: Which registers should be restored?\n" +";;\n" +" move.d [cris_reg+0x38],$sp ; Restore SP (R14)\n" +" move [cris_reg+0x56],$srp ; Restore the subroutine return pointer.\n" +" move [cris_reg+0x5E],$dccr ; Restore DCCR\n" +" move [cris_reg+0x66],$usp ; Restore USP\n" +" reti ; Return from the interrupt routine\n" +" nop\n" +"\n"); + +/* Use this static breakpoint in the start-up only. */ + +void +breakpoint(void) +{ + kgdb_started = 1; + is_dyn_brkp = 0; /* This is a static, not a dynamic breakpoint. */ + __asm__ volatile ("break 8"); /* Jump to handle_breakpoint. */ +} + +/* initialize kgdb. doesn't break into the debugger, but sets up irq and ports */ + +void +kgdb_init(void) +{ + /* could initialize debug port as well but it's done in head.S already... */ + + /* breakpoint handler is now set in irq.c */ + set_int_vector(8, kgdb_handle_serial); + + enableDebugIRQ(); +} + +/****************************** End of file **********************************/ |