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Diffstat (limited to 'arch/sh/kernel/kgdb_stub.c')
| -rw-r--r-- | arch/sh/kernel/kgdb_stub.c | 1491 |
1 files changed, 1491 insertions, 0 deletions
diff --git a/arch/sh/kernel/kgdb_stub.c b/arch/sh/kernel/kgdb_stub.c new file mode 100644 index 0000000..42638b9 --- /dev/null +++ b/arch/sh/kernel/kgdb_stub.c @@ -0,0 +1,1491 @@ +/* + * May be copied or modified under the terms of the GNU General Public + * License. See linux/COPYING for more information. + * + * Containes extracts from code by Glenn Engel, Jim Kingdon, + * David Grothe <dave@gcom.com>, Tigran Aivazian <tigran@sco.com>, + * Amit S. Kale <akale@veritas.com>, William Gatliff <bgat@open-widgets.com>, + * Ben Lee, Steve Chamberlain and Benoit Miller <fulg@iname.com>. + * + * This version by Henry Bell <henry.bell@st.com> + * Minor modifications by Jeremy Siegel <jsiegel@mvista.com> + * + * Contains low-level support for remote debug using GDB. + * + * To enable debugger support, two things need to happen. 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. + * A breakpoint also needs to be generated to begin communication. This + * is most easily accomplished by a call to breakpoint() which does + * a trapa if the initialisation phase has been successfully completed. + * + * In this case, set_debug_traps() is not used to "take over" exceptions; + * other kernel code is modified instead to enter the kgdb functions here + * when appropriate (see entry.S for breakpoint traps and NMI interrupts, + * see traps.c for kernel error exceptions). + * + * 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 + * XAA..AA,LLLL: Same, but data is binary (not hex) OK or ENN + * + * c Resume at current address SNN ( signal NN) + * cAA..AA Continue at address AA..AA SNN + * CNN; Resume at current address with signal SNN + * CNN;AA..AA Resume at address AA..AA with signal SNN + * + * s Step one instruction SNN + * sAA..AA Step one instruction from AA..AA SNN + * SNN; Step one instruction with signal SNN + * SNNAA..AA Step one instruction from AA..AA w/NN SNN + * + * k kill (Detach GDB) + * + * d Toggle debug flag + * D Detach GDB + * + * Hct Set thread t for operations, OK or ENN + * c = 'c' (step, cont), c = 'g' (other + * operations) + * + * qC Query current thread ID QCpid + * qfThreadInfo Get list of current threads (first) m<id> + * qsThreadInfo " " " " " (subsequent) + * qOffsets Get section offsets Text=x;Data=y;Bss=z + * + * TXX Find if thread XX is alive OK or ENN + * ? What was the last sigval ? SNN (signal NN) + * O Output to GDB console + * + * Remote communication protocol. + * + * A debug packet whose contents are <data> is encapsulated for + * transmission in the form: + * + * $ <data> # CSUM1 CSUM2 + * + * <data> must be ASCII alphanumeric and cannot include characters + * '$' or '#'. If <data> starts with two characters followed by + * ':', then the existing stubs interpret this as a sequence number. + * + * CSUM1 and CSUM2 are ascii hex representation of an 8-bit + * checksum of <data>, 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 + * + * Responses can be run-length encoded to save space. A '*' means that + * the next character is an ASCII encoding giving a repeat count which + * stands for that many repititions of the character preceding the '*'. + * The encoding is n+29, yielding a printable character where n >=3 + * (which is where RLE starts to win). Don't use an n > 126. + * + * So "0* " means the same as "0000". + */ + +#include <linux/string.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/smp.h> +#include <linux/spinlock.h> +#include <linux/delay.h> +#include <linux/linkage.h> +#include <linux/init.h> + +#include <asm/system.h> +#include <asm/current.h> +#include <asm/signal.h> +#include <asm/pgtable.h> +#include <asm/ptrace.h> +#include <asm/kgdb.h> + +#ifdef CONFIG_SH_KGDB_CONSOLE +#include <linux/console.h> +#endif + +/* Function pointers for linkage */ +kgdb_debug_hook_t *kgdb_debug_hook; +kgdb_bus_error_hook_t *kgdb_bus_err_hook; + +int (*kgdb_getchar)(void); +void (*kgdb_putchar)(int); + +static void put_debug_char(int c) +{ + if (!kgdb_putchar) + return; + (*kgdb_putchar)(c); +} +static int get_debug_char(void) +{ + if (!kgdb_getchar) + return -1; + return (*kgdb_getchar)(); +} + +/* Num chars in in/out bound buffers, register packets need NUMREGBYTES * 2 */ +#define BUFMAX 1024 +#define NUMREGBYTES (MAXREG*4) +#define OUTBUFMAX (NUMREGBYTES*2+512) + +enum regs { + R0 = 0, R1, R2, R3, R4, R5, R6, R7, + R8, R9, R10, R11, R12, R13, R14, R15, + PC, PR, GBR, VBR, MACH, MACL, SR, + /* */ + MAXREG +}; + +static unsigned int registers[MAXREG]; +struct kgdb_regs trap_registers; + +char kgdb_in_gdb_mode; +char in_nmi; /* Set during NMI to prevent reentry */ +int kgdb_nofault; /* Boolean to ignore bus errs (i.e. in GDB) */ +int kgdb_enabled = 1; /* Default to enabled, cmdline can disable */ +int kgdb_halt; + +/* Exposed for user access */ +struct task_struct *kgdb_current; +unsigned int kgdb_g_imask; +int kgdb_trapa_val; +int kgdb_excode; + +/* Default values for SCI (can override via kernel args in setup.c) */ +#ifndef CONFIG_KGDB_DEFPORT +#define CONFIG_KGDB_DEFPORT 1 +#endif + +#ifndef CONFIG_KGDB_DEFBAUD +#define CONFIG_KGDB_DEFBAUD 115200 +#endif + +#if defined(CONFIG_KGDB_DEFPARITY_E) +#define CONFIG_KGDB_DEFPARITY 'E' +#elif defined(CONFIG_KGDB_DEFPARITY_O) +#define CONFIG_KGDB_DEFPARITY 'O' +#else /* CONFIG_KGDB_DEFPARITY_N */ +#define CONFIG_KGDB_DEFPARITY 'N' +#endif + +#ifdef CONFIG_KGDB_DEFBITS_7 +#define CONFIG_KGDB_DEFBITS '7' +#else /* CONFIG_KGDB_DEFBITS_8 */ +#define CONFIG_KGDB_DEFBITS '8' +#endif + +/* SCI/UART settings, used in kgdb_console_setup() */ +int kgdb_portnum = CONFIG_KGDB_DEFPORT; +int kgdb_baud = CONFIG_KGDB_DEFBAUD; +char kgdb_parity = CONFIG_KGDB_DEFPARITY; +char kgdb_bits = CONFIG_KGDB_DEFBITS; + +/* Jump buffer for setjmp/longjmp */ +static jmp_buf rem_com_env; + +/* TRA differs sh3/4 */ +#if defined(CONFIG_CPU_SH3) +#define TRA 0xffffffd0 +#elif defined(CONFIG_CPU_SH4) +#define TRA 0xff000020 +#endif + +/* Macros for single step instruction identification */ +#define OPCODE_BT(op) (((op) & 0xff00) == 0x8900) +#define OPCODE_BF(op) (((op) & 0xff00) == 0x8b00) +#define OPCODE_BTF_DISP(op) (((op) & 0x80) ? (((op) | 0xffffff80) << 1) : \ + (((op) & 0x7f ) << 1)) +#define OPCODE_BFS(op) (((op) & 0xff00) == 0x8f00) +#define OPCODE_BTS(op) (((op) & 0xff00) == 0x8d00) +#define OPCODE_BRA(op) (((op) & 0xf000) == 0xa000) +#define OPCODE_BRA_DISP(op) (((op) & 0x800) ? (((op) | 0xfffff800) << 1) : \ + (((op) & 0x7ff) << 1)) +#define OPCODE_BRAF(op) (((op) & 0xf0ff) == 0x0023) +#define OPCODE_BRAF_REG(op) (((op) & 0x0f00) >> 8) +#define OPCODE_BSR(op) (((op) & 0xf000) == 0xb000) +#define OPCODE_BSR_DISP(op) (((op) & 0x800) ? (((op) | 0xfffff800) << 1) : \ + (((op) & 0x7ff) << 1)) +#define OPCODE_BSRF(op) (((op) & 0xf0ff) == 0x0003) +#define OPCODE_BSRF_REG(op) (((op) >> 8) & 0xf) +#define OPCODE_JMP(op) (((op) & 0xf0ff) == 0x402b) +#define OPCODE_JMP_REG(op) (((op) >> 8) & 0xf) +#define OPCODE_JSR(op) (((op) & 0xf0ff) == 0x400b) +#define OPCODE_JSR_REG(op) (((op) >> 8) & 0xf) +#define OPCODE_RTS(op) ((op) == 0xb) +#define OPCODE_RTE(op) ((op) == 0x2b) + +#define SR_T_BIT_MASK 0x1 +#define STEP_OPCODE 0xc320 +#define BIOS_CALL_TRAP 0x3f + +/* Exception codes as per SH-4 core manual */ +#define ADDRESS_ERROR_LOAD_VEC 7 +#define ADDRESS_ERROR_STORE_VEC 8 +#define TRAP_VEC 11 +#define INVALID_INSN_VEC 12 +#define INVALID_SLOT_VEC 13 +#define NMI_VEC 14 +#define USER_BREAK_VEC 15 +#define SERIAL_BREAK_VEC 58 + +/* Misc static */ +static int stepped_address; +static short stepped_opcode; +static const char hexchars[] = "0123456789abcdef"; +static char in_buffer[BUFMAX]; +static char out_buffer[OUTBUFMAX]; + +static void kgdb_to_gdb(const char *s); + +#ifdef CONFIG_KGDB_THREAD +static struct task_struct *trapped_thread; +static struct task_struct *current_thread; +typedef unsigned char threadref[8]; +#define BUF_THREAD_ID_SIZE 16 +#endif + +/* Return addr as a real volatile address */ +static inline unsigned int ctrl_inl(const unsigned long addr) +{ + return *(volatile unsigned long *) addr; +} + +/* Correctly set *addr using volatile */ +static inline void ctrl_outl(const unsigned int b, unsigned long addr) +{ + *(volatile unsigned long *) addr = b; +} + +/* Get high hex bits */ +static char highhex(const int x) +{ + return hexchars[(x >> 4) & 0xf]; +} + +/* Get low hex bits */ +static char lowhex(const int x) +{ + return hexchars[x & 0xf]; +} + +/* Convert ch to hex */ +static int hex(const 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 hex, placing result in buf. + Returns a pointer to the last char put in buf (null) */ +static char *mem_to_hex(const char *mem, char *buf, const int count) +{ + int i; + int ch; + unsigned short s_val; + unsigned long l_val; + + /* Check for 16 or 32 */ + if (count == 2 && ((long) mem & 1) == 0) { + s_val = *(unsigned short *) mem; + mem = (char *) &s_val; + } else if (count == 4 && ((long) mem & 3) == 0) { + l_val = *(unsigned long *) mem; + mem = (char *) &l_val; + } + for (i = 0; i < count; i++) { + ch = *mem++; + *buf++ = highhex(ch); + *buf++ = lowhex(ch); + } + *buf = 0; + 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 */ +static char *hex_to_mem(const char *buf, char *mem, const 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); +} + +/* While finding valid hex chars, convert to an integer, then return it */ +static int hex_to_int(char **ptr, int *int_value) +{ + int num_chars = 0; + int hex_value; + + *int_value = 0; + + while (**ptr) { + hex_value = hex(**ptr); + if (hex_value >= 0) { + *int_value = (*int_value << 4) | hex_value; + num_chars++; + } else + break; + (*ptr)++; + } + return num_chars; +} + +/* Copy the binary array pointed to by buf into mem. Fix $, #, + and 0x7d escaped with 0x7d. Return a pointer to the character + after the last byte written. */ +static char *ebin_to_mem(const char *buf, char *mem, int count) +{ + for (; count > 0; count--, buf++) { + if (*buf == 0x7d) + *mem++ = *(++buf) ^ 0x20; + else + *mem++ = *buf; + } + return mem; +} + +/* Pack a hex byte */ +static char *pack_hex_byte(char *pkt, int byte) +{ + *pkt++ = hexchars[(byte >> 4) & 0xf]; + *pkt++ = hexchars[(byte & 0xf)]; + return pkt; +} + +#ifdef CONFIG_KGDB_THREAD + +/* Pack a thread ID */ +static char *pack_threadid(char *pkt, threadref * id) +{ + char *limit; + unsigned char *altid; + + altid = (unsigned char *) id; + + limit = pkt + BUF_THREAD_ID_SIZE; + while (pkt < limit) + pkt = pack_hex_byte(pkt, *altid++); + return pkt; +} + +/* Convert an integer into our threadref */ +static void int_to_threadref(threadref * id, const int value) +{ + unsigned char *scan = (unsigned char *) id; + int i = 4; + + while (i--) + *scan++ = 0; + + *scan++ = (value >> 24) & 0xff; + *scan++ = (value >> 16) & 0xff; + *scan++ = (value >> 8) & 0xff; + *scan++ = (value & 0xff); +} + +/* Return a task structure ptr for a particular pid */ +static struct task_struct *get_thread(int pid) +{ + struct task_struct *thread; + + /* Use PID_MAX w/gdb for pid 0 */ + if (pid == PID_MAX) pid = 0; + + /* First check via PID */ + thread = find_task_by_pid(pid); + + if (thread) + return thread; + + /* Start at the start */ + thread = init_tasks[0]; + + /* Walk along the linked list of tasks */ + do { + if (thread->pid == pid) + return thread; + thread = thread->next_task; + } while (thread != init_tasks[0]); + + return NULL; +} + +#endif /* CONFIG_KGDB_THREAD */ + +/* Scan for the start char '$', read the packet and check the checksum */ +static void get_packet(char *buffer, int buflen) +{ + unsigned char checksum; + unsigned char xmitcsum; + int i; + int count; + char ch; + + do { + /* Ignore everything until the start character */ + while ((ch = get_debug_char()) != '$'); + + checksum = 0; + xmitcsum = -1; + count = 0; + + /* Now, read until a # or end of buffer is found */ + while (count < (buflen - 1)) { + ch = get_debug_char(); + + if (ch == '#') + break; + + checksum = checksum + ch; + buffer[count] = ch; + count = count + 1; + } + + buffer[count] = 0; + + /* Continue to read checksum following # */ + if (ch == '#') { + xmitcsum = hex(get_debug_char()) << 4; + xmitcsum += hex(get_debug_char()); + + /* Checksum */ + if (checksum != xmitcsum) + put_debug_char('-'); /* Failed checksum */ + else { + /* Ack successful transfer */ + put_debug_char('+'); + + /* If a sequence char is present, reply + the sequence ID */ + if (buffer[2] == ':') { + put_debug_char(buffer[0]); + put_debug_char(buffer[1]); + + /* Remove sequence chars from buffer */ + count = strlen(buffer); + for (i = 3; i <= count; i++) + buffer[i - 3] = buffer[i]; + } + } + } + } + while (checksum != xmitcsum); /* Keep trying while we fail */ +} + +/* Send the packet in the buffer with run-length encoding */ +static void put_packet(char *buffer) +{ + int checksum; + char *src; + int runlen; + int encode; + + do { + src = buffer; + put_debug_char('$'); + checksum = 0; + + /* Continue while we still have chars left */ + while (*src) { + /* Check for runs up to 99 chars long */ + for (runlen = 1; runlen < 99; runlen++) { + if (src[0] != src[runlen]) + break; + } + + if (runlen > 3) { + /* Got a useful amount, send encoding */ + encode = runlen + ' ' - 4; + put_debug_char(*src); checksum += *src; + put_debug_char('*'); checksum += '*'; + put_debug_char(encode); checksum += encode; + src += runlen; + } else { + /* Otherwise just send the current char */ + put_debug_char(*src); checksum += *src; + src += 1; + } + } + + /* '#' Separator, put high and low components of checksum */ + put_debug_char('#'); + put_debug_char(highhex(checksum)); + put_debug_char(lowhex(checksum)); + } + while ((get_debug_char()) != '+'); /* While no ack */ +} + +/* A bus error has occurred - perform a longjmp to return execution and + allow handling of the error */ +static void kgdb_handle_bus_error(void) +{ + longjmp(rem_com_env, 1); +} + +/* Translate SH-3/4 exception numbers to unix-like signal values */ +static int compute_signal(const int excep_code) +{ + int sigval; + + switch (excep_code) { + + case INVALID_INSN_VEC: + case INVALID_SLOT_VEC: + sigval = SIGILL; + break; + case ADDRESS_ERROR_LOAD_VEC: + case ADDRESS_ERROR_STORE_VEC: + sigval = SIGSEGV; + break; + + case SERIAL_BREAK_VEC: + case NMI_VEC: + sigval = SIGINT; + break; + + case USER_BREAK_VEC: + case TRAP_VEC: + sigval = SIGTRAP; + break; + + default: + sigval = SIGBUS; /* "software generated" */ + break; + } + + return (sigval); +} + +/* Make a local copy of the registers passed into the handler (bletch) */ +static void kgdb_regs_to_gdb_regs(const struct kgdb_regs *regs, + int *gdb_regs) +{ + gdb_regs[R0] = regs->regs[R0]; + gdb_regs[R1] = regs->regs[R1]; + gdb_regs[R2] = regs->regs[R2]; + gdb_regs[R3] = regs->regs[R3]; + gdb_regs[R4] = regs->regs[R4]; + gdb_regs[R5] = regs->regs[R5]; + gdb_regs[R6] = regs->regs[R6]; + gdb_regs[R7] = regs->regs[R7]; + gdb_regs[R8] = regs->regs[R8]; + gdb_regs[R9] = regs->regs[R9]; + gdb_regs[R10] = regs->regs[R10]; + gdb_regs[R11] = regs->regs[R11]; + gdb_regs[R12] = regs->regs[R12]; + gdb_regs[R13] = regs->regs[R13]; + gdb_regs[R14] = regs->regs[R14]; + gdb_regs[R15] = regs->regs[R15]; + gdb_regs[PC] = regs->pc; + gdb_regs[PR] = regs->pr; + gdb_regs[GBR] = regs->gbr; + gdb_regs[MACH] = regs->mach; + gdb_regs[MACL] = regs->macl; + gdb_regs[SR] = regs->sr; + gdb_regs[VBR] = regs->vbr; +} + +/* Copy local gdb registers back to kgdb regs, for later copy to kernel */ +static void gdb_regs_to_kgdb_regs(const int *gdb_regs, + struct kgdb_regs *regs) +{ + regs->regs[R0] = gdb_regs[R0]; + regs->regs[R1] = gdb_regs[R1]; + regs->regs[R2] = gdb_regs[R2]; + regs->regs[R3] = gdb_regs[R3]; + regs->regs[R4] = gdb_regs[R4]; + regs->regs[R5] = gdb_regs[R5]; + regs->regs[R6] = gdb_regs[R6]; + regs->regs[R7] = gdb_regs[R7]; + regs->regs[R8] = gdb_regs[R8]; + regs->regs[R9] = gdb_regs[R9]; + regs->regs[R10] = gdb_regs[R10]; + regs->regs[R11] = gdb_regs[R11]; + regs->regs[R12] = gdb_regs[R12]; + regs->regs[R13] = gdb_regs[R13]; + regs->regs[R14] = gdb_regs[R14]; + regs->regs[R15] = gdb_regs[R15]; + regs->pc = gdb_regs[PC]; + regs->pr = gdb_regs[PR]; + regs->gbr = gdb_regs[GBR]; + regs->mach = gdb_regs[MACH]; + regs->macl = gdb_regs[MACL]; + regs->sr = gdb_regs[SR]; + regs->vbr = gdb_regs[VBR]; +} + +#ifdef CONFIG_KGDB_THREAD +/* Make a local copy of registers from the specified thread */ +asmlinkage void ret_from_fork(void); +static void thread_regs_to_gdb_regs(const struct task_struct *thread, + int *gdb_regs) +{ + int regno; + int *tregs; + + /* Initialize to zero */ + for (regno = 0; regno < MAXREG; regno++) + gdb_regs[regno] = 0; + + /* Just making sure... */ + if (thread == NULL) + return; + + /* A new fork has pt_regs on the stack from a fork() call */ + if (thread->thread.pc == (unsigned long)ret_from_fork) { + + int vbr_val; + struct pt_regs *kregs; + kregs = (struct pt_regs*)thread->thread.sp; + + gdb_regs[R0] = kregs->regs[R0]; + gdb_regs[R1] = kregs->regs[R1]; + gdb_regs[R2] = kregs->regs[R2]; + gdb_regs[R3] = kregs->regs[R3]; + gdb_regs[R4] = kregs->regs[R4]; + gdb_regs[R5] = kregs->regs[R5]; + gdb_regs[R6] = kregs->regs[R6]; + gdb_regs[R7] = kregs->regs[R7]; + gdb_regs[R8] = kregs->regs[R8]; + gdb_regs[R9] = kregs->regs[R9]; + gdb_regs[R10] = kregs->regs[R10]; + gdb_regs[R11] = kregs->regs[R11]; + gdb_regs[R12] = kregs->regs[R12]; + gdb_regs[R13] = kregs->regs[R13]; + gdb_regs[R14] = kregs->regs[R14]; + gdb_regs[R15] = kregs->regs[R15]; + gdb_regs[PC] = kregs->pc; + gdb_regs[PR] = kregs->pr; + gdb_regs[GBR] = kregs->gbr; + gdb_regs[MACH] = kregs->mach; + gdb_regs[MACL] = kregs->macl; + gdb_regs[SR] = kregs->sr; + + asm("stc vbr, %0":"=r"(vbr_val)); + gdb_regs[VBR] = vbr_val; + return; + } + + /* Otherwise, we have only some registers from switch_to() */ + tregs = (int *)thread->thread.sp; + gdb_regs[R15] = (int)tregs; + gdb_regs[R14] = *tregs++; + gdb_regs[R13] = *tregs++; + gdb_regs[R12] = *tregs++; + gdb_regs[R11] = *tregs++; + gdb_regs[R10] = *tregs++; + gdb_regs[R9] = *tregs++; + gdb_regs[R8] = *tregs++; + gdb_regs[PR] = *tregs++; + gdb_regs[GBR] = *tregs++; + gdb_regs[PC] = thread->thread.pc; +} +#endif /* CONFIG_KGDB_THREAD */ + +/* Calculate the new address for after a step */ +static short *get_step_address(void) +{ + short op = *(short *) trap_registers.pc; + long addr; + + /* BT */ + if (OPCODE_BT(op)) { + if (trap_registers.sr & SR_T_BIT_MASK) + addr = trap_registers.pc + 4 + OPCODE_BTF_DISP(op); + else + addr = trap_registers.pc + 2; + } + + /* BTS */ + else if (OPCODE_BTS(op)) { + if (trap_registers.sr & SR_T_BIT_MASK) + addr = trap_registers.pc + 4 + OPCODE_BTF_DISP(op); + else + addr = trap_registers.pc + 4; /* Not in delay slot */ + } + + /* BF */ + else if (OPCODE_BF(op)) { + if (!(trap_registers.sr & SR_T_BIT_MASK)) + addr = trap_registers.pc + 4 + OPCODE_BTF_DISP(op); + else + addr = trap_registers.pc + 2; + } + + /* BFS */ + else if (OPCODE_BFS(op)) { + if (!(trap_registers.sr & SR_T_BIT_MASK)) + addr = trap_registers.pc + 4 + OPCODE_BTF_DISP(op); + else + addr = trap_registers.pc + 4; /* Not in delay slot */ + } + + /* BRA */ + else if (OPCODE_BRA(op)) + addr = trap_registers.pc + 4 + OPCODE_BRA_DISP(op); + + /* BRAF */ + else if (OPCODE_BRAF(op)) + addr = trap_registers.pc + 4 + + trap_registers.regs[OPCODE_BRAF_REG(op)]; + + /* BSR */ + else if (OPCODE_BSR(op)) + addr = trap_registers.pc + 4 + OPCODE_BSR_DISP(op); + + /* BSRF */ + else if (OPCODE_BSRF(op)) + addr = trap_registers.pc + 4 + + trap_registers.regs[OPCODE_BSRF_REG(op)]; + + /* JMP */ + else if (OPCODE_JMP(op)) + addr = trap_registers.regs[OPCODE_JMP_REG(op)]; + + /* JSR */ + else if (OPCODE_JSR(op)) + addr = trap_registers.regs[OPCODE_JSR_REG(op)]; + + /* RTS */ + else if (OPCODE_RTS(op)) + addr = trap_registers.pr; + + /* RTE */ + else if (OPCODE_RTE(op)) + addr = trap_registers.regs[15]; + + /* Other */ + else + addr = trap_registers.pc + 2; + + kgdb_flush_icache_range(addr, addr + 2); + return (short *) addr; +} + +/* Set up a single-step. Replace the instruction immediately after the + current instruction (i.e. next in the expected flow of control) with a + trap instruction, so that returning will cause only a single instruction + to be executed. Note that this model is slightly broken for instructions + with delay slots (e.g. B[TF]S, BSR, BRA etc), where both the branch + and the instruction in the delay slot will be executed. */ +static void do_single_step(void) +{ + unsigned short *addr = 0; + + /* Determine where the target instruction will send us to */ + addr = get_step_address(); + stepped_address = (int)addr; + + /* Replace it */ + stepped_opcode = *(short *)addr; + *addr = STEP_OPCODE; + + /* Flush and return */ + kgdb_flush_icache_range((long) addr, (long) addr + 2); + return; +} + +/* Undo a single step */ +static void undo_single_step(void) +{ + /* If we have stepped, put back the old instruction */ + /* Use stepped_address in case we stopped elsewhere */ + if (stepped_opcode != 0) { + *(short*)stepped_address = stepped_opcode; + kgdb_flush_icache_range(stepped_address, stepped_address + 2); + } + stepped_opcode = 0; +} + +/* Send a signal message */ +static void send_signal_msg(const int signum) +{ +#ifndef CONFIG_KGDB_THREAD + out_buffer[0] = 'S'; + out_buffer[1] = highhex(signum); + out_buffer[2] = lowhex(signum); + out_buffer[3] = 0; + put_packet(out_buffer); +#else /* CONFIG_KGDB_THREAD */ + int threadid; + threadref thref; + char *out = out_buffer; + const char *tstring = "thread"; + + *out++ = 'T'; + *out++ = highhex(signum); + *out++ = lowhex(signum); + + while (*tstring) { + *out++ = *tstring++; + } + *out++ = ':'; + + threadid = trapped_thread->pid; + if (threadid == 0) threadid = PID_MAX; + int_to_threadref(&thref, threadid); + pack_threadid(out, &thref); + out += BUF_THREAD_ID_SIZE; + *out++ = ';'; + + *out = 0; + put_packet(out_buffer); +#endif /* CONFIG_KGDB_THREAD */ +} + +/* Reply that all was well */ +static void send_ok_msg(void) +{ + strcpy(out_buffer, "OK"); + put_packet(out_buffer); +} + +/* Reply that an error occurred */ +static void send_err_msg(void) +{ + strcpy(out_buffer, "E01"); + put_packet(out_buffer); +} + +/* Empty message indicates unrecognised command */ +static void send_empty_msg(void) +{ + put_packet(""); +} + +/* Read memory due to 'm' message */ +static void read_mem_msg(void) +{ + char *ptr; + int addr; + int length; + + /* Jmp, disable bus error handler */ + if (setjmp(rem_com_env) == 0) { + + kgdb_nofault = 1; + + /* Walk through, have m<addr>,<length> */ + ptr = &in_buffer[1]; + if (hex_to_int(&ptr, &addr) && (*ptr++ == ',')) + if (hex_to_int(&ptr, &length)) { + ptr = 0; + if (length * 2 > OUTBUFMAX) + length = OUTBUFMAX / 2; + mem_to_hex((char *) addr, out_buffer, length); + } + if (ptr) + send_err_msg(); + else + put_packet(out_buffer); + } else + send_err_msg(); + + /* Restore bus error handler */ + kgdb_nofault = 0; +} + +/* Write memory due to 'M' or 'X' message */ +static void write_mem_msg(int binary) +{ + char *ptr; + int addr; + int length; + + if (setjmp(rem_com_env) == 0) { + + kgdb_nofault = 1; + + /* Walk through, have M<addr>,<length>:<data> */ + ptr = &in_buffer[1]; + if (hex_to_int(&ptr, &addr) && (*ptr++ == ',')) + if (hex_to_int(&ptr, &length) && (*ptr++ == ':')) { + if (binary) + ebin_to_mem(ptr, (char*)addr, length); + else + hex_to_mem(ptr, (char*)addr, length); + kgdb_flush_icache_range(addr, addr + length); + ptr = 0; + send_ok_msg(); + } + if (ptr) + send_err_msg(); + } else + send_err_msg(); + + /* Restore bus error handler */ + kgdb_nofault = 0; +} + +/* Continue message */ +static void continue_msg(void) +{ + /* Try to read optional parameter, PC unchanged if none */ + char *ptr = &in_buffer[1]; + int addr; + + if (hex_to_int(&ptr, &addr)) + trap_registers.pc = addr; +} + +/* Continue message with signal */ +static void continue_with_sig_msg(void) +{ + int signal; + char *ptr = &in_buffer[1]; + int addr; + + /* Report limitation */ + kgdb_to_gdb("Cannot force signal in kgdb, continuing anyway.\n"); + + /* Signal */ + hex_to_int(&ptr, &signal); + if (*ptr == ';') + ptr++; + + /* Optional address */ + if (hex_to_int(&ptr, &addr)) + trap_registers.pc = addr; +} + +/* Step message */ +static void step_msg(void) +{ + continue_msg(); + do_single_step(); +} + +/* Step message with signal */ +static void step_with_sig_msg(void) +{ + continue_with_sig_msg(); + do_single_step(); +} + +/* Send register contents */ +static void send_regs_msg(void) +{ +#ifdef CONFIG_KGDB_THREAD + if (!current_thread) + kgdb_regs_to_gdb_regs(&trap_registers, registers); + else + thread_regs_to_gdb_regs(current_thread, registers); +#else + kgdb_regs_to_gdb_regs(&trap_registers, registers); +#endif + + mem_to_hex((char *) registers, out_buffer, NUMREGBYTES); + put_packet(out_buffer); +} + +/* Set register contents - currently can't set other thread's registers */ +static void set_regs_msg(void) +{ +#ifdef CONFIG_KGDB_THREAD + if (!current_thread) { +#endif + kgdb_regs_to_gdb_regs(&trap_registers, registers); + hex_to_mem(&in_buffer[1], (char *) registers, NUMREGBYTES); + gdb_regs_to_kgdb_regs(registers, &trap_registers); + send_ok_msg(); +#ifdef CONFIG_KGDB_THREAD + } else + send_err_msg(); +#endif +} + + +#ifdef CONFIG_KGDB_THREAD + +/* Set the status for a thread */ +void set_thread_msg(void) +{ + int threadid; + struct task_struct *thread = NULL; + char *ptr; + + switch (in_buffer[1]) { + + /* To select which thread for gG etc messages, i.e. supported */ + case 'g': + + ptr = &in_buffer[2]; + hex_to_int(&ptr, &threadid); + thread = get_thread(threadid); + + /* If we haven't found it */ + if (!thread) { + send_err_msg(); + break; + } + + /* Set current_thread (or not) */ + if (thread == trapped_thread) + current_thread = NULL; + else + current_thread = thread; + send_ok_msg(); + break; + + /* To select which thread for cCsS messages, i.e. unsupported */ + case 'c': + send_ok_msg(); + break; + + default: + send_empty_msg(); + break; + } +} + +/* Is a thread alive? */ +static void thread_status_msg(void) +{ + char *ptr; + int threadid; + struct task_struct *thread = NULL; + + ptr = &in_buffer[1]; + hex_to_int(&ptr, &threadid); + thread = get_thread(threadid); + if (thread) + send_ok_msg(); + else + send_err_msg(); +} +/* Send the current thread ID */ +static void thread_id_msg(void) +{ + int threadid; + threadref thref; + + out_buffer[0] = 'Q'; + out_buffer[1] = 'C'; + + if (current_thread) + threadid = current_thread->pid; + else if (trapped_thread) + threadid = trapped_thread->pid; + else /* Impossible, but just in case! */ + { + send_err_msg(); + return; + } + + /* Translate pid 0 to PID_MAX for gdb */ + if (threadid == 0) threadid = PID_MAX; + + int_to_threadref(&thref, threadid); + pack_threadid(out_buffer + 2, &thref); + out_buffer[2 + BUF_THREAD_ID_SIZE] = '\0'; + put_packet(out_buffer); +} + +/* Send thread info */ +static void thread_info_msg(void) +{ + struct task_struct *thread = NULL; + int threadid; + char *pos; + threadref thref; + + /* Start with 'm' */ + out_buffer[0] = 'm'; + pos = &out_buffer[1]; + + /* For all possible thread IDs - this will overrun if > 44 threads! */ + /* Start at 1 and include PID_MAX (since GDB won't use pid 0...) */ + for (threadid = 1; threadid <= PID_MAX; threadid++) { + + read_lock(&tasklist_lock); + thread = get_thread(threadid); + read_unlock(&tasklist_lock); + + /* If it's a valid thread */ + if (thread) { + int_to_threadref(&thref, threadid); + pack_threadid(pos, &thref); + pos += BUF_THREAD_ID_SIZE; + *pos++ = ','; + } + } + *--pos = 0; /* Lose final comma */ + put_packet(out_buffer); + +} + +/* Return printable info for gdb's 'info threads' command */ +static void thread_extra_info_msg(void) +{ + int threadid; + struct task_struct *thread = NULL; + char buffer[20], *ptr; + int i; + + /* Extract thread ID */ + ptr = &in_buffer[17]; + hex_to_int(&ptr, &threadid); + thread = get_thread(threadid); + + /* If we don't recognise it, say so */ + if (thread == NULL) + strcpy(buffer, "(unknown)"); + else + strcpy(buffer, thread->comm); + + /* Construct packet */ + for (i = 0, ptr = out_buffer; buffer[i]; i++) + ptr = pack_hex_byte(ptr, buffer[i]); + + if (thread->thread.pc == (unsigned long)ret_from_fork) { + strcpy(buffer, "<new fork>"); + for (i = 0; buffer[i]; i++) + ptr = pack_hex_byte(ptr, buffer[i]); + } + + *ptr = '\0'; + put_packet(out_buffer); +} + +/* Handle all qFooBarBaz messages - have to use an if statement as + opposed to a switch because q messages can have > 1 char id. */ +static void query_msg(void) +{ + const char *q_start = &in_buffer[1]; + + /* qC = return current thread ID */ + if (strncmp(q_start, "C", 1) == 0) + thread_id_msg(); + + /* qfThreadInfo = query all threads (first) */ + else if (strncmp(q_start, "fThreadInfo", 11) == 0) + thread_info_msg(); + + /* qsThreadInfo = query all threads (subsequent). We know we have sent + them all after the qfThreadInfo message, so there are no to send */ + else if (strncmp(q_start, "sThreadInfo", 11) == 0) + put_packet("l"); /* el = last */ + + /* qThreadExtraInfo = supply printable information per thread */ + else if (strncmp(q_start, "ThreadExtraInfo", 15) == 0) + thread_extra_info_msg(); + + /* Unsupported - empty message as per spec */ + else + send_empty_msg(); +} +#endif /* CONFIG_KGDB_THREAD */ + +/* + * Bring up the ports.. + */ +static int kgdb_serial_setup(void) +{ + extern int kgdb_console_setup(struct console *co, char *options); + struct console dummy; + + kgdb_console_setup(&dummy, 0); + + return 0; +} + +/* The command loop, read and act on requests */ +static void kgdb_command_loop(const int excep_code, const int trapa_value) +{ + int sigval; + + if (excep_code == NMI_VEC) { +#ifndef CONFIG_KGDB_NMI + KGDB_PRINTK("Ignoring unexpected NMI?\n"); + return; +#else /* CONFIG_KGDB_NMI */ + if (!kgdb_enabled) { + kgdb_enabled = 1; + kgdb_init(); + } +#endif /* CONFIG_KGDB_NMI */ + } + + /* Ignore if we're disabled */ + if (!kgdb_enabled) + return; + +#ifdef CONFIG_KGDB_THREAD + /* Until GDB specifies a thread */ + current_thread = NULL; + trapped_thread = current; +#endif + + /* Enter GDB mode (e.g. after detach) */ + if (!kgdb_in_gdb_mode) { + /* Do serial setup, notify user, issue preemptive ack */ + kgdb_serial_setup(); + KGDB_PRINTK("Waiting for GDB (on %s%d at %d baud)\n", + (kgdb_porttype ? kgdb_porttype->name : ""), + kgdb_portnum, kgdb_baud); + kgdb_in_gdb_mode = 1; + put_debug_char('+'); + } + + /* Reply to host that an exception has occurred */ + sigval = compute_signal(excep_code); + send_signal_msg(sigval); + + /* TRAP_VEC exception indicates a software trap inserted in place of + code by GDB so back up PC by one instruction, as this instruction + will later be replaced by its original one. Do NOT do this for + trap 0xff, since that indicates a compiled-in breakpoint which + will not be replaced (and we would retake the trap forever) */ + if ((excep_code == TRAP_VEC) && (trapa_value != (0xff << 2))) { + trap_registers.pc -= 2; + } + + /* Undo any stepping we may have done */ + undo_single_step(); + + while (1) { + + out_buffer[0] = 0; + get_packet(in_buffer, BUFMAX); + + /* Examine first char of buffer to see what we need to do */ + switch (in_buffer[0]) { + + case '?': /* Send which signal we've received */ + send_signal_msg(sigval); + break; + + case 'g': /* Return the values of the CPU registers */ + send_regs_msg(); + break; + + case 'G': /* Set the value of the CPU registers */ + set_regs_msg(); + break; + + case 'm': /* Read LLLL bytes address AA..AA */ + read_mem_msg(); + break; + + case 'M': /* Write LLLL bytes address AA..AA, ret OK */ + write_mem_msg(0); /* 0 = data in hex */ + break; + + case 'X': /* Write LLLL bytes esc bin address AA..AA */ + if (kgdb_bits == '8') + write_mem_msg(1); /* 1 = data in binary */ + else + send_empty_msg(); + break; + + case 'C': /* Continue, signum included, we ignore it */ + continue_with_sig_msg(); + return; + + case 'c': /* Continue at address AA..AA (optional) */ + continue_msg(); + return; + + case 'S': /* Step, signum included, we ignore it */ + step_with_sig_msg(); + return; + + case 's': /* Step one instruction from AA..AA */ + step_msg(); + return; + +#ifdef CONFIG_KGDB_THREAD + + case 'H': /* Task related */ + set_thread_msg(); + break; + + case 'T': /* Query thread status */ + thread_status_msg(); + break; + + case 'q': /* Handle query - currently thread-related */ + query_msg(); + break; +#endif + + case 'k': /* 'Kill the program' with a kernel ? */ + break; + + case 'D': /* Detach from program, send reply OK */ + kgdb_in_gdb_mode = 0; + send_ok_msg(); + get_debug_char(); + return; + + default: + send_empty_msg(); + break; + } + } +} + +/* There has been an exception, most likely a breakpoint. */ +void kgdb_handle_exception(struct pt_regs *regs) +{ + int excep_code, vbr_val; + int count; + int trapa_value = ctrl_inl(TRA); + + /* Copy kernel regs (from stack) */ + for (count = 0; count < 16; count++) + trap_registers.regs[count] = regs->regs[count]; + trap_registers.pc = regs->pc; + trap_registers.pr = regs->pr; + trap_registers.sr = regs->sr; + trap_registers.gbr = regs->gbr; + trap_registers.mach = regs->mach; + trap_registers.macl = regs->macl; + + asm("stc vbr, %0":"=r"(vbr_val)); + trap_registers.vbr = vbr_val; + + /* Get excode for command loop call, user access */ + asm("stc r2_bank, %0":"=r"(excep_code)); + kgdb_excode = excep_code; + + /* Other interesting environment items for reference */ + asm("stc r6_bank, %0":"=r"(kgdb_g_imask)); + kgdb_current = current; + kgdb_trapa_val = trapa_value; + + /* Act on the exception */ + kgdb_command_loop(excep_code >> 5, trapa_value); + + kgdb_current = NULL; + + /* Copy back the (maybe modified) registers */ + for (count = 0; count < 16; count++) + regs->regs[count] = trap_registers.regs[count]; + regs->pc = trap_registers.pc; + regs->pr = trap_registers.pr; + regs->sr = trap_registers.sr; + regs->gbr = trap_registers.gbr; + regs->mach = trap_registers.mach; + regs->macl = trap_registers.macl; + + vbr_val = trap_registers.vbr; + asm("ldc %0, vbr": :"r"(vbr_val)); + + return; +} + +/* Trigger a breakpoint by function */ +void breakpoint(void) +{ + if (!kgdb_enabled) { + kgdb_enabled = 1; + kgdb_init(); + } + BREAKPOINT(); +} + +/* Initialise the KGDB data structures and serial configuration */ +int kgdb_init(void) +{ + if (!kgdb_enabled) + return 1; + + in_nmi = 0; + kgdb_nofault = 0; + stepped_opcode = 0; + kgdb_in_gdb_mode = 0; + + if (kgdb_serial_setup() != 0) { + KGDB_PRINTK("serial setup error\n"); + return -1; + } + + /* Init ptr to exception handler */ + kgdb_debug_hook = kgdb_handle_exception; + kgdb_bus_err_hook = kgdb_handle_bus_error; + + /* Enter kgdb now if requested, or just report init done */ + if (kgdb_halt) { + kgdb_in_gdb_mode = 1; + put_debug_char('+'); + breakpoint(); + } + else + { + KGDB_PRINTK("stub is initialized.\n"); + } + + return 0; +} + +/* Make function available for "user messages"; console will use it too. */ + +char gdbmsgbuf[BUFMAX]; +#define MAXOUT ((BUFMAX-2)/2) + +static void kgdb_msg_write(const char *s, unsigned count) +{ + int i; + int wcount; + char *bufptr; + + /* 'O'utput */ + gdbmsgbuf[0] = 'O'; + + /* Fill and send buffers... */ + while (count > 0) { + bufptr = gdbmsgbuf + 1; + + /* Calculate how many this time */ + wcount = (count > MAXOUT) ? MAXOUT : count; + + /* Pack in hex chars */ + for (i = 0; i < wcount; i++) + bufptr = pack_hex_byte(bufptr, s[i]); + *bufptr = '\0'; + + /* Move up */ + s += wcount; + count -= wcount; + + /* Write packet */ + put_packet(gdbmsgbuf); + } +} + +static void kgdb_to_gdb(const char *s) +{ + kgdb_msg_write(s, strlen(s)); +} + +#ifdef CONFIG_SH_KGDB_CONSOLE +void kgdb_console_write(struct console *co, const char *s, unsigned count) +{ + /* Bail if we're not talking to GDB */ + if (!kgdb_in_gdb_mode) + return; + + kgdb_msg_write(s, count); +} +#endif |
