diff options
| -rw-r--r-- | include/linux/kgdb.h | 1 | ||||
| -rw-r--r-- | kernel/debug/Makefile | 3 | ||||
| -rw-r--r-- | kernel/debug/debug_core.c | 994 | ||||
| -rw-r--r-- | kernel/debug/debug_core.h | 55 | ||||
| -rw-r--r-- | kernel/debug/gdbstub.c | 934 |
5 files changed, 1030 insertions, 957 deletions
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index 19ec41a..4830142 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -264,6 +264,7 @@ extern unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs); extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops); extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops); +extern struct kgdb_io *dbg_io_ops; extern int kgdb_hex2long(char **ptr, unsigned long *long_val); extern int kgdb_mem2hex(char *mem, char *buf, int count); diff --git a/kernel/debug/Makefile b/kernel/debug/Makefile index 5d78504..fd4dc6e 100644 --- a/kernel/debug/Makefile +++ b/kernel/debug/Makefile @@ -2,5 +2,4 @@ # Makefile for the linux kernel debugger # -obj-$(CONFIG_KGDB) += debug_core.o - +obj-$(CONFIG_KGDB) += debug_core.o gdbstub.o diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 11f3515..7e03969 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -1,5 +1,5 @@ /* - * KGDB stub. + * Kernel Debug Core * * Maintainer: Jason Wessel <jason.wessel@windriver.com> * @@ -9,7 +9,7 @@ * Copyright (C) 2004 Pavel Machek <pavel@suse.cz> * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org> * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. - * Copyright (C) 2005-2008 Wind River Systems, Inc. + * Copyright (C) 2005-2009 Wind River Systems, Inc. * Copyright (C) 2007 MontaVista Software, Inc. * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> * @@ -37,7 +37,6 @@ #include <linux/kernel.h> #include <linux/module.h> #include <linux/ptrace.h> -#include <linux/reboot.h> #include <linux/string.h> #include <linux/delay.h> #include <linux/sched.h> @@ -52,34 +51,12 @@ #include <asm/byteorder.h> #include <asm/atomic.h> #include <asm/system.h> -#include <asm/unaligned.h> -static int kgdb_break_asap; - -#define KGDB_MAX_THREAD_QUERY 17 -struct kgdb_state { - int ex_vector; - int signo; - int err_code; - int cpu; - int pass_exception; - unsigned long thr_query; - unsigned long threadid; - long kgdb_usethreadid; - struct pt_regs *linux_regs; -}; +#include "debug_core.h" -/* Exception state values */ -#define DCPU_WANT_MASTER 0x1 /* Waiting to become a master kgdb cpu */ -#define DCPU_NEXT_MASTER 0x2 /* Transition from one master cpu to another */ -#define DCPU_IS_SLAVE 0x4 /* Slave cpu enter exception */ -#define DCPU_SSTEP 0x8 /* CPU is single stepping */ +static int kgdb_break_asap; -static struct debuggerinfo_struct { - void *debuggerinfo; - struct task_struct *task; - int exception_state; -} kgdb_info[NR_CPUS]; +struct debuggerinfo_struct kgdb_info[NR_CPUS]; /** * kgdb_connected - Is a host GDB connected to us? @@ -93,7 +70,7 @@ static int kgdb_io_module_registered; /* Guard for recursive entry */ static int exception_level; -static struct kgdb_io *kgdb_io_ops; +struct kgdb_io *dbg_io_ops; static DEFINE_SPINLOCK(kgdb_registration_lock); /* kgdb console driver is loaded */ @@ -136,16 +113,7 @@ struct task_struct *kgdb_usethread; struct task_struct *kgdb_contthread; int kgdb_single_step; -pid_t kgdb_sstep_pid; - -/* Our I/O buffers. */ -static char remcom_in_buffer[BUFMAX]; -static char remcom_out_buffer[BUFMAX]; - -/* Storage for the registers, in GDB format. */ -static unsigned long gdb_regs[(NUMREGBYTES + - sizeof(unsigned long) - 1) / - sizeof(unsigned long)]; +static pid_t kgdb_sstep_pid; /* to keep track of the CPU which is doing the single stepping*/ atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); @@ -247,324 +215,6 @@ void __weak kgdb_disable_hw_debug(struct pt_regs *regs) } /* - * GDB remote protocol parser: - */ - -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; -} - -/* scan for the sequence $<data>#<checksum> */ -static void get_packet(char *buffer) -{ - unsigned char checksum; - unsigned char xmitcsum; - int count; - char ch; - - do { - /* - * Spin and wait around for the start character, ignore all - * other characters: - */ - while ((ch = (kgdb_io_ops->read_char())) != '$') - /* nothing */; - - kgdb_connected = 1; - checksum = 0; - xmitcsum = -1; - - count = 0; - - /* - * now, read until a # or end of buffer is found: - */ - while (count < (BUFMAX - 1)) { - ch = kgdb_io_ops->read_char(); - if (ch == '#') - break; - checksum = checksum + ch; - buffer[count] = ch; - count = count + 1; - } - buffer[count] = 0; - - if (ch == '#') { - xmitcsum = hex(kgdb_io_ops->read_char()) << 4; - xmitcsum += hex(kgdb_io_ops->read_char()); - - if (checksum != xmitcsum) - /* failed checksum */ - kgdb_io_ops->write_char('-'); - else - /* successful transfer */ - kgdb_io_ops->write_char('+'); - if (kgdb_io_ops->flush) - kgdb_io_ops->flush(); - } - } while (checksum != xmitcsum); -} - -/* - * Send the packet in buffer. - * Check for gdb connection if asked for. - */ -static void put_packet(char *buffer) -{ - unsigned char checksum; - int count; - char ch; - - /* - * $<packet info>#<checksum>. - */ - while (1) { - kgdb_io_ops->write_char('$'); - checksum = 0; - count = 0; - - while ((ch = buffer[count])) { - kgdb_io_ops->write_char(ch); - checksum += ch; - count++; - } - - kgdb_io_ops->write_char('#'); - kgdb_io_ops->write_char(hex_asc_hi(checksum)); - kgdb_io_ops->write_char(hex_asc_lo(checksum)); - if (kgdb_io_ops->flush) - kgdb_io_ops->flush(); - - /* Now see what we get in reply. */ - ch = kgdb_io_ops->read_char(); - - if (ch == 3) - ch = kgdb_io_ops->read_char(); - - /* If we get an ACK, we are done. */ - if (ch == '+') - return; - - /* - * If we get the start of another packet, this means - * that GDB is attempting to reconnect. We will NAK - * the packet being sent, and stop trying to send this - * packet. - */ - if (ch == '$') { - kgdb_io_ops->write_char('-'); - if (kgdb_io_ops->flush) - kgdb_io_ops->flush(); - return; - } - } -} - -/* - * Convert the memory pointed to by mem into hex, placing result in buf. - * Return a pointer to the last char put in buf (null). May return an error. - */ -int kgdb_mem2hex(char *mem, char *buf, int count) -{ - char *tmp; - int err; - - /* - * We use the upper half of buf as an intermediate buffer for the - * raw memory copy. Hex conversion will work against this one. - */ - tmp = buf + count; - - err = probe_kernel_read(tmp, mem, count); - if (!err) { - while (count > 0) { - buf = pack_hex_byte(buf, *tmp); - tmp++; - count--; - } - - *buf = 0; - } - - return err; -} - -/* - * Copy the binary array pointed to by buf into mem. Fix $, #, and - * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success. - * The input buf is overwitten with the result to write to mem. - */ -static int kgdb_ebin2mem(char *buf, char *mem, int count) -{ - int size = 0; - char *c = buf; - - while (count-- > 0) { - c[size] = *buf++; - if (c[size] == 0x7d) - c[size] = *buf++ ^ 0x20; - size++; - } - - return probe_kernel_write(mem, c, size); -} - -/* - * Convert the hex array pointed to by buf into binary to be placed in mem. - * Return a pointer to the character AFTER the last byte written. - * May return an error. - */ -int kgdb_hex2mem(char *buf, char *mem, int count) -{ - char *tmp_raw; - char *tmp_hex; - - /* - * We use the upper half of buf as an intermediate buffer for the - * raw memory that is converted from hex. - */ - tmp_raw = buf + count * 2; - - tmp_hex = tmp_raw - 1; - while (tmp_hex >= buf) { - tmp_raw--; - *tmp_raw = hex(*tmp_hex--); - *tmp_raw |= hex(*tmp_hex--) << 4; - } - - return probe_kernel_write(mem, tmp_raw, count); -} - -/* - * While we find nice hex chars, build a long_val. - * Return number of chars processed. - */ -int kgdb_hex2long(char **ptr, unsigned long *long_val) -{ - int hex_val; - int num = 0; - int negate = 0; - - *long_val = 0; - - if (**ptr == '-') { - negate = 1; - (*ptr)++; - } - while (**ptr) { - hex_val = hex(**ptr); - if (hex_val < 0) - break; - - *long_val = (*long_val << 4) | hex_val; - num++; - (*ptr)++; - } - - if (negate) - *long_val = -*long_val; - - return num; -} - -/* Write memory due to an 'M' or 'X' packet. */ -static int write_mem_msg(int binary) -{ - char *ptr = &remcom_in_buffer[1]; - unsigned long addr; - unsigned long length; - int err; - - if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && - kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { - if (binary) - err = kgdb_ebin2mem(ptr, (char *)addr, length); - else - err = kgdb_hex2mem(ptr, (char *)addr, length); - if (err) - return err; - if (CACHE_FLUSH_IS_SAFE) - flush_icache_range(addr, addr + length); - return 0; - } - - return -EINVAL; -} - -static void error_packet(char *pkt, int error) -{ - error = -error; - pkt[0] = 'E'; - pkt[1] = hex_asc[(error / 10)]; - pkt[2] = hex_asc[(error % 10)]; - pkt[3] = '\0'; -} - -/* - * Thread ID accessors. We represent a flat TID space to GDB, where - * the per CPU idle threads (which under Linux all have PID 0) are - * remapped to negative TIDs. - */ - -#define BUF_THREAD_ID_SIZE 16 - -static char *pack_threadid(char *pkt, unsigned char *id) -{ - char *limit; - - limit = pkt + BUF_THREAD_ID_SIZE; - while (pkt < limit) - pkt = pack_hex_byte(pkt, *id++); - - return pkt; -} - -static void int_to_threadref(unsigned char *id, int value) -{ - unsigned char *scan; - int i = 4; - - scan = (unsigned char *)id; - while (i--) - *scan++ = 0; - put_unaligned_be32(value, scan); -} - -static struct task_struct *getthread(struct pt_regs *regs, int tid) -{ - /* - * Non-positive TIDs are remapped to the cpu shadow information - */ - if (tid == 0 || tid == -1) - tid = -atomic_read(&kgdb_active) - 2; - if (tid < -1 && tid > -NR_CPUS - 2) { - if (kgdb_info[-tid - 2].task) - return kgdb_info[-tid - 2].task; - else - return idle_task(-tid - 2); - } - if (tid <= 0) { - printk(KERN_ERR "KGDB: Internal thread select error\n"); - dump_stack(); - return NULL; - } - - /* - * find_task_by_pid_ns() does not take the tasklist lock anymore - * but is nicely RCU locked - hence is a pretty resilient - * thing to use: - */ - return find_task_by_pid_ns(tid, &init_pid_ns); -} - -/* * Some architectures need cache flushes when we set/clear a * breakpoint: */ @@ -584,7 +234,7 @@ static void kgdb_flush_swbreak_addr(unsigned long addr) /* * SW breakpoint management: */ -static int kgdb_activate_sw_breakpoints(void) +int dbg_activate_sw_breakpoints(void) { unsigned long addr; int error; @@ -610,7 +260,7 @@ static int kgdb_activate_sw_breakpoints(void) return ret; } -static int kgdb_set_sw_break(unsigned long addr) +int dbg_set_sw_break(unsigned long addr) { int err = kgdb_validate_break_address(addr); int breakno = -1; @@ -675,7 +325,7 @@ static int kgdb_deactivate_sw_breakpoints(void) return ret; } -static int kgdb_remove_sw_break(unsigned long addr) +int dbg_remove_sw_break(unsigned long addr) { int i; @@ -701,7 +351,7 @@ int kgdb_isremovedbreak(unsigned long addr) return 0; } -static int remove_all_break(void) +int dbg_remove_all_break(void) { unsigned long addr; int error; @@ -729,53 +379,6 @@ setundefined: } /* - * Remap normal tasks to their real PID, - * CPU shadow threads are mapped to -CPU - 2 - */ -static inline int shadow_pid(int realpid) -{ - if (realpid) - return realpid; - - return -raw_smp_processor_id() - 2; -} - -static char gdbmsgbuf[BUFMAX + 1]; - -static void kgdb_msg_write(const char *s, int len) -{ - char *bufptr; - int wcount; - int i; - - /* 'O'utput */ - gdbmsgbuf[0] = 'O'; - - /* Fill and send buffers... */ - while (len > 0) { - bufptr = gdbmsgbuf + 1; - - /* Calculate how many this time */ - if ((len << 1) > (BUFMAX - 2)) - wcount = (BUFMAX - 2) >> 1; - else - wcount = len; - - /* Pack in hex chars */ - for (i = 0; i < wcount; i++) - bufptr = pack_hex_byte(bufptr, s[i]); - *bufptr = '\0'; - - /* Move up */ - s += wcount; - len -= wcount; - - /* Write packet */ - put_packet(gdbmsgbuf); - } -} - -/* * Return true if there is a valid kgdb I/O module. Also if no * debugger is attached a message can be printed to the console about * waiting for the debugger to attach. @@ -786,7 +389,7 @@ static void kgdb_msg_write(const char *s, int len) */ static int kgdb_io_ready(int print_wait) { - if (!kgdb_io_ops) + if (!dbg_io_ops) return 0; if (kgdb_connected) return 1; @@ -797,525 +400,6 @@ static int kgdb_io_ready(int print_wait) return 1; } -/* - * All the functions that start with gdb_cmd are the various - * operations to implement the handlers for the gdbserial protocol - * where KGDB is communicating with an external debugger - */ - -/* Handle the '?' status packets */ -static void gdb_cmd_status(struct kgdb_state *ks) -{ - /* - * We know that this packet is only sent - * during initial connect. So to be safe, - * we clear out our breakpoints now in case - * GDB is reconnecting. - */ - remove_all_break(); - - remcom_out_buffer[0] = 'S'; - pack_hex_byte(&remcom_out_buffer[1], ks->signo); -} - -/* Handle the 'g' get registers request */ -static void gdb_cmd_getregs(struct kgdb_state *ks) -{ - struct task_struct *thread; - void *local_debuggerinfo; - int i; - - thread = kgdb_usethread; - if (!thread) { - thread = kgdb_info[ks->cpu].task; - local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; - } else { - local_debuggerinfo = NULL; - for_each_online_cpu(i) { - /* - * Try to find the task on some other - * or possibly this node if we do not - * find the matching task then we try - * to approximate the results. - */ - if (thread == kgdb_info[i].task) - local_debuggerinfo = kgdb_info[i].debuggerinfo; - } - } - - /* - * All threads that don't have debuggerinfo should be - * in schedule() sleeping, since all other CPUs - * are in kgdb_wait, and thus have debuggerinfo. - */ - if (local_debuggerinfo) { - pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); - } else { - /* - * Pull stuff saved during switch_to; nothing - * else is accessible (or even particularly - * relevant). - * - * This should be enough for a stack trace. - */ - sleeping_thread_to_gdb_regs(gdb_regs, thread); - } - kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); -} - -/* Handle the 'G' set registers request */ -static void gdb_cmd_setregs(struct kgdb_state *ks) -{ - kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); - - if (kgdb_usethread && kgdb_usethread != current) { - error_packet(remcom_out_buffer, -EINVAL); - } else { - gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); - strcpy(remcom_out_buffer, "OK"); - } -} - -/* Handle the 'm' memory read bytes */ -static void gdb_cmd_memread(struct kgdb_state *ks) -{ - char *ptr = &remcom_in_buffer[1]; - unsigned long length; - unsigned long addr; - int err; - - if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && - kgdb_hex2long(&ptr, &length) > 0) { - err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); - if (err) - error_packet(remcom_out_buffer, err); - } else { - error_packet(remcom_out_buffer, -EINVAL); - } -} - -/* Handle the 'M' memory write bytes */ -static void gdb_cmd_memwrite(struct kgdb_state *ks) -{ - int err = write_mem_msg(0); - - if (err) - error_packet(remcom_out_buffer, err); - else - strcpy(remcom_out_buffer, "OK"); -} - -/* Handle the 'X' memory binary write bytes */ -static void gdb_cmd_binwrite(struct kgdb_state *ks) -{ - int err = write_mem_msg(1); - - if (err) - error_packet(remcom_out_buffer, err); - else - strcpy(remcom_out_buffer, "OK"); -} - -/* Handle the 'D' or 'k', detach or kill packets */ -static void gdb_cmd_detachkill(struct kgdb_state *ks) -{ - int error; - - /* The detach case */ - if (remcom_in_buffer[0] == 'D') { - error = remove_all_break(); - if (error < 0) { - error_packet(remcom_out_buffer, error); - } else { - strcpy(remcom_out_buffer, "OK"); - kgdb_connected = 0; - } - put_packet(remcom_out_buffer); - } else { - /* - * Assume the kill case, with no exit code checking, - * trying to force detach the debugger: - */ - remove_all_break(); - kgdb_connected = 0; - } -} - -/* Handle the 'R' reboot packets */ -static int gdb_cmd_reboot(struct kgdb_state *ks) -{ - /* For now, only honor R0 */ - if (strcmp(remcom_in_buffer, "R0") == 0) { - printk(KERN_CRIT "Executing emergency reboot\n"); - strcpy(remcom_out_buffer, "OK"); - put_packet(remcom_out_buffer); - - /* - * Execution should not return from - * machine_emergency_restart() - */ - machine_emergency_restart(); - kgdb_connected = 0; - - return 1; - } - return 0; -} - -/* Handle the 'q' query packets */ -static void gdb_cmd_query(struct kgdb_state *ks) -{ - struct task_struct *g; - struct task_struct *p; - unsigned char thref[8]; - char *ptr; - int i; - int cpu; - int finished = 0; - - switch (remcom_in_buffer[1]) { - case 's': - case 'f': - if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) { - error_packet(remcom_out_buffer, -EINVAL); - break; - } - - i = 0; - remcom_out_buffer[0] = 'm'; - ptr = remcom_out_buffer + 1; - if (remcom_in_buffer[1] == 'f') { - /* Each cpu is a shadow thread */ - for_each_online_cpu(cpu) { - ks->thr_query = 0; - int_to_threadref(thref, -cpu - 2); - pack_threadid(ptr, thref); - ptr += BUF_THREAD_ID_SIZE; - *(ptr++) = ','; - i++; - } - } - - do_each_thread(g, p) { - if (i >= ks->thr_query && !finished) { - int_to_threadref(thref, p->pid); - pack_threadid(ptr, thref); - ptr += BUF_THREAD_ID_SIZE; - *(ptr++) = ','; - ks->thr_query++; - if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0) - finished = 1; - } - i++; - } while_each_thread(g, p); - - *(--ptr) = '\0'; - break; - - case 'C': - /* Current thread id */ - strcpy(remcom_out_buffer, "QC"); - ks->threadid = shadow_pid(current->pid); - int_to_threadref(thref, ks->threadid); - pack_threadid(remcom_out_buffer + 2, thref); - break; - case 'T': - if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) { - error_packet(remcom_out_buffer, -EINVAL); - break; - } - ks->threadid = 0; - ptr = remcom_in_buffer + 17; - kgdb_hex2long(&ptr, &ks->threadid); - if (!getthread(ks->linux_regs, ks->threadid)) { - error_packet(remcom_out_buffer, -EINVAL); - break; - } - if ((int)ks->threadid > 0) { - kgdb_mem2hex(getthread(ks->linux_regs, - ks->threadid)->comm, - remcom_out_buffer, 16); - } else { - static char tmpstr[23 + BUF_THREAD_ID_SIZE]; - - sprintf(tmpstr, "shadowCPU%d", - (int)(-ks->threadid - 2)); - kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr)); - } - break; - } -} - -/* Handle the 'H' task query packets */ -static void gdb_cmd_task(struct kgdb_state *ks) -{ - struct task_struct *thread; - char *ptr; - - switch (remcom_in_buffer[1]) { - case 'g': - ptr = &remcom_in_buffer[2]; - kgdb_hex2long(&ptr, &ks->threadid); - thread = getthread(ks->linux_regs, ks->threadid); - if (!thread && ks->threadid > 0) { - error_packet(remcom_out_buffer, -EINVAL); - break; - } - kgdb_usethread = thread; - ks->kgdb_usethreadid = ks->threadid; - strcpy(remcom_out_buffer, "OK"); - break; - case 'c': - ptr = &remcom_in_buffer[2]; - kgdb_hex2long(&ptr, &ks->threadid); - if (!ks->threadid) { - kgdb_contthread = NULL; - } else { - thread = getthread(ks->linux_regs, ks->threadid); - if (!thread && ks->threadid > 0) { - error_packet(remcom_out_buffer, -EINVAL); - break; - } - kgdb_contthread = thread; - } - strcpy(remcom_out_buffer, "OK"); - break; - } -} - -/* Handle the 'T' thread query packets */ -static void gdb_cmd_thread(struct kgdb_state *ks) -{ - char *ptr = &remcom_in_buffer[1]; - struct task_struct *thread; - - kgdb_hex2long(&ptr, &ks->threadid); - thread = getthread(ks->linux_regs, ks->threadid); - if (thread) - strcpy(remcom_out_buffer, "OK"); - else - error_packet(remcom_out_buffer, -EINVAL); -} - -/* Handle the 'z' or 'Z' breakpoint remove or set packets */ -static void gdb_cmd_break(struct kgdb_state *ks) -{ - /* - * Since GDB-5.3, it's been drafted that '0' is a software - * breakpoint, '1' is a hardware breakpoint, so let's do that. - */ - char *bpt_type = &remcom_in_buffer[1]; - char *ptr = &remcom_in_buffer[2]; - unsigned long addr; - unsigned long length; - int error = 0; - - if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { - /* Unsupported */ - if (*bpt_type > '4') - return; - } else { - if (*bpt_type != '0' && *bpt_type != '1') - /* Unsupported. */ - return; - } - - /* - * Test if this is a hardware breakpoint, and - * if we support it: - */ - if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) - /* Unsupported. */ - return; - - if (*(ptr++) != ',') { - error_packet(remcom_out_buffer, -EINVAL); - return; - } - if (!kgdb_hex2long(&ptr, &addr)) { - error_packet(remcom_out_buffer, -EINVAL); - return; - } - if (*(ptr++) != ',' || - !kgdb_hex2long(&ptr, &length)) { - error_packet(remcom_out_buffer, -EINVAL); - return; - } - - if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') - error = kgdb_set_sw_break(addr); - else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') - error = kgdb_remove_sw_break(addr); - else if (remcom_in_buffer[0] == 'Z') - error = arch_kgdb_ops.set_hw_breakpoint(addr, - (int)length, *bpt_type - '0'); - else if (remcom_in_buffer[0] == 'z') - error = arch_kgdb_ops.remove_hw_breakpoint(addr, - (int) length, *bpt_type - '0'); - - if (error == 0) - strcpy(remcom_out_buffer, "OK"); - else - error_packet(remcom_out_buffer, error); -} - -/* Handle the 'C' signal / exception passing packets */ -static int gdb_cmd_exception_pass(struct kgdb_state *ks) -{ - /* C09 == pass exception - * C15 == detach kgdb, pass exception - */ - if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { - - ks->pass_exception = 1; - remcom_in_buffer[0] = 'c'; - - } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { - - ks->pass_exception = 1; - remcom_in_buffer[0] = 'D'; - remove_all_break(); - kgdb_connected = 0; - return 1; - - } else { - kgdb_msg_write("KGDB only knows signal 9 (pass)" - " and 15 (pass and disconnect)\n" - "Executing a continue without signal passing\n", 0); - remcom_in_buffer[0] = 'c'; - } - - /* Indicate fall through */ - return -1; -} - -/* - * This function performs all gdbserial command procesing - */ -static int gdb_serial_stub(struct kgdb_state *ks) -{ - int error = 0; - int tmp; - - /* Clear the out buffer. */ - memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); - - if (kgdb_connected) { - unsigned char thref[8]; - char *ptr; - - /* Reply to host that an exception has occurred */ - ptr = remcom_out_buffer; - *ptr++ = 'T'; - ptr = pack_hex_byte(ptr, ks->signo); - ptr += strlen(strcpy(ptr, "thread:")); - int_to_threadref(thref, shadow_pid(current->pid)); - ptr = pack_threadid(ptr, thref); - *ptr++ = ';'; - put_packet(remcom_out_buffer); - } - - kgdb_usethread = kgdb_info[ks->cpu].task; - ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid); - ks->pass_exception = 0; - - while (1) { - error = 0; - - /* Clear the out buffer. */ - memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); - - get_packet(remcom_in_buffer); - - switch (remcom_in_buffer[0]) { - case '?': /* gdbserial status */ - gdb_cmd_status(ks); - break; - case 'g': /* return the value of the CPU registers */ - gdb_cmd_getregs(ks); - break; - case 'G': /* set the value of the CPU registers - return OK */ - gdb_cmd_setregs(ks); - break; - case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ - gdb_cmd_memread(ks); - break; - case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */ - gdb_cmd_memwrite(ks); - break; - case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */ - gdb_cmd_binwrite(ks); - break; - /* kill or detach. KGDB should treat this like a - * continue. - */ - case 'D': /* Debugger detach */ - case 'k': /* Debugger detach via kill */ - gdb_cmd_detachkill(ks); - goto default_handle; - case 'R': /* Reboot */ - if (gdb_cmd_reboot(ks)) - goto default_handle; - break; - case 'q': /* query command */ - gdb_cmd_query(ks); - break; - case 'H': /* task related */ - gdb_cmd_task(ks); - break; - case 'T': /* Query thread status */ - gdb_cmd_thread(ks); - break; - case 'z': /* Break point remove */ - case 'Z': /* Break point set */ - gdb_cmd_break(ks); - break; - case 'C': /* Exception passing */ - tmp = gdb_cmd_exception_pass(ks); - if (tmp > 0) - goto default_handle; - if (tmp == 0) - break; - /* Fall through on tmp < 0 */ - case 'c': /* Continue packet */ - case 's': /* Single step packet */ - if (kgdb_contthread && kgdb_contthread != current) { - /* Can't switch threads in kgdb */ - error_packet(remcom_out_buffer, -EINVAL); - break; - } - kgdb_activate_sw_breakpoints(); - /* Fall through to default processing */ - default: -default_handle: - error = kgdb_arch_handle_exception(ks->ex_vector, - ks->signo, - ks->err_code, - remcom_in_buffer, - remcom_out_buffer, - ks->linux_regs); - /* - * Leave cmd processing on error, detach, - * kill, continue, or single step. - */ - if (error >= 0 || remcom_in_buffer[0] == 'D' || - remcom_in_buffer[0] == 'k') { - error = 0; - goto kgdb_exit; - } - - } - - /* reply to the request */ - put_packet(remcom_out_buffer); - } - -kgdb_exit: - if (ks->pass_exception) - error = 1; - return error; -} - static int kgdb_reenter_check(struct kgdb_state *ks) { unsigned long addr; @@ -1334,17 +418,17 @@ static int kgdb_reenter_check(struct kgdb_state *ks) * user because the user planted a breakpoint in a place that * KGDB needs in order to function. */ - if (kgdb_remove_sw_break(addr) == 0) { + if (dbg_remove_sw_break(addr) == 0) { exception_level = 0; kgdb_skipexception(ks->ex_vector, ks->linux_regs); - kgdb_activate_sw_breakpoints(); + dbg_activate_sw_breakpoints(); printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n", addr); WARN_ON_ONCE(1); return 1; } - remove_all_break(); + dbg_remove_all_break(); kgdb_skipexception(ks->ex_vector, ks->linux_regs); if (exception_level > 1) { @@ -1430,7 +514,7 @@ return_normal: if (!kgdb_io_ready(1)) { error = 1; - goto kgdb_restore; /* No I/O connection, so resume the system */ + goto kgdb_restore; /* No I/O connection, resume the system */ } /* @@ -1440,8 +524,8 @@ return_normal: goto kgdb_restore; /* Call the I/O driver's pre_exception routine */ - if (kgdb_io_ops->pre_exception) - kgdb_io_ops->pre_exception(); + if (dbg_io_ops->pre_exception) + dbg_io_ops->pre_exception(); kgdb_disable_hw_debug(ks->linux_regs); @@ -1485,8 +569,8 @@ return_normal: error = gdb_serial_stub(ks); /* Call the I/O driver's post_exception routine */ - if (kgdb_io_ops->post_exception) - kgdb_io_ops->post_exception(); + if (dbg_io_ops->post_exception) + dbg_io_ops->post_exception(); atomic_dec(&cpu_in_kgdb[ks->cpu]); @@ -1585,7 +669,7 @@ static void kgdb_console_write(struct console *co, const char *s, return; local_irq_save(flags); - kgdb_msg_write(s, count); + gdbstub_msg_write(s, count); local_irq_restore(flags); } @@ -1597,9 +681,9 @@ static struct console kgdbcons = { }; #ifdef CONFIG_MAGIC_SYSRQ -static void sysrq_handle_gdb(int key, struct tty_struct *tty) +static void sysrq_handle_dbg(int key, struct tty_struct *tty) { - if (!kgdb_io_ops) { + if (!dbg_io_ops) { printk(KERN_CRIT "ERROR: No KGDB I/O module available\n"); return; } @@ -1609,8 +693,8 @@ static void sysrq_handle_gdb(int key, struct tty_struct *tty) kgdb_breakpoint(); } -static struct sysrq_key_op sysrq_gdb_op = { - .handler = sysrq_handle_gdb, +static struct sysrq_key_op sysrq_dbg_op = { + .handler = sysrq_handle_dbg, .help_msg = "debug(G)", .action_msg = "DEBUG", }; @@ -1622,7 +706,7 @@ static void kgdb_register_callbacks(void) kgdb_io_module_registered = 1; kgdb_arch_init(); #ifdef CONFIG_MAGIC_SYSRQ - register_sysrq_key('g', &sysrq_gdb_op); + register_sysrq_key('g', &sysrq_dbg_op); #endif if (kgdb_use_con && !kgdb_con_registered) { register_console(&kgdbcons); @@ -1642,7 +726,7 @@ static void kgdb_unregister_callbacks(void) kgdb_io_module_registered = 0; kgdb_arch_exit(); #ifdef CONFIG_MAGIC_SYSRQ - unregister_sysrq_key('g', &sysrq_gdb_op); + unregister_sysrq_key('g', &sysrq_dbg_op); #endif if (kgdb_con_registered) { unregister_console(&kgdbcons); @@ -1661,17 +745,17 @@ static void kgdb_initial_breakpoint(void) /** * kgdb_register_io_module - register KGDB IO module - * @new_kgdb_io_ops: the io ops vector + * @new_dbg_io_ops: the io ops vector * * Register it with the KGDB core. */ -int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops) +int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops) { int err; spin_lock(&kgdb_registration_lock); - if (kgdb_io_ops) { + if (dbg_io_ops) { spin_unlock(&kgdb_registration_lock); printk(KERN_ERR "kgdb: Another I/O driver is already " @@ -1679,20 +763,20 @@ int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops) return -EBUSY; } - if (new_kgdb_io_ops->init) { - err = new_kgdb_io_ops->init(); + if (new_dbg_io_ops->init) { + err = new_dbg_io_ops->init(); if (err) { spin_unlock(&kgdb_registration_lock); return err; } } - kgdb_io_ops = new_kgdb_io_ops; + dbg_io_ops = new_dbg_io_ops; spin_unlock(&kgdb_registration_lock); printk(KERN_INFO "kgdb: Registered I/O driver %s.\n", - new_kgdb_io_ops->name); + new_dbg_io_ops->name); /* Arm KGDB now. */ kgdb_register_callbacks(); @@ -1706,11 +790,11 @@ EXPORT_SYMBOL_GPL(kgdb_register_io_module); /** * kkgdb_unregister_io_module - unregister KGDB IO module - * @old_kgdb_io_ops: the io ops vector + * @old_dbg_io_ops: the io ops vector * * Unregister it with the KGDB core. */ -void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops) +void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) { BUG_ON(kgdb_connected); @@ -1722,14 +806,14 @@ void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops) spin_lock(&kgdb_registration_lock); - WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops); - kgdb_io_ops = NULL; + WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops); + dbg_io_ops = NULL; spin_unlock(&kgdb_registration_lock); printk(KERN_INFO "kgdb: Unregistered I/O driver %s, debugger disabled.\n", - old_kgdb_io_ops->name); + old_dbg_io_ops->name); } EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); diff --git a/kernel/debug/debug_core.h b/kernel/debug/debug_core.h new file mode 100644 index 0000000..db554f9 --- /dev/null +++ b/kernel/debug/debug_core.h @@ -0,0 +1,55 @@ +/* + * Created by: Jason Wessel <jason.wessel@windriver.com> + * + * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#ifndef _DEBUG_CORE_H_ +#define _DEBUG_CORE_H_ +/* + * These are the private implementation headers between the kernel + * debugger core and the debugger front end code. + */ + +/* kernel debug core data structures */ +struct kgdb_state { + int ex_vector; + int signo; + int err_code; + int cpu; + int pass_exception; + unsigned long thr_query; + unsigned long threadid; + long kgdb_usethreadid; + struct pt_regs *linux_regs; +}; + +/* Exception state values */ +#define DCPU_WANT_MASTER 0x1 /* Waiting to become a master kgdb cpu */ +#define DCPU_NEXT_MASTER 0x2 /* Transition from one master cpu to another */ +#define DCPU_IS_SLAVE 0x4 /* Slave cpu enter exception */ +#define DCPU_SSTEP 0x8 /* CPU is single stepping */ + +struct debuggerinfo_struct { + void *debuggerinfo; + struct task_struct *task; + int exception_state; +}; + +extern struct debuggerinfo_struct kgdb_info[]; + +/* kernel debug core break point routines */ +extern int dbg_remove_all_break(void); +extern int dbg_set_sw_break(unsigned long addr); +extern int dbg_remove_sw_break(unsigned long addr); +extern int dbg_activate_sw_breakpoints(void); + +/* gdbstub interface functions */ +extern int gdb_serial_stub(struct kgdb_state *ks); +extern void gdbstub_msg_write(const char *s, int len); + +#endif /* _DEBUG_CORE_H_ */ diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c new file mode 100644 index 0000000..ccdf092 --- /dev/null +++ b/kernel/debug/gdbstub.c @@ -0,0 +1,934 @@ +/* + * Kernel Debug Core + * + * Maintainer: Jason Wessel <jason.wessel@windriver.com> + * + * Copyright (C) 2000-2001 VERITAS Software Corporation. + * Copyright (C) 2002-2004 Timesys Corporation + * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com> + * Copyright (C) 2004 Pavel Machek <pavel@suse.cz> + * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org> + * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. + * Copyright (C) 2005-2009 Wind River Systems, Inc. + * Copyright (C) 2007 MontaVista Software, Inc. + * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> + * + * Contributors at various stages not listed above: + * Jason Wessel ( jason.wessel@windriver.com ) + * George Anzinger <george@mvista.com> + * Anurekh Saxena (anurekh.saxena@timesys.com) + * Lake Stevens Instrument Division (Glenn Engel) + * Jim Kingdon, Cygnus Support. + * + * Original KGDB stub: David Grothe <dave@gcom.com>, + * Tigran Aivazian <tigran@sco.com> + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#include <linux/kernel.h> +#include <linux/kgdb.h> +#include <linux/reboot.h> +#include <linux/uaccess.h> +#include <asm/cacheflush.h> +#include <asm/unaligned.h> +#include "debug_core.h" + +#define KGDB_MAX_THREAD_QUERY 17 + +/* Our I/O buffers. */ +static char remcom_in_buffer[BUFMAX]; +static char remcom_out_buffer[BUFMAX]; + +/* Storage for the registers, in GDB format. */ +static unsigned long gdb_regs[(NUMREGBYTES + + sizeof(unsigned long) - 1) / + sizeof(unsigned long)]; + +/* + * GDB remote protocol parser: + */ + +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; +} + +/* scan for the sequence $<data>#<checksum> */ +static void get_packet(char *buffer) +{ + unsigned char checksum; + unsigned char xmitcsum; + int count; + char ch; + + do { + /* + * Spin and wait around for the start character, ignore all + * other characters: + */ + while ((ch = (dbg_io_ops->read_char())) != '$') + /* nothing */; + + kgdb_connected = 1; + checksum = 0; + xmitcsum = -1; + + count = 0; + + /* + * now, read until a # or end of buffer is found: + */ + while (count < (BUFMAX - 1)) { + ch = dbg_io_ops->read_char(); + if (ch == '#') + break; + checksum = checksum + ch; + buffer[count] = ch; + count = count + 1; + } + buffer[count] = 0; + + if (ch == '#') { + xmitcsum = hex(dbg_io_ops->read_char()) << 4; + xmitcsum += hex(dbg_io_ops->read_char()); + + if (checksum != xmitcsum) + /* failed checksum */ + dbg_io_ops->write_char('-'); + else + /* successful transfer */ + dbg_io_ops->write_char('+'); + if (dbg_io_ops->flush) + dbg_io_ops->flush(); + } + } while (checksum != xmitcsum); +} + +/* + * Send the packet in buffer. + * Check for gdb connection if asked for. + */ +static void put_packet(char *buffer) +{ + unsigned char checksum; + int count; + char ch; + + /* + * $<packet info>#<checksum>. + */ + while (1) { + dbg_io_ops->write_char('$'); + checksum = 0; + count = 0; + + while ((ch = buffer[count])) { + dbg_io_ops->write_char(ch); + checksum += ch; + count++; + } + + dbg_io_ops->write_char('#'); + dbg_io_ops->write_char(hex_asc_hi(checksum)); + dbg_io_ops->write_char(hex_asc_lo(checksum)); + if (dbg_io_ops->flush) + dbg_io_ops->flush(); + + /* Now see what we get in reply. */ + ch = dbg_io_ops->read_char(); + + if (ch == 3) + ch = dbg_io_ops->read_char(); + + /* If we get an ACK, we are done. */ + if (ch == '+') + return; + + /* + * If we get the start of another packet, this means + * that GDB is attempting to reconnect. We will NAK + * the packet being sent, and stop trying to send this + * packet. + */ + if (ch == '$') { + dbg_io_ops->write_char('-'); + if (dbg_io_ops->flush) + dbg_io_ops->flush(); + return; + } + } +} + +static char gdbmsgbuf[BUFMAX + 1]; + +void gdbstub_msg_write(const char *s, int len) +{ + char *bufptr; + int wcount; + int i; + + /* 'O'utput */ + gdbmsgbuf[0] = 'O'; + + /* Fill and send buffers... */ + while (len > 0) { + bufptr = gdbmsgbuf + 1; + + /* Calculate how many this time */ + if ((len << 1) > (BUFMAX - 2)) + wcount = (BUFMAX - 2) >> 1; + else + wcount = len; + + /* Pack in hex chars */ + for (i = 0; i < wcount; i++) + bufptr = pack_hex_byte(bufptr, s[i]); + *bufptr = '\0'; + + /* Move up */ + s += wcount; + len -= wcount; + + /* Write packet */ + put_packet(gdbmsgbuf); + } +} + +/* + * Convert the memory pointed to by mem into hex, placing result in + * buf. Return a pointer to the last char put in buf (null). May + * return an error. + */ +int kgdb_mem2hex(char *mem, char *buf, int count) +{ + char *tmp; + int err; + + /* + * We use the upper half of buf as an intermediate buffer for the + * raw memory copy. Hex conversion will work against this one. + */ + tmp = buf + count; + + err = probe_kernel_read(tmp, mem, count); + if (!err) { + while (count > 0) { + buf = pack_hex_byte(buf, *tmp); + tmp++; + count--; + } + + *buf = 0; + } + + return err; +} + +/* + * Convert the hex array pointed to by buf into binary to be placed in + * mem. Return a pointer to the character AFTER the last byte + * written. May return an error. + */ +int kgdb_hex2mem(char *buf, char *mem, int count) +{ + char *tmp_raw; + char *tmp_hex; + + /* + * We use the upper half of buf as an intermediate buffer for the + * raw memory that is converted from hex. + */ + tmp_raw = buf + count * 2; + + tmp_hex = tmp_raw - 1; + while (tmp_hex >= buf) { + tmp_raw--; + *tmp_raw = hex(*tmp_hex--); + *tmp_raw |= hex(*tmp_hex--) << 4; + } + + return probe_kernel_write(mem, tmp_raw, count); +} + +/* + * While we find nice hex chars, build a long_val. + * Return number of chars processed. + */ +int kgdb_hex2long(char **ptr, unsigned long *long_val) +{ + int hex_val; + int num = 0; + int negate = 0; + + *long_val = 0; + + if (**ptr == '-') { + negate = 1; + (*ptr)++; + } + while (**ptr) { + hex_val = hex(**ptr); + if (hex_val < 0) + break; + + *long_val = (*long_val << 4) | hex_val; + num++; + (*ptr)++; + } + + if (negate) + *long_val = -*long_val; + + return num; +} + +/* + * Copy the binary array pointed to by buf into mem. Fix $, #, and + * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success. + * The input buf is overwitten with the result to write to mem. + */ +static int kgdb_ebin2mem(char *buf, char *mem, int count) +{ + int size = 0; + char *c = buf; + + while (count-- > 0) { + c[size] = *buf++; + if (c[size] == 0x7d) + c[size] = *buf++ ^ 0x20; + size++; + } + + return probe_kernel_write(mem, c, size); +} + +/* Write memory due to an 'M' or 'X' packet. */ +static int write_mem_msg(int binary) +{ + char *ptr = &remcom_in_buffer[1]; + unsigned long addr; + unsigned long length; + int err; + + if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && + kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { + if (binary) + err = kgdb_ebin2mem(ptr, (char *)addr, length); + else + err = kgdb_hex2mem(ptr, (char *)addr, length); + if (err) + return err; + if (CACHE_FLUSH_IS_SAFE) + flush_icache_range(addr, addr + length); + return 0; + } + + return -EINVAL; +} + +static void error_packet(char *pkt, int error) +{ + error = -error; + pkt[0] = 'E'; + pkt[1] = hex_asc[(error / 10)]; + pkt[2] = hex_asc[(error % 10)]; + pkt[3] = '\0'; +} + +/* + * Thread ID accessors. We represent a flat TID space to GDB, where + * the per CPU idle threads (which under Linux all have PID 0) are + * remapped to negative TIDs. + */ + +#define BUF_THREAD_ID_SIZE 16 + +static char *pack_threadid(char *pkt, unsigned char *id) +{ + char *limit; + + limit = pkt + BUF_THREAD_ID_SIZE; + while (pkt < limit) + pkt = pack_hex_byte(pkt, *id++); + + return pkt; +} + +static void int_to_threadref(unsigned char *id, int value) +{ + unsigned char *scan; + int i = 4; + + scan = (unsigned char *)id; + while (i--) + *scan++ = 0; + put_unaligned_be32(value, scan); +} + +static struct task_struct *getthread(struct pt_regs *regs, int tid) +{ + /* + * Non-positive TIDs are remapped to the cpu shadow information + */ + if (tid == 0 || tid == -1) + tid = -atomic_read(&kgdb_active) - 2; + if (tid < -1 && tid > -NR_CPUS - 2) { + if (kgdb_info[-tid - 2].task) + return kgdb_info[-tid - 2].task; + else + return idle_task(-tid - 2); + } + if (tid <= 0) { + printk(KERN_ERR "KGDB: Internal thread select error\n"); + dump_stack(); + return NULL; + } + + /* + * find_task_by_pid_ns() does not take the tasklist lock anymore + * but is nicely RCU locked - hence is a pretty resilient + * thing to use: + */ + return find_task_by_pid_ns(tid, &init_pid_ns); +} + + +/* + * Remap normal tasks to their real PID, + * CPU shadow threads are mapped to -CPU - 2 + */ +static inline int shadow_pid(int realpid) +{ + if (realpid) + return realpid; + + return -raw_smp_processor_id() - 2; +} + +/* + * All the functions that start with gdb_cmd are the various + * operations to implement the handlers for the gdbserial protocol + * where KGDB is communicating with an external debugger + */ + +/* Handle the '?' status packets */ +static void gdb_cmd_status(struct kgdb_state *ks) +{ + /* + * We know that this packet is only sent + * during initial connect. So to be safe, + * we clear out our breakpoints now in case + * GDB is reconnecting. + */ + dbg_remove_all_break(); + + remcom_out_buffer[0] = 'S'; + pack_hex_byte(&remcom_out_buffer[1], ks->signo); +} + +/* Handle the 'g' get registers request */ +static void gdb_cmd_getregs(struct kgdb_state *ks) +{ + struct task_struct *thread; + void *local_debuggerinfo; + int i; + + thread = kgdb_usethread; + if (!thread) { + thread = kgdb_info[ks->cpu].task; + local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; + } else { + local_debuggerinfo = NULL; + for_each_online_cpu(i) { + /* + * Try to find the task on some other + * or possibly this node if we do not + * find the matching task then we try + * to approximate the results. + */ + if (thread == kgdb_info[i].task) + local_debuggerinfo = kgdb_info[i].debuggerinfo; + } + } + + /* + * All threads that don't have debuggerinfo should be + * in schedule() sleeping, since all other CPUs + * are in kgdb_wait, and thus have debuggerinfo. + */ + if (local_debuggerinfo) { + pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); + } else { + /* + * Pull stuff saved during switch_to; nothing + * else is accessible (or even particularly + * relevant). + * + * This should be enough for a stack trace. + */ + sleeping_thread_to_gdb_regs(gdb_regs, thread); + } + kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); +} + +/* Handle the 'G' set registers request */ +static void gdb_cmd_setregs(struct kgdb_state *ks) +{ + kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); + + if (kgdb_usethread && kgdb_usethread != current) { + error_packet(remcom_out_buffer, -EINVAL); + } else { + gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); + strcpy(remcom_out_buffer, "OK"); + } +} + +/* Handle the 'm' memory read bytes */ +static void gdb_cmd_memread(struct kgdb_state *ks) +{ + char *ptr = &remcom_in_buffer[1]; + unsigned long length; + unsigned long addr; + int err; + + if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && + kgdb_hex2long(&ptr, &length) > 0) { + err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); + if (err) + error_packet(remcom_out_buffer, err); + } else { + error_packet(remcom_out_buffer, -EINVAL); + } +} + +/* Handle the 'M' memory write bytes */ +static void gdb_cmd_memwrite(struct kgdb_state *ks) +{ + int err = write_mem_msg(0); + + if (err) + error_packet(remcom_out_buffer, err); + else + strcpy(remcom_out_buffer, "OK"); +} + +/* Handle the 'X' memory binary write bytes */ +static void gdb_cmd_binwrite(struct kgdb_state *ks) +{ + int err = write_mem_msg(1); + + if (err) + error_packet(remcom_out_buffer, err); + else + strcpy(remcom_out_buffer, "OK"); +} + +/* Handle the 'D' or 'k', detach or kill packets */ +static void gdb_cmd_detachkill(struct kgdb_state *ks) +{ + int error; + + /* The detach case */ + if (remcom_in_buffer[0] == 'D') { + error = dbg_remove_all_break(); + if (error < 0) { + error_packet(remcom_out_buffer, error); + } else { + strcpy(remcom_out_buffer, "OK"); + kgdb_connected = 0; + } + put_packet(remcom_out_buffer); + } else { + /* + * Assume the kill case, with no exit code checking, + * trying to force detach the debugger: + */ + dbg_remove_all_break(); + kgdb_connected = 0; + } +} + +/* Handle the 'R' reboot packets */ +static int gdb_cmd_reboot(struct kgdb_state *ks) +{ + /* For now, only honor R0 */ + if (strcmp(remcom_in_buffer, "R0") == 0) { + printk(KERN_CRIT "Executing emergency reboot\n"); + strcpy(remcom_out_buffer, "OK"); + put_packet(remcom_out_buffer); + + /* + * Execution should not return from + * machine_emergency_restart() + */ + machine_emergency_restart(); + kgdb_connected = 0; + + return 1; + } + return 0; +} + +/* Handle the 'q' query packets */ +static void gdb_cmd_query(struct kgdb_state *ks) +{ + struct task_struct *g; + struct task_struct *p; + unsigned char thref[8]; + char *ptr; + int i; + int cpu; + int finished = 0; + + switch (remcom_in_buffer[1]) { + case 's': + case 'f': + if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + + i = 0; + remcom_out_buffer[0] = 'm'; + ptr = remcom_out_buffer + 1; + if (remcom_in_buffer[1] == 'f') { + /* Each cpu is a shadow thread */ + for_each_online_cpu(cpu) { + ks->thr_query = 0; + int_to_threadref(thref, -cpu - 2); + pack_threadid(ptr, thref); + ptr += BUF_THREAD_ID_SIZE; + *(ptr++) = ','; + i++; + } + } + + do_each_thread(g, p) { + if (i >= ks->thr_query && !finished) { + int_to_threadref(thref, p->pid); + pack_threadid(ptr, thref); + ptr += BUF_THREAD_ID_SIZE; + *(ptr++) = ','; + ks->thr_query++; + if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0) + finished = 1; + } + i++; + } while_each_thread(g, p); + + *(--ptr) = '\0'; + break; + + case 'C': + /* Current thread id */ + strcpy(remcom_out_buffer, "QC"); + ks->threadid = shadow_pid(current->pid); + int_to_threadref(thref, ks->threadid); + pack_threadid(remcom_out_buffer + 2, thref); + break; + case 'T': + if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + ks->threadid = 0; + ptr = remcom_in_buffer + 17; + kgdb_hex2long(&ptr, &ks->threadid); + if (!getthread(ks->linux_regs, ks->threadid)) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + if ((int)ks->threadid > 0) { + kgdb_mem2hex(getthread(ks->linux_regs, + ks->threadid)->comm, + remcom_out_buffer, 16); + } else { + static char tmpstr[23 + BUF_THREAD_ID_SIZE]; + + sprintf(tmpstr, "shadowCPU%d", + (int)(-ks->threadid - 2)); + kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr)); + } + break; + } +} + +/* Handle the 'H' task query packets */ +static void gdb_cmd_task(struct kgdb_state *ks) +{ + struct task_struct *thread; + char *ptr; + + switch (remcom_in_buffer[1]) { + case 'g': + ptr = &remcom_in_buffer[2]; + kgdb_hex2long(&ptr, &ks->threadid); + thread = getthread(ks->linux_regs, ks->threadid); + if (!thread && ks->threadid > 0) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + kgdb_usethread = thread; + ks->kgdb_usethreadid = ks->threadid; + strcpy(remcom_out_buffer, "OK"); + break; + case 'c': + ptr = &remcom_in_buffer[2]; + kgdb_hex2long(&ptr, &ks->threadid); + if (!ks->threadid) { + kgdb_contthread = NULL; + } else { + thread = getthread(ks->linux_regs, ks->threadid); + if (!thread && ks->threadid > 0) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + kgdb_contthread = thread; + } + strcpy(remcom_out_buffer, "OK"); + break; + } +} + +/* Handle the 'T' thread query packets */ +static void gdb_cmd_thread(struct kgdb_state *ks) +{ + char *ptr = &remcom_in_buffer[1]; + struct task_struct *thread; + + kgdb_hex2long(&ptr, &ks->threadid); + thread = getthread(ks->linux_regs, ks->threadid); + if (thread) + strcpy(remcom_out_buffer, "OK"); + else + error_packet(remcom_out_buffer, -EINVAL); +} + +/* Handle the 'z' or 'Z' breakpoint remove or set packets */ +static void gdb_cmd_break(struct kgdb_state *ks) +{ + /* + * Since GDB-5.3, it's been drafted that '0' is a software + * breakpoint, '1' is a hardware breakpoint, so let's do that. + */ + char *bpt_type = &remcom_in_buffer[1]; + char *ptr = &remcom_in_buffer[2]; + unsigned long addr; + unsigned long length; + int error = 0; + + if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { + /* Unsupported */ + if (*bpt_type > '4') + return; + } else { + if (*bpt_type != '0' && *bpt_type != '1') + /* Unsupported. */ + return; + } + + /* + * Test if this is a hardware breakpoint, and + * if we support it: + */ + if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) + /* Unsupported. */ + return; + + if (*(ptr++) != ',') { + error_packet(remcom_out_buffer, -EINVAL); + return; + } + if (!kgdb_hex2long(&ptr, &addr)) { + error_packet(remcom_out_buffer, -EINVAL); + return; + } + if (*(ptr++) != ',' || + !kgdb_hex2long(&ptr, &length)) { + error_packet(remcom_out_buffer, -EINVAL); + return; + } + + if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') + error = dbg_set_sw_break(addr); + else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') + error = dbg_remove_sw_break(addr); + else if (remcom_in_buffer[0] == 'Z') + error = arch_kgdb_ops.set_hw_breakpoint(addr, + (int)length, *bpt_type - '0'); + else if (remcom_in_buffer[0] == 'z') + error = arch_kgdb_ops.remove_hw_breakpoint(addr, + (int) length, *bpt_type - '0'); + + if (error == 0) + strcpy(remcom_out_buffer, "OK"); + else + error_packet(remcom_out_buffer, error); +} + +/* Handle the 'C' signal / exception passing packets */ +static int gdb_cmd_exception_pass(struct kgdb_state *ks) +{ + /* C09 == pass exception + * C15 == detach kgdb, pass exception + */ + if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { + + ks->pass_exception = 1; + remcom_in_buffer[0] = 'c'; + + } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { + + ks->pass_exception = 1; + remcom_in_buffer[0] = 'D'; + dbg_remove_all_break(); + kgdb_connected = 0; + return 1; + + } else { + gdbstub_msg_write("KGDB only knows signal 9 (pass)" + " and 15 (pass and disconnect)\n" + "Executing a continue without signal passing\n", 0); + remcom_in_buffer[0] = 'c'; + } + + /* Indicate fall through */ + return -1; +} + +/* + * This function performs all gdbserial command procesing + */ +int gdb_serial_stub(struct kgdb_state *ks) +{ + int error = 0; + int tmp; + + /* Clear the out buffer. */ + memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); + + if (kgdb_connected) { + unsigned char thref[8]; + char *ptr; + + /* Reply to host that an exception has occurred */ + ptr = remcom_out_buffer; + *ptr++ = 'T'; + ptr = pack_hex_byte(ptr, ks->signo); + ptr += strlen(strcpy(ptr, "thread:")); + int_to_threadref(thref, shadow_pid(current->pid)); + ptr = pack_threadid(ptr, thref); + *ptr++ = ';'; + put_packet(remcom_out_buffer); + } + + kgdb_usethread = kgdb_info[ks->cpu].task; + ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid); + ks->pass_exception = 0; + + while (1) { + error = 0; + + /* Clear the out buffer. */ + memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); + + get_packet(remcom_in_buffer); + + switch (remcom_in_buffer[0]) { + case '?': /* gdbserial status */ + gdb_cmd_status(ks); + break; + case 'g': /* return the value of the CPU registers */ + gdb_cmd_getregs(ks); + break; + case 'G': /* set the value of the CPU registers - return OK */ + gdb_cmd_setregs(ks); + break; + case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ + gdb_cmd_memread(ks); + break; + case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */ + gdb_cmd_memwrite(ks); + break; + case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */ + gdb_cmd_binwrite(ks); + break; + /* kill or detach. KGDB should treat this like a + * continue. + */ + case 'D': /* Debugger detach */ + case 'k': /* Debugger detach via kill */ + gdb_cmd_detachkill(ks); + goto default_handle; + case 'R': /* Reboot */ + if (gdb_cmd_reboot(ks)) + goto default_handle; + break; + case 'q': /* query command */ + gdb_cmd_query(ks); + break; + case 'H': /* task related */ + gdb_cmd_task(ks); + break; + case 'T': /* Query thread status */ + gdb_cmd_thread(ks); + break; + case 'z': /* Break point remove */ + case 'Z': /* Break point set */ + gdb_cmd_break(ks); + break; + case 'C': /* Exception passing */ + tmp = gdb_cmd_exception_pass(ks); + if (tmp > 0) + goto default_handle; + if (tmp == 0) + break; + /* Fall through on tmp < 0 */ + case 'c': /* Continue packet */ + case 's': /* Single step packet */ + if (kgdb_contthread && kgdb_contthread != current) { + /* Can't switch threads in kgdb */ + error_packet(remcom_out_buffer, -EINVAL); + break; + } + dbg_activate_sw_breakpoints(); + /* Fall through to default processing */ + default: +default_handle: + error = kgdb_arch_handle_exception(ks->ex_vector, + ks->signo, + ks->err_code, + remcom_in_buffer, + remcom_out_buffer, + ks->linux_regs); + /* + * Leave cmd processing on error, detach, + * kill, continue, or single step. + */ + if (error >= 0 || remcom_in_buffer[0] == 'D' || + remcom_in_buffer[0] == 'k') { + error = 0; + goto kgdb_exit; + } + + } + + /* reply to the request */ + put_packet(remcom_out_buffer); + } + +kgdb_exit: + if (ks->pass_exception) + error = 1; + return error; +} |