kgdb源代码分析(2.6.27)第四章－命令实现

(kernel/kgdb.c)
107 /*
108 * Holds information about breakpoints in a kernel. These breakpoints are
109 * added and removed by gdb.
110 */
111 static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
112 [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
113 };

(include/linux/kgdb.h)
98 struct kgdb_bkpt {
99 unsigned long bpt_addr;
100 unsigned char saved_instr[BREAK_INSTR_SIZE];
101 enum kgdb_bptype type;
102 enum kgdb_bpstate state;
103 };

(include/linux/kgdb.h)
  83 enum kgdb_bptype {
  84         BP_BREAKPOINT = 0,
  85         BP_HARDWARE_BREAKPOINT,
  86         BP_WRITE_WATCHPOINT,
  87         BP_READ_WATCHPOINT,
  88         BP_ACCESS_WATCHPOINT
  89 };
  90
  91 enum kgdb_bpstate {
  92         BP_UNDEFINED = 0,
  93         BP_REMOVED,
  94         BP_SET,
  95         BP_ACTIVE
  96 };

(kernel/kgdb.c)
 616 /*
 617 * SW breakpoint management:
 618 */
 619 static int kgdb_activate_sw_breakpoints(void)
 620 {
 621           unsigned long addr;
622   int error = 0;
623   int i;
624
625   for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
626            if (kgdb_break[i].state != BP_SET)
627                      continue;
628
629            addr = kgdb_break[i].bpt_addr;
630            error = kgdb_arch_set_breakpoint(addr,
631                              kgdb_break[i].saved_instr);
632            if (error)
633                      return error;
634
635            kgdb_flush_swbreak_addr(addr);
636            kgdb_break[i].state = BP_ACTIVE;
637   }
638   return 0;
639 }

(kernel/kgdb.c)
 167 /*
 168 * Weak aliases for breakpoint management,
 169 * can be overriden by architectures when needed:
 170 */
 171 int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
 172 {
 173        int err;
 174
 175       err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
 176        if (err)
 177                    return err;
 178
 179        return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
 180                                    BREAK_INSTR_SIZE);
 181 }