NAME

ipkdb — machine-dependent interface to ipkdb

SYNOPSIS

#include <ipkdb/ipkdb.h>

void
ipkdb_init(void);

void
ipkdb_connect(int when);

int
ipkdbcmds(void);

void
ipkdbinit(void);

void
ipkdb_trap(void);

int
ipkdb_poll(void);

int
ipkdbif_init(struct ipkdb_if *kip);

int
ipkdbfbyte(u_char *c);

int
ipkdbsbyte(u_char *c, int i);

DESCRIPTION

The machine-dependent code must support this interface for operation with ipkdb(4).

During system bootstrap, machine-dependent code must invoke ipkdb_init(). If the kernel is booted with RB_KDB set in boothowto (see boothowto(9)), ipkdb(4) is enabled by invoking ipkdb_connect(), setting the when argument to 0.

ipkdbcmds() is invoked by machine-dependent code when the trap mechanism determines that the debugger should be entered, i.e., on a single step or breakpoint interrupt from kernel code. The trapping mechanism should already have stored the registers into the global area ipkdbregs. The layout of this area must be the same as that expected by gdb(1). Valid return values are:

IPKDB_CMD_RUN

user wants to continue

IPKDB_CMD_STEP

user wants to do single stepping

IPKDB_CMD_EXIT

user has detached from debugging

FUNCTIONS

The machine-dependent code must provide the following functions for the machine-independent code.

ipkdbinit()

This routine gets called when the debugger should be entered for the first time.

ipkdb_trap()

This routine is part of the trap handler. Whenever a trap happens (e.g., when hitting a breakpoint during debugging), ipkdb_trap() decides if the Debugger needs to be called. If there are other ways to decide that, it's not necessary to provide an ipkdb_trap() implementation.

ipkdb_poll()

This routine gets called after a panic to check for a key press by the user. If implemented it allows the user to press any key on the console to do the automatic reboot after a panic. Otherwise the debugging interface will wait forever for some remote debugger to attach in case of a panic.

ipkdbif_init(kip)

In order to be able to find the debugging interface, the network driver must invoke ipkdbif_init() with kip specifying a struct ipkdb_if plus some additional parameters that allow it to access the devices registers, hopefully using bus_space(9) methods. In the ipkdb_if structure, the attach routine must initialize the following fields:

myenetaddr

fill this with the own ethernet address of the device/machine

flags

mark at least IPKDB_MYHW here

name

name of the device, only used for a message

start

routine called every time ipkdb is entered

leave

routine called every time ipkdb is left

receive

routine called to receive a packet

send

routine called to send a packet

Additional fields that may be set are:

myinetaddr

fill this with the own internet address, and mark IPKDB_MYIP in flags

port

may be used as a pointer to some device

ipkdbfbyte(c)

This routine should fetch a byte from address c. It must not enter any trap handling code, but instead return -1 on inability to access the data.

ipkdbsbyte(c, i)

This routine should set the byte pointed to by c to the value given as i. The routine must not enter any trap handling code. Furthermore it should reset the modification bit in the relevant page table entry to the value before the store.

SEE ALSO

ipkdb(4), boothowto(9)