- Add support for specifying expressions in add-symbol-file (Nick Hibma)

- Add patches from src/ bits for:
  - kernel core debugging for i386
  - thread debugging for i386 and alpha (Doug Rabson)

This patch allows debugging -current kernels compiled with gcc-3.1.

Reviewed by:	dfr
Approved by:	obrien

1 files changed, 1058 insertions, 0 deletions

diff --git a/devel/gdb66/files/patch-kvm-fbsd.c b/devel/gdb66/files/patch-kvm-fbsd.c
new file mode 100644
index 000000000000..e5a83f189cfb
--- /dev/null
+++ b/devel/gdb66/files/patch-kvm-fbsd.c
@@ -0,0 +1,1058 @@
+--- gdb/kvm-fbsd.c	Mon Jun  3 11:32:24 2002
++++ gdb/kvm-fbsd.c	Mon Jun  3 11:30:35 2002
+@@ -0,0 +1,1055 @@
++/* Live and postmortem kernel debugging functions for FreeBSD.
++   Copyright 1996 Free Software Foundation, Inc.
++
++This file is part of GDB.
++
++This program is free software; you can redistribute it and/or modify
++it under the terms of the GNU General Public License as published by
++the Free Software Foundation; either version 2 of the License, or
++(at your option) any later version.
++
++This program is distributed in the hope that it will be useful,
++but WITHOUT ANY WARRANTY; without even the implied warranty of
++MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
++GNU General Public License for more details.
++
++You should have received a copy of the GNU General Public License
++along with this program; if not, write to the Free Software
++Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
++
++/* $FreeBSD: /tmp/pcvs/ports/devel/gdb66/files/Attic/patch-kvm-fbsd.c,v 1.1 2002-06-06 03:56:34 mp Exp $ */
++
++#include "defs.h"
++
++#include <ctype.h>
++#include <errno.h>
++#include <signal.h>
++#include <fcntl.h>
++#include <paths.h>
++#include <sys/sysctl.h>
++#include <sys/param.h>
++#include <sys/time.h>
++#include <sys/proc.h>
++#include <sys/user.h>
++#include "frame.h"  /* required by inferior.h */
++#include "inferior.h"
++#include "symtab.h"
++#include "symfile.h"
++#include "objfiles.h"
++#include "command.h"
++#include "bfd.h"
++#include "target.h"
++#include "gdbcore.h"
++#include <sys/stat.h>
++#include <unistd.h>
++#include <vm/vm.h>
++#include <vm/vm_param.h>
++
++#include <machine/vmparam.h>
++#include <machine/pcb.h>
++#include <machine/tss.h>
++#include <machine/frame.h>
++
++#if __FreeBSD_version >= 500032 && defined(i386)
++#define _KERNEL
++#include <sys/pcpu.h>
++#undef _KERNEL
++
++static void kcore_files_info PARAMS ((struct target_ops *));
++
++static void kcore_close PARAMS ((int));
++
++static void get_kcore_registers PARAMS ((int));
++
++static int kcore_xfer_kmem PARAMS ((CORE_ADDR, char *, int, int, struct mem_attrib *attrib, struct target_ops *));
++
++static int xfer_umem PARAMS ((CORE_ADDR, char *, int, int));
++
++static CORE_ADDR ksym_lookup PARAMS ((const char *));
++
++static int read_pcb PARAMS ((int, CORE_ADDR));
++
++static struct proc * curProc PARAMS ((void));
++
++static int set_proc_context PARAMS ((CORE_ADDR paddr));
++
++static void kcore_open PARAMS ((char *filename, int from_tty));
++
++static void kcore_detach PARAMS ((char *args, int from_tty));
++
++static void set_proc_cmd PARAMS ((char *arg, int from_tty));
++
++static void set_cpu_cmd PARAMS ((char *arg, int from_tty));
++
++static CORE_ADDR kvtophys PARAMS ((int, CORE_ADDR));
++
++static int physrd PARAMS ((int, u_int, char*, int));
++
++static int kvm_open PARAMS ((const char *efile, char *cfile, char *sfile,
++			     int perm, char *errout));
++
++static int kvm_close PARAMS ((int fd));
++
++static int kvm_write PARAMS ((int core_kd, CORE_ADDR memaddr,
++			      char *myaddr, int len));
++
++static int kvm_read PARAMS ((int core_kd, CORE_ADDR memaddr,
++			     char *myaddr, int len));
++
++static int kvm_uread PARAMS ((int core_kd, struct proc *p,
++			      CORE_ADDR memaddr, char *myaddr,
++			      int len));
++
++static int kernel_core_file_hook PARAMS ((int fd, CORE_ADDR addr,
++					  char *buf, int len));
++
++static CORE_ADDR kvm_getpcpu PARAMS ((int cfd, int cpuid));
++
++static struct kinfo_proc * kvm_getprocs PARAMS ((int cfd, int op,
++						CORE_ADDR proc, int *cnt));
++
++extern struct target_ops kcore_ops;	/* Forward decl */
++
++/* Non-zero means we are debugging a kernel core file */
++int kernel_debugging = 0;
++int kernel_writablecore = 0;
++
++static char *core_file;
++static int core_kd = -1;
++static struct proc *cur_proc;
++static CORE_ADDR kernel_start;
++
++static CORE_ADDR pcpu;
++#define	PCPU_OFFSET(name)						\
++	offsetof(struct pcpu, pc_ ## name)
++
++/*
++ * Symbol names of kernel entry points.  Use special frames.
++ */
++#define	KSYM_TRAP	"calltrap"
++#define	KSYM_INTR	"Xintr"
++#define	KSYM_FASTINTR	"Xfastintr"
++#define	KSYM_SYSCALL	"Xsyscall"
++
++/*
++ * Read the "thing" at kernel address 'addr' into the space pointed to
++ * by point.  The length of the "thing" is determined by the type of p.
++ * Result is non-zero if transfer fails.
++ */
++#define kvread(addr, p) \
++	(target_read_memory ((CORE_ADDR)(addr), (char *)(p), sizeof(*(p))))
++
++
++
++/*
++ * The following is FreeBSD-specific hackery to decode special frames
++ * and elide the assembly-language stub.  This could be made faster by
++ * defining a frame_type field in the machine-dependent frame information,
++ * but we don't think that's too important right now.
++ */
++enum frametype { tf_normal, tf_trap, tf_interrupt, tf_syscall };
++
++CORE_ADDR
++fbsd_kern_frame_saved_pc (fr)
++struct frame_info *fr;
++{
++       struct minimal_symbol *sym;
++       CORE_ADDR this_saved_pc;
++       enum frametype frametype;
++
++       this_saved_pc = read_memory_integer (fr->frame + 4, 4);
++       sym = lookup_minimal_symbol_by_pc (this_saved_pc);
++       frametype = tf_normal;
++       if (sym != NULL) {
++               if (strcmp (SYMBOL_NAME(sym), KSYM_TRAP) == 0)
++                       frametype = tf_trap;
++               else if (strncmp (SYMBOL_NAME(sym), KSYM_INTR,
++                   strlen(KSYM_INTR)) == 0 || strncmp (SYMBOL_NAME(sym),
++                   KSYM_FASTINTR, strlen(KSYM_FASTINTR)) == 0)
++                       frametype = tf_interrupt;
++               else if (strcmp (SYMBOL_NAME(sym), KSYM_SYSCALL) == 0)
++                       frametype = tf_syscall;
++       }
++
++       switch (frametype) {
++       case tf_normal:
++               return (this_saved_pc);
++
++#define oEIP   offsetof(struct trapframe, tf_eip)
++
++       case tf_trap:
++               return (read_memory_integer (fr->frame + 8 + oEIP, 4));
++
++       case tf_interrupt:
++               return (read_memory_integer (fr->frame + 12 + oEIP, 4));
++
++       case tf_syscall:
++               return (read_memory_integer (fr->frame + 8 + oEIP, 4));
++#undef oEIP
++       }
++}
++
++static CORE_ADDR
++ksym_lookup (name)
++const char *name;
++{
++	struct minimal_symbol *sym;
++
++	sym = lookup_minimal_symbol (name, NULL, NULL);
++	if (sym == NULL)
++		error ("kernel symbol `%s' not found.", name);
++
++	return SYMBOL_VALUE_ADDRESS (sym);
++}
++
++static struct proc *
++curProc ()
++{
++  struct proc *p;
++  struct thread *td;
++  CORE_ADDR addr = pcpu + PCPU_OFFSET (curthread);
++
++  if (kvread (addr, &td))
++    error ("cannot read thread pointer at %x\n", addr);
++  addr = (CORE_ADDR)td + offsetof(struct thread, td_proc);
++  if (kvread (addr, &p))
++    error ("cannot read proc pointer at %x\n", addr);
++  return p;
++}
++
++/*
++ * Set the process context to that of the proc structure at
++ * system address paddr.
++ */
++static int
++set_proc_context (paddr)
++	CORE_ADDR paddr;
++{
++  struct proc p;
++
++  if (paddr < kernel_start)
++    return (1);
++
++  cur_proc = (struct proc *)paddr;
++#ifdef notyet
++  set_kernel_boundaries (cur_proc);
++#endif
++
++  /* Fetch all registers from core file */
++  target_fetch_registers (-1);
++
++  /* Now, set up the frame cache, and print the top of stack */
++  flush_cached_frames ();
++  set_current_frame (create_new_frame (read_fp (), read_pc ()));
++  select_frame (get_current_frame (), 0);
++  return (0);
++}
++
++/* Discard all vestiges of any previous core file
++   and mark data and stack spaces as empty.  */
++
++/* ARGSUSED */
++static void
++kcore_close (quitting)
++     int quitting;
++{
++  inferior_ptid = null_ptid;	/* Avoid confusion from thread stuff */
++
++  if (core_kd)
++    {
++      kvm_close (core_kd);
++      free (core_file);
++      core_file = NULL;
++      core_kd = -1;
++    }
++}
++
++/* This routine opens and sets up the core file bfd */
++
++static void
++kcore_open (filename, from_tty)
++     char *filename;
++     int from_tty;
++{
++  const char *p;
++  struct cleanup *old_chain;
++  char buf[256], *cp;
++  int ontop;
++  CORE_ADDR addr;
++  struct pcb pcb;
++
++  target_preopen (from_tty);
++
++  unpush_target (&kcore_ops);
++
++  if (!filename)
++    {
++      /*error (core_kd?*/
++      error ( (core_kd >= 0)?
++	     "No core file specified.  (Use `detach' to stop debugging a core file.)"
++	     : "No core file specified.");
++    }
++
++  filename = tilde_expand (filename);
++  if (filename[0] != '/')
++    {
++      cp = concat (current_directory, "/", filename, NULL);
++      free (filename);
++      filename = cp;
++    }
++
++  old_chain = make_cleanup (free, filename);
++
++  /*
++   * gdb doesn't really do anything if the exec-file couldn't
++   * be opened (in that case exec_bfd is NULL). Usually that's
++   * no big deal, but kvm_open needs the exec-file's name,
++   * which results in dereferencing a NULL pointer, a real NO-NO !
++   * So, check here if the open of the exec-file succeeded.
++   */
++  if (exec_bfd == NULL) /* the open failed */
++    error ("kgdb could not open the exec-file, please check the name you used !");
++
++  core_kd = kvm_open (exec_bfd->filename, filename, NULL,
++		      kernel_writablecore? O_RDWR : O_RDONLY, "kgdb: ");
++  if (core_kd < 0)
++    perror_with_name (filename);
++
++  /* Looks semi-reasonable. Toss the old core file and work on the new. */
++
++  discard_cleanups (old_chain);	/* Don't free filename any more */
++  core_file = filename;
++  ontop = !push_target (&kcore_ops);
++
++  kernel_start = bfd_get_start_address (exec_bfd); /* XXX */
++
++  /* print out the panic string if there is one */
++  if (kvread (ksym_lookup ("panicstr"), &addr) == 0
++      && addr != 0
++      && target_read_memory (addr, buf, sizeof (buf)) == 0)
++    {
++      for (cp = buf; cp < &buf[sizeof (buf)] && *cp; cp++)
++	if (!isascii (*cp) || (!isprint (*cp) && !isspace (*cp)))
++	  *cp = '?';
++      *cp = '\0';
++      if (buf[0] != '\0')
++	printf ("panicstr: %s\n", buf);
++    }
++
++  /* Print all the panic messages if possible. */
++  if (symfile_objfile != NULL)
++    {
++      printf ("panic messages:\n---\n");
++      snprintf (buf, sizeof buf,
++		"/sbin/dmesg -N %s -M %s | \
++		 /usr/bin/awk '/^(panic:|Fatal trap) / { printing = 1 } \
++			       { if (printing) print $0 }'",
++		symfile_objfile->name, filename);
++      fflush(stdout);
++      system (buf);
++      printf ("---\n");
++    }
++
++  if (!ontop)
++    {
++      warning ("you won't be able to access this core file until you terminate\n\
++your %s; do ``info files''", target_longname);
++      return;
++    }
++
++  /* we may need this later */
++  cur_proc = (struct proc *)curProc ();
++  /* Now, set up the frame cache, and print the top of stack */
++  flush_cached_frames ();
++  set_current_frame (create_new_frame (read_fp (), read_pc ()));
++  select_frame (get_current_frame (), 0);
++  print_stack_frame (selected_frame, selected_frame_level, 1);
++}
++
++static void
++kcore_detach (args, from_tty)
++     char *args;
++     int from_tty;
++{
++  if (args)
++    error ("Too many arguments");
++  unpush_target (&kcore_ops);
++  reinit_frame_cache ();
++  if (from_tty)
++    printf_filtered ("No kernel core file now.\n");
++}
++
++/* Get the registers out of a core file.  This is the machine-
++   independent part.  Fetch_core_registers is the machine-dependent
++   part, typically implemented in the xm-file for each architecture.  */
++
++/* We just get all the registers, so we don't use regno.  */
++/* ARGSUSED */
++static void
++get_kcore_registers (regno)
++     int regno;
++{
++  struct pcb *pcbaddr;
++  struct thread *mainthread;
++
++  /* find the pcb for the current process */
++  if (cur_proc == NULL)
++    error ("get_kcore_registers no proc");
++  if (kvread (&TAILQ_FIRST(&cur_proc->p_threads), &mainthread)) /* XXXKSE */
++    error ("cannot read main thread for proc at %#x", cur_proc);
++  if (kvread (&mainthread->td_pcb, &pcbaddr)) /* XXXKSE */
++    error ("cannot read pcb pointer for proc at %#x", cur_proc);
++  if (read_pcb (core_kd, (CORE_ADDR)pcbaddr) < 0)
++    error ("cannot read pcb at %#x", pcbaddr);
++}
++
++static void
++kcore_files_info (t)
++     struct target_ops *t;
++{
++  printf ("\t`%s'\n", core_file);
++}
++
++static CORE_ADDR
++ksym_maxuseraddr()
++{
++  static CORE_ADDR maxuseraddr;
++  struct minimal_symbol *sym;
++
++  if (maxuseraddr == 0)
++    {
++      sym = lookup_minimal_symbol ("PTmap", NULL, NULL);
++      if (sym == NULL) {
++	maxuseraddr = VM_MAXUSER_ADDRESS;
++      } else {
++	maxuseraddr = SYMBOL_VALUE_ADDRESS (sym);
++      }
++    }
++  return maxuseraddr;
++}
++
++static int
++kcore_xfer_kmem (memaddr, myaddr, len, write, attrib, target)
++     CORE_ADDR memaddr;
++     char *myaddr;
++     int len;
++     int write;
++     struct mem_attrib *attrib;
++     struct target_ops *target;
++{
++  int ns;
++  int nu;
++
++  if (memaddr >= ksym_maxuseraddr())
++    nu = 0;
++  else
++    {
++      nu = xfer_umem (memaddr, myaddr, len, write);
++      if (nu <= 0)
++	return (0);
++      if (nu == len)
++	return (nu);
++      memaddr += nu;
++      if (memaddr != ksym_maxuseraddr())
++	return (nu);
++      myaddr += nu;
++      len -= nu;
++    }
++
++  ns = (write ? kvm_write : kvm_read) (core_kd, memaddr, myaddr, len);
++  if (ns < 0)
++    ns = 0;
++
++  return (nu + ns);
++}
++
++static int
++xfer_umem (memaddr, myaddr, len, write)
++     CORE_ADDR memaddr;
++     char *myaddr;
++     int len;
++     int write; /* ignored */
++{
++  int n;
++  struct proc proc;
++
++  if (cur_proc == NULL || kvread (cur_proc, &proc))
++    error ("cannot read proc at %#x", cur_proc);
++  n = kvm_uread (core_kd, &proc, memaddr, myaddr, len) ;
++
++  if (n < 0)
++    return 0;
++  return n;
++}
++
++static CORE_ADDR
++ksym_kernbase()
++{
++  static CORE_ADDR kernbase;
++  struct minimal_symbol *sym;
++
++  if (kernbase == 0)
++    {
++      sym = lookup_minimal_symbol ("kernbase", NULL, NULL);
++      if (sym == NULL) {
++	kernbase = KERNBASE;
++      } else {
++	kernbase = SYMBOL_VALUE_ADDRESS (sym);
++      }
++    }
++  return kernbase;
++}
++
++#define	KERNOFF		(ksym_kernbase())
++#define	INKERNEL(x)	((x) >= KERNOFF)
++
++static CORE_ADDR sbr;
++static CORE_ADDR curpcb;
++static int found_pcb;
++static int devmem;
++static int kfd;
++static struct pcb pcb;
++
++static void
++set_proc_cmd (arg, from_tty)
++     char *arg;
++     int from_tty;
++{
++  CORE_ADDR paddr;
++  struct kinfo_proc *kp;
++  int cnt = 0;
++
++  if (!arg)
++    error_no_arg ("proc address for new current process");
++  if (!kernel_debugging)
++    error ("not debugging kernel");
++
++  paddr = (CORE_ADDR)parse_and_eval_address (arg);
++  /* assume it's a proc pointer if it's in the kernel */
++  if (paddr >= kernel_start) {
++    if (set_proc_context(paddr))
++      error("invalid proc address");
++    } else {
++      kp = kvm_getprocs(core_kd, KERN_PROC_PID, paddr, &cnt);
++      if (!cnt)
++        error("invalid pid");
++      if (set_proc_context((CORE_ADDR)kp->ki_paddr))
++        error("invalid proc address");
++  }
++}
++
++static void
++set_cpu_cmd (arg, from_tty)
++     char *arg;
++     int from_tty;
++{
++  CORE_ADDR paddr;
++  CORE_ADDR pcaddr;
++  struct kinfo_proc *kp;
++  int cpu, cfd;
++
++  if (!arg)
++    error_no_arg ("cpu number");
++  if (!kernel_debugging)
++    error ("not debugging kernel");
++
++  cfd = core_kd;
++  cpu = (int)parse_and_eval_address (arg);
++  if ((pcaddr = kvm_getpcpu (cfd, cpu)) == NULL)
++    error ("cpu number out of range");
++
++  pcpu = pcaddr;
++  curpcb = kvtophys(cfd, pcpu + PCPU_OFFSET (curpcb));
++  physrd (cfd, curpcb, (char*)&curpcb, sizeof curpcb);
++
++  if (!devmem)
++    paddr = ksym_lookup ("dumppcb") - KERNOFF;
++  else
++    paddr = kvtophys (cfd, curpcb);
++  read_pcb (cfd, paddr);
++  printf ("initial pcb at %lx\n", (unsigned long)paddr);
++
++  if ((cur_proc = curProc()))
++    target_fetch_registers (-1);
++
++  /* Now, set up the frame cache, and print the top of stack */
++  flush_cached_frames ();
++  set_current_frame (create_new_frame (read_fp (), read_pc ()));
++  select_frame (get_current_frame (), 0);
++  print_stack_frame (selected_frame, selected_frame_level, 1);
++}
++
++/* substitutes for the stuff in libkvm which doesn't work */
++/* most of this was taken from the old kgdb */
++
++/* we don't need all this stuff, but the call should look the same */
++
++static int
++kvm_open (efile, cfile, sfile, perm, errout)
++     const char *efile;
++     char *cfile;
++     char *sfile;		/* makes this kvm_open more compatible to the one in libkvm */
++     int perm;
++     char *errout;		/* makes this kvm_open more compatible to the one in libkvm */
++{
++  struct stat stb;
++  int cfd;
++  CORE_ADDR paddr;
++
++  if ((cfd = open (cfile, perm, 0)) < 0)
++    return (cfd);
++
++  if ((pcpu = kvm_getpcpu (cfd, 0)) == NULL)
++    return (-1);
++
++  fstat (cfd, &stb);
++  if ((stb.st_mode & S_IFMT) == S_IFCHR
++      && stb.st_rdev == makedev (2, 0))
++    {
++      devmem = 1;
++      kfd = open (_PATH_KMEM, perm, 0);
++    }
++
++  physrd (cfd, ksym_lookup ("IdlePTD") - KERNOFF, (char*)&sbr, sizeof sbr);
++  printf ("IdlePTD at phsyical address 0x%08lx\n", (unsigned long)sbr);
++  curpcb = kvtophys(cfd, pcpu + PCPU_OFFSET (curpcb));
++  physrd (cfd, curpcb, (char*)&curpcb, sizeof curpcb);
++
++  found_pcb = 1; /* for vtophys */
++  if (!devmem)
++    paddr = ksym_lookup ("dumppcb") - KERNOFF;
++  else
++    paddr = kvtophys (cfd, curpcb);
++  read_pcb (cfd, paddr);
++  printf ("initial pcb at physical address 0x%08lx\n", (unsigned long)paddr);
++
++  return (cfd);
++}
++
++static int
++kvm_close (fd)
++     int fd;
++{
++  return (close (fd));
++}
++
++static int
++kvm_write (core_kd, memaddr, myaddr, len)
++     int core_kd;
++     CORE_ADDR memaddr;
++     char *myaddr;
++{
++  int cc;
++
++  if (devmem)
++    {
++      if (kfd > 0)
++	{
++	  /*
++	   * Just like kvm_read, only we write.
++	   */
++	  errno = 0;
++	  if (lseek (kfd, (off_t)memaddr, 0) < 0
++	      && errno != 0)
++	    {
++	      error ("kvm_write:invalid address (%x)", memaddr);
++	      return (0);
++	    }
++	  cc = write (kfd, myaddr, len);
++	  if (cc < 0)
++	    {
++	      error ("kvm_write:write failed");
++	      return (0);
++	    }
++	  else if (cc < len)
++	    error ("kvm_write:short write");
++	  return (cc);
++	}
++      else
++	return (0);
++    }
++  else
++    {
++      printf ("kvm_write not implemented for dead kernels\n");
++      return (0);
++    }
++  /* NOTREACHED */
++}
++
++static int
++kvm_read (core_kd, memaddr, myaddr, len)
++     int core_kd;
++     CORE_ADDR memaddr;
++     char *myaddr;
++{
++  return (kernel_core_file_hook (core_kd, memaddr, myaddr, len));
++}
++
++static int
++kvm_uread (core_kd, p, memaddr, myaddr, len)
++     int core_kd;
++     register struct proc *p;
++     CORE_ADDR memaddr;
++     char *myaddr;
++     int len;
++{
++  register char *cp;
++  char procfile[MAXPATHLEN];
++  ssize_t amount;
++  int fd;
++
++  if (devmem) 
++    {
++      sprintf (procfile, "/proc/%d/mem", p->p_pid);
++      fd = open (procfile, O_RDONLY, 0);
++      if (fd < 0)
++	{
++	  error ("cannot open %s", procfile);
++	  close (fd);
++	  return (0);
++	}
++
++      cp = myaddr;
++      while (len > 0)
++	{
++	  errno = 0;
++	  if (lseek (fd, (off_t)memaddr, 0) == -1 && errno != 0)
++	    {
++	      error ("invalid address (%x) in %s", memaddr, procfile);
++	      break;
++	    }
++	  amount = read (fd, cp, len);
++	  if (amount < 0)
++	    {
++	      error ("error reading %s", procfile);
++	      break;
++	    }
++	  if (amount == 0)
++	    {
++	      error ("EOF reading %s", procfile);
++	      break;
++	    }
++	  cp += amount;
++	  memaddr += amount;
++	  len -= amount;
++	}
++
++      close (fd);
++      return ((ssize_t) (cp - myaddr));
++    }
++  else
++    return (kernel_core_file_hook (core_kd, memaddr, myaddr, len));
++}
++
++static struct kinfo_proc kp;
++
++/*
++ * try to do what kvm_proclist in libkvm would do
++ */
++static int
++kvm_proclist (cfd, pid, p, cnt)
++int cfd, pid, *cnt;
++struct proc *p;
++{
++  struct proc lp;
++
++  for (; p != NULL; p = LIST_NEXT(&lp, p_list)) {
++      if (!kvm_read(cfd, (CORE_ADDR)p, (char *)&lp, sizeof (lp)))
++            return (0);
++       if (lp.p_pid != pid)
++           continue;
++       kp.ki_paddr = p;
++       *cnt = 1;
++       return (1);
++  }
++  *cnt = 0;
++  return (0);
++}
++
++/*
++ * try to do what kvm_deadprocs in libkvm would do
++ */
++static struct kinfo_proc *
++kvm_deadprocs (cfd, pid, cnt)
++int cfd, pid, *cnt;
++{
++  CORE_ADDR allproc, zombproc;
++  struct proc *p;
++
++  allproc = ksym_lookup("allproc");
++  if (kvm_read(cfd, allproc, (char *)&p, sizeof (p)) == 0)
++      return (NULL);
++  kvm_proclist (cfd, pid, p, cnt);
++  if (!*cnt) {
++      zombproc = ksym_lookup("zombproc");
++      if (kvm_read(cfd, zombproc, (char *)&p, sizeof (p)) == 0)
++           return (NULL);
++       kvm_proclist (cfd, pid, p, cnt);
++  }
++  return (&kp);
++}
++
++static CORE_ADDR
++kvm_getpcpu (cfd, cpuid)
++int cfd, cpuid;
++{
++  SLIST_HEAD(, pcpu) pcpu_head;
++  struct pcpu lpc;
++  struct pcpu *pc;
++
++  physrd (cfd, ksym_lookup ("cpuhead") - KERNOFF, (char*)&pcpu_head,
++    sizeof pcpu_head);
++  pc = SLIST_FIRST (&pcpu_head);
++  for (; pc != NULL; pc = SLIST_NEXT (&lpc, pc_allcpu))
++    {
++      kvm_read (cfd, (CORE_ADDR)pc, (char*)&lpc, sizeof lpc);
++      if (lpc.pc_cpuid == cpuid)
++        break;
++    }
++
++  return ((CORE_ADDR)pc);
++}
++
++/*
++ * try to do what kvm_getprocs in libkvm would do
++ */
++static struct kinfo_proc *
++kvm_getprocs (cfd, op, proc, cnt)
++int cfd, op, *cnt;
++CORE_ADDR proc;
++{
++  int mib[4], size;
++
++  *cnt = 0;
++  /* assume it's a pid */
++  if (devmem) { /* "live" kernel, use sysctl */
++      mib[0] = CTL_KERN;
++      mib[1] = KERN_PROC;
++      mib[2] = KERN_PROC_PID;
++      mib[3] = (int)proc;
++      size = sizeof (kp);
++      if (sysctl (mib, 4, &kp, &size, NULL, 0) < 0) {
++            perror("sysctl");
++            *cnt = 0;
++            return (NULL);
++      }
++      if (!size)
++            *cnt = 0;
++      else
++            *cnt = 1;
++      return (&kp);
++  } else
++      return (kvm_deadprocs (cfd, (int)proc, cnt));
++}
++
++static int
++physrd (cfd, addr, dat, len)
++     int cfd;
++     u_int addr;
++     char *dat;
++     int len;
++{
++  if (lseek (cfd, (off_t)addr, L_SET) == -1)
++    return (-1);
++  return (read (cfd, dat, len));
++}
++
++static CORE_ADDR
++kvtophys (fd, addr)
++     int fd;
++     CORE_ADDR addr;
++{
++  CORE_ADDR v;
++  unsigned int pte;
++  static CORE_ADDR PTD = -1;
++  CORE_ADDR current_ptd;
++
++  /*
++   * We may no longer have a linear system page table...
++   *
++   * Here's the scoop.  IdlePTD contains the physical address
++   * of a page table directory that always maps the kernel.
++   * IdlePTD is in memory that is mapped 1-to-1, so we can
++   * find it easily given its 'virtual' address from ksym_lookup().
++   * For hysterical reasons, the value of IdlePTD is stored in sbr.
++   *
++   * To look up a kernel address, we first convert it to a 1st-level
++   * address and look it up in IdlePTD.  This gives us the physical
++   * address of a page table page; we extract the 2nd-level part of
++   * VA and read the 2nd-level pte.  Finally, we add the offset part
++   * of the VA into the physical address from the pte and return it.
++   *
++   * User addresses are a little more complicated.  If we don't have
++   * a current PCB from read_pcb(), we use PTD, which is the (fixed)
++   * virtual address of the current ptd.  Since it's NOT in 1-to-1
++   * kernel space, we must look it up using IdlePTD.  If we do have
++   * a pcb, we get the ptd from pcb_ptd.
++   */
++
++  if (INKERNEL (addr))
++    current_ptd = sbr;
++  else if (found_pcb == 0)
++    {
++      if (PTD == -1)
++	PTD = kvtophys (fd, ksym_lookup ("PTD"));
++      current_ptd = PTD;
++    }
++  else
++    current_ptd = pcb.pcb_cr3;
++
++  /*
++   * Read the first-level page table (ptd).
++   */
++  v = current_ptd + ( (unsigned)addr >> PDRSHIFT) * sizeof pte;
++  if (physrd (fd, v, (char *)&pte, sizeof pte) < 0 || (pte&PG_V) == 0)
++    return (~0);
++
++  if (pte & PG_PS)
++    {
++      /*
++       * No second-level page table; ptd describes one 4MB page.
++       * (We assume that the kernel wouldn't set PG_PS without enabling
++       * it cr0, and that the kernel doesn't support 36-bit physical
++       * addresses).
++       */
++#define	PAGE4M_MASK	(NBPDR - 1)
++#define	PG_FRAME4M	(~PAGE4M_MASK)
++      addr = (pte & PG_FRAME4M) + (addr & PAGE4M_MASK);
++    }
++  else
++    {
++      /*
++       * Read the second-level page table.
++       */
++      v = (pte&PG_FRAME) + ((addr >> PAGE_SHIFT)&(NPTEPG-1)) * sizeof pte;
++      if (physrd (fd, v, (char *) &pte, sizeof (pte)) < 0 || (pte&PG_V) == 0)
++	return (~0);
++
++      addr = (pte & PG_FRAME) + (addr & PAGE_MASK);
++    }
++#if 0
++  printf ("vtophys (%x) -> %x\n", oldaddr, addr);
++#endif
++  return (addr);
++}
++
++static int
++read_pcb (fd, uaddr)
++     int fd;
++     CORE_ADDR uaddr;
++{
++  int i;
++  int noreg;
++  CORE_ADDR nuaddr = uaddr;
++
++  /* need this for the `proc' command to work */
++  if (INKERNEL(uaddr))
++      nuaddr = kvtophys(fd, uaddr);
++
++  if (physrd (fd, nuaddr, (char *)&pcb, sizeof pcb) < 0)
++    {
++      error ("cannot read pcb at %x\n", uaddr);
++      return (-1);
++    }
++
++  /*
++   * get the register values out of the sys pcb and
++   * store them where `read_register' will find them.
++   */
++  /*
++   * XXX many registers aren't available.
++   * XXX for the non-core case, the registers are stale - they are for
++   *     the last context switch to the debugger.
++   * XXX gcc's register numbers aren't all #defined in tm-i386.h.
++   */
++  noreg = 0;
++  for (i = 0; i < 3; ++i)		/* eax,ecx,edx */
++    supply_register (i, (char *)&noreg);
++  supply_register (3, (char *)&pcb.pcb_ebx);
++  supply_register (SP_REGNUM, (char *)&pcb.pcb_esp);
++  supply_register (FP_REGNUM, (char *)&pcb.pcb_ebp);
++  supply_register (6, (char *)&pcb.pcb_esi);
++  supply_register (7, (char *)&pcb.pcb_edi);
++  supply_register (PC_REGNUM, (char *)&pcb.pcb_eip);
++  for (i = 9; i < 14; ++i)		/* eflags, cs, ss, ds, es, fs */
++    supply_register (i, (char *)&noreg);
++  supply_register (15, (char *)&pcb.pcb_gs);
++
++  /* XXX 80387 registers? */
++}
++
++/*
++ * read len bytes from kernel virtual address 'addr' into local
++ * buffer 'buf'.  Return numbert of bytes if read ok, 0 otherwise.  On read
++ * errors, portion of buffer not read is zeroed.
++ */
++
++static int
++kernel_core_file_hook (fd, addr, buf, len)
++     int fd;
++     CORE_ADDR addr;
++     char *buf;
++     int len;
++{
++  int i;
++  CORE_ADDR paddr;
++  register char *cp;
++  int cc;
++
++  cp = buf;
++
++  while (len > 0)
++    {
++      paddr = kvtophys (fd, addr);
++      if (paddr == ~0)
++	{
++	  memset (buf, '\000', len);
++	  break;
++	}
++      /* we can't read across a page boundary */
++      i = min (len, PAGE_SIZE - (addr & PAGE_MASK));
++      if ( (cc = physrd (fd, paddr, cp, i)) <= 0)
++	{
++	  memset (cp, '\000', len);
++	  return (cp - buf);
++	}
++      cp += cc;
++      addr += cc;
++      len -= cc;
++    }
++  return (cp - buf);
++}
++
++static struct target_ops kcore_ops;
++
++#else
++int kernel_debugging = 0;
++#endif
++
++void
++_initialize_kcorelow()
++{
++#if __FreeBSD_version >= 500032 && defined(i386)
++  kcore_ops.to_shortname = "kcore";
++  kcore_ops.to_longname = "Kernel core dump file";
++  kcore_ops.to_doc =
++    "Use a core file as a target.  Specify the filename of the core file.";
++  kcore_ops.to_open = kcore_open;
++  kcore_ops.to_close = kcore_close;
++  kcore_ops.to_attach = find_default_attach;
++  kcore_ops.to_detach = kcore_detach;
++  kcore_ops.to_fetch_registers = get_kcore_registers;
++  kcore_ops.to_xfer_memory = kcore_xfer_kmem;
++  kcore_ops.to_files_info = kcore_files_info;
++  kcore_ops.to_create_inferior = find_default_create_inferior;
++  kcore_ops.to_stratum = kcore_stratum;
++  kcore_ops.to_has_memory = 1;
++  kcore_ops.to_has_stack = 1;
++  kcore_ops.to_has_registers = 1;
++  kcore_ops.to_magic = OPS_MAGIC;
++
++  add_target (&kcore_ops);
++  add_com ("proc", class_obscure, set_proc_cmd, "Set current process context");
++  add_com ("cpu", class_obscure, set_cpu_cmd, "Set current cpu");
++#endif
++}