Live & postmortem kernel debugging support for the alpha platform.

This was modeled after NetBSD's kernel debugging support.

Reviewed by: Doug Rabson <dfr@nlsystems.com>

gnu/usr.bin/binutils/gdb/Makefile.alpha

@@ -1,7 +1,8 @@
 #
-# $Id$
+# $Id: Makefile.alpha,v 1.1 1999/05/02 11:31:55 dfr Exp $
 #
 
-XSRCS+= freebsd-nat.c alpha-tdep.c
+XSRCS+= freebsd-nat.c alpha-tdep.c kvm-fbsd.c
+LDADD+= -lkvm
 
 .PATH: ${.CURDIR}/alpha

gnu/usr.bin/binutils/gdb/alpha/freebsd-nat.c

@@ -144,3 +144,30 @@ supply_fpregset (fp)
     supply_register (regno + 32, (char *)&fp->fpr_regs[regno]);
 }
 #endif	/* HAVE_FPREGSET_T */
+
+/*
+ * Get registers from a kernel crash dump or live kernel.
+ * Called by kvm-fbsd.c:get_kcore_registers().
+ */
+fetch_kcore_registers (pcbp)
+  struct pcb *pcbp;
+{
+
+  /* First clear out any garbage. */
+  memset(registers, '\0', REGISTER_BYTES);
+
+  /* SP */
+  *(long *) &registers[REGISTER_BYTE (SP_REGNUM)] =
+    pcbp->pcb_hw.apcb_ksp;
+
+  /* S0 through S6 */
+  memcpy (&registers[REGISTER_BYTE (S0_REGNUM)],
+          &pcbp->pcb_context[0], 7 * sizeof(long));
+
+  /* PC */
+  *(long *) &registers[REGISTER_BYTE (PC_REGNUM)] =
+    pcbp->pcb_context[7];
+
+  registers_fetched ();
+}
+

gnu/usr.bin/binutils/gdb/alpha/kvm-fbsd.c

@@ -0,0 +1,435 @@
+/* Kernel core dump functions below target vector, for GDB.
+   Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995
+   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.
+*/
+
+/*
+ * This works like "remote" but, you use it like this:
+ *     target kcore /dev/mem
+ * or
+ *     target kcore /var/crash/host/core.0
+ *
+ * This way makes it easy to short-circut the whole bfd monster,
+ * and direct the inferior stuff to our libkvm implementation.
+ */
+
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/proc.h>
+#include <sys/user.h>
+#include <errno.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <kvm.h>
+
+#include "defs.h"
+#include "gdb_string.h"
+#include "frame.h"  /* required by inferior.h */
+#include "inferior.h"
+#include "symtab.h"
+#include "command.h"
+#include "bfd.h"
+#include "target.h"
+#include "gdbcore.h"
+
+static void
+kcore_files_info PARAMS ((struct target_ops *));
+
+static void
+kcore_close PARAMS ((int));
+
+static void
+get_kcore_registers PARAMS ((int));
+
+static int
+xfer_mem PARAMS ((CORE_ADDR, char *, int, int, struct target_ops *));
+
+static int
+xfer_umem PARAMS ((CORE_ADDR, char *, int, int));
+
+static char		*core_file;
+static kvm_t		*core_kd;
+static struct pcb	cur_pcb;
+
+static struct target_ops kcore_ops;
+int kernel_writablecore;
+
+/*
+ * 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))))
+
+
+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);
+}
+
+/*
+ * Provide the address of an initial PCB to use.
+ * If this is a crash dump, try for "dumppcb".
+ * If no "dumppcb" or it's /dev/mem, use proc0.
+ * Return the core address of the PCB we found.
+ */
+static CORE_ADDR
+initial_pcb()
+{
+  struct minimal_symbol *sym;
+  CORE_ADDR addr;
+  void *val;
+
+  /* Make sure things are open... */
+  if (!core_kd || !core_file)
+    return (0);
+
+  /* If this is NOT /dev/mem try for dumppcb. */
+  if (strncmp(core_file, "/dev/", 5)) {
+    sym = lookup_minimal_symbol("dumppcb", NULL, NULL);
+    if (sym != NULL) {
+      addr = SYMBOL_VALUE_ADDRESS(sym);
+      return (addr);
+    }
+  }
+
+  /*
+   * OK, just use proc0pcb.  Note that curproc might
+   * not exist, and if it does, it will point to gdb.
+   * Therefore, just use proc0 and let the user set
+   * some other context if they care about it.
+   */
+  addr = ksym_lookup("proc0paddr");
+  if (kvread(addr, &val)) {
+    error("cannot read proc0paddr pointer at %x\n", addr);
+    val = 0;
+  }
+
+  return ((CORE_ADDR)val);
+}
+
+/*
+ * Set the current context to that of the PCB struct
+ * at the system address passed.
+ */
+static int
+set_context(addr)
+  CORE_ADDR addr;
+{
+
+  if (kvread(addr, &cur_pcb))
+    error("cannot read pcb at %#x", addr);
+
+  /* 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_pid = 0;		/* Avoid confusion from thread stuff */
+
+  if (core_kd) {
+    kvm_close(core_kd);
+    free(core_file);
+    core_file = NULL;
+    core_kd = NULL;
+  }
+}
+
+/* This routine opens and sets up the core file bfd.  */
+
+static void
+kcore_open (filename, from_tty)
+     char *filename;	/* the core file */
+     int from_tty;
+{
+  kvm_t		*kd;
+  const char *p;
+  struct cleanup *old_chain;
+  char buf[256], *cp;
+  int ontop;
+  CORE_ADDR addr;
+
+  target_preopen (from_tty);
+
+  /* The exec file is required for symbols. */
+  if (exec_bfd == NULL)
+    error("No kernel exec file specified");
+
+  if (core_kd) {
+    error ("No core file specified."
+	   "  (Use `detach' to stop debugging a core file.)");
+    return;
+  }
+
+  if (!filename) {
+    error ("No core file specified.");
+    return;
+  }
+
+  filename = tilde_expand (filename);
+  if (filename[0] != '/') {
+    cp = concat (current_directory, "/", filename, NULL);
+    free (filename);
+    filename = cp;
+  }
+
+  old_chain = make_cleanup (free, filename);
+
+  kd = kvm_open (bfd_get_filename(exec_bfd), filename, NULL,
+		 kernel_writablecore ? O_RDWR: O_RDONLY, 0);
+  if (kd == NULL) {
+    perror_with_name (filename);
+    return;
+  }
+
+  /* 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;
+  unpush_target (&kcore_ops);
+  ontop = !push_target (&kcore_ops);
+
+  /* Note unpush_target (above) calls kcore_close. */
+  core_kd = kd;
+
+  /* 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_filtered("panic: %s\n", buf);
+  }
+
+  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;
+  }
+
+  /* Now, set up process context, and print the top of stack */
+  (void)set_context(initial_pcb());
+  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;
+{
+
+  /*
+   * XXX - Only read the pcb when set_context() is called.
+   * When looking at a live kernel this may be a problem,
+   * but the user can do another "proc" or "pcb" command to
+   * grab a new copy of the pcb...
+   */
+
+  /*
+   * Zero out register set then fill in the ones we know about.
+   */
+  fetch_kcore_registers (&cur_pcb);
+}
+
+static void
+kcore_files_info (t)
+  struct target_ops *t;
+{
+  printf_filtered ("\t`%s'\n", core_file);
+}
+
+/* If mourn is being called in all the right places, this could be say
+   `gdb internal error' (since generic_mourn calls breakpoint_init_inferior).  */
+
+static int
+ignore (addr, contents)
+     CORE_ADDR addr;
+     char *contents;
+{
+  return 0;
+}
+
+static int
+xfer_kmem (memaddr, myaddr, len, write, target)
+  CORE_ADDR memaddr;
+  char *myaddr;
+  int len;
+  int write;
+  struct target_ops *target;
+{
+  int n;
+
+#if 0	/* XXX */
+  if (it is a user address)
+    return xfer_umem(memaddr, myaddr, len, write);
+#endif
+
+  if (core_kd == NULL)
+    return 0;
+
+  if (write)
+    n = kvm_write(core_kd, memaddr, myaddr, len);
+  else
+    n = kvm_read (core_kd, memaddr, myaddr, len) ;
+  if (n < 0) {
+    fprintf_unfiltered (gdb_stderr, "can not access 0x%x, %s\n",
+			memaddr, kvm_geterr(core_kd));
+    n = 0;
+  }
+
+  return n;
+}
+
+#if 0	/* XXX */
+static int
+xfer_umem (memaddr, myaddr, len, write)
+  CORE_ADDR memaddr;
+  char *myaddr;
+  int len;
+  int write; /* ignored */
+{
+  int n;
+  struct proc proc;
+
+  if (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;
+}
+#endif
+
+static void
+set_proc_cmd(arg)
+  char *arg;
+{
+  CORE_ADDR addr;
+  void *val;
+
+  if (!arg)
+    error_no_arg("proc address for the new context");
+
+  if (core_kd == NULL)
+    error("no kernel core file");
+
+  addr = (CORE_ADDR)parse_and_eval_address(arg);
+
+  /* Read the PCB address in proc structure. */
+  addr += (int) &((struct proc *)0)->p_addr;
+  if (kvread(addr, &val))
+    error("cannot read u area ptr");
+
+  if (set_context((CORE_ADDR)val))
+    error("invalid proc address");
+}
+
+static void
+set_pcb_cmd(arg)
+  char *arg;
+{
+  CORE_ADDR addr;
+  void *val;
+
+  if (!arg)
+    error_no_arg("pcb address for the new context");
+
+  if (core_kd == NULL)
+    error("no kernel core file");
+
+  addr = (CORE_ADDR)parse_and_eval_address(arg);
+
+  if (set_context(addr))
+    error("invalid pcb address");
+}
+
+
+
+void
+_initialize_kcorelow()
+{
+  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 = 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");
+}

gnu/usr.bin/binutils/gdb/alpha/nm.h

@@ -69,3 +69,26 @@ extern CORE_ADDR alpha_u_regs_offset();
 
 extern int kernel_debugging;
 extern int kernel_writablecore;
+
+#define ADDITIONAL_OPTIONS \
+        {"kernel", no_argument, &kernel_debugging, 1}, \
+        {"k", no_argument, &kernel_debugging, 1}, \
+        {"wcore", no_argument, &kernel_writablecore, 1}, \
+        {"w", no_argument, &kernel_writablecore, 1},
+
+#define ADDITIONAL_OPTION_HELP \
+        "\
+  --kernel           Enable kernel debugging.\n\
+  --wcore            Make core file writable (only works for /dev/mem).\n\
+                     This option only works while debugging a kernel !!\n\
+"
+
+#define DEFAULT_PROMPT kernel_debugging?"(kgdb) ":"(gdb) "
+
+/* misuse START_PROGRESS to test whether we're running as kgdb */
+/* START_PROGRESS is called at the top of main */
+#undef START_PROGRESS
+#define START_PROGRESS(STR,N) \
+  if (!strcmp(STR, "kgdb")) \
+     kernel_debugging = 1;
+

gnu/usr.bin/binutils/gdb/alpha/tm.h

@@ -22,6 +22,10 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 #define TM_FREEBSDALPHA_H
 
 #include "alpha/tm-alpha.h"
+#ifndef S0_REGNUM
+#define S0_REGNUM (T7_REGNUM+1)
+#endif
+
 
 /* Number of traps that happen between exec'ing the shell to run an
    inferior, and when we finally get to the inferior code.  This is 2