ChangeLog:

	* arm-linux-nat.c: Include "observer.h" and "gdbthread.h".
	(PTRACE_GETHBPREGS, PTRACE_SETHBPREGS): Define.
	(struct arm_linux_hwbp_cap): New type.
	(arm_linux_get_hwbp_cap): New function.
	(arm_linux_get_hw_breakpoint_count): Likewise.
	(arm_linux_get_hw_watchpoint_count): Likewise.
	(arm_linux_can_use_hw_breakpoint): Likewise.
	(arm_hwbp_type): New type.
	(arm_hwbp_control_t): Likewise.
	(struct arm_linux_hw_breakpoint): Likewise.
	(struct arm_linux_thread_points): Likewise.
	(arm_threads): New global variable.
	(arm_linux_find_breakpoints_by_tid): New function.
	(arm_hwbp_control_initialize): Likewise.
	(arm_hwbp_control_is_enabled): Likewise.
	(arm_hwbp_control_disable): Likewise.
	(arm_linux_hw_breakpoint_initialize): Likewise.
	(arm_linux_get_hwbp_type): Likewise.
	(arm_linux_hw_watchpoint_initialize): Likewise.
	(arm_linux_hw_breakpoint_equal): Likewise.
	(arm_linux_insert_hw_breakpoint1): Likewise.
	(arm_linux_remove_hw_breakpoint1): Likewise.
	(arm_linux_insert_hw_breakpoint): Likewise.
	(arm_linux_remove_hw_breakpoint): Likewise.
	(arm_linux_region_ok_for_hw_watchpoint): Likewise.
	(arm_linux_insert_watchpoint): Likewise.
	(arm_linux_remove_watchpoint): Likewise.
	(arm_linux_stopped_data_address): Likewise.
	(arm_linux_stopped_by_watchpoint): Likewise.
	(arm_linux_watchpoint_addr_within_range): Likewise.
	(arm_linux_new_thread): Likewise.
	(arm_linux_thread_exit): Likewise.
	(_initialize_arm_linux_nat): Install hardware breakpoint/watchpoint
	related target callbacks.  Register arm_linux_new_thread and
	arm_linux_thread_exit.
	* arm-tdep.h (arm_pc_is_thumb): Add prototype.
	* arm-tdep.c (arm_pc_is_thumb): Make global.
	(arm_gdbarch_init): Call set_gdbarch_have_nonsteppable_watchpoint.

testsuite/ChangeLog:

	* lib/gdb.exp (skip_hw_breakpoint_tests): Add arm*-*-* target.
	(skip_hw_watchpoint_tests): Likewise.
	(skip_hw_watchpoint_multi_tests): Likewise.

1 files changed, 580 insertions, 0 deletions

diff --git a/gdb/arm-linux-nat.c b/gdb/arm-linux-nat.c
index e501882..43f4fde 100644
--- a/gdb/arm-linux-nat.c
+++ b/gdb/arm-linux-nat.c
@@ -26,6 +26,8 @@
 #include "linux-nat.h"
 #include "target-descriptions.h"
 #include "auxv.h"
+#include "observer.h"
+#include "gdbthread.h"
 
 #include "arm-tdep.h"
 #include "arm-linux-tdep.h"
@@ -61,6 +63,11 @@
 #define PTRACE_SETVFPREGS 28
 #endif
 
+#ifndef PTRACE_GETHBPREGS
+#define PTRACE_GETHBPREGS 29
+#define PTRACE_SETHBPREGS 30
+#endif
+
 /* These are in <asm/elf.h> in current kernels.  */
 #define HWCAP_VFP       64
 #define HWCAP_IWMMXT    512
@@ -739,6 +746,564 @@ arm_linux_read_description (struct target_ops *ops)
   return NULL;
 }
 
+/* Information describing the hardware breakpoint capabilities.  */
+struct arm_linux_hwbp_cap
+{
+  gdb_byte arch;
+  gdb_byte max_wp_length;
+  gdb_byte wp_count;
+  gdb_byte bp_count;
+};
+
+/* Get hold of the Hardware Breakpoint information for the target we are
+   attached to.  Returns NULL if the kernel doesn't support Hardware 
+   breakpoints at all, or a pointer to the information structure.  */
+static const struct arm_linux_hwbp_cap *
+arm_linux_get_hwbp_cap (void)
+{
+  /* The info structure we return.  */
+  static struct arm_linux_hwbp_cap info;
+
+  /* Is INFO in a good state?  -1 means that no attempt has been made to
+     initialize INFO; 0 means an attempt has been made, but it failed; 1
+     means INFO is in an initialized state.  */
+  static int available = -1;
+
+  if (available == -1)
+    {
+      int tid;
+      unsigned int val;
+
+      tid = GET_THREAD_ID (inferior_ptid);
+      if (ptrace (PTRACE_GETHBPREGS, tid, 0, &val) < 0)
+	available = 0;
+      else
+	{
+	  info.arch = (gdb_byte)((val >> 24) & 0xff);
+	  info.max_wp_length = (gdb_byte)((val >> 16) & 0xff);
+	  info.wp_count = (gdb_byte)((val >> 8) & 0xff);
+	  info.bp_count = (gdb_byte)(val & 0xff);
+	  available = (info.arch != 0);
+	}
+    }
+
+  return available == 1 ? &info : NULL;
+}
+
+/* How many hardware breakpoints are available?  */
+static int
+arm_linux_get_hw_breakpoint_count (void)
+{
+  const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap ();
+  return cap != NULL ? cap->bp_count : 0;
+}
+
+/* How many hardware watchpoints are available?  */
+static int
+arm_linux_get_hw_watchpoint_count (void)
+{
+  const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap ();
+  return cap != NULL ? cap->wp_count : 0;
+}
+
+/* Have we got a free break-/watch-point available for use?  Returns -1 if
+   there is not an appropriate resource available, otherwise returns 1.  */
+static int
+arm_linux_can_use_hw_breakpoint (int type, int cnt, int ot)
+{
+  if (type == bp_hardware_watchpoint || type == bp_read_watchpoint
+      || type == bp_access_watchpoint || type == bp_watchpoint)
+    {
+      if (cnt + ot > arm_linux_get_hw_watchpoint_count ())
+	return -1;
+    }
+  else if (type == bp_hardware_breakpoint)
+    {
+      if (cnt > arm_linux_get_hw_breakpoint_count ())
+	return -1;
+    }
+  else
+    gdb_assert (FALSE);
+
+  return 1;
+}
+
+/* Enum describing the different types of ARM hardware break-/watch-points.  */
+typedef enum
+{
+  arm_hwbp_break = 0,
+  arm_hwbp_load = 1,
+  arm_hwbp_store = 2,
+  arm_hwbp_access = 3
+} arm_hwbp_type;
+
+/* Type describing an ARM Hardware Breakpoint Control register value.  */
+typedef unsigned int arm_hwbp_control_t;
+
+/* Structure used to keep track of hardware break-/watch-points.  */
+struct arm_linux_hw_breakpoint
+{
+  /* Address to break on, or being watched.  */
+  unsigned int address;
+  /* Control register for break-/watch- point.  */
+  arm_hwbp_control_t control;
+};
+
+/* Structure containing arrays of the break and watch points which are have
+   active in each thread.
+
+   The Linux ptrace interface to hardware break-/watch-points presents the 
+   values in a vector centred around 0 (which is used fo generic information).
+   Positive indicies refer to breakpoint addresses/control registers, negative
+   indices to watchpoint addresses/control registers.
+
+   The Linux vector is indexed as follows:
+      -((i << 1) + 2): Control register for watchpoint i.
+      -((i << 1) + 1): Address register for watchpoint i.
+                    0: Information register.
+       ((i << 1) + 1): Address register for breakpoint i.
+       ((i << 1) + 2): Control register for breakpoint i.
+
+   This structure is used as a per-thread cache of the state stored by the 
+   kernel, so that we don't need to keep calling into the kernel to find a 
+   free breakpoint.
+
+   We treat break-/watch-points with their enable bit clear as being deleted.
+   */
+typedef struct arm_linux_thread_points
+{
+  /* Thread ID.  */
+  int tid;
+  /* Breakpoints for thread.  */
+  struct arm_linux_hw_breakpoint *bpts;
+  /* Watchpoint for threads.  */
+  struct arm_linux_hw_breakpoint *wpts;
+} *arm_linux_thread_points_p;
+DEF_VEC_P (arm_linux_thread_points_p);
+
+/* Vector of hardware breakpoints for each thread.  */
+VEC(arm_linux_thread_points_p) *arm_threads = NULL;
+
+/* Find the list of hardware break-/watch-points for a thread with id TID.
+   If no list exists for TID we return NULL if ALLOC_NEW is 0, otherwise we
+   create a new list and return that.  */
+static struct arm_linux_thread_points *
+arm_linux_find_breakpoints_by_tid (int tid, int alloc_new)
+{
+  int i;
+  struct arm_linux_thread_points *t;
+
+  for (i = 0; VEC_iterate (arm_linux_thread_points_p, arm_threads, i, t); ++i)
+    {
+      if (t->tid == tid)
+	return t;
+    }
+
+  t = NULL;
+
+  if (alloc_new)
+    {
+      t = xmalloc (sizeof (struct arm_linux_thread_points));
+      t->tid = tid;
+      t->bpts = xzalloc (arm_linux_get_hw_breakpoint_count ()
+			 * sizeof (struct arm_linux_hw_breakpoint));
+      t->wpts = xzalloc (arm_linux_get_hw_watchpoint_count ()
+			 * sizeof (struct arm_linux_hw_breakpoint));
+      VEC_safe_push (arm_linux_thread_points_p, arm_threads, t);
+    }
+
+  return t;
+}
+
+/* Initialize an ARM hardware break-/watch-point control register value.
+   BYTE_ADDRESS_SELECT is the mask of bytes to trigger on; HWBP_TYPE is the 
+   type of break-/watch-point; ENABLE indicates whether the point is enabled.
+   */
+static arm_hwbp_control_t 
+arm_hwbp_control_initialize (unsigned byte_address_select,
+			     arm_hwbp_type hwbp_type,
+			     int enable)
+{
+  gdb_assert ((byte_address_select & ~0xffU) == 0);
+  gdb_assert (hwbp_type != arm_hwbp_break 
+	      || ((byte_address_select & 0xfU) != 0));
+
+  return (byte_address_select << 5) | (hwbp_type << 3) | (3 << 1) | enable;
+}
+
+/* Does the breakpoint control value CONTROL have the enable bit set?  */
+static int
+arm_hwbp_control_is_enabled (arm_hwbp_control_t control)
+{
+  return control & 0x1;
+}
+
+/* Change a breakpoint control word so that it is in the disabled state.  */
+static arm_hwbp_control_t
+arm_hwbp_control_disable (arm_hwbp_control_t control)
+{
+  return control & ~0x1;
+}
+
+/* Initialise the hardware breakpoint structure P.  The breakpoint will be
+   enabled, and will point to the placed address of BP_TGT.  */
+static void
+arm_linux_hw_breakpoint_initialize (struct gdbarch *gdbarch,
+				    struct bp_target_info *bp_tgt,
+				    struct arm_linux_hw_breakpoint *p)
+{
+  unsigned mask;
+  CORE_ADDR address = bp_tgt->placed_address;
+
+  /* We have to create a mask for the control register which says which bits
+     of the word pointed to by address to break on.  */
+  if (arm_pc_is_thumb (gdbarch, address))
+    mask = 0x3 << (address & 2);
+  else
+    mask = 0xf;
+
+  p->address = (unsigned int) (address & ~3);
+  p->control = arm_hwbp_control_initialize (mask, arm_hwbp_break, 1);
+}
+
+/* Get the ARM hardware breakpoint type from the RW value we're given when
+   asked to set a watchpoint.  */
+static arm_hwbp_type 
+arm_linux_get_hwbp_type (int rw)
+{
+  if (rw == hw_read)
+    return arm_hwbp_load;
+  else if (rw == hw_write)
+    return arm_hwbp_store;
+  else
+    return arm_hwbp_access;
+}
+
+/* Initialize the hardware breakpoint structure P for a watchpoint at ADDR
+   to LEN.  The type of watchpoint is given in RW.  */
+static void
+arm_linux_hw_watchpoint_initialize (CORE_ADDR addr, int len, int rw,
+				    struct arm_linux_hw_breakpoint *p)
+{
+  const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap ();
+  unsigned mask;
+
+  gdb_assert (cap != NULL);
+  gdb_assert (cap->max_wp_length != 0);
+
+  mask = (1 << len) - 1;
+
+  p->address = (unsigned int) addr;
+  p->control = arm_hwbp_control_initialize (mask, 
+					    arm_linux_get_hwbp_type (rw), 1);
+}
+
+/* Are two break-/watch-points equal?  */
+static int
+arm_linux_hw_breakpoint_equal (const struct arm_linux_hw_breakpoint *p1,
+			       const struct arm_linux_hw_breakpoint *p2)
+{
+  return p1->address == p2->address && p1->control == p2->control;
+}
+
+/* Insert the hardware breakpoint (WATCHPOINT = 0) or watchpoint (WATCHPOINT
+   =1) BPT for thread TID.  */
+static void
+arm_linux_insert_hw_breakpoint1 (const struct arm_linux_hw_breakpoint* bpt, 
+				int tid, int watchpoint)
+{
+  struct arm_linux_thread_points *t = arm_linux_find_breakpoints_by_tid (tid, 1);
+  gdb_byte count, i;
+  struct arm_linux_hw_breakpoint* bpts;
+  int dir;
+
+  gdb_assert (t != NULL);
+
+  if (watchpoint)
+    {
+      count = arm_linux_get_hw_watchpoint_count ();
+      bpts = t->wpts;
+      dir = -1;
+    }
+  else
+    {
+      count = arm_linux_get_hw_breakpoint_count ();
+      bpts = t->bpts;
+      dir = 1;
+    }
+
+  for (i = 0; i < count; ++i)
+    if (!arm_hwbp_control_is_enabled (bpts[i].control))
+      {
+	errno = 0;
+	if (ptrace (PTRACE_SETHBPREGS, tid, dir * ((i << 1) + 1), 
+		    &bpt->address) < 0)
+	  perror_with_name (_("Unexpected error setting breakpoint address"));
+	if (ptrace (PTRACE_SETHBPREGS, tid, dir * ((i << 1) + 2), 
+		    &bpt->control) < 0)
+	  perror_with_name (_("Unexpected error setting breakpoint"));
+
+	memcpy (bpts + i, bpt, sizeof (struct arm_linux_hw_breakpoint));
+	break;
+      }
+
+  gdb_assert (i != count);
+}
+
+/* Remove the hardware breakpoint (WATCHPOINT = 0) or watchpoint
+   (WATCHPOINT = 1) BPT for thread TID.  */
+static void
+arm_linux_remove_hw_breakpoint1 (const struct arm_linux_hw_breakpoint *bpt, 
+				 int tid, int watchpoint)
+{
+  struct arm_linux_thread_points *t = arm_linux_find_breakpoints_by_tid (tid, 0);
+  gdb_byte count, i;
+  struct arm_linux_hw_breakpoint *bpts;
+  int dir;
+
+  gdb_assert (t != NULL);
+
+  if (watchpoint)
+    {
+      count = arm_linux_get_hw_watchpoint_count ();
+      bpts = t->wpts;
+      dir = -1;
+    }
+  else
+    {
+      count = arm_linux_get_hw_breakpoint_count ();
+      bpts = t->bpts;
+      dir = 1;
+    }
+
+  for (i = 0; i < count; ++i)
+    if (arm_linux_hw_breakpoint_equal (bpt, bpts + i))
+      {
+	errno = 0;
+	bpts[i].control = arm_hwbp_control_disable (bpts[i].control);
+	if (ptrace (PTRACE_SETHBPREGS, tid, dir * ((i << 1) + 2), 
+		    &bpts[i].control) < 0)
+	  perror_with_name (_("Unexpected error clearing breakpoint"));
+	break;
+      }
+
+  gdb_assert (i != count);
+}
+
+/* Insert a Hardware breakpoint.  */
+static int
+arm_linux_insert_hw_breakpoint (struct gdbarch *gdbarch, 
+				struct bp_target_info *bp_tgt)
+{
+  ptid_t ptid;
+  struct lwp_info *lp;
+  struct arm_linux_hw_breakpoint p;
+
+  if (arm_linux_get_hw_breakpoint_count () == 0)
+    return -1;
+
+  arm_linux_hw_breakpoint_initialize (gdbarch, bp_tgt, &p);
+  ALL_LWPS (lp, ptid)
+    arm_linux_insert_hw_breakpoint1 (&p, TIDGET (ptid), 0);
+
+  return 0;
+}
+
+/* Remove a hardware breakpoint.  */
+static int
+arm_linux_remove_hw_breakpoint (struct gdbarch *gdbarch, 
+				struct bp_target_info *bp_tgt)
+{
+  ptid_t ptid;
+  struct lwp_info *lp;
+  struct arm_linux_hw_breakpoint p;
+
+  if (arm_linux_get_hw_breakpoint_count () == 0)
+    return -1;
+
+  arm_linux_hw_breakpoint_initialize (gdbarch, bp_tgt, &p);
+  ALL_LWPS (lp, ptid)
+    arm_linux_remove_hw_breakpoint1 (&p, TIDGET (ptid), 0);
+
+  return 0;
+}
+
+/* Are we able to use a hardware watchpoint for the LEN bytes starting at 
+   ADDR?  */
+static int
+arm_linux_region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
+{
+  const struct arm_linux_hwbp_cap *cap = arm_linux_get_hwbp_cap ();
+  CORE_ADDR max_wp_length, aligned_addr;
+
+  /* Can not set watchpoints for zero or negative lengths.  */
+  if (len <= 0)
+    return 0;
+
+  /* Need to be able to use the ptrace interface.  */
+  if (cap == NULL || cap->wp_count == 0)
+    return 0;
+
+  /* Test that the range [ADDR, ADDR + LEN) fits into the largest address
+     range covered by a watchpoint.  */
+  max_wp_length = (CORE_ADDR)cap->max_wp_length;
+  aligned_addr = addr & ~(max_wp_length - 1);
+
+  if (aligned_addr + max_wp_length < addr + len)
+    return 0;
+
+  /* The current ptrace interface can only handle watchpoints that are a
+     power of 2.  */
+  if ((len & (len - 1)) != 0)
+    return 0;
+
+  /* All tests passed so we must be able to set a watchpoint.  */
+  return 1;
+}
+
+/* Insert a Hardware breakpoint.  */
+static int
+arm_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw,
+			     struct expression *cond)
+{
+  ptid_t ptid;
+  struct lwp_info *lp;
+  struct arm_linux_hw_breakpoint p;
+
+  if (arm_linux_get_hw_watchpoint_count () == 0)
+    return -1;
+
+  arm_linux_hw_watchpoint_initialize (addr, len, rw, &p);
+  ALL_LWPS (lp, ptid)
+    arm_linux_insert_hw_breakpoint1 (&p, TIDGET (ptid), 1);
+
+  return 0;
+}
+
+/* Remove a hardware breakpoint.  */
+static int
+arm_linux_remove_watchpoint (CORE_ADDR addr, int len, int rw,
+			     struct expression *cond)
+{
+  ptid_t ptid;
+  struct lwp_info *lp;
+  struct arm_linux_hw_breakpoint p;
+
+  if (arm_linux_get_hw_watchpoint_count () == 0)
+    return -1;
+
+  arm_linux_hw_watchpoint_initialize (addr, len, rw, &p);
+  ALL_LWPS (lp, ptid)
+    arm_linux_remove_hw_breakpoint1 (&p, TIDGET (ptid), 1);
+
+  return 0;
+}
+
+/* What was the data address the target was stopped on accessing.  */
+static int
+arm_linux_stopped_data_address (struct target_ops *target, CORE_ADDR *addr_p)
+{
+  struct siginfo *siginfo_p = linux_nat_get_siginfo (inferior_ptid);
+  int slot = siginfo_p->si_errno;
+
+  /* This must be a hardware breakpoint.  */
+  if (siginfo_p->si_signo != SIGTRAP
+      || (siginfo_p->si_code & 0xffff) != 0x0004 /* TRAP_HWBKPT */)
+    return 0;
+
+  /* We must be able to set hardware watchpoints.  */
+  if (arm_linux_get_hw_watchpoint_count () == 0)
+    return 0;
+
+  /* If we are in a positive slot then we're looking at a breakpoint and not
+     a watchpoint.  */
+  if (slot >= 0)
+    return 0;
+
+  *addr_p = (CORE_ADDR) (uintptr_t) siginfo_p->si_addr;
+  return 1;
+}
+
+/* Has the target been stopped by hitting a watchpoint?  */
+static int
+arm_linux_stopped_by_watchpoint (void)
+{
+  CORE_ADDR addr;
+  return arm_linux_stopped_data_address (&current_target, &addr);
+}
+
+static int
+arm_linux_watchpoint_addr_within_range (struct target_ops *target,
+					CORE_ADDR addr,
+					CORE_ADDR start, int length)
+{
+  return start <= addr && start + length - 1 >= addr;
+}
+
+/* Handle thread creation.  We need to copy the breakpoints and watchpoints
+   in the parent thread to the child thread.  */
+static void
+arm_linux_new_thread (ptid_t ptid)
+{
+  int tid = TIDGET (ptid);
+  const struct arm_linux_hwbp_cap *info = arm_linux_get_hwbp_cap ();
+
+  if (info != NULL)
+    {
+      int i;
+      struct arm_linux_thread_points *p;
+      struct arm_linux_hw_breakpoint *bpts;
+
+      if (VEC_empty (arm_linux_thread_points_p, arm_threads))
+	return;
+
+      /* Get a list of breakpoints from any thread. */
+      p = VEC_last (arm_linux_thread_points_p, arm_threads);
+
+      /* Copy that thread's breakpoints and watchpoints to the new thread. */
+      for (i = 0; i < info->bp_count; i++)
+	if (arm_hwbp_control_is_enabled (p->bpts[i].control))
+	  arm_linux_insert_hw_breakpoint1 (p->bpts + i, tid, 0);
+      for (i = 0; i < info->wp_count; i++)
+	if (arm_hwbp_control_is_enabled (p->wpts[i].control))
+	  arm_linux_insert_hw_breakpoint1 (p->wpts + i, tid, 1);
+    }
+}
+
+/* Handle thread exit.  Tidy up the memory that has been allocated for the
+   thread.  */
+static void
+arm_linux_thread_exit (struct thread_info *tp, int silent)
+{
+  const struct arm_linux_hwbp_cap *info = arm_linux_get_hwbp_cap ();
+
+  if (info != NULL)
+    {
+      int i;
+      int tid = TIDGET (tp->ptid);
+      struct arm_linux_thread_points *t = NULL, *p;
+
+      for (i = 0; 
+	   VEC_iterate (arm_linux_thread_points_p, arm_threads, i, p); i++)
+	{
+	  if (p->tid == tid)
+	    {
+	      t = p;
+	      break;
+	    }
+	}
+
+      if (t == NULL)
+	return;
+
+      VEC_unordered_remove (arm_linux_thread_points_p, arm_threads, i);
+
+      xfree (t->bpts);
+      xfree (t->wpts);
+      xfree (t);
+    }
+}
+
 void _initialize_arm_linux_nat (void);
 
 void
@@ -755,8 +1320,23 @@ _initialize_arm_linux_nat (void)
   t->to_fetch_registers = arm_linux_fetch_inferior_registers;
   t->to_store_registers = arm_linux_store_inferior_registers;
 
+  /* Add our hardware breakpoint and watchpoint implementation.  */
+  t->to_can_use_hw_breakpoint = arm_linux_can_use_hw_breakpoint;
+  t->to_insert_hw_breakpoint = arm_linux_insert_hw_breakpoint;
+  t->to_remove_hw_breakpoint = arm_linux_remove_hw_breakpoint;
+  t->to_region_ok_for_hw_watchpoint = arm_linux_region_ok_for_hw_watchpoint;
+  t->to_insert_watchpoint = arm_linux_insert_watchpoint;
+  t->to_remove_watchpoint = arm_linux_remove_watchpoint;
+  t->to_stopped_by_watchpoint = arm_linux_stopped_by_watchpoint;
+  t->to_stopped_data_address = arm_linux_stopped_data_address;
+  t->to_watchpoint_addr_within_range = arm_linux_watchpoint_addr_within_range;
+
   t->to_read_description = arm_linux_read_description;
 
   /* Register the target.  */
   linux_nat_add_target (t);
+
+  /* Handle thread creation and exit */
+  observer_attach_thread_exit (arm_linux_thread_exit);
+  linux_nat_set_new_thread (t, arm_linux_new_thread);
 }