Add the target_ops needed for software breakpoints in GDBServer.

This patch is in preparation for software breakpoints on ARM linux.  It
refactors breakpoint and breakpoint_len into breakpoint_kind_from_pc and
sw_breakpoint_from kind to prepare the case where we have multiple types of
breakpoints.

Kind is the type of breakpoint (hardware or software) to be inserted, usually it
is the lenght of the software breakpoint but can be something else depending on
the target.

This patch introduces the linux_target_ops breakpoint_kind_from_pc and
sw_breakpoint_from_kind.

breakpoint_kind_from_pc returns the breakpoint kind and adjusts the PC to the
real memory location in case a flag was present in the PC. E.g the instruction
mode on ARM.

sw_breakpoint_from_kind returns the software breakpoint for this kind as a
string of bytes, the length of the breakpoint is adjusted for the breakpoint's
size in memory.

For targets that have only one kind of breakpoint, the default value 0 is
returned by linux_breakpoint_kind_from_pc so that not all targets need to
implement the breakpoint_kind_from_pc operation.

No regressions, tested on Ubuntu 14.04 on ARMv7 and x86
With gdbserver-{native,extended} / { -marm -mthumb }

Also since the target_ops have been changed compilation was tested on
affected archs namely : aarch64, arm, bfin, cris, crisv32, m32r,
m68k, mips, nios2, ppc, s390, sparc, tic6x, tile, x86, steins.

Not tested : sh

gdb/gdbserver/ChangeLog:

	* linux-aarch64-low.c (aarch64_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-arm-low.c (arm_breakpoint_kind_from_pc): New function.
	(arm_sw_breakpoint_from_kind): New function.
	* linux-bfin-low.c (bfin_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-cris-low.c (cris_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-crisv32-low.c (cris_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-low.c (linux_wait_1): Call breakpoint_kind_from_pc
	and sw_breakpoint_from_kind to increment the pc.
	(linux_breakpoint_kind_from_pc): New function.
	(linux_sw_breakpoint_from_kind): New function.
	(struct target_ops) <sw_breakpoint_from_kind>: Initialize field.
	(initialize_low): Call breakpoint_kind_from_pc and
	sw_breakpoint_from_kind to replace breakpoint_data/len.
	* linux-low.h (struct linux_target_ops) <breakpoint_kind_from_pc>:
	New field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Likewise.
	* linux-m32r-low.c (m32r_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-m68k-low.c (m68k_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-mips-low.c (mips_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-nios2-low.c (nios2_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-ppc-low.c (ppc_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-s390-low.c (s390_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-sh-low.c (sh_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-sparc-low.c (sparc_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-tic6x-low.c (tic6x_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-tile-low.c (tile_sw_breakpoint_from_kind): New function.
	* linux-x86-low.c (x86_sw_breakpoint_from_kind): New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
	* linux-xtensa-low.c (xtensa_sw_breakpoint_from_kind) New function.
	(struct linux_target_ops) <breakpoint>: Remove.
	(struct linux_target_ops) <breakpoint_len>: Remove.
	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.

21 files changed, 356 insertions, 62 deletions

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 8e73d9f..10ae158 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,96 @@
 2015-10-21  Antoine Tremblay  <antoine.tremblay@ericsson.com>
 
+	* linux-aarch64-low.c (aarch64_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-arm-low.c (arm_breakpoint_kind_from_pc): New function.
+	(arm_sw_breakpoint_from_kind): New function.
+	* linux-bfin-low.c (bfin_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-cris-low.c (cris_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-crisv32-low.c (cris_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-low.c (linux_wait_1): Call breakpoint_kind_from_pc
+	and sw_breakpoint_from_kind to increment the pc.
+	(linux_breakpoint_kind_from_pc): New function.
+	(linux_sw_breakpoint_from_kind): New function.
+	(struct target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	(initialize_low): Call breakpoint_kind_from_pc and
+	sw_breakpoint_from_kind to replace breakpoint_data/len.
+	* linux-low.h (struct linux_target_ops) <breakpoint_kind_from_pc>:
+	New field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Likewise.
+	* linux-m32r-low.c (m32r_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-m68k-low.c (m68k_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-mips-low.c (mips_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-nios2-low.c (nios2_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-ppc-low.c (ppc_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-s390-low.c (s390_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-sh-low.c (sh_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-sparc-low.c (sparc_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-tic6x-low.c (tic6x_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-tile-low.c (tile_sw_breakpoint_from_kind): New function.
+	* linux-x86-low.c (x86_sw_breakpoint_from_kind): New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+	* linux-xtensa-low.c (xtensa_sw_breakpoint_from_kind) New function.
+	(struct linux_target_ops) <breakpoint>: Remove.
+	(struct linux_target_ops) <breakpoint_len>: Remove.
+	(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
+	(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
+
+2015-10-21  Antoine Tremblay  <antoine.tremblay@ericsson.com>
+
 	* linux-cris-low.c (cris_get_pc): Remove void arg.
 
 2015-10-16  Aleksandar Ristovski  <aristovski@qnx.com>
diff --git a/gdb/gdbserver/linux-aarch64-low.c b/gdb/gdbserver/linux-aarch64-low.c
index 780c5e3..cb49a04 100644
--- a/gdb/gdbserver/linux-aarch64-low.c
+++ b/gdb/gdbserver/linux-aarch64-low.c
@@ -2931,6 +2931,15 @@ aarch64_supports_range_stepping (void)
   return 1;
 }
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+aarch64_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = aarch64_breakpoint_len;
+  return aarch64_breakpoint;
+}
+
 struct linux_target_ops the_low_target =
 {
   aarch64_arch_setup,
@@ -2940,8 +2949,8 @@ struct linux_target_ops the_low_target =
   NULL, /* fetch_register */
   aarch64_get_pc,
   aarch64_set_pc,
-  (const unsigned char *) &aarch64_breakpoint,
-  aarch64_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  aarch64_sw_breakpoint_from_kind,
   NULL, /* breakpoint_reinsert_addr */
   0,    /* decr_pc_after_break */
   aarch64_breakpoint_at,
diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
index a277bb6..3a56620 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -913,26 +913,34 @@ arm_regs_info (void)
     return &regs_info_arm;
 }
 
-struct linux_target_ops the_low_target = {
-  arm_arch_setup,
-  arm_regs_info,
-  arm_cannot_fetch_register,
-  arm_cannot_store_register,
-  NULL, /* fetch_register */
-  arm_get_pc,
-  arm_set_pc,
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
 
+static const gdb_byte *
+arm_sw_breakpoint_from_kind (int kind , int *size)
+{
+  *size = arm_breakpoint_len;
   /* Define an ARM-mode breakpoint; we only set breakpoints in the C
      library, which is most likely to be ARM.  If the kernel supports
      clone events, we will never insert a breakpoint, so even a Thumb
      C library will work; so will mixing EABI/non-EABI gdbserver and
      application.  */
 #ifndef __ARM_EABI__
-  (const unsigned char *) &arm_breakpoint,
+  return (const gdb_byte *) &arm_breakpoint;
 #else
-  (const unsigned char *) &arm_eabi_breakpoint,
+  return (const gdb_byte *) &arm_eabi_breakpoint;
 #endif
-  arm_breakpoint_len,
+}
+
+struct linux_target_ops the_low_target = {
+  arm_arch_setup,
+  arm_regs_info,
+  arm_cannot_fetch_register,
+  arm_cannot_store_register,
+  NULL, /* fetch_register */
+  arm_get_pc,
+  arm_set_pc,
+  NULL, /* breakpoint_kind_from_pc */
+  arm_sw_breakpoint_from_kind,
   arm_reinsert_addr,
   0,
   arm_breakpoint_at,
diff --git a/gdb/gdbserver/linux-bfin-low.c b/gdb/gdbserver/linux-bfin-low.c
index 4002f22..d3b83fc 100644
--- a/gdb/gdbserver/linux-bfin-low.c
+++ b/gdb/gdbserver/linux-bfin-low.c
@@ -73,7 +73,16 @@ bfin_set_pc (struct regcache *regcache, CORE_ADDR pc)
 }
 
 #define bfin_breakpoint_len 2
-static const unsigned char bfin_breakpoint[bfin_breakpoint_len] = {0xa1, 0x00};
+static const gdb_byte bfin_breakpoint[bfin_breakpoint_len] = {0xa1, 0x00};
+
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+bfin_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = bfin_breakpoint_len;
+  return bfin_breakpoint;
+}
 
 static int
 bfin_breakpoint_at (CORE_ADDR where)
@@ -122,8 +131,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   bfin_get_pc,
   bfin_set_pc,
-  bfin_breakpoint,
-  bfin_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  bfin_sw_breakpoint_from_kind,
   NULL, /* breakpoint_reinsert_addr */
   2,
   bfin_breakpoint_at,
diff --git a/gdb/gdbserver/linux-cris-low.c b/gdb/gdbserver/linux-cris-low.c
index 135e37a..d7b70e3 100644
--- a/gdb/gdbserver/linux-cris-low.c
+++ b/gdb/gdbserver/linux-cris-low.c
@@ -81,6 +81,15 @@ cris_set_pc (struct regcache *regcache, CORE_ADDR pc)
 static const unsigned short cris_breakpoint = 0xe938;
 #define cris_breakpoint_len 2
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+cris_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = cris_breakpoint_len;
+  return (const gdb_byte *) &cris_breakpoint;
+}
+
 static int
 cris_breakpoint_at (CORE_ADDR where)
 {
@@ -140,8 +149,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   cris_get_pc,
   cris_set_pc,
-  (const unsigned char *) &cris_breakpoint,
-  cris_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  cris_sw_breakpoint_from_kind,
   cris_reinsert_addr,
   0,
   cris_breakpoint_at,
diff --git a/gdb/gdbserver/linux-crisv32-low.c b/gdb/gdbserver/linux-crisv32-low.c
index 5120863..f97122e 100644
--- a/gdb/gdbserver/linux-crisv32-low.c
+++ b/gdb/gdbserver/linux-crisv32-low.c
@@ -77,6 +77,15 @@ cris_set_pc (struct regcache *regcache, CORE_ADDR pc)
 static const unsigned short cris_breakpoint = 0xe938;
 #define cris_breakpoint_len 2
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+cris_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = cris_breakpoint_len;
+  return (const gdb_byte *) &cris_breakpoint;
+}
+
 static int
 cris_breakpoint_at (CORE_ADDR where)
 {
@@ -420,8 +429,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   cris_get_pc,
   cris_set_pc,
-  (const unsigned char *) &cris_breakpoint,
-  cris_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  cris_sw_breakpoint_from_kind,
   cris_reinsert_addr,
   0,
   cris_breakpoint_at,
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 3a1a6ae..398c0aa 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -3012,7 +3012,12 @@ linux_wait_1 (ptid_t ptid,
   if (!ptid_equal (step_over_bkpt, null_ptid)
       && event_child->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT)
     {
-      unsigned int increment_pc = the_low_target.breakpoint_len;
+      int increment_pc = 0;
+      int breakpoint_kind = 0;
+      CORE_ADDR stop_pc = event_child->stop_pc;
+
+      breakpoint_kind = the_target->breakpoint_kind_from_pc (&stop_pc);
+      the_target->sw_breakpoint_from_kind (breakpoint_kind, &increment_pc);
 
       if (debug_threads)
 	{
@@ -6932,6 +6937,28 @@ current_lwp_ptid (void)
   return ptid_of (current_thread);
 }
 
+/* Implementation of the target_ops method "breakpoint_kind_from_pc".  */
+
+static int
+linux_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
+{
+  if (the_low_target.breakpoint_kind_from_pc != NULL)
+    return (*the_low_target.breakpoint_kind_from_pc) (pcptr);
+  else
+    /* Default breakpoint kind value.  */
+    return 0;
+}
+
+/* Implementation of the target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+linux_sw_breakpoint_from_kind (int kind, int *size)
+{
+  gdb_assert (the_low_target.sw_breakpoint_from_kind != NULL);
+
+  return (*the_low_target.sw_breakpoint_from_kind) (kind, size);
+}
+
 static struct target_ops linux_target_ops = {
   linux_create_inferior,
   linux_arch_setup,
@@ -7026,6 +7053,8 @@ static struct target_ops linux_target_ops = {
   linux_mntns_open_cloexec,
   linux_mntns_unlink,
   linux_mntns_readlink,
+  linux_breakpoint_kind_from_pc,
+  linux_sw_breakpoint_from_kind
 };
 
 static void
@@ -7053,10 +7082,20 @@ void
 initialize_low (void)
 {
   struct sigaction sigchld_action;
+  int breakpoint_kind = 0;
+  int breakpoint_size = 0;
+  const gdb_byte *breakpoint = NULL;
+
   memset (&sigchld_action, 0, sizeof (sigchld_action));
   set_target_ops (&linux_target_ops);
-  set_breakpoint_data (the_low_target.breakpoint,
-		       the_low_target.breakpoint_len);
+
+  breakpoint_kind = the_target->breakpoint_kind_from_pc (NULL);
+  breakpoint = the_target->sw_breakpoint_from_kind (breakpoint_kind,
+						    &breakpoint_size);
+
+  set_breakpoint_data (breakpoint,
+		       breakpoint_size);
+
   linux_init_signals ();
   linux_ptrace_init_warnings ();
 
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index f8f6e78..28dd4db 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -141,8 +141,13 @@ struct linux_target_ops
 
   CORE_ADDR (*get_pc) (struct regcache *regcache);
   void (*set_pc) (struct regcache *regcache, CORE_ADDR newpc);
-  const unsigned char *breakpoint;
-  int breakpoint_len;
+
+  /* See target.h for details.  */
+  int (*breakpoint_kind_from_pc) (CORE_ADDR *pcptr);
+
+  /* See target.h for details.  */
+  const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
+
   CORE_ADDR (*breakpoint_reinsert_addr) (void);
 
   int decr_pc_after_break;
diff --git a/gdb/gdbserver/linux-m32r-low.c b/gdb/gdbserver/linux-m32r-low.c
index 8ffeda2..bb1002f 100644
--- a/gdb/gdbserver/linux-m32r-low.c
+++ b/gdb/gdbserver/linux-m32r-low.c
@@ -73,6 +73,15 @@ m32r_set_pc (struct regcache *regcache, CORE_ADDR pc)
 static const unsigned short m32r_breakpoint = 0x10f1;
 #define m32r_breakpoint_len 2
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+m32r_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = m32r_breakpoint_len;
+  return (const gdb_byte *) &m32r_breakpoint;
+}
+
 static int
 m32r_breakpoint_at (CORE_ADDR where)
 {
@@ -120,8 +129,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   m32r_get_pc,
   m32r_set_pc,
-  (const unsigned char *) &m32r_breakpoint,
-  m32r_breakpoint_len,
+  NULL, /* breakpoint_from_pc */
+  m32r_sw_breakpoint_from_kind,
   NULL,
   0,
   m32r_breakpoint_at,
diff --git a/gdb/gdbserver/linux-m68k-low.c b/gdb/gdbserver/linux-m68k-low.c
index 39c9cc5..ba8e5e9 100644
--- a/gdb/gdbserver/linux-m68k-low.c
+++ b/gdb/gdbserver/linux-m68k-low.c
@@ -122,9 +122,18 @@ static struct regset_info m68k_regsets[] = {
   { 0, 0, 0, -1, -1, NULL, NULL }
 };
 
-static const unsigned char m68k_breakpoint[] = { 0x4E, 0x4F };
+static const gdb_byte m68k_breakpoint[] = { 0x4E, 0x4F };
 #define m68k_breakpoint_len 2
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+m68k_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = m68k_breakpoint_len;
+  return m68k_breakpoint;
+}
+
 static CORE_ADDR
 m68k_get_pc (struct regcache *regcache)
 {
@@ -215,8 +224,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   m68k_get_pc,
   m68k_set_pc,
-  m68k_breakpoint,
-  m68k_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  m68k_sw_breakpoint_from_kind,
   NULL,
   2,
   m68k_breakpoint_at,
diff --git a/gdb/gdbserver/linux-mips-low.c b/gdb/gdbserver/linux-mips-low.c
index d1181b6..344d7a5 100644
--- a/gdb/gdbserver/linux-mips-low.c
+++ b/gdb/gdbserver/linux-mips-low.c
@@ -266,6 +266,15 @@ mips_set_pc (struct regcache *regcache, CORE_ADDR pc)
 static const unsigned int mips_breakpoint = 0x0005000d;
 #define mips_breakpoint_len 4
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+mips_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = mips_breakpoint_len;
+  return (const gdb_byte *) &mips_breakpoint;
+}
+
 /* We only place breakpoints in empty marker functions, and thread locking
    is outside of the function.  So rather than importing software single-step,
    we can just run until exit.  */
@@ -881,8 +890,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   mips_get_pc,
   mips_set_pc,
-  (const unsigned char *) &mips_breakpoint,
-  mips_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  mips_sw_breakpoint_from_kind,
   mips_reinsert_addr,
   0,
   mips_breakpoint_at,
diff --git a/gdb/gdbserver/linux-nios2-low.c b/gdb/gdbserver/linux-nios2-low.c
index 71542b4..95a2d9e 100644
--- a/gdb/gdbserver/linux-nios2-low.c
+++ b/gdb/gdbserver/linux-nios2-low.c
@@ -127,9 +127,23 @@ nios2_set_pc (struct regcache *regcache, CORE_ADDR pc)
 #define NIOS2_BREAKPOINT 0x003b6ffa
 #endif
 
+/* We only register the 4-byte breakpoint, even on R2 targets which also
+   support 2-byte breakpoints.  Since there is no supports_z_point_type
+   function provided, gdbserver never inserts software breakpoints itself
+   and instead relies on GDB to insert the breakpoint of the correct length
+   via a memory write.  */
 static const unsigned int nios2_breakpoint = NIOS2_BREAKPOINT;
 #define nios2_breakpoint_len 4
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+nios2_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = nios2_breakpoint_len;
+  return (const gdb_byte *) &nios2_breakpoint;
+}
+
 /* Implement the breakpoint_reinsert_addr linux_target_ops method.  */
 
 static CORE_ADDR
@@ -263,14 +277,8 @@ struct linux_target_ops the_low_target =
   NULL,
   nios2_get_pc,
   nios2_set_pc,
-
-  /* We only register the 4-byte breakpoint, even on R2 targets which also
-     support 2-byte breakpoints.  Since there is no supports_z_point_type
-     function provided, gdbserver never inserts software breakpoints itself
-     and instead relies on GDB to insert the breakpoint of the correct length
-     via a memory write.  */
-  (const unsigned char *) &nios2_breakpoint,
-  nios2_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  nios2_sw_breakpoint_from_kind,
   nios2_reinsert_addr,
   0,
   nios2_breakpoint_at,
diff --git a/gdb/gdbserver/linux-ppc-low.c b/gdb/gdbserver/linux-ppc-low.c
index 188fac0..6e6a936 100644
--- a/gdb/gdbserver/linux-ppc-low.c
+++ b/gdb/gdbserver/linux-ppc-low.c
@@ -486,6 +486,15 @@ ppc_arch_setup (void)
 static const unsigned int ppc_breakpoint = 0x7d821008;
 #define ppc_breakpoint_len 4
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+ppc_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = ppc_breakpoint_len;
+  return (const gdb_byte *) &ppc_breakpoint;
+}
+
 static int
 ppc_breakpoint_at (CORE_ADDR where)
 {
@@ -685,8 +694,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   ppc_get_pc,
   ppc_set_pc,
-  (const unsigned char *) &ppc_breakpoint,
-  ppc_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  ppc_sw_breakpoint_from_kind,
   NULL,
   0,
   ppc_breakpoint_at,
diff --git a/gdb/gdbserver/linux-s390-low.c b/gdb/gdbserver/linux-s390-low.c
index 8a0a689..2ba1221 100644
--- a/gdb/gdbserver/linux-s390-low.c
+++ b/gdb/gdbserver/linux-s390-low.c
@@ -394,9 +394,18 @@ static struct regset_info s390_regsets[] = {
 };
 
 
-static const unsigned char s390_breakpoint[] = { 0, 1 };
+static const gdb_byte s390_breakpoint[] = { 0, 1 };
 #define s390_breakpoint_len 2
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+s390_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = s390_breakpoint_len;
+  return s390_breakpoint;
+}
+
 static CORE_ADDR
 s390_get_pc (struct regcache *regcache)
 {
@@ -665,8 +674,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   s390_get_pc,
   s390_set_pc,
-  s390_breakpoint,
-  s390_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  s390_sw_breakpoint_from_kind,
   NULL,
   s390_breakpoint_len,
   s390_breakpoint_at,
diff --git a/gdb/gdbserver/linux-sh-low.c b/gdb/gdbserver/linux-sh-low.c
index 218d4d3..f7f3239 100644
--- a/gdb/gdbserver/linux-sh-low.c
+++ b/gdb/gdbserver/linux-sh-low.c
@@ -77,6 +77,15 @@ sh_set_pc (struct regcache *regcache, CORE_ADDR pc)
 static const unsigned short sh_breakpoint = 0xc3c3;
 #define sh_breakpoint_len 2
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+sh_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = sh_breakpoint_len;
+  return (const gdb_byte *) &sh_breakpoint;
+}
+
 static int
 sh_breakpoint_at (CORE_ADDR where)
 {
@@ -148,8 +157,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   sh_get_pc,
   sh_set_pc,
-  (const unsigned char *) &sh_breakpoint,
-  sh_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  sh_sw_breakpoint_from_kind,
   NULL,
   0,
   sh_breakpoint_at,
diff --git a/gdb/gdbserver/linux-sparc-low.c b/gdb/gdbserver/linux-sparc-low.c
index 796af8a..0691867 100644
--- a/gdb/gdbserver/linux-sparc-low.c
+++ b/gdb/gdbserver/linux-sparc-low.c
@@ -235,11 +235,19 @@ sparc_get_pc (struct regcache *regcache)
   return pc;
 }
 
-static const unsigned char sparc_breakpoint[INSN_SIZE] = {
+static const gdb_byte sparc_breakpoint[INSN_SIZE] = {
   0x91, 0xd0, 0x20, 0x01
 };
 #define sparc_breakpoint_len INSN_SIZE
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const unsigned char *
+sparc_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = sparc_breakpoint_len;
+  return sparc_breakpoint;
+}
 
 static int
 sparc_breakpoint_at (CORE_ADDR where)
@@ -323,8 +331,8 @@ struct linux_target_ops the_low_target = {
   sparc_get_pc,
   /* No sparc_set_pc is needed.  */
   NULL,
-  (const unsigned char *) sparc_breakpoint,
-  sparc_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  sparc_sw_breakpoint_from_kind,
   sparc_reinsert_addr,
   0,
   sparc_breakpoint_at,
diff --git a/gdb/gdbserver/linux-tic6x-low.c b/gdb/gdbserver/linux-tic6x-low.c
index a2ac3ee..d9476fd 100644
--- a/gdb/gdbserver/linux-tic6x-low.c
+++ b/gdb/gdbserver/linux-tic6x-low.c
@@ -171,6 +171,16 @@ extern struct linux_target_ops the_low_target;
 
 static int *tic6x_regmap;
 static unsigned int tic6x_breakpoint;
+#define tic6x_breakpoint_len 4
+
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+tic6x_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = tic6x_breakpoint_len;
+  return (const gdb_byte *) &tic6x_breakpoint;
+}
 
 /* Forward definition.  */
 static struct usrregs_info tic6x_usrregs_info;
@@ -247,8 +257,6 @@ tic6x_set_pc (struct regcache *regcache, CORE_ADDR pc)
   supply_register_by_name (regcache, "PC", newpc.buf);
 }
 
-#define tic6x_breakpoint_len 4
-
 static int
 tic6x_breakpoint_at (CORE_ADDR where)
 {
@@ -367,8 +375,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   tic6x_get_pc,
   tic6x_set_pc,
-  (const unsigned char *) &tic6x_breakpoint,
-  tic6x_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  tic6x_sw_breakpoint_from_kind,
   NULL,
   0,
   tic6x_breakpoint_at,
diff --git a/gdb/gdbserver/linux-tile-low.c b/gdb/gdbserver/linux-tile-low.c
index 6aaea6a..e31a620 100644
--- a/gdb/gdbserver/linux-tile-low.c
+++ b/gdb/gdbserver/linux-tile-low.c
@@ -88,6 +88,15 @@ tile_set_pc (struct regcache *regcache, CORE_ADDR pc)
 static uint64_t tile_breakpoint = 0x400b3cae70166000ULL;
 #define tile_breakpoint_len 8
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+tile_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = tile_breakpoint_len;
+  return (const gdb_byte *) &tile_breakpoint;
+}
+
 static int
 tile_breakpoint_at (CORE_ADDR where)
 {
@@ -182,8 +191,8 @@ struct linux_target_ops the_low_target =
   NULL,
   tile_get_pc,
   tile_set_pc,
-  (const unsigned char *) &tile_breakpoint,
-  tile_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  tile_sw_breakpoint_from_kind,
   NULL,
   0,
   tile_breakpoint_at,
diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index 20d4257..406d552 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -502,7 +502,7 @@ x86_set_pc (struct regcache *regcache, CORE_ADDR pc)
     }
 }
 
-static const unsigned char x86_breakpoint[] = { 0xCC };
+static const gdb_byte x86_breakpoint[] = { 0xCC };
 #define x86_breakpoint_len 1
 
 static int
@@ -3243,6 +3243,15 @@ x86_emit_ops (void)
     return &i386_emit_ops;
 }
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+x86_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = x86_breakpoint_len;
+  return x86_breakpoint;
+}
+
 static int
 x86_supports_range_stepping (void)
 {
@@ -3261,8 +3270,8 @@ struct linux_target_ops the_low_target =
   NULL, /* fetch_register */
   x86_get_pc,
   x86_set_pc,
-  x86_breakpoint,
-  x86_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  x86_sw_breakpoint_from_kind,
   NULL,
   1,
   x86_breakpoint_at,
diff --git a/gdb/gdbserver/linux-xtensa-low.c b/gdb/gdbserver/linux-xtensa-low.c
index debe467..fa6f418 100644
--- a/gdb/gdbserver/linux-xtensa-low.c
+++ b/gdb/gdbserver/linux-xtensa-low.c
@@ -151,9 +151,18 @@ static struct regset_info xtensa_regsets[] = {
 #define XTENSA_BREAKPOINT {0x2d,0xf0}
 #endif
 
-static const unsigned char xtensa_breakpoint[] = XTENSA_BREAKPOINT;
+static const gdb_byte xtensa_breakpoint[] = XTENSA_BREAKPOINT;
 #define xtensa_breakpoint_len 2
 
+/* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
+
+static const gdb_byte *
+xtensa_sw_breakpoint_from_kind (int kind, int *size)
+{
+  *size = xtensa_breakpoint_len;
+  return xtensa_breakpoint;
+}
+
 static CORE_ADDR
 xtensa_get_pc (struct regcache *regcache)
 {
@@ -234,8 +243,8 @@ struct linux_target_ops the_low_target = {
   NULL, /* fetch_register */
   xtensa_get_pc,
   xtensa_set_pc,
-  xtensa_breakpoint,
-  xtensa_breakpoint_len,
+  NULL, /* breakpoint_kind_from_pc */
+  xtensa_sw_breakpoint_from_kind,
   NULL,
   0,
   xtensa_breakpoint_at,
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index a2842b4..e4c0639 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -441,6 +441,16 @@ struct target_ops
      readlink(2).  */
   ssize_t (*multifs_readlink) (int pid, const char *filename,
 			       char *buf, size_t bufsiz);
+
+  /* Return the breakpoint kind for this target based on PC.  The PCPTR is
+     adjusted to the real memory location in case a flag (e.g., the Thumb bit on
+     ARM) was present in the PC.  */
+  int (*breakpoint_kind_from_pc) (CORE_ADDR *pcptr);
+
+  /* Return the software breakpoint from KIND.  KIND can have target
+     specific meaning like the Z0 kind parameter.
+     SIZE is set to the software breakpoint's length in memory.  */
+  const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
 };
 
 extern struct target_ops *the_target;