arm: FreeBSD/ARMv6 port

Sponsored by:	The FreeBSD Foundation

11 files changed, 402 insertions, 193 deletions

diff --git a/src/arm/Gis_signal_frame.c b/src/arm/Gis_signal_frame.c
deleted file mode 100644
index bfae4c6b..00000000
--- a/src/arm/Gis_signal_frame.c
+++ /dev/null
@@ -1,96 +0,0 @@
-/* libunwind - a platform-independent unwind library
-   Copyright (C) 2008 CodeSourcery
-   Copyright 2011 Linaro Limited
-
-This file is part of libunwind.
-
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
-
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
-
-#include <stdio.h>
-#include "unwind_i.h"
-
-#ifdef __linux__
-#define ARM_NR_sigreturn 119
-#define ARM_NR_rt_sigreturn 173
-#define ARM_NR_OABI_SYSCALL_BASE 0x900000
-
-/* ARM EABI sigreturn (the syscall number is loaded into r7) */
-#define MOV_R7_SIGRETURN (0xe3a07000UL | ARM_NR_sigreturn)
-#define MOV_R7_RT_SIGRETURN (0xe3a07000UL | ARM_NR_rt_sigreturn)
-
-/* ARM OABI sigreturn (using SWI) */
-#define ARM_SIGRETURN \
-  (0xef000000UL | ARM_NR_sigreturn | ARM_NR_OABI_SYSCALL_BASE)
-#define ARM_RT_SIGRETURN \
-  (0xef000000UL | ARM_NR_rt_sigreturn | ARM_NR_OABI_SYSCALL_BASE)
-
-/* Thumb sigreturn (two insns, syscall number is loaded into r7) */
-#define THUMB_SIGRETURN (0xdf00UL << 16 | 0x2700 | ARM_NR_sigreturn)
-#define THUMB_RT_SIGRETURN (0xdf00UL << 16 | 0x2700 | ARM_NR_rt_sigreturn)
-
-/* Thumb2 sigreturn (mov.w r7, $SYS_ify(rt_sigreturn/sigreturn)) */
-#define THUMB2_SIGRETURN (((0x0700 | ARM_NR_sigreturn) << 16) | \
-                                       0xf04f)
-#define THUMB2_RT_SIGRETURN (((0x0700 | ARM_NR_rt_sigreturn) << 16) | \
-                                       0xf04f)
-/* TODO: with different toolchains, there are a lot more possibilities */
-#endif /* __linux__ */
-
-/* Returns 1 in case of a non-RT signal frame and 2 in case of a RT signal
-   frame. */
-PROTECTED int
-unw_is_signal_frame (unw_cursor_t *cursor)
-{
-#ifdef __linux__
-  struct cursor *c = (struct cursor *) cursor;
-  unw_word_t w0, ip;
-  unw_addr_space_t as;
-  unw_accessors_t *a;
-  void *arg;
-  int ret;
-
-  as = c->dwarf.as;
-  a = unw_get_accessors (as);
-  arg = c->dwarf.as_arg;
-
-  /* The least bit denotes thumb/arm mode. Do not read there. */
-  ip = c->dwarf.ip & ~0x1;
-
-  if ((ret = (*a->access_mem) (as, ip, &w0, 0, arg)) < 0)
-    return ret;
-
-  /* Return 1 if the IP points to a non-RT sigreturn sequence.  */
-  if (w0 == MOV_R7_SIGRETURN || w0 == ARM_SIGRETURN || w0 == THUMB_SIGRETURN
-           || w0 == THUMB2_SIGRETURN)
-    return 1;
-  /* Return 2 if the IP points to a RT sigreturn sequence.  */
-  else if (w0 == MOV_R7_RT_SIGRETURN || w0 == ARM_RT_SIGRETURN
-           || w0 == THUMB_RT_SIGRETURN || w0 == THUMB2_RT_SIGRETURN)
-    return 2;
-
-  return 0;
-#elif defined(__QNX__)
-  /* Not supported yet */
-  return 0;
-#else
-  printf ("%s: implement me\n", __FUNCTION__);
-  return -UNW_ENOINFO;
-#endif
-}
diff --git a/src/arm/Gos-freebsd.c b/src/arm/Gos-freebsd.c
new file mode 100644
index 00000000..3b9d2c3e
--- /dev/null
+++ b/src/arm/Gos-freebsd.c
@@ -0,0 +1,129 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2008 CodeSourcery
+   Copyright 2011 Linaro Limited
+   Copyright (C) 2012 Tommi Rantala <tt.rantala@gmail.com>
+   Copyright 2015 The FreeBSD Foundation
+
+   Portions of this software were developed by Konstantin Belousov
+   under sponsorship from the FreeBSD Foundation.
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+#include <stdio.h>
+#include <signal.h>
+#include "unwind_i.h"
+#include "offsets.h"
+#include "ex_tables.h"
+
+PROTECTED int
+unw_handle_signal_frame (unw_cursor_t *cursor)
+{
+  struct cursor *c = (struct cursor *) cursor;
+  int ret, fmt;
+  unw_word_t sc_addr, sp, sp_addr = c->dwarf.cfa;
+  struct dwarf_loc sp_loc = DWARF_LOC (sp_addr, 0);
+
+  if ((ret = dwarf_get (&c->dwarf, sp_loc, &sp)) < 0)
+    return -UNW_EUNSPEC;
+  fmt = unw_is_signal_frame(cursor);
+
+  c->dwarf.pi_valid = 0;
+
+  if (fmt == UNW_ARM_FRAME_SYSCALL)
+   {
+    c->sigcontext_format = ARM_SCF_FREEBSD_SYSCALL;
+    c->frame_info.frame_type = UNW_ARM_FRAME_SYSCALL;
+    c->frame_info.cfa_reg_offset = 0;
+    c->dwarf.loc[UNW_ARM_R7] = c->dwarf.loc[UNW_ARM_R12];
+    dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R14], &c->dwarf.ip);
+    return 1;
+   }
+
+  c->sigcontext_format = ARM_SCF_FREEBSD_SIGFRAME;
+  sc_addr = sp_addr;
+
+  /* Save the SP and PC to be able to return execution at this point
+     later in time (unw_resume).  */
+  c->sigcontext_sp = c->dwarf.cfa;
+  c->sigcontext_pc = c->dwarf.ip;
+
+  c->sigcontext_addr = sc_addr;
+  c->frame_info.frame_type = UNW_ARM_FRAME_SIGRETURN;
+  c->frame_info.cfa_reg_offset = sc_addr - sp_addr;
+
+  /* Update the dwarf cursor.
+     Set the location of the registers to the corresponding addresses of the
+     uc_mcontext / sigcontext structure contents.  */
+#define ROFF(n)	(FREEBSD_SC_UCONTEXT_OFF + FREEBSD_UC_MCONTEXT_OFF + \
+  FREEBSD_MC_R0_OFF + (n) * 4)
+#define SL(n) \
+  c->dwarf.loc[UNW_ARM_R ## n] = DWARF_LOC (sc_addr + ROFF(n), 0);
+  SL(0); SL(1); SL(2); SL(3); SL(4); SL(5); SL(6); SL(7);
+  SL(8); SL(9); SL(10); SL(11); SL(12); SL(13); SL(14); SL(15);
+#undef SL
+#undef ROFF
+
+  /* Set SP/CFA and PC/IP.  */
+  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R13], &c->dwarf.cfa);
+  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R15], &c->dwarf.ip);
+
+  return 1;
+}
+
+/* Returns 1 in case of a non-RT signal frame and 2 in case of a RT signal
+   frame. */
+PROTECTED int
+unw_is_signal_frame (unw_cursor_t *cursor)
+{
+  struct cursor *c = (struct cursor *) cursor;
+  unw_word_t w0, w1, w2, w3, ip;
+  unw_addr_space_t as;
+  unw_accessors_t *a;
+  void *arg;
+  int ret;
+
+  as = c->dwarf.as;
+  a = unw_get_accessors (as);
+  arg = c->dwarf.as_arg;
+
+  ip = c->dwarf.ip;
+
+  if ((ret = (*a->access_mem) (as, ip, &w0, 0, arg)) < 0)
+    return ret;
+  if ((ret = (*a->access_mem) (as, ip + 4, &w1, 0, arg)) < 0)
+    return ret;
+  if ((ret = (*a->access_mem) (as, ip + 8, &w2, 0, arg)) < 0)
+    return ret;
+  if ((ret = (*a->access_mem) (as, ip + 12, &w3, 0, arg)) < 0)
+    return ret;
+
+  if (w0 == 0xe1a0000d && w1 == 0xe2800040 && w2 == 0xe59f700c &&
+    w3 == 0xef0001a1)
+     return UNW_ARM_FRAME_SIGRETURN;
+
+  if ((ret = (*a->access_mem) (as, ip - 4, &w0, 0, arg)) < 0)
+    return ret;
+  if (w0 == 0xef000000)
+    return UNW_ARM_FRAME_SYSCALL;
+
+  return 0;
+}
diff --git a/src/arm/Gos-linux.c b/src/arm/Gos-linux.c
new file mode 100644
index 00000000..585c2014
--- /dev/null
+++ b/src/arm/Gos-linux.c
@@ -0,0 +1,182 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2008 CodeSourcery
+   Copyright 2011 Linaro Limited
+   Copyright (C) 2012 Tommi Rantala <tt.rantala@gmail.com>
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+#include <stdio.h>
+#include <signal.h>
+#include "unwind_i.h"
+#include "offsets.h"
+
+PROTECTED int
+unw_handle_signal_frame (unw_cursor_t *cursor)
+{
+  struct cursor *c = (struct cursor *) cursor;
+  int ret;
+  unw_word_t sc_addr, sp, sp_addr = c->dwarf.cfa;
+  struct dwarf_loc sp_loc = DWARF_LOC (sp_addr, 0);
+
+  if ((ret = dwarf_get (&c->dwarf, sp_loc, &sp)) < 0)
+    return -UNW_EUNSPEC;
+
+  /* Obtain signal frame type (non-RT or RT). */
+  ret = unw_is_signal_frame (cursor);
+
+  /* Save the SP and PC to be able to return execution at this point
+     later in time (unw_resume).  */
+  c->sigcontext_sp = c->dwarf.cfa;
+  c->sigcontext_pc = c->dwarf.ip;
+
+  /* Since kernel version 2.6.18 the non-RT signal frame starts with a
+     ucontext while the RT signal frame starts with a siginfo, followed
+     by a sigframe whose first element is an ucontext.
+     Prior 2.6.18 the non-RT signal frame starts with a sigcontext while
+     the RT signal frame starts with two pointers followed by a siginfo
+     and an ucontext. The first pointer points to the start of the siginfo
+     structure and the second one to the ucontext structure.  */
+
+  if (ret == 1)
+    {
+      /* Handle non-RT signal frames. Check if the first word on the stack
+         is the magic number.  */
+      if (sp == 0x5ac3c35a)
+        {
+          c->sigcontext_format = ARM_SCF_LINUX_SIGFRAME;
+          sc_addr = sp_addr + LINUX_UC_MCONTEXT_OFF;
+        }
+      else
+        {
+          c->sigcontext_format = ARM_SCF_LINUX_OLD_SIGFRAME;
+          sc_addr = sp_addr;
+        }
+    }
+  else if (ret == 2)
+    {
+      /* Handle RT signal frames. Check if the first word on the stack is a
+         pointer to the siginfo structure.  */
+      if (sp == sp_addr + 8)
+        {
+          c->sigcontext_format = ARM_SCF_LINUX_OLD_RT_SIGFRAME;
+          sc_addr = sp_addr + 8 + sizeof (siginfo_t) + LINUX_UC_MCONTEXT_OFF;
+        }
+      else
+        {
+          c->sigcontext_format = ARM_SCF_LINUX_RT_SIGFRAME;
+          sc_addr = sp_addr + sizeof (siginfo_t) + LINUX_UC_MCONTEXT_OFF;
+        }
+    }
+  else
+    return -UNW_EUNSPEC;
+
+  c->sigcontext_addr = sc_addr;
+  c->frame_info.frame_type = UNW_ARM_FRAME_SIGRETURN;
+  c->frame_info.cfa_reg_offset = sc_addr - sp_addr;
+
+  /* Update the dwarf cursor.
+     Set the location of the registers to the corresponding addresses of the
+     uc_mcontext / sigcontext structure contents.  */
+  c->dwarf.loc[UNW_ARM_R0] = DWARF_LOC (sc_addr + LINUX_SC_R0_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R1] = DWARF_LOC (sc_addr + LINUX_SC_R1_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R2] = DWARF_LOC (sc_addr + LINUX_SC_R2_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R3] = DWARF_LOC (sc_addr + LINUX_SC_R3_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R4] = DWARF_LOC (sc_addr + LINUX_SC_R4_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R5] = DWARF_LOC (sc_addr + LINUX_SC_R5_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R6] = DWARF_LOC (sc_addr + LINUX_SC_R6_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R7] = DWARF_LOC (sc_addr + LINUX_SC_R7_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R8] = DWARF_LOC (sc_addr + LINUX_SC_R8_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R9] = DWARF_LOC (sc_addr + LINUX_SC_R9_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R10] = DWARF_LOC (sc_addr + LINUX_SC_R10_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R11] = DWARF_LOC (sc_addr + LINUX_SC_FP_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R12] = DWARF_LOC (sc_addr + LINUX_SC_IP_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R13] = DWARF_LOC (sc_addr + LINUX_SC_SP_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R14] = DWARF_LOC (sc_addr + LINUX_SC_LR_OFF, 0);
+  c->dwarf.loc[UNW_ARM_R15] = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0);
+
+  /* Set SP/CFA and PC/IP.  */
+  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R13], &c->dwarf.cfa);
+  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R15], &c->dwarf.ip);
+
+  c->dwarf.pi_valid = 0;
+
+  return 1;
+}
+
+#define ARM_NR_sigreturn 119
+#define ARM_NR_rt_sigreturn 173
+#define ARM_NR_OABI_SYSCALL_BASE 0x900000
+
+/* ARM EABI sigreturn (the syscall number is loaded into r7) */
+#define MOV_R7_SIGRETURN (0xe3a07000UL | ARM_NR_sigreturn)
+#define MOV_R7_RT_SIGRETURN (0xe3a07000UL | ARM_NR_rt_sigreturn)
+
+/* ARM OABI sigreturn (using SWI) */
+#define ARM_SIGRETURN \
+  (0xef000000UL | ARM_NR_sigreturn | ARM_NR_OABI_SYSCALL_BASE)
+#define ARM_RT_SIGRETURN \
+  (0xef000000UL | ARM_NR_rt_sigreturn | ARM_NR_OABI_SYSCALL_BASE)
+
+/* Thumb sigreturn (two insns, syscall number is loaded into r7) */
+#define THUMB_SIGRETURN (0xdf00UL << 16 | 0x2700 | ARM_NR_sigreturn)
+#define THUMB_RT_SIGRETURN (0xdf00UL << 16 | 0x2700 | ARM_NR_rt_sigreturn)
+
+/* Thumb2 sigreturn (mov.w r7, $SYS_ify(rt_sigreturn/sigreturn)) */
+#define THUMB2_SIGRETURN (((0x0700 | ARM_NR_sigreturn) << 16) | \
+                                       0xf04f)
+#define THUMB2_RT_SIGRETURN (((0x0700 | ARM_NR_rt_sigreturn) << 16) | \
+                                       0xf04f)
+/* TODO: with different toolchains, there are a lot more possibilities */
+
+/* Returns 1 in case of a non-RT signal frame and 2 in case of a RT signal
+   frame. */
+PROTECTED int
+unw_is_signal_frame (unw_cursor_t *cursor)
+{
+  struct cursor *c = (struct cursor *) cursor;
+  unw_word_t w0, ip;
+  unw_addr_space_t as;
+  unw_accessors_t *a;
+  void *arg;
+  int ret;
+
+  as = c->dwarf.as;
+  a = unw_get_accessors (as);
+  arg = c->dwarf.as_arg;
+
+  /* The least bit denotes thumb/arm mode. Do not read there. */
+  ip = c->dwarf.ip & ~0x1;
+
+  if ((ret = (*a->access_mem) (as, ip, &w0, 0, arg)) < 0)
+    return ret;
+
+  /* Return 1 if the IP points to a non-RT sigreturn sequence.  */
+  if (w0 == MOV_R7_SIGRETURN || w0 == ARM_SIGRETURN || w0 == THUMB_SIGRETURN
+           || w0 == THUMB2_SIGRETURN)
+    return 1;
+  /* Return 2 if the IP points to a RT sigreturn sequence.  */
+  else if (w0 == MOV_R7_RT_SIGRETURN || w0 == ARM_RT_SIGRETURN
+           || w0 == THUMB_RT_SIGRETURN || w0 == THUMB2_RT_SIGRETURN)
+    return 2;
+
+  return 0;
+}
diff --git a/src/arm/Gos-other.c b/src/arm/Gos-other.c
new file mode 100644
index 00000000..66f38b1d
--- /dev/null
+++ b/src/arm/Gos-other.c
@@ -0,0 +1,48 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2008 CodeSourcery
+   Copyright 2011 Linaro Limited
+   Copyright (C) 2012 Tommi Rantala <tt.rantala@gmail.com>
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+#include <stdio.h>
+#include <signal.h>
+#include "unwind_i.h"
+#include "offsets.h"
+
+PROTECTED int
+unw_handle_signal_frame (unw_cursor_t *cursor)
+{
+  return -UNW_EUNSPEC;
+}
+
+PROTECTED int
+unw_is_signal_frame (unw_cursor_t *cursor)
+{
+#if defined(__QNX__)
+  /* Not supported yet */
+  return 0;
+#else
+  printf ("%s: implement me\n", __FUNCTION__);
+  return -UNW_ENOINFO;
+#endif
+}
diff --git a/src/arm/Gstep.c b/src/arm/Gstep.c
index b3463eff..6679455e 100644
--- a/src/arm/Gstep.c
+++ b/src/arm/Gstep.c
@@ -80,99 +80,6 @@ arm_exidx_step (struct cursor *c)
 }
 
 PROTECTED int
-unw_handle_signal_frame (unw_cursor_t *cursor)
-{
-  struct cursor *c = (struct cursor *) cursor;
-  int ret;
-  unw_word_t sc_addr, sp, sp_addr = c->dwarf.cfa;
-  struct dwarf_loc sp_loc = DWARF_LOC (sp_addr, 0);
-
-  if ((ret = dwarf_get (&c->dwarf, sp_loc, &sp)) < 0)
-    return -UNW_EUNSPEC;
-
-  /* Obtain signal frame type (non-RT or RT). */
-  ret = unw_is_signal_frame (cursor);
-
-  /* Save the SP and PC to be able to return execution at this point
-     later in time (unw_resume).  */
-  c->sigcontext_sp = c->dwarf.cfa;
-  c->sigcontext_pc = c->dwarf.ip;
-
-  /* Since kernel version 2.6.18 the non-RT signal frame starts with a
-     ucontext while the RT signal frame starts with a siginfo, followed
-     by a sigframe whose first element is an ucontext.
-     Prior 2.6.18 the non-RT signal frame starts with a sigcontext while
-     the RT signal frame starts with two pointers followed by a siginfo
-     and an ucontext. The first pointer points to the start of the siginfo
-     structure and the second one to the ucontext structure.  */
-
-  if (ret == 1)
-    {
-      /* Handle non-RT signal frames. Check if the first word on the stack
-         is the magic number.  */
-      if (sp == 0x5ac3c35a)
-        {
-          c->sigcontext_format = ARM_SCF_LINUX_SIGFRAME;
-          sc_addr = sp_addr + LINUX_UC_MCONTEXT_OFF;
-        }
-      else
-        {
-          c->sigcontext_format = ARM_SCF_LINUX_OLD_SIGFRAME;
-          sc_addr = sp_addr;
-        }
-    }
-  else if (ret == 2)
-    {
-      /* Handle RT signal frames. Check if the first word on the stack is a
-         pointer to the siginfo structure.  */
-      if (sp == sp_addr + 8)
-        {
-          c->sigcontext_format = ARM_SCF_LINUX_OLD_RT_SIGFRAME;
-          sc_addr = sp_addr + 8 + sizeof (siginfo_t) + LINUX_UC_MCONTEXT_OFF;
-        }
-      else
-        {
-          c->sigcontext_format = ARM_SCF_LINUX_RT_SIGFRAME;
-          sc_addr = sp_addr + sizeof (siginfo_t) + LINUX_UC_MCONTEXT_OFF;
-        }
-    }
-  else
-    return -UNW_EUNSPEC;
-
-  c->sigcontext_addr = sc_addr;
-  c->frame_info.frame_type = UNW_ARM_FRAME_SIGRETURN;
-  c->frame_info.cfa_reg_offset = sc_addr - sp_addr;
-
-  /* Update the dwarf cursor.
-     Set the location of the registers to the corresponding addresses of the
-     uc_mcontext / sigcontext structure contents.  */
-  c->dwarf.loc[UNW_ARM_R0] = DWARF_LOC (sc_addr + LINUX_SC_R0_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R1] = DWARF_LOC (sc_addr + LINUX_SC_R1_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R2] = DWARF_LOC (sc_addr + LINUX_SC_R2_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R3] = DWARF_LOC (sc_addr + LINUX_SC_R3_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R4] = DWARF_LOC (sc_addr + LINUX_SC_R4_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R5] = DWARF_LOC (sc_addr + LINUX_SC_R5_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R6] = DWARF_LOC (sc_addr + LINUX_SC_R6_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R7] = DWARF_LOC (sc_addr + LINUX_SC_R7_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R8] = DWARF_LOC (sc_addr + LINUX_SC_R8_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R9] = DWARF_LOC (sc_addr + LINUX_SC_R9_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R10] = DWARF_LOC (sc_addr + LINUX_SC_R10_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R11] = DWARF_LOC (sc_addr + LINUX_SC_FP_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R12] = DWARF_LOC (sc_addr + LINUX_SC_IP_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R13] = DWARF_LOC (sc_addr + LINUX_SC_SP_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R14] = DWARF_LOC (sc_addr + LINUX_SC_LR_OFF, 0);
-  c->dwarf.loc[UNW_ARM_R15] = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0);
-
-  /* Set SP/CFA and PC/IP.  */
-  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R13], &c->dwarf.cfa);
-  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R15], &c->dwarf.ip);
-
-  c->dwarf.pi_valid = 0;
-
-  return 1;
-}
-
-PROTECTED int
 unw_step (unw_cursor_t *cursor)
 {
   struct cursor *c = (struct cursor *) cursor;
@@ -216,14 +123,18 @@ unw_step (unw_cursor_t *cursor)
 
   /* Fall back on APCS frame parsing.
      Note: This won't work in case the ARM EABI is used. */
+#ifdef __FreeBSD__
+  if (0)
+#else
   if (unlikely (ret < 0))
+#endif
     {
       if (UNW_TRY_METHOD(UNW_ARM_METHOD_FRAME))
         {
+          Debug (13, "dwarf_step() failed (ret=%d), trying frame-chain\n", ret);
           ret = UNW_ESUCCESS;
           /* DWARF unwinding failed, try to follow APCS/optimized APCS frame chain */
           unw_word_t instr, i;
-          Debug (13, "dwarf_step() failed (ret=%d), trying frame-chain\n", ret);
           dwarf_loc_t ip_loc, fp_loc;
           unw_word_t frame;
           /* Mark all registers unsaved, since we don't know where
@@ -266,7 +177,7 @@ unw_step (unw_cursor_t *cursor)
               c->dwarf.loc[UNW_ARM_R12] = ip_loc;
               c->dwarf.loc[UNW_ARM_R11] = fp_loc;
               c->dwarf.pi_valid = 0;
-              Debug(15, "ip=%lx\n", c->dwarf.ip);
+              Debug(15, "ip=%x\n", c->dwarf.ip);
             }
           else
             {
diff --git a/src/arm/Gtrace.c b/src/arm/Gtrace.c
index 135563a3..2f277520 100644
--- a/src/arm/Gtrace.c
+++ b/src/arm/Gtrace.c
@@ -503,7 +503,7 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
 
     case UNW_ARM_FRAME_SIGRETURN:
       cfa = cfa + f->cfa_reg_offset; /* cfa now points to ucontext_t.  */
-
+#if defined(__linux__)
       ACCESS_MEM_FAST(ret, c->validate, d, cfa + LINUX_SC_PC_OFF, pc);
       if (likely(ret >= 0))
         ACCESS_MEM_FAST(ret, c->validate, d, cfa + LINUX_SC_R7_OFF, r7);
@@ -513,6 +513,9 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
          doesn't save the link register in the prologue, e.g. kill. */
       if (likely(ret >= 0))
         ACCESS_MEM_FAST(ret, c->validate, d, cfa + LINUX_SC_LR_OFF, lr);
+#elif defined(__FreeBSD__)
+      printf("XXX\n");
+#endif
 
       /* Resume stack at signal restoration point. The stack is not
          necessarily continuous here, especially with sigaltstack(). */
@@ -522,6 +525,10 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
       d->use_prev_instr = 0;
       break;
 
+    case UNW_ARM_FRAME_SYSCALL:
+      printf("XXX1\n");
+      break;
+
     default:
       /* We cannot trace through this frame, give up and tell the
           caller we had to stop.  Data collected so far may still be
diff --git a/src/arm/Los-freebsd.c b/src/arm/Los-freebsd.c
new file mode 100644
index 00000000..a75a205d
--- /dev/null
+++ b/src/arm/Los-freebsd.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gos-freebsd.c"
+#endif
diff --git a/src/arm/Los-linux.c b/src/arm/Los-linux.c
new file mode 100644
index 00000000..3cc18aab
--- /dev/null
+++ b/src/arm/Los-linux.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gos-linux.c"
+#endif
diff --git a/src/arm/Los-other.c b/src/arm/Los-other.c
new file mode 100644
index 00000000..a75a205d
--- /dev/null
+++ b/src/arm/Los-other.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gos-freebsd.c"
+#endif
diff --git a/src/arm/getcontext.S b/src/arm/getcontext.S
index c52992bf..7e187844 100644
--- a/src/arm/getcontext.S
+++ b/src/arm/getcontext.S
@@ -35,8 +35,15 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 _Uarm_getcontext:
 	stmfd sp!, {r0, r1}
 	@ store r0
+#if defined(__linux__)
 	str r0, [r0, #LINUX_UC_MCONTEXT_OFF + LINUX_SC_R0_OFF]
 	add r0, r0, #LINUX_UC_MCONTEXT_OFF + LINUX_SC_R0_OFF
+#elif defined(__FreeBSD__)
+	str r0, [r0, #FREEBSD_UC_MCONTEXT_OFF + FREEBSD_MC_R0_OFF]
+	add r0, r0, #FREEBSD_UC_MCONTEXT_OFF + FREEBSD_MC_R0_OFF
+#else
+#error Fix me
+#endif
 	@ store r1 to r12
 	stmib r0, {r1-r12}
 	@ reconstruct r13 at call site, then store
@@ -50,7 +57,7 @@ _Uarm_getcontext:
 	str r1, [r0, #15 * 4]
 	ldmfd sp!, {r0, r1}
 	bx lr
-#ifdef __linux__
+#if defined(__linux__) || defined(__FreeBSD__)
  /* We do not need executable stack.  */
  .section  .note.GNU-stack,"",%progbits
 #endif
diff --git a/src/arm/offsets.h b/src/arm/offsets.h
index a63847be..62170110 100644
--- a/src/arm/offsets.h
+++ b/src/arm/offsets.h
@@ -34,3 +34,9 @@
 #define LINUX_SC_PC_OFF         0x48
 #define LINUX_SC_CPSR_OFF       0x4C
 #define LINUX_SC_FAULTADDR_OFF  0x50
+
+/* FreeBSD-specific definitions: */
+
+#define FREEBSD_SC_UCONTEXT_OFF		0x40
+#define	FREEBSD_UC_MCONTEXT_OFF		0x10
+#define FREEBSD_MC_R0_OFF		0