diff --git a/configure.in b/configure.in
index e5d4ac28..dec0fea3 100644
--- a/configure.in
+++ b/configure.in
@@ -73,6 +73,13 @@ AC_CHECK_DECLS(PT_IO, [], [],
 #endif
 #include <sys/ptrace.h>
 ])
+AC_CHECK_DECLS(PT_GETREGS, [], [],
+[$ac_includes_default
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#include <sys/ptrace.h>
+])
 AC_CHECK_DECLS(PT_GETFPREGS, [], [],
 [$ac_includes_default
 #if HAVE_SYS_TYPES_H
diff --git a/src/ptrace/_UPT_access_reg.c b/src/ptrace/_UPT_access_reg.c
index 60e006b9..a85b900f 100644
--- a/src/ptrace/_UPT_access_reg.c
+++ b/src/ptrace/_UPT_access_reg.c
@@ -33,6 +33,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 # include "tdep-ia64/rse.h"
 #endif
 
+#if HAVE_DECL_PTRACE_POKEUSER || HAVE_TTRACE
 int
 _UPT_access_reg (unw_addr_space_t as, unw_regnum_t reg, unw_word_t *val,
 		 int write, void *arg)
@@ -252,3 +253,40 @@ _UPT_access_reg (unw_addr_space_t as, unw_regnum_t reg, unw_word_t *val,
   Debug (1, "bad register number %u (error: %s)\n", reg, strerror (errno));
   return -UNW_EBADREG;
 }
+#elif HAVE_DECL_PT_GETREGS
+int
+_UPT_access_reg (unw_addr_space_t as, unw_regnum_t reg, unw_word_t *val,
+		 int write, void *arg)
+{
+  struct UPT_info *ui = arg;
+  pid_t pid = ui->pid;
+  gregset_t regs;
+  char *r;
+
+#if UNW_DEBUG
+  if (write)
+    Debug (16, "%s <- %lx\n", unw_regname (reg), (long) *val);
+#endif
+  if ((unsigned) reg >= sizeof (_UPT_reg_offset) / sizeof (_UPT_reg_offset[0]))
+    {
+      errno = EINVAL;
+      goto badreg;
+    }
+  r = (char *)&regs + _UPT_reg_offset[reg];
+  if (ptrace(PT_GETREGS, pid, (caddr_t)&regs, 0) == -1)
+    goto badreg;
+  if (write) {
+      memcpy(r, val, sizeof(unw_word_t));
+      if (ptrace(PT_SETREGS, pid, (caddr_t)&regs, 0) == -1)
+        goto badreg;
+  } else
+      memcpy(val, r, sizeof(unw_word_t));
+  return 0;
+
+ badreg:
+  Debug (1, "bad register number %u (error: %s)\n", reg, strerror (errno));
+  return -UNW_EBADREG;
+}
+#else
+#error Port me
+#endif
diff --git a/src/ptrace/_UPT_reg_offset.c b/src/ptrace/_UPT_reg_offset.c
index f586fb72..83dbcc31 100644
--- a/src/ptrace/_UPT_reg_offset.c
+++ b/src/ptrace/_UPT_reg_offset.c
@@ -25,6 +25,8 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 
 #include "_UPT_internal.h"
 
+#include <stddef.h>
+
 #ifdef HAVE_ASM_PTRACE_OFFSETS_H
 # include <asm/ptrace_offsets.h>
 #endif
@@ -265,6 +267,31 @@ int _UPT_reg_offset[UNW_REG_LAST + 1] =
 /*  EFLAGS		= 0x38, */
 /*  SS			= 0x40 */
 #elif defined(UNW_TARGET_X86_64)
+#if defined(__FreeBSD__)
+#define UNW_R_OFF(R, r) \
+    [UNW_X86_64_##R]	= offsetof(gregset_t, r_##r),
+    UNW_R_OFF(RAX, rax)
+    UNW_R_OFF(RDX, rdx)
+    UNW_R_OFF(RCX, rcx)
+    UNW_R_OFF(RBX, rbx)
+    UNW_R_OFF(RSI, rsi)
+    UNW_R_OFF(RDI, rdi)
+    UNW_R_OFF(RBP, rbp)
+    UNW_R_OFF(RSP, rsp)
+    UNW_R_OFF(R8, r8)
+    UNW_R_OFF(R9, r9)
+    UNW_R_OFF(R10, r10)
+    UNW_R_OFF(R11, r11)
+    UNW_R_OFF(R12, r12)
+    UNW_R_OFF(R13, r13)
+    UNW_R_OFF(R14, r14)
+    UNW_R_OFF(R15, r15)
+    UNW_R_OFF(RIP, rip)
+//  UNW_R_OFF(CS, cs)
+//  UNW_R_OFF(EFLAGS, rflags)
+//  UNW_R_OFF(SS, ss)
+#undef UNW_R_OFF
+#else
     [UNW_X86_64_RAX]	= 0x50,
     [UNW_X86_64_RDX]	= 0x60,
     [UNW_X86_64_RCX]	= 0x58,
@@ -286,6 +313,7 @@ int _UPT_reg_offset[UNW_REG_LAST + 1] =
 //  [UNW_X86_64_EFLAGS]	= 0x90,
 //  [UNW_X86_64_RSP]	= 0x98,
 //  [UNW_X86_64_SS]	= 0xa0
+#endif
 #elif defined(UNW_TARGET_PPC32)
 #elif defined(UNW_TARGET_PPC64)
 #elif defined(UNW_TARGET_ARM)