Add port to Linux on IBM Z (s390x)

This adds a port to Linux on the IBM Z platform (a.k.a s390x). It only
supports the 64-bit ABI. Most functionality is working and all the tests
pass with the exception of the coredump tests*.

Unwinding is only supported if DWARF unwind information is present.
libunwind can't currently make use of the backchain (if present).

The getcontext/setcontext functions only preserve/restore a subset of
registers. Currently this only consists of callee-saved registers and
some parameter registers.

Vector registers and access registers are not saved (and aren't callee-
saved) by getcontext and cannot currently be modified. They will however
be restored unmodified after resuming a context from a signal handler.

There is no special libunwind support for setjmp, the functionality is
emulated using glibc (I think all the ports do this for modern Linux
kernels).

* Unwinding on s390x requires floating point register access which the
coredump library doesn't currently support.

45 files changed, 2400 insertions, 1 deletions

diff --git a/Makefile.am b/Makefile.am
index 711d9100..8132fa4c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -41,6 +41,9 @@ endif
 if ARCH_SH
 include_HEADERS += include/libunwind-sh.h
 endif
+if ARCH_S390X
+include_HEADERS += include/libunwind-s390x.h
+endif
 
 if !REMOTE_ONLY
 include_HEADERS += include/libunwind.h include/unwind.h
@@ -84,6 +87,8 @@ noinst_HEADERS = include/dwarf.h include/dwarf_i.h include/dwarf-eh.h	\
 	include/tdep-ppc64/jmpbuf.h include/tdep-ppc64/libunwind_i.h	\
 	include/tdep-sh/dwarf-config.h					\
 	include/tdep-sh/jmpbuf.h include/tdep-sh/libunwind_i.h		\
+	include/tdep-s390x/dwarf-config.h				\
+	include/tdep-s390x/jmpbuf.h include/tdep-s390x/libunwind_i.h	\
 	include/tdep/libunwind_i.h					\
 	include/tdep/jmpbuf.h include/tdep/dwarf-config.h
 
diff --git a/configure.ac b/configure.ac
index 0c512597..2cb006af 100644
--- a/configure.ac
+++ b/configure.ac
@@ -175,6 +175,7 @@ AM_CONDITIONAL(ARCH_PPC32, test x$target_arch = xppc32)
 AM_CONDITIONAL(ARCH_PPC64, test x$target_arch = xppc64)
 AM_CONDITIONAL(ARCH_SH, test x$target_arch = xsh)
 AM_CONDITIONAL(ARCH_TILEGX, test x$target_arch = xtilegx)
+AM_CONDITIONAL(ARCH_S390X, test x$target_arch = xs390x)
 AM_CONDITIONAL(OS_LINUX, expr x$target_os : xlinux >/dev/null)
 AM_CONDITIONAL(OS_HPUX, expr x$target_os : xhpux >/dev/null)
 AM_CONDITIONAL(OS_FREEBSD, expr x$target_os : xfreebsd >/dev/null)
@@ -183,7 +184,7 @@ AM_CONDITIONAL(OS_QNX, expr x$target_os : xnto-qnx >/dev/null)
 AC_MSG_CHECKING([for ELF helper width])
 case "${target_arch}" in
 (arm|hppa|ppc32|x86|sh) use_elf32=yes; AC_MSG_RESULT([32]);;
-(aarch64|ia64|ppc64|x86_64|tilegx)  use_elf64=yes; AC_MSG_RESULT([64]);;
+(aarch64|ia64|ppc64|x86_64|s390x|tilegx)  use_elf64=yes; AC_MSG_RESULT([64]);;
 (mips)                 use_elfxx=yes; AC_MSG_RESULT([xx]);;
 *)                     AC_MSG_ERROR([Unknown ELF target: ${target_arch}])
 esac
diff --git a/include/libunwind-s390x.h b/include/libunwind-s390x.h
new file mode 100644
index 00000000..d95d700e
--- /dev/null
+++ b/include/libunwind-s390x.h
@@ -0,0 +1,144 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2002-2004 Hewlett-Packard Co
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for s390x by Michael Munday <mike.munday@ibm.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.  */
+
+#ifndef LIBUNWIND_H
+#define LIBUNWIND_H
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+#include <sys/types.h>
+#include <inttypes.h>
+#include <ucontext.h>
+
+#define UNW_TARGET              s390x
+#define UNW_TARGET_S390X        1
+
+#define _U_TDEP_QP_TRUE 0       /* see libunwind-dynamic.h  */
+
+/* This needs to be big enough to accommodate "struct cursor", while
+   leaving some slack for future expansion.  Changing this value will
+   require recompiling all users of this library.  Stack allocation is
+   relatively cheap and unwind-state copying is relatively rare, so we
+   want to err on making it rather too big than too small.  */
+#define UNW_TDEP_CURSOR_LEN     384
+
+typedef uint64_t unw_word_t;
+typedef int64_t unw_sword_t;
+
+typedef long double unw_tdep_fpreg_t;
+
+typedef enum
+  {
+    /* general purpose registers */
+    UNW_S390X_R0,
+    UNW_S390X_R1,
+    UNW_S390X_R2,
+    UNW_S390X_R3,
+    UNW_S390X_R4,
+    UNW_S390X_R5,
+    UNW_S390X_R6,
+    UNW_S390X_R7,
+    UNW_S390X_R8,
+    UNW_S390X_R9,
+    UNW_S390X_R10,
+    UNW_S390X_R11,
+    UNW_S390X_R12,
+    UNW_S390X_R13,
+    UNW_S390X_R14,
+    UNW_S390X_R15,
+
+    /* floating point registers */
+    UNW_S390X_F0,
+    UNW_S390X_F1,
+    UNW_S390X_F2,
+    UNW_S390X_F3,
+    UNW_S390X_F4,
+    UNW_S390X_F5,
+    UNW_S390X_F6,
+    UNW_S390X_F7,
+    UNW_S390X_F8,
+    UNW_S390X_F9,
+    UNW_S390X_F10,
+    UNW_S390X_F11,
+    UNW_S390X_F12,
+    UNW_S390X_F13,
+    UNW_S390X_F14,
+    UNW_S390X_F15,
+
+    /* PSW */
+    UNW_S390X_IP,
+
+    UNW_TDEP_LAST_REG = UNW_S390X_IP,
+
+    /* TODO: access, vector registers */
+
+    /* frame info (read-only) */
+    UNW_S390X_CFA,
+
+    UNW_TDEP_IP = UNW_S390X_IP,
+    UNW_TDEP_SP = UNW_S390X_R15,
+
+    /* TODO: placeholders */
+    UNW_TDEP_EH = UNW_S390X_R0,
+  }
+s390x_regnum_t;
+
+#define UNW_TDEP_NUM_EH_REGS    2       /* XXX Not sure what this means */
+
+typedef struct unw_tdep_save_loc
+  {
+    /* Additional target-dependent info on a save location.  */
+    char unused;
+  }
+unw_tdep_save_loc_t;
+
+/* On s390x, we can directly use ucontext_t as the unwind context.  */
+typedef ucontext_t unw_tdep_context_t;
+
+typedef struct
+  {
+    /* no s390x-specific auxiliary proc-info */
+    char unused;
+  }
+unw_tdep_proc_info_t;
+
+#include "libunwind-dynamic.h"
+#include "libunwind-common.h"
+
+#define unw_tdep_getcontext             UNW_ARCH_OBJ(getcontext)
+#define unw_tdep_is_fpreg               UNW_ARCH_OBJ(is_fpreg)
+
+extern int unw_tdep_getcontext (unw_tdep_context_t *);
+extern int unw_tdep_is_fpreg (int);
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}
+#endif
+
+#endif /* LIBUNWIND_H */
diff --git a/include/libunwind.h.in b/include/libunwind.h.in
index 7a56168c..a13e7767 100644
--- a/include/libunwind.h.in
+++ b/include/libunwind.h.in
@@ -25,6 +25,8 @@
 # include "libunwind-x86_64.h"
 #elif defined __tilegx__
 # include "libunwind-tilegx.h"
+#elif defined __s390x__
+# include "libunwind-s390x.h"
 #else
 # error "Unsupported arch"
 #endif
diff --git a/include/tdep-s390x/dwarf-config.h b/include/tdep-s390x/dwarf-config.h
new file mode 100644
index 00000000..ca419bd5
--- /dev/null
+++ b/include/tdep-s390x/dwarf-config.h
@@ -0,0 +1,52 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2003, 2005 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.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.  */
+
+/* copy of include/tdep-x86/dwarf-config.h, modified slightly for x86-64
+   some consolidation is possible here */
+
+#ifndef dwarf_config_h
+#define dwarf_config_h
+
+/* derived from DWARF register mappings in Z ELF ABI */
+#define DWARF_NUM_PRESERVED_REGS        66
+#define DWARF_REGNUM_MAP_LENGTH         DWARF_NUM_PRESERVED_REGS
+
+/* Return TRUE if the ADDR_SPACE uses big-endian byte-order.  */
+#define dwarf_is_big_endian(addr_space) 1
+
+/* Convert a pointer to a dwarf_cursor structure to a pointer to
+   unw_cursor_t.  */
+#define dwarf_to_cursor(c)      ((unw_cursor_t *) (c))
+
+typedef struct dwarf_loc
+  {
+    unw_word_t val;
+    unw_word_t type;            /* see S390X_LOC_TYPE_* macros.  */
+  }
+dwarf_loc_t;
+
+#endif /* dwarf_config_h */
diff --git a/include/tdep-s390x/jmpbuf.h b/include/tdep-s390x/jmpbuf.h
new file mode 100644
index 00000000..50923752
--- /dev/null
+++ b/include/tdep-s390x/jmpbuf.h
@@ -0,0 +1,35 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2004 Hewlett-Packard Co
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.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.  */
+
+#if defined __linux__
+
+/* Use glibc's jump-buffer indices; NPTL peeks at SP: */
+
+#define JB_SP           9  // __gregs[9]
+#define JB_RP           8  // __gregs[8]
+#define JB_MASK_SAVED   18 // __mask_was_saved
+#define JB_MASK         19 // __saved_mask
+
+#endif
diff --git a/include/tdep-s390x/libunwind_i.h b/include/tdep-s390x/libunwind_i.h
new file mode 100644
index 00000000..4296ea4b
--- /dev/null
+++ b/include/tdep-s390x/libunwind_i.h
@@ -0,0 +1,262 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2002-2005 Hewlett-Packard Co
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.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.  */
+
+#ifndef S390X_LIBUNWIND_I_H
+#define S390X_LIBUNWIND_I_H
+
+/* Target-dependent definitions that are internal to libunwind but need
+   to be shared with target-independent code.  */
+
+#include <stdlib.h>
+#include <libunwind.h>
+
+#include "elf64.h"
+#include "mempool.h"
+#include "dwarf.h"
+
+struct unw_addr_space
+  {
+    struct unw_accessors acc;
+    unw_caching_policy_t caching_policy;
+#ifdef HAVE_ATOMIC_OPS_H
+    AO_t cache_generation;
+#else
+    uint32_t cache_generation;
+#endif
+    unw_word_t dyn_generation;          /* see dyn-common.h */
+    unw_word_t dyn_info_list_addr;      /* (cached) dyn_info_list_addr */
+    struct dwarf_rs_cache global_cache;
+    struct unw_debug_frame_list *debug_frames;
+   };
+
+struct cursor
+  {
+    struct dwarf_cursor dwarf;          /* must be first */
+
+    /* Format of sigcontext structure and address at which it is
+       stored: */
+    enum
+      {
+        S390X_SCF_NONE              = 0, /* no signal frame encountered */
+        S390X_SCF_LINUX_SIGFRAME    = 1, /* Linux struct sigcontext */
+        S390X_SCF_LINUX_RT_SIGFRAME = 2, /* Linux ucontext_t */
+      }
+    sigcontext_format;
+    unw_word_t sigcontext_addr;
+    unw_word_t sigcontext_sp;
+    unw_word_t sigcontext_pc;
+    int validate;
+    ucontext_t *uc;
+  };
+
+static inline ucontext_t *
+dwarf_get_uc(const struct dwarf_cursor *cursor)
+{
+  const struct cursor *c = (struct cursor *) cursor->as_arg;
+  return c->uc;
+}
+
+#define DWARF_GET_LOC(l)        ((l).val)
+# define DWARF_LOC_TYPE_MEM     (0 << 0)
+# define DWARF_LOC_TYPE_FP      (1 << 0)
+# define DWARF_LOC_TYPE_REG     (1 << 1)
+# define DWARF_LOC_TYPE_VAL     (1 << 2)
+
+# define DWARF_IS_REG_LOC(l)    (((l).type & DWARF_LOC_TYPE_REG) != 0)
+# define DWARF_IS_FP_LOC(l)     (((l).type & DWARF_LOC_TYPE_FP) != 0)
+# define DWARF_IS_MEM_LOC(l)    ((l).type == DWARF_LOC_TYPE_MEM)
+# define DWARF_IS_VAL_LOC(l)    (((l).type & DWARF_LOC_TYPE_VAL) != 0)
+
+# define DWARF_LOC(r, t)        ((dwarf_loc_t) { .val = (r), .type = (t) })
+# define DWARF_VAL_LOC(c,v)     DWARF_LOC ((v), DWARF_LOC_TYPE_VAL)
+# define DWARF_MEM_LOC(c,m)     DWARF_LOC ((m), DWARF_LOC_TYPE_MEM)
+
+#ifdef UNW_LOCAL_ONLY
+# define DWARF_NULL_LOC         DWARF_LOC (0, 0)
+# define DWARF_IS_NULL_LOC(l)   (DWARF_GET_LOC (l) == 0)
+# define DWARF_REG_LOC(c,r)     (DWARF_LOC((unw_word_t)                      \
+                                 tdep_uc_addr(dwarf_get_uc(c), (r)), 0))
+# define DWARF_FPREG_LOC(c,r)   (DWARF_LOC((unw_word_t)                      \
+                                 tdep_uc_addr(dwarf_get_uc(c), (r)), 0))
+
+#else /* !UNW_LOCAL_ONLY */
+
+# define DWARF_NULL_LOC         DWARF_LOC (0, 0)
+# define DWARF_IS_NULL_LOC(l)                                           \
+                ({ dwarf_loc_t _l = (l); _l.val == 0 && _l.type == 0; })
+# define DWARF_REG_LOC(c,r)     DWARF_LOC((r), DWARF_LOC_TYPE_REG)
+# define DWARF_FPREG_LOC(c,r)   DWARF_LOC((r), (DWARF_LOC_TYPE_REG      \
+                                                | DWARF_LOC_TYPE_FP))
+
+#endif /* !UNW_LOCAL_ONLY */
+
+static inline int
+dwarf_getfp (struct dwarf_cursor *c, dwarf_loc_t loc, unw_fpreg_t *val)
+{
+  assert(sizeof unw_fpreg_t == sizeof unw_word_t);
+
+  if (DWARF_IS_NULL_LOC (loc))
+    return -UNW_EBADREG;
+
+  if (DWARF_IS_FP_LOC (loc))
+    return (*c->as->acc.access_fpreg) (c->as, DWARF_GET_LOC (loc), val,
+                                       0, c->as_arg);
+  /* FPRs may be saved in GPRs */
+  if (DWARF_IS_REG_LOC (loc))
+    return (*c->as->acc.access_reg) (c->as, DWARF_GET_LOC (loc), (unw_word_t*)val,
+                                     0, c->as_arg);
+  if (DWARF_IS_MEM_LOC (loc))
+    return (*c->as->acc.access_mem) (c->as, DWARF_GET_LOC (loc), (unw_word_t*)val,
+                                     0, c->as_arg);
+  assert(DWARF_IS_VAL_LOC (loc));
+  *val = *(unw_fpreg_t*) DWARF_GET_LOC (loc);
+  return 0;
+}
+
+static inline int
+dwarf_putfp (struct dwarf_cursor *c, dwarf_loc_t loc, unw_fpreg_t val)
+{
+  assert(sizeof unw_fpreg_t == sizeof unw_word_t);
+  assert(!DWARF_IS_VAL_LOC (loc));
+
+  if (DWARF_IS_NULL_LOC (loc))
+    return -UNW_EBADREG;
+
+  if (DWARF_IS_FP_LOC (loc))
+    return (*c->as->acc.access_fpreg) (c->as, DWARF_GET_LOC (loc), &val,
+                                       1, c->as_arg);
+  /* FPRs may be saved in GPRs */
+  if (DWARF_IS_REG_LOC (loc))
+    return (*c->as->acc.access_reg) (c->as, DWARF_GET_LOC (loc), (unw_word_t*) &val,
+                                     1, c->as_arg);
+
+  assert(DWARF_IS_MEM_LOC (loc));
+  return (*c->as->acc.access_mem) (c->as, DWARF_GET_LOC (loc), (unw_word_t*) &val,
+                                   1, c->as_arg);
+}
+
+static inline int
+dwarf_get (struct dwarf_cursor *c, dwarf_loc_t loc, unw_word_t *val)
+{
+  assert(sizeof unw_fpreg_t == sizeof unw_word_t);
+
+  if (DWARF_IS_NULL_LOC (loc))
+    return -UNW_EBADREG;
+
+  if (DWARF_IS_REG_LOC (loc))
+    return (*c->as->acc.access_reg) (c->as, DWARF_GET_LOC (loc), val,
+                                     0, c->as_arg);
+  if (DWARF_IS_MEM_LOC (loc))
+    return (*c->as->acc.access_mem) (c->as, DWARF_GET_LOC (loc), val,
+                                     0, c->as_arg);
+  /* GPRs may be saved in FPRs */
+  if (DWARF_IS_FP_LOC (loc))
+    return (*c->as->acc.access_fpreg) (c->as, DWARF_GET_LOC (loc), (unw_fpreg_t*)val,
+                                       0, c->as_arg);
+  assert(DWARF_IS_VAL_LOC (loc));
+  *val = DWARF_GET_LOC (loc);
+  return 0;
+}
+
+static inline int
+dwarf_put (struct dwarf_cursor *c, dwarf_loc_t loc, unw_word_t val)
+{
+  assert(sizeof unw_fpreg_t == sizeof unw_word_t);
+  assert(!DWARF_IS_VAL_LOC (loc));
+
+  if (DWARF_IS_NULL_LOC (loc))
+    return -UNW_EBADREG;
+
+  if (DWARF_IS_REG_LOC (loc))
+    return (*c->as->acc.access_reg) (c->as, DWARF_GET_LOC (loc), &val,
+                                     1, c->as_arg);
+  /* GPRs may be saved in FPRs */
+  if (DWARF_IS_FP_LOC (loc))
+    return (*c->as->acc.access_fpreg) (c->as, DWARF_GET_LOC (loc), (unw_fpreg_t*) &val,
+                                       1, c->as_arg);
+
+  assert(DWARF_IS_MEM_LOC (loc));
+  return (*c->as->acc.access_mem) (c->as, DWARF_GET_LOC (loc), &val,
+                                   1, c->as_arg);
+}
+
+#define tdep_getcontext_trace           unw_getcontext
+#define tdep_init_done                  UNW_OBJ(init_done)
+#define tdep_init_mem_validate          UNW_OBJ(init_mem_validate)
+#define tdep_init                       UNW_OBJ(init)
+/* Platforms that support UNW_INFO_FORMAT_TABLE need to define
+   tdep_search_unwind_table.  */
+#define tdep_search_unwind_table        dwarf_search_unwind_table
+#define tdep_find_unwind_table          dwarf_find_unwind_table
+#define tdep_get_elf_image              UNW_ARCH_OBJ(get_elf_image)
+#define tdep_get_exe_image_path         UNW_ARCH_OBJ(get_exe_image_path)
+#define tdep_access_reg                 UNW_OBJ(access_reg)
+#define tdep_access_fpreg               UNW_OBJ(access_fpreg)
+#define tdep_fetch_frame(c,ip,n)        do {} while(0)
+#define tdep_cache_frame(c)             0
+#define tdep_reuse_frame(c,rs)          do {} while(0)
+#define tdep_stash_frame(cs,rs)         do {} while(0)
+#define tdep_trace(cur,addr,n)          (-UNW_ENOINFO)
+#define tdep_uc_addr                    UNW_OBJ(uc_addr)
+
+#ifdef UNW_LOCAL_ONLY
+# define tdep_find_proc_info(c,ip,n)                            \
+        dwarf_find_proc_info((c)->as, (ip), &(c)->pi, (n),      \
+                                       (c)->as_arg)
+# define tdep_put_unwind_info(as,pi,arg)                \
+        dwarf_put_unwind_info((as), (pi), (arg))
+#else
+# define tdep_find_proc_info(c,ip,n)                                    \
+        (*(c)->as->acc.find_proc_info)((c)->as, (ip), &(c)->pi, (n),    \
+                                       (c)->as_arg)
+# define tdep_put_unwind_info(as,pi,arg)                        \
+        (*(as)->acc.put_unwind_info)((as), (pi), (arg))
+#endif
+
+#define tdep_get_as(c)                  ((c)->dwarf.as)
+#define tdep_get_as_arg(c)              ((c)->dwarf.as_arg)
+#define tdep_get_ip(c)                  ((c)->dwarf.ip)
+#define tdep_big_endian(as)             1
+
+extern int tdep_init_done;
+
+extern void tdep_init (void);
+extern void tdep_init_mem_validate (void);
+extern int tdep_search_unwind_table (unw_addr_space_t as, unw_word_t ip,
+                                     unw_dyn_info_t *di, unw_proc_info_t *pi,
+                                     int need_unwind_info, void *arg);
+extern void *tdep_uc_addr (unw_tdep_context_t *uc, int reg);
+extern int tdep_get_elf_image (struct elf_image *ei, pid_t pid, unw_word_t ip,
+                               unsigned long *segbase, unsigned long *mapoff,
+                               char *path, size_t pathlen);
+extern void tdep_get_exe_image_path (char *path);
+extern int tdep_access_reg (struct cursor *c, unw_regnum_t reg,
+                            unw_word_t *valp, int write);
+extern int tdep_access_fpreg (struct cursor *c, unw_regnum_t reg,
+                              unw_fpreg_t *valp, int write);
+
+#endif /* S390X_LIBUNWIND_I_H */
diff --git a/include/tdep/libunwind_i.h.in b/include/tdep/libunwind_i.h.in
index af05a7fb..c4729964 100644
--- a/include/tdep/libunwind_i.h.in
+++ b/include/tdep/libunwind_i.h.in
@@ -25,6 +25,8 @@
 # include "tdep-x86_64/libunwind_i.h"
 #elif defined __tilegx__
 # include "tdep-tilegx/libunwind_i.h"
+#elif defined __s390x__
+# include "tdep-s390x/libunwind_i.h"
 #else
 # error "Unsupported arch"
 #endif
diff --git a/src/Makefile.am b/src/Makefile.am
index a557d8d1..8d72ef0b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -463,6 +463,30 @@ libunwind_sh_la_SOURCES_sh = $(libunwind_la_SOURCES_sh_common)		\
 	sh/Gglobal.c sh/Ginit.c sh/Ginit_local.c sh/Ginit_remote.c	\
 	sh/Gis_signal_frame.c sh/Gregs.c sh/Gresume.c sh/Gstep.c
 
+# The list of files that go both into libunwind and libunwind-s390x:
+noinst_HEADERS += s390x/init.h s390x/unwind_i.h
+libunwind_la_SOURCES_s390x_common = $(libunwind_la_SOURCES_common)	\
+	s390x/is_fpreg.c s390x/regname.c
+
+# The list of files that go into libunwind:
+libunwind_la_SOURCES_s390x = $(libunwind_la_SOURCES_s390x_common)	    \
+	$(libunwind_la_SOURCES_local)					    \
+	s390x/Lapply_reg_state.c s390x/Lreg_states_iterate.c		    \
+	s390x/Lcreate_addr_space.c s390x/Lget_save_loc.c s390x/Lglobal.c    \
+	s390x/Linit.c s390x/Linit_local.c s390x/Linit_remote.c	            \
+	s390x/Lget_proc_info.c s390x/Lregs.c s390x/Lresume.c		    \
+	s390x/Lis_signal_frame.c s390x/Lstep.c				    \
+	s390x/getcontext.S s390x/setcontext.S
+
+# The list of files that go into libunwind-s390x:
+libunwind_s390x_la_SOURCES_s390x = $(libunwind_la_SOURCES_s390x_common)     \
+	$(libunwind_la_SOURCES_generic)					    \
+	s390x/Gapply_reg_state.c s390x/Greg_states_iterate.c	            \
+	s390x/Gcreate_addr_space.c s390x/Gget_save_loc.c s390x/Gglobal.c    \
+	s390x/Ginit.c s390x/Ginit_local.c s390x/Ginit_remote.c	            \
+	s390x/Gget_proc_info.c s390x/Gregs.c s390x/Gresume.c		    \
+	s390x/Gis_signal_frame.c s390x/Gstep.c
+
 if REMOTE_ONLY
 install-exec-hook:
 #	Nothing to do here....
@@ -662,7 +686,19 @@ if !REMOTE_ONLY
  libunwind_sh_la_LIBADD += libunwind.la -lc
 endif
  libunwind_setjmp_la_SOURCES += sh/siglongjmp.S
+else
+if ARCH_S390X
+ lib_LTLIBRARIES += libunwind-s390x.la
+ libunwind_la_SOURCES = $(libunwind_la_SOURCES_s390x)
+ libunwind_s390x_la_SOURCES = $(libunwind_s390x_la_SOURCES_s390x)
+ libunwind_s390x_la_LDFLAGS = $(COMMON_SO_LDFLAGS) -version-info $(SOVERSION)
+ libunwind_s390x_la_LIBADD = libunwind-dwarf-generic.la
+ libunwind_s390x_la_LIBADD += libunwind-elf64.la
+if !REMOTE_ONLY
+ libunwind_s390x_la_LIBADD += libunwind.la -lc
+endif
 
+endif # ARCH_S390X
 endif # ARCH_SH
 endif # ARCH_PPC64
 endif # ARCH_PPC32
diff --git a/src/coredump/_UCD_access_reg_linux.c b/src/coredump/_UCD_access_reg_linux.c
index 208d8d27..43792f84 100644
--- a/src/coredump/_UCD_access_reg_linux.c
+++ b/src/coredump/_UCD_access_reg_linux.c
@@ -54,6 +54,9 @@ _UCD_access_reg (unw_addr_space_t as,
 #elif defined(UNW_TARGET_TILEGX)
   if (regnum > UNW_TILEGX_CFA)
     goto badreg;
+#elif defined(UNW_TARGET_S390X)
+  if (regnum > UNW_S390X_R15)
+    goto badreg;
 #else
 #if defined(UNW_TARGET_MIPS)
   static const uint8_t remap_regs[] =
diff --git a/src/dwarf/Gparser.c b/src/dwarf/Gparser.c
index 7d255aee..7ddd8ded 100644
--- a/src/dwarf/Gparser.c
+++ b/src/dwarf/Gparser.c
@@ -831,6 +831,14 @@ apply_reg_state (struct dwarf_cursor *c, struct dwarf_reg_state *rs)
           break;
 
         case DWARF_WHERE_REG:
+#ifdef __s390x__
+          /* GPRs can be saved in FPRs on s390x */
+          if (unw_is_fpreg (dwarf_to_unw_regnum (rs->reg.val[i])))
+            {
+              new_loc[i] = DWARF_FPREG_LOC (c, dwarf_to_unw_regnum (rs->reg.val[i]));
+              break;
+            }
+#endif
           new_loc[i] = DWARF_REG_LOC (c, dwarf_to_unw_regnum (rs->reg.val[i]));
           break;
 
diff --git a/src/ptrace/_UPT_reg_offset.c b/src/ptrace/_UPT_reg_offset.c
index c82d1c98..52be7999 100644
--- a/src/ptrace/_UPT_reg_offset.c
+++ b/src/ptrace/_UPT_reg_offset.c
@@ -632,6 +632,40 @@ const int _UPT_reg_offset[UNW_REG_LAST + 1] =
     [UNW_TILEGX_R54]    = 0x1b0,
     [UNW_TILEGX_R55]    = 0x1b8,
     [UNW_TILEGX_PC]     = 0x1a0
+#elif defined(UNW_TARGET_S390X)
+    [UNW_S390X_R0]      = 0x10,
+    [UNW_S390X_R1]      = 0x18,
+    [UNW_S390X_R2]      = 0x20,
+    [UNW_S390X_R3]      = 0x28,
+    [UNW_S390X_R4]      = 0x30,
+    [UNW_S390X_R5]      = 0x38,
+    [UNW_S390X_R6]      = 0x40,
+    [UNW_S390X_R7]      = 0x48,
+    [UNW_S390X_R8]      = 0x50,
+    [UNW_S390X_R9]      = 0x58,
+    [UNW_S390X_R10]     = 0x60,
+    [UNW_S390X_R11]     = 0x68,
+    [UNW_S390X_R12]     = 0x70,
+    [UNW_S390X_R13]     = 0x78,
+    [UNW_S390X_R14]     = 0x80,
+    [UNW_S390X_R15]     = 0x88,
+    [UNW_S390X_F0]      = 0xe0,
+    [UNW_S390X_F1]      = 0xe8,
+    [UNW_S390X_F2]      = 0xf0,
+    [UNW_S390X_F3]      = 0xf8,
+    [UNW_S390X_F4]      = 0x100,
+    [UNW_S390X_F5]      = 0x108,
+    [UNW_S390X_F6]      = 0x110,
+    [UNW_S390X_F7]      = 0x118,
+    [UNW_S390X_F8]      = 0x120,
+    [UNW_S390X_F9]      = 0x128,
+    [UNW_S390X_F10]     = 0x130,
+    [UNW_S390X_F11]     = 0x138,
+    [UNW_S390X_F12]     = 0x140,
+    [UNW_S390X_F13]     = 0x148,
+    [UNW_S390X_F14]     = 0x150,
+    [UNW_S390X_F15]     = 0x150,
+    [UNW_S390X_IP]      = 0x08
 #else
 # error Fix me.
 #endif
diff --git a/src/s390x/Gapply_reg_state.c b/src/s390x/Gapply_reg_state.c
new file mode 100644
index 00000000..eec93046
--- /dev/null
+++ b/src/s390x/Gapply_reg_state.c
@@ -0,0 +1,37 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2002-2003 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.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 "unwind_i.h"
+
+PROTECTED int
+unw_apply_reg_state (unw_cursor_t *cursor,
+		     void *reg_states_data)
+{
+  struct cursor *c = (struct cursor *) cursor;
+
+  return dwarf_apply_reg_state (&c->dwarf, (dwarf_reg_state_t *)reg_states_data);
+}
diff --git a/src/s390x/Gcreate_addr_space.c b/src/s390x/Gcreate_addr_space.c
new file mode 100644
index 00000000..9c264c07
--- /dev/null
+++ b/src/s390x/Gcreate_addr_space.c
@@ -0,0 +1,62 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2003 Hewlett-Packard Co
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
+   Copyright (C) 2012 Tommi Rantala <tt.rantala@gmail.com>
+   Modified for s390x by Michael Munday <mike.munday@ibm.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 <stdlib.h>
+
+#include "unwind_i.h"
+
+#if defined(_BIG_ENDIAN) && !defined(__BIG_ENDIAN)
+#define __BIG_ENDIAN _BIG_ENDIAN
+#endif
+
+PROTECTED unw_addr_space_t
+unw_create_addr_space (unw_accessors_t *a, int byte_order)
+{
+#ifdef UNW_LOCAL_ONLY
+  return NULL;
+#else
+  unw_addr_space_t as;
+
+  /*
+   * s390x supports only big-endian.
+   */
+  if (byte_order != 0 && byte_order != __BIG_ENDIAN)
+    return NULL;
+
+  as = malloc (sizeof (*as));
+  if (!as)
+    return NULL;
+
+  memset (as, 0, sizeof (*as));
+
+  as->acc = *a;
+
+  return as;
+#endif
+}
diff --git a/src/s390x/Gget_proc_info.c b/src/s390x/Gget_proc_info.c
new file mode 100644
index 00000000..8def62d2
--- /dev/null
+++ b/src/s390x/Gget_proc_info.c
@@ -0,0 +1,48 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2002-2003 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.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 "unwind_i.h"
+
+PROTECTED int
+unw_get_proc_info (unw_cursor_t *cursor, unw_proc_info_t *pi)
+{
+  struct cursor *c = (struct cursor *) cursor;
+
+  if (dwarf_make_proc_info (&c->dwarf) < 0)
+    {
+      /* On x86-64, some key routines such as _start() and _dl_start()
+         are missing DWARF unwind info.  We don't want to fail in that
+         case, because those frames are uninteresting and just mark
+         the end of the frame-chain anyhow.  */
+      memset (pi, 0, sizeof (*pi));
+      pi->start_ip = c->dwarf.ip;
+      pi->end_ip = c->dwarf.ip + 1;
+      return 0;
+    }
+  *pi = c->dwarf.pi;
+  return 0;
+}
diff --git a/src/s390x/Gget_save_loc.c b/src/s390x/Gget_save_loc.c
new file mode 100644
index 00000000..7a672031
--- /dev/null
+++ b/src/s390x/Gget_save_loc.c
@@ -0,0 +1,86 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2004 Hewlett-Packard Co
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
+   Modified for s390x by Michael Munday <mike.munday@ibm.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 "unwind_i.h"
+
+PROTECTED int
+unw_get_save_loc (unw_cursor_t *cursor, int reg, unw_save_loc_t *sloc)
+{
+  struct cursor *c = (struct cursor *) cursor;
+  dwarf_loc_t loc;
+
+  loc = DWARF_NULL_LOC;         /* default to "not saved" */
+
+  switch (reg)
+    {
+    case UNW_S390X_R6:
+    case UNW_S390X_R7:
+    case UNW_S390X_R8:
+    case UNW_S390X_R9:
+    case UNW_S390X_R10:
+    case UNW_S390X_R11:
+    case UNW_S390X_R12:
+    case UNW_S390X_R13:
+    case UNW_S390X_R15:
+    case UNW_S390X_F8:
+    case UNW_S390X_F9:
+    case UNW_S390X_F10:
+    case UNW_S390X_F11:
+    case UNW_S390X_F12:
+    case UNW_S390X_F13:
+    case UNW_S390X_F14:
+    case UNW_S390X_F15:
+      loc = c->dwarf.loc[reg];
+      break;
+
+    default:
+      break;
+    }
+
+  memset (sloc, 0, sizeof (*sloc));
+
+  if (DWARF_IS_NULL_LOC (loc))
+    {
+      sloc->type = UNW_SLT_NONE;
+      return 0;
+    }
+
+#if !defined(UNW_LOCAL_ONLY)
+  if (DWARF_IS_REG_LOC (loc))
+    {
+      sloc->type = UNW_SLT_REG;
+      sloc->u.regnum = DWARF_GET_LOC (loc);
+    }
+  else
+#endif
+    {
+      sloc->type = UNW_SLT_MEMORY;
+      sloc->u.addr = DWARF_GET_LOC (loc);
+    }
+  return 0;
+}
diff --git a/src/s390x/Gglobal.c b/src/s390x/Gglobal.c
new file mode 100644
index 00000000..e2abe89d
--- /dev/null
+++ b/src/s390x/Gglobal.c
@@ -0,0 +1,101 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2003, 2005 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
+   Modified for s390x by Michael Munday <mike.munday@ibm.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 "config.h"
+#include "unwind_i.h"
+#include "dwarf_i.h"
+
+HIDDEN define_lock (s390x_lock);
+HIDDEN int tdep_init_done;
+
+/* The API register numbers are exactly the same as the .eh_frame
+   registers, for now at least.  */
+HIDDEN const uint8_t dwarf_to_unw_regnum_map[DWARF_NUM_PRESERVED_REGS] =
+  {
+    UNW_S390X_R0,
+    UNW_S390X_R1,
+    UNW_S390X_R2,
+    UNW_S390X_R3,
+    UNW_S390X_R4,
+    UNW_S390X_R5,
+    UNW_S390X_R6,
+    UNW_S390X_R7,
+    UNW_S390X_R8,
+    UNW_S390X_R9,
+    UNW_S390X_R10,
+    UNW_S390X_R11,
+    UNW_S390X_R12,
+    UNW_S390X_R13,
+    UNW_S390X_R14,
+    UNW_S390X_R15,
+
+    UNW_S390X_F0,
+    UNW_S390X_F2,
+    UNW_S390X_F4,
+    UNW_S390X_F6,
+    UNW_S390X_F1,
+    UNW_S390X_F3,
+    UNW_S390X_F5,
+    UNW_S390X_F7,
+    UNW_S390X_F8,
+    UNW_S390X_F10,
+    UNW_S390X_F12,
+    UNW_S390X_F14,
+    UNW_S390X_F9,
+    UNW_S390X_F11,
+    UNW_S390X_F13,
+    UNW_S390X_F15,
+  };
+
+HIDDEN void
+tdep_init (void)
+{
+  intrmask_t saved_mask;
+
+  sigfillset (&unwi_full_mask);
+
+  lock_acquire (&s390x_lock, saved_mask);
+  {
+    if (tdep_init_done)
+      /* another thread else beat us to it... */
+      goto out;
+
+    mi_init ();
+
+    dwarf_init ();
+
+    tdep_init_mem_validate ();
+
+#ifndef UNW_REMOTE_ONLY
+    s390x_local_addr_space_init ();
+#endif
+    tdep_init_done = 1; /* signal that we're initialized... */
+  }
+ out:
+  lock_release (&s390x_lock, saved_mask);
+}
diff --git a/src/s390x/Ginit.c b/src/s390x/Ginit.c
new file mode 100644
index 00000000..260a1f96
--- /dev/null
+++ b/src/s390x/Ginit.c
@@ -0,0 +1,364 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2002 Hewlett-Packard Co
+   Copyright (C) 2007 David Mosberger-Tang
+        Contributed by David Mosberger-Tang <dmosberger@gmail.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
+   Modified for s390x by Michael Munday <mike.munday@ibm.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.  */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+
+#include "unwind_i.h"
+
+#ifdef UNW_REMOTE_ONLY
+
+/* unw_local_addr_space is a NULL pointer in this case.  */
+PROTECTED unw_addr_space_t unw_local_addr_space;
+
+#else /* !UNW_REMOTE_ONLY */
+
+static struct unw_addr_space local_addr_space;
+
+PROTECTED unw_addr_space_t unw_local_addr_space = &local_addr_space;
+
+HIDDEN unw_dyn_info_list_t _U_dyn_info_list;
+
+static inline void *
+uc_addr (ucontext_t *uc, int reg)
+{
+  if (reg >= UNW_S390X_R0 && reg <= UNW_S390X_R15)
+    return &uc->uc_mcontext.gregs[reg - UNW_S390X_R0];
+  if (reg >= UNW_S390X_F0 && reg <= UNW_S390X_F15)
+    return &uc->uc_mcontext.fpregs.fprs[reg - UNW_S390X_F0];
+  if (reg == UNW_S390X_IP)
+    return &uc->uc_mcontext.psw.addr;
+
+  return NULL;
+}
+
+# ifdef UNW_LOCAL_ONLY
+
+HIDDEN void *
+tdep_uc_addr (ucontext_t *uc, int reg)
+{
+  return uc_addr (uc, reg);
+}
+
+# endif /* UNW_LOCAL_ONLY */
+
+/* XXX fix me: there is currently no way to locate the dyn-info list
+       by a remote unwinder.  On ia64, this is done via a special
+       unwind-table entry.  Perhaps something similar can be done with
+       DWARF2 unwind info.  */
+
+static void
+put_unwind_info (unw_addr_space_t as, unw_proc_info_t *proc_info, void *arg)
+{
+  /* it's a no-op */
+}
+
+static int
+get_dyn_info_list_addr (unw_addr_space_t as, unw_word_t *dyn_info_list_addr,
+                        void *arg)
+{
+  *dyn_info_list_addr = (unw_word_t) &_U_dyn_info_list;
+  return 0;
+}
+
+#define PAGE_SIZE 4096
+#define PAGE_START(a)   ((a) & ~(PAGE_SIZE-1))
+
+static int mem_validate_pipe[2] = {-1, -1};
+
+static inline void
+open_pipe (void)
+{
+  /* ignore errors for closing invalid fd's */
+  close (mem_validate_pipe[0]);
+  close (mem_validate_pipe[1]);
+
+  pipe2 (mem_validate_pipe, O_CLOEXEC | O_NONBLOCK);
+}
+
+ALWAYS_INLINE
+static int
+write_validate (void *addr)
+{
+  int ret = -1;
+  ssize_t bytes = 0;
+
+  do
+    {
+      char buf;
+      bytes = read (mem_validate_pipe[0], &buf, 1);
+    }
+  while ( errno == EINTR );
+
+  int valid_read = (bytes > 0 || errno == EAGAIN || errno == EWOULDBLOCK);
+  if (!valid_read)
+    {
+      // re-open closed pipe
+      open_pipe ();
+    }
+
+  do
+    {
+      ret = write (mem_validate_pipe[1], addr, 1);
+    }
+  while ( errno == EINTR );
+
+  return ret;
+}
+
+static int (*mem_validate_func) (void *addr, size_t len);
+static int msync_validate (void *addr, size_t len)
+{
+  if (msync (addr, len, MS_ASYNC) != 0)
+    {
+      return -1;
+    }
+
+  return write_validate (addr);
+}
+
+#ifdef HAVE_MINCORE
+static int mincore_validate (void *addr, size_t len)
+{
+  unsigned char mvec[2]; /* Unaligned access may cross page boundary */
+  size_t i;
+
+  /* mincore could fail with EAGAIN but we conservatively return -1
+     instead of looping. */
+  if (mincore (addr, len, mvec) != 0)
+    {
+      return -1;
+    }
+
+  for (i = 0; i < (len + PAGE_SIZE - 1) / PAGE_SIZE; i++)
+    {
+      if (!(mvec[i] & 1)) return -1;
+    }
+
+  return write_validate (addr);
+}
+#endif
+
+/* Initialise memory validation method. On linux kernels <2.6.21,
+   mincore() returns incorrect value for MAP_PRIVATE mappings,
+   such as stacks. If mincore() was available at compile time,
+   check if we can actually use it. If not, use msync() instead. */
+HIDDEN void
+tdep_init_mem_validate (void)
+{
+  open_pipe ();
+
+#ifdef HAVE_MINCORE
+  unsigned char present = 1;
+  unw_word_t addr = PAGE_START((unw_word_t)&present);
+  unsigned char mvec[1];
+  int ret;
+  while ((ret = mincore ((void*)addr, PAGE_SIZE, mvec)) == -1 &&
+         errno == EAGAIN) {}
+  if (ret == 0 && (mvec[0] & 1))
+    {
+      Debug(1, "using mincore to validate memory\n");
+      mem_validate_func = mincore_validate;
+    }
+  else
+#endif
+    {
+      Debug(1, "using msync to validate memory\n");
+      mem_validate_func = msync_validate;
+    }
+}
+
+/* Cache of already validated addresses */
+#define NLGA 4
+static unw_word_t last_good_addr[NLGA];
+static int lga_victim;
+
+static int
+validate_mem (unw_word_t addr)
+{
+  int i, victim;
+  size_t len;
+
+  if (PAGE_START(addr + sizeof (unw_word_t) - 1) == PAGE_START(addr))
+    len = PAGE_SIZE;
+  else
+    len = PAGE_SIZE * 2;
+
+  addr = PAGE_START(addr);
+
+  if (addr == 0)
+    return -1;
+
+  for (i = 0; i < NLGA; i++)
+    {
+      if (last_good_addr[i] && (addr == last_good_addr[i]))
+        return 0;
+    }
+
+  if (mem_validate_func ((void *) addr, len) == -1)
+    return -1;
+
+  victim = lga_victim;
+  for (i = 0; i < NLGA; i++) {
+    if (!last_good_addr[victim]) {
+      last_good_addr[victim++] = addr;
+      return 0;
+    }
+    victim = (victim + 1) % NLGA;
+  }
+
+  /* All slots full. Evict the victim. */
+  last_good_addr[victim] = addr;
+  victim = (victim + 1) % NLGA;
+  lga_victim = victim;
+
+  return 0;
+}
+
+static int
+access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val, int write,
+            void *arg)
+{
+  if (unlikely (write))
+    {
+      Debug (16, "mem[%016lx] <- %lx\n", addr, *val);
+      *(unw_word_t *) addr = *val;
+    }
+  else
+    {
+      /* validate address */
+      const struct cursor *c = (const struct cursor *)arg;
+      if (likely (c != NULL) && unlikely (c->validate)
+          && unlikely (validate_mem (addr))) {
+        Debug (16, "mem[%016lx] -> invalid\n", addr);
+        return -1;
+      }
+      *val = *(unw_word_t *) addr;
+      Debug (16, "mem[%016lx] -> %lx\n", addr, *val);
+    }
+  return 0;
+}
+
+static int
+access_reg (unw_addr_space_t as, unw_regnum_t reg, unw_word_t *val, int write,
+            void *arg)
+{
+  unw_word_t *addr;
+  ucontext_t *uc = ((struct cursor *)arg)->uc;
+
+  if (unw_is_fpreg (reg))
+    goto badreg;
+
+  if (!(addr = uc_addr (uc, reg)))
+    goto badreg;
+
+  if (write)
+    {
+      *(unw_word_t *) addr = *val;
+      Debug (12, "%s <- 0x%016lx\n", unw_regname (reg), *val);
+    }
+  else
+    {
+      *val = *(unw_word_t *) addr;
+      Debug (12, "%s -> 0x%016lx\n", unw_regname (reg), *val);
+    }
+  return 0;
+
+ badreg:
+  Debug (1, "bad register number %u\n", reg);
+  return -UNW_EBADREG;
+}
+
+static int
+access_fpreg (unw_addr_space_t as, unw_regnum_t reg, unw_fpreg_t *val,
+              int write, void *arg)
+{
+  ucontext_t *uc = ((struct cursor *)arg)->uc;
+  unw_fpreg_t *addr;
+
+  if (!unw_is_fpreg (reg))
+    goto badreg;
+
+  if (!(addr = uc_addr (uc, reg)))
+    goto badreg;
+
+  if (write)
+    {
+      Debug (12, "%s <- %08lx.%08lx.%08lx\n", unw_regname (reg),
+             ((long *)val)[0], ((long *)val)[1], ((long *)val)[2]);
+      *(unw_fpreg_t *) addr = *val;
+    }
+  else
+    {
+      *val = *(unw_fpreg_t *) addr;
+      Debug (12, "%s -> %08lx.%08lx.%08lx\n", unw_regname (reg),
+             ((long *)val)[0], ((long *)val)[1], ((long *)val)[2]);
+    }
+  return 0;
+
+ badreg:
+  Debug (1, "bad register number %u\n", reg);
+  /* attempt to access a non-preserved register */
+  return -UNW_EBADREG;
+}
+
+static int
+get_static_proc_name (unw_addr_space_t as, unw_word_t ip,
+                      char *buf, size_t buf_len, unw_word_t *offp,
+                      void *arg)
+{
+  return _Uelf64_get_proc_name (as, getpid (), ip, buf, buf_len, offp);
+}
+
+HIDDEN void
+s390x_local_addr_space_init (void)
+{
+  memset (&local_addr_space, 0, sizeof (local_addr_space));
+  local_addr_space.caching_policy = UNW_CACHE_GLOBAL;
+  local_addr_space.acc.find_proc_info = dwarf_find_proc_info;
+  local_addr_space.acc.put_unwind_info = put_unwind_info;
+  local_addr_space.acc.get_dyn_info_list_addr = get_dyn_info_list_addr;
+  local_addr_space.acc.access_mem = access_mem;
+  local_addr_space.acc.access_reg = access_reg;
+  local_addr_space.acc.access_fpreg = access_fpreg;
+  local_addr_space.acc.resume = s390x_local_resume;
+  local_addr_space.acc.get_proc_name = get_static_proc_name;
+  unw_flush_cache (&local_addr_space, 0, 0);
+
+  memset (last_good_addr, 0, sizeof (unw_word_t) * NLGA);
+  lga_victim = 0;
+}
+
+#endif /* !UNW_REMOTE_ONLY */
diff --git a/src/s390x/Ginit_local.c b/src/s390x/Ginit_local.c
new file mode 100644
index 00000000..7696f11c
--- /dev/null
+++ b/src/s390x/Ginit_local.c
@@ -0,0 +1,81 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2002-2003 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.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 "unwind_i.h"
+#include "init.h"
+
+#ifdef UNW_REMOTE_ONLY
+
+PROTECTED int
+unw_init_local (unw_cursor_t *cursor, ucontext_t *uc)
+{
+  return -UNW_EINVAL;
+}
+
+#else /* !UNW_REMOTE_ONLY */
+
+static int
+unw_init_local_common (unw_cursor_t *cursor, ucontext_t *uc, unsigned use_prev_instr)
+{
+  struct cursor *c = (struct cursor *) cursor;
+
+  if (unlikely (!tdep_init_done))
+    tdep_init ();
+
+  Debug (1, "(cursor=%p)\n", c);
+
+  c->dwarf.as = unw_local_addr_space;
+  c->dwarf.as_arg = c;
+  c->uc = uc;
+  c->validate = 0;
+  return common_init (c, use_prev_instr);
+}
+
+PROTECTED int
+unw_init_local (unw_cursor_t *cursor, ucontext_t *uc)
+{
+  return unw_init_local_common(cursor, uc, 1);
+}
+
+PROTECTED int
+unw_init_local2 (unw_cursor_t *cursor, ucontext_t *uc, int flag)
+{
+  if (!flag)
+    {
+      return unw_init_local_common(cursor, uc, 1);
+    }
+  else if (flag == UNW_INIT_SIGNAL_FRAME)
+    {
+      return unw_init_local_common(cursor, uc, 0);
+    }
+  else
+    {
+      return -UNW_EINVAL;
+    }
+}
+
+#endif /* !UNW_REMOTE_ONLY */
diff --git a/src/s390x/Ginit_remote.c b/src/s390x/Ginit_remote.c
new file mode 100644
index 00000000..f3b7bb97
--- /dev/null
+++ b/src/s390x/Ginit_remote.c
@@ -0,0 +1,57 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2003 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.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 "init.h"
+#include "unwind_i.h"
+
+PROTECTED int
+unw_init_remote (unw_cursor_t *cursor, unw_addr_space_t as, void *as_arg)
+{
+#ifdef UNW_LOCAL_ONLY
+  return -UNW_EINVAL;
+#else /* !UNW_LOCAL_ONLY */
+  struct cursor *c = (struct cursor *) cursor;
+
+  if (!tdep_init_done)
+    tdep_init ();
+
+  Debug (1, "(cursor=%p)\n", c);
+
+  c->dwarf.as = as;
+  if (as == unw_local_addr_space)
+    {
+      c->dwarf.as_arg = c;
+      c->uc = as_arg;
+    }
+  else
+    {
+      c->dwarf.as_arg = as_arg;
+      c->uc = NULL;
+    }
+  return common_init (c, 0);
+#endif /* !UNW_LOCAL_ONLY */
+}
diff --git a/src/s390x/Gis_signal_frame.c b/src/s390x/Gis_signal_frame.c
new file mode 100644
index 00000000..161e46fd
--- /dev/null
+++ b/src/s390x/Gis_signal_frame.c
@@ -0,0 +1,77 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2012 Tommi Rantala <tt.rantala@gmail.com>
+   Copyright (C) 2013 Linaro Limited
+   Copyright (C) 2017 IBM
+
+   Modified for s390x by Michael Munday <mike.munday@ibm.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 "unwind_i.h"
+
+/* The restorer stub will be a system call:
+   - rt_sigreturn: svc 173 (0x0aad)
+   - sigreturn:    svc 119 (0x0a77)
+*/
+
+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, shift = 48;
+
+  as = c->dwarf.as;
+  a = unw_get_accessors (as);
+  arg = c->dwarf.as_arg;
+
+  /* Align the instruction pointer to 8 bytes so that we guarantee
+     an 8 byte read from it won't cross a page boundary.
+     Instructions on s390x are 2 byte aligned.  */
+  ip = c->dwarf.ip & ~7;
+  shift -= (c->dwarf.ip - ip) * 8;
+
+  ret = (*a->access_mem) (as, ip, &w0, 0, arg);
+  if (ret < 0)
+    return ret;
+
+  /* extract first 2 bytes of the next instruction */
+  w0 = (w0 >> shift) & 0xffff;
+
+  /* sigreturn */
+  if (w0 == 0x0a77)
+    return 1;
+
+  /* rt_sigreturn */
+  if (w0 == 0x0aad)
+    return 2;
+
+  return 0;
+
+#else
+  return -UNW_ENOINFO;
+#endif
+}
diff --git a/src/s390x/Greg_states_iterate.c b/src/s390x/Greg_states_iterate.c
new file mode 100644
index 00000000..a39837a1
--- /dev/null
+++ b/src/s390x/Greg_states_iterate.c
@@ -0,0 +1,37 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2002-2003 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.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 "unwind_i.h"
+
+PROTECTED int
+unw_reg_states_iterate (unw_cursor_t *cursor,
+			unw_reg_states_callback cb, void *token)
+{
+  struct cursor *c = (struct cursor *) cursor;
+
+  return dwarf_reg_states_iterate (&c->dwarf, cb, token);
+}
diff --git a/src/s390x/Gregs.c b/src/s390x/Gregs.c
new file mode 100644
index 00000000..1a48833d
--- /dev/null
+++ b/src/s390x/Gregs.c
@@ -0,0 +1,116 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2002-2004 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
+   Modified for s390x by Michael Munday <mike.munday@ibm.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 "unwind_i.h"
+
+HIDDEN int
+tdep_access_reg (struct cursor *c, unw_regnum_t reg, unw_word_t *valp,
+                 int write)
+{
+  dwarf_loc_t loc = DWARF_NULL_LOC;
+
+  switch (reg)
+    {
+    case UNW_S390X_CFA:
+      if (write)
+        return -UNW_EREADONLYREG;
+      *valp = c->dwarf.cfa;
+      return 0;
+
+    case UNW_S390X_R0:
+    case UNW_S390X_R1:
+    case UNW_S390X_R2:
+    case UNW_S390X_R3:
+    case UNW_S390X_R4:
+    case UNW_S390X_R5:
+    case UNW_S390X_R6:
+    case UNW_S390X_R7:
+    case UNW_S390X_R8:
+    case UNW_S390X_R9:
+    case UNW_S390X_R10:
+    case UNW_S390X_R11:
+    case UNW_S390X_R12:
+    case UNW_S390X_R13:
+    case UNW_S390X_R14:
+    case UNW_S390X_IP:
+      loc = c->dwarf.loc[reg];
+      break;
+
+    case UNW_S390X_R15:
+      if (write)
+        return -UNW_EREADONLYREG;
+      loc = c->dwarf.loc[reg];
+      break;
+
+    default:
+      Debug (1, "bad register number %u\n", reg);
+      return -UNW_EBADREG;
+    }
+
+  if (write)
+    return dwarf_put (&c->dwarf, loc, *valp);
+  else
+    return dwarf_get (&c->dwarf, loc, valp);
+}
+
+HIDDEN int
+tdep_access_fpreg (struct cursor *c, unw_regnum_t reg, unw_fpreg_t *valp,
+                   int write)
+{
+  dwarf_loc_t loc = DWARF_NULL_LOC;
+
+  switch (reg)
+    {
+    case UNW_S390X_F0:
+    case UNW_S390X_F1:
+    case UNW_S390X_F2:
+    case UNW_S390X_F3:
+    case UNW_S390X_F4:
+    case UNW_S390X_F5:
+    case UNW_S390X_F6:
+    case UNW_S390X_F7:
+    case UNW_S390X_F8:
+    case UNW_S390X_F9:
+    case UNW_S390X_F10:
+    case UNW_S390X_F11:
+    case UNW_S390X_F12:
+    case UNW_S390X_F13:
+    case UNW_S390X_F14:
+    case UNW_S390X_F15:
+      loc = c->dwarf.loc[reg];
+      break;
+    default:
+      Debug (1, "bad register number %u\n", reg);
+      return -UNW_EBADREG;
+    }
+
+  if (write)
+    return dwarf_putfp (&c->dwarf, loc, *valp);
+  else
+    return dwarf_getfp (&c->dwarf, loc, valp);
+}
diff --git a/src/s390x/Gresume.c b/src/s390x/Gresume.c
new file mode 100644
index 00000000..8712ce76
--- /dev/null
+++ b/src/s390x/Gresume.c
@@ -0,0 +1,160 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2002-2004 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.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 <stdlib.h>
+
+#include "unwind_i.h"
+
+#ifndef UNW_REMOTE_ONLY
+
+HIDDEN inline int
+s390x_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg)
+{
+  struct cursor *c = (struct cursor *) cursor;
+  ucontext_t uc = *c->uc;
+  ucontext_t *rt = NULL;
+  struct sigcontext *sc = NULL;
+  int i;
+  unw_word_t sp, ip;
+  uc.uc_mcontext.psw.addr = c->dwarf.ip;
+
+  /* Ensure c->pi is up-to-date.  On x86-64, it's relatively common to
+     be missing DWARF unwind info.  We don't want to fail in that
+     case, because the frame-chain still would let us do a backtrace
+     at least.  */
+  dwarf_make_proc_info (&c->dwarf);
+
+  switch (c->sigcontext_format)
+    {
+    case S390X_SCF_NONE:
+      Debug (8, "resuming at ip=%llx via setcontext()\n",
+                (unsigned long long) c->dwarf.ip);
+      setcontext (&uc);
+      abort(); /* unreachable */
+    case S390X_SCF_LINUX_SIGFRAME:
+      Debug (8, "resuming at ip=%llx via signal trampoline\n",
+                (unsigned long long) c->dwarf.ip);
+      sc = (struct sigcontext*)c->sigcontext_addr;
+      for (i = UNW_S390X_R0; i <= UNW_S390X_R15; ++i)
+        sc->sregs->regs.gprs[i-UNW_S390X_R0] = uc.uc_mcontext.gregs[i-UNW_S390X_R0];
+      for (i = UNW_S390X_F0; i <= UNW_S390X_F15; ++i)
+        sc->sregs->fpregs.fprs[i-UNW_S390X_F0] = uc.uc_mcontext.fpregs.fprs[i-UNW_S390X_F0].d;
+      sc->sregs->regs.psw.addr = uc.uc_mcontext.psw.addr;
+
+      sp = c->sigcontext_sp;
+      ip = c->sigcontext_pc;
+      __asm__ __volatile__ (
+        "lgr 15, %[sp]\n"
+        "br %[ip]\n"
+        : : [sp] "r" (sp), [ip] "r" (ip)
+      );
+      abort(); /* unreachable */
+    case S390X_SCF_LINUX_RT_SIGFRAME:
+      Debug (8, "resuming at ip=%llx via signal trampoline\n",
+                (unsigned long long) c->dwarf.ip);
+      rt = (ucontext_t*)c->sigcontext_addr;
+      for (i = UNW_S390X_R0; i <= UNW_S390X_R15; ++i)
+        rt->uc_mcontext.gregs[i-UNW_S390X_R0] = uc.uc_mcontext.gregs[i-UNW_S390X_R0];
+      for (i = UNW_S390X_F0; i <= UNW_S390X_F15; ++i)
+        rt->uc_mcontext.fpregs.fprs[i-UNW_S390X_F0] = uc.uc_mcontext.fpregs.fprs[i-UNW_S390X_F0];
+      rt->uc_mcontext.psw.addr = uc.uc_mcontext.psw.addr;
+
+      sp = c->sigcontext_sp;
+      ip = c->sigcontext_pc;
+      __asm__ __volatile__ (
+        "lgr 15, %[sp]\n"
+        "br %[ip]\n"
+        : : [sp] "r" (sp), [ip] "r" (ip)
+      );
+      abort(); /* unreachable */
+    }
+  return -UNW_EINVAL;
+}
+
+#endif /* !UNW_REMOTE_ONLY */
+
+/* This routine is responsible for copying the register values in
+   cursor C and establishing them as the current machine state. */
+
+static inline int
+establish_machine_state (struct cursor *c)
+{
+  int (*access_reg) (unw_addr_space_t, unw_regnum_t, unw_word_t *,
+                     int write, void *);
+  int (*access_fpreg) (unw_addr_space_t, unw_regnum_t, unw_fpreg_t *,
+                       int write, void *);
+  unw_addr_space_t as = c->dwarf.as;
+  void *arg = c->dwarf.as_arg;
+  unw_fpreg_t fpval;
+  unw_word_t val;
+  int reg;
+
+  access_reg = as->acc.access_reg;
+  access_fpreg = as->acc.access_fpreg;
+
+  Debug (8, "copying out cursor state\n");
+
+  for (reg = 0; reg <= UNW_REG_LAST; ++reg)
+    {
+      Debug (16, "copying %s %d\n", unw_regname (reg), reg);
+      if (unw_is_fpreg (reg))
+        {
+          if (tdep_access_fpreg (c, reg, &fpval, 0) >= 0)
+            (*access_fpreg) (as, reg, &fpval, 1, arg);
+        }
+      else
+        {
+          if (tdep_access_reg (c, reg, &val, 0) >= 0)
+            (*access_reg) (as, reg, &val, 1, arg);
+        }
+    }
+
+  if (c->dwarf.args_size)
+    {
+      if (tdep_access_reg (c, UNW_S390X_R15, &val, 0) >= 0)
+        {
+          val += c->dwarf.args_size;
+          (*access_reg) (as, UNW_S390X_R15, &val, 1, arg);
+        }
+    }
+  return 0;
+}
+
+PROTECTED int
+unw_resume (unw_cursor_t *cursor)
+{
+  struct cursor *c = (struct cursor *) cursor;
+  int ret;
+
+  Debug (1, "(cursor=%p)\n", c);
+
+  if ((ret = establish_machine_state (c)) < 0)
+    return ret;
+
+  return (*c->dwarf.as->acc.resume) (c->dwarf.as, (unw_cursor_t *) c,
+                                     c->dwarf.as_arg);
+}
diff --git a/src/s390x/Gstep.c b/src/s390x/Gstep.c
new file mode 100644
index 00000000..4d9a8dfc
--- /dev/null
+++ b/src/s390x/Gstep.c
@@ -0,0 +1,146 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2002-2004 Hewlett-Packard Co
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
+   Modified for s390x by Michael Munday <mike.munday@ibm.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 "unwind_i.h"
+#include <signal.h>
+
+PROTECTED int
+unw_handle_signal_frame (unw_cursor_t *cursor)
+{
+  struct cursor *c = (struct cursor *) cursor;
+  int ret, i;
+  unw_word_t sc_addr, sp, *gprs, *fprs, *psw;
+
+  ret = dwarf_get (&c->dwarf, c->dwarf.loc[UNW_S390X_R15], &sp);
+  if (ret < 0)
+    return ret;
+
+  /* Save the SP and PC to be able to return execution at this point
+     later in time (unw_resume).  */
+  c->sigcontext_sp = sp;
+  c->sigcontext_pc = c->dwarf.ip;
+  switch (c->sigcontext_format)
+    {
+    case S390X_SCF_LINUX_SIGFRAME: /* sigreturn */
+      sc_addr = sp + 160;
+      gprs = ((struct sigcontext*)sc_addr)->sregs->regs.gprs;
+      fprs = (unw_word_t*)((struct sigcontext*)sc_addr)->sregs->fpregs.fprs;
+      psw  = &((struct sigcontext*)sc_addr)->sregs->regs.psw.addr;
+      break;
+    case S390X_SCF_LINUX_RT_SIGFRAME: /* rt_sigreturn */
+      sc_addr = sp + sizeof(siginfo_t) + 8 + 160;
+      gprs = ((ucontext_t*)sc_addr)->uc_mcontext.gregs;
+      fprs = (unw_word_t*)((ucontext_t*)sc_addr)->uc_mcontext.fpregs.fprs;
+      psw  = &((ucontext_t*)sc_addr)->uc_mcontext.psw.addr;
+      break;
+    default:
+      return -UNW_EUNSPEC;
+    }
+
+  c->sigcontext_addr = sc_addr;
+
+  /* Update the dwarf cursor.
+     Set the location of the registers to the corresponding addresses of the
+     uc_mcontext / sigcontext structure contents.  */
+  for (i = UNW_S390X_R0; i <= UNW_S390X_R15; ++i)
+    c->dwarf.loc[i] = DWARF_MEM_LOC (c, (unw_word_t) &gprs[i-UNW_S390X_R0]);
+  for (i = UNW_S390X_F0; i <= UNW_S390X_F15; ++i)
+    c->dwarf.loc[i] = DWARF_MEM_LOC (c, (unw_word_t) &fprs[i-UNW_S390X_F0]);
+
+  c->dwarf.loc[UNW_S390X_IP] = DWARF_MEM_LOC (c, (unw_word_t) psw);
+
+  /* Set SP/CFA and PC/IP.
+     Normally the default CFA on s390x is r15+160. We do not add that offset
+     here because dwarf_step will add the offset.  */
+  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_S390X_R15], &c->dwarf.cfa);
+  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_S390X_IP], &c->dwarf.ip);
+
+  c->dwarf.pi_valid = 0;
+  c->dwarf.use_prev_instr = 0;
+
+  return 1;
+}
+
+PROTECTED int
+unw_step (unw_cursor_t *cursor)
+{
+  struct cursor *c = (struct cursor *) cursor;
+  int ret = 0, val = c->validate, sig;
+
+#if CONSERVATIVE_CHECKS
+  c->validate = 1;
+#endif
+
+  Debug (1, "(cursor=%p, ip=0x%016lx, cfa=0x%016lx)\n",
+         c, c->dwarf.ip, c->dwarf.cfa);
+
+  /* Try DWARF-based unwinding... */
+  c->sigcontext_format = S390X_SCF_NONE;
+  ret = dwarf_step (&c->dwarf);
+
+#if CONSERVATIVE_CHECKS
+  c->validate = val;
+#endif
+
+  if (unlikely (ret == -UNW_ENOINFO))
+    {
+      /* GCC doesn't currently emit debug information for signal
+         trampolines on s390x so we check for them explicitly.
+
+         If there isn't debug information available we could also
+         try using the backchain (if available).
+
+         Other platforms also detect PLT entries here. That's
+         tricky to do reliably on s390x so I've left it out for
+         now.  */
+
+      /* Memory accesses here are quite likely to be unsafe. */
+      c->validate = 1;
+
+      /* Check if this is a signal frame. */
+      sig = unw_is_signal_frame (cursor);
+      if (sig > 0)
+        {
+          c->sigcontext_format = sig;
+          ret = unw_handle_signal_frame (cursor);
+        }
+      else
+        {
+          c->dwarf.ip = 0;
+          ret = 0;
+        }
+
+      c->validate = val;
+      return ret;
+    }
+
+  if (unlikely (ret > 0 && c->dwarf.ip == 0))
+    return 0;
+
+  return ret;
+}
diff --git a/src/s390x/Lapply_reg_state.c b/src/s390x/Lapply_reg_state.c
new file mode 100644
index 00000000..7ebada48
--- /dev/null
+++ b/src/s390x/Lapply_reg_state.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gapply_reg_state.c"
+#endif
diff --git a/src/s390x/Lcreate_addr_space.c b/src/s390x/Lcreate_addr_space.c
new file mode 100644
index 00000000..0f2dc6be
--- /dev/null
+++ b/src/s390x/Lcreate_addr_space.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gcreate_addr_space.c"
+#endif
diff --git a/src/s390x/Lget_proc_info.c b/src/s390x/Lget_proc_info.c
new file mode 100644
index 00000000..69028b01
--- /dev/null
+++ b/src/s390x/Lget_proc_info.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gget_proc_info.c"
+#endif
diff --git a/src/s390x/Lget_save_loc.c b/src/s390x/Lget_save_loc.c
new file mode 100644
index 00000000..9ea048a9
--- /dev/null
+++ b/src/s390x/Lget_save_loc.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gget_save_loc.c"
+#endif
diff --git a/src/s390x/Lglobal.c b/src/s390x/Lglobal.c
new file mode 100644
index 00000000..8c43a67c
--- /dev/null
+++ b/src/s390x/Lglobal.c
@@ -0,0 +1,6 @@
+#define UNW_LOCAL_ONLY
+#include "config.h"
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gglobal.c"
+#endif
diff --git a/src/s390x/Linit.c b/src/s390x/Linit.c
new file mode 100644
index 00000000..e9abfdd4
--- /dev/null
+++ b/src/s390x/Linit.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Ginit.c"
+#endif
diff --git a/src/s390x/Linit_local.c b/src/s390x/Linit_local.c
new file mode 100644
index 00000000..68a1687e
--- /dev/null
+++ b/src/s390x/Linit_local.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Ginit_local.c"
+#endif
diff --git a/src/s390x/Linit_remote.c b/src/s390x/Linit_remote.c
new file mode 100644
index 00000000..58cb04ab
--- /dev/null
+++ b/src/s390x/Linit_remote.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Ginit_remote.c"
+#endif
diff --git a/src/s390x/Lis_signal_frame.c b/src/s390x/Lis_signal_frame.c
new file mode 100644
index 00000000..b9a7c4f5
--- /dev/null
+++ b/src/s390x/Lis_signal_frame.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gis_signal_frame.c"
+#endif
diff --git a/src/s390x/Lreg_states_iterate.c b/src/s390x/Lreg_states_iterate.c
new file mode 100644
index 00000000..f1eb1e79
--- /dev/null
+++ b/src/s390x/Lreg_states_iterate.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Greg_states_iterate.c"
+#endif
diff --git a/src/s390x/Lregs.c b/src/s390x/Lregs.c
new file mode 100644
index 00000000..2c9c75cd
--- /dev/null
+++ b/src/s390x/Lregs.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gregs.c"
+#endif
diff --git a/src/s390x/Lresume.c b/src/s390x/Lresume.c
new file mode 100644
index 00000000..41a8cf00
--- /dev/null
+++ b/src/s390x/Lresume.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gresume.c"
+#endif
diff --git a/src/s390x/Lstep.c b/src/s390x/Lstep.c
new file mode 100644
index 00000000..c1ac3c75
--- /dev/null
+++ b/src/s390x/Lstep.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if defined(UNW_LOCAL_ONLY) && !defined(UNW_REMOTE_ONLY)
+#include "Gstep.c"
+#endif
diff --git a/src/s390x/getcontext.S b/src/s390x/getcontext.S
new file mode 100644
index 00000000..d35a3cf3
--- /dev/null
+++ b/src/s390x/getcontext.S
@@ -0,0 +1,74 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2008 Google, Inc
+	Contributed by Paul Pluzhnikov <ppluzhnikov@google.com>
+   Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org>
+   Copyright (C) 2017 IBM
+
+   Modified for s390x by Michael Munday <mike.munday@ibm.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.  */
+
+// int _Us390x_getcontext (unw_tdep_context_t *ucp)
+
+	.global _Us390x_getcontext
+	.type _Us390x_getcontext, @function
+_Us390x_getcontext:
+	.cfi_startproc
+
+	// Save the minimal set of registers required to restore the
+	// context. Generally speaking this is just the preserved
+	// registers but we've also saved the parameter registers
+	// so that return values can be modified too.
+
+	// save PSW address
+	// (not strictly needed but makes other code simpler)
+	stg   %r14,0x30(%r2)
+
+	// floating point parameters (not strictly needed)
+	std   %f0,0x100(%r2)
+	std   %f2,0x110(%r2)
+	std   %f4,0x120(%r2)
+	std   %f6,0x130(%r2)
+
+	// floating point preserved registers
+	stfpc 0xf8(%r2)
+	std   %f8,0x140(%r2)
+	std   %f9,0x148(%r2)
+	std   %f10,0x150(%r2)
+	std   %f11,0x158(%r2)
+	std   %f12,0x160(%r2)
+	std   %f13,0x168(%r2)
+	std   %f14,0x170(%r2)
+	std   %f15,0x178(%r2)
+
+	// preserved registers and parameters
+	lgr   %r1,%r2
+	lghi  %r2,0
+	stmg  %r2,%r15,0x48(%r1)
+
+	br    %r14
+
+	.cfi_endproc
+	.size _Us390x_getcontext, . - _Us390x_getcontext
+
+	// We do not need executable stack.
+	.section        .note.GNU-stack,"",@progbits
diff --git a/src/s390x/init.h b/src/s390x/init.h
new file mode 100644
index 00000000..86ced38f
--- /dev/null
+++ b/src/s390x/init.h
@@ -0,0 +1,71 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2002 Hewlett-Packard Co
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
+   Modified for s390x by Michael Munday <mike.munday@ibm.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 "unwind_i.h"
+
+static inline int
+common_init (struct cursor *c, unsigned use_prev_instr)
+{
+  int ret;
+  int i;
+
+  for (i = UNW_S390X_R0; i <= UNW_S390X_R15; ++i) {
+    c->dwarf.loc[i] = DWARF_REG_LOC(&c->dwarf, i);
+  }
+  for (i = UNW_S390X_F0; i <= UNW_S390X_F15; ++i) {
+    c->dwarf.loc[i] = DWARF_FPREG_LOC(&c->dwarf, i);
+  }
+  /* IP isn't a real register, it is encoded in the PSW */
+  c->dwarf.loc[UNW_S390X_IP] = DWARF_REG_LOC(&c->dwarf, UNW_S390X_IP);
+
+  ret = dwarf_get (&c->dwarf, c->dwarf.loc[UNW_S390X_IP], &c->dwarf.ip);
+  if (ret < 0)
+    return ret;
+
+  /* Normally the CFA offset on s390x is biased, however this is taken
+     into account by the CFA offset in dwarf_step, so here we just mark
+     make it equal to the stack pointer.  */
+  ret = dwarf_get (&c->dwarf, DWARF_REG_LOC (&c->dwarf, UNW_S390X_R15),
+                   &c->dwarf.cfa);
+  if (ret < 0)
+    return ret;
+
+  c->sigcontext_format = S390X_SCF_NONE;
+  c->sigcontext_addr = 0;
+
+  c->dwarf.args_size = 0;
+  c->dwarf.stash_frames = 0;
+  c->dwarf.use_prev_instr = use_prev_instr;
+  c->dwarf.pi_valid = 0;
+  c->dwarf.pi_is_dynamic = 0;
+  c->dwarf.hint = 0;
+  c->dwarf.prev_rs = 0;
+  c->dwarf.eh_valid_mask = 0;
+
+  return 0;
+}
diff --git a/src/s390x/is_fpreg.c b/src/s390x/is_fpreg.c
new file mode 100644
index 00000000..eb0a9c4d
--- /dev/null
+++ b/src/s390x/is_fpreg.c
@@ -0,0 +1,36 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (c) 2004-2005 Hewlett-Packard Development Company, L.P.
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
+   Modified for s390x by Michael Munday <mike.munday@ibm.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 "libunwind_i.h"
+
+PROTECTED int
+unw_is_fpreg (int regnum)
+{
+  /* vector registers? */
+  return regnum >= UNW_S390X_F0 && regnum <= UNW_S390X_F15;
+}
diff --git a/src/s390x/regname.c b/src/s390x/regname.c
new file mode 100644
index 00000000..28932a01
--- /dev/null
+++ b/src/s390x/regname.c
@@ -0,0 +1,57 @@
+/* libunwind - a platform-independent unwind library
+
+        Contributed by Max Asbock <masbock@us.ibm.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 "unwind_i.h"
+
+static const char *regname[] =
+  {
+    [UNW_S390X_R0]="R0",
+    [UNW_S390X_R1]="R1",
+    [UNW_S390X_R2]="R2",
+    [UNW_S390X_R3]="R3",
+    [UNW_S390X_R4]="R4",
+    [UNW_S390X_R5]="R5",
+    [UNW_S390X_R6]="R6",
+    [UNW_S390X_R7]="R7",
+    [UNW_S390X_R8]="R8",
+    [UNW_S390X_R9]="R9",
+    [UNW_S390X_R10]="R10",
+    [UNW_S390X_R11]="R11",
+    [UNW_S390X_R12]="R12",
+    [UNW_S390X_R13]="R13",
+    [UNW_S390X_R14]="R14",
+    [UNW_S390X_R15]="R15",
+
+    [UNW_S390X_IP]="IP"
+   };
+
+PROTECTED const char *
+unw_regname (unw_regnum_t reg)
+{
+  if (reg < (unw_regnum_t) ARRAY_SIZE (regname))
+    return regname[reg];
+  else
+    return "???";
+}
diff --git a/src/s390x/setcontext.S b/src/s390x/setcontext.S
new file mode 100644
index 00000000..6cf55688
--- /dev/null
+++ b/src/s390x/setcontext.S
@@ -0,0 +1,76 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2008 Google, Inc
+	Contributed by Paul Pluzhnikov <ppluzhnikov@google.com>
+   Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org>
+   Copyright (C) 2017 IBM
+
+   Modified for s390x by Michael Munday <mike.munday@ibm.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.  */
+
+// int _Us390x_setcontext (const ucontext_t *ucp)
+
+	.global _Us390x_setcontext
+	.type _Us390x_setcontext, @function
+_Us390x_setcontext:
+	.cfi_startproc
+
+	// Must only restore registers saved by getcontext, other fields
+	// in the ucontext_t might be uninitialised.
+
+	// Stop this function being unwound. We are clobbering callee-save
+	// registers in this function so unwinding it is unsafe.
+	// Ideally we'd save callee-save registers, update the CFI for them
+	// and then switch to the new CFI once the context switch is
+	// complete.
+	.cfi_undefined %r14
+
+	// floating point parameters
+	ld    %f0,0x100(%r2)
+	ld    %f2,0x110(%r2)
+	ld    %f4,0x120(%r2)
+	ld    %f6,0x130(%r2)
+
+	// floating point preserved registers
+	lfpc  0xf8(%r2)
+	ld    %f8,0x140(%r2)
+	ld    %f9,0x148(%r2)
+	ld    %f10,0x150(%r2)
+	ld    %f11,0x158(%r2)
+	ld    %f12,0x160(%r2)
+	ld    %f13,0x168(%r2)
+	ld    %f14,0x170(%r2)
+	ld    %f15,0x178(%r2)
+
+	// preserved registers and parameters
+	lgr   %r1,%r2
+	lmg   %r2,%r15,0x48(%r1)
+
+	// restore PSW address
+	lg    %r1,0x30(%r1)
+	br    %r1
+
+	.cfi_endproc
+	.size _Us390x_setcontext, . - _Us390x_setcontext
+
+	// We do not need executable stack.
+	.section        .note.GNU-stack,"",@progbits
diff --git a/src/s390x/unwind_i.h b/src/s390x/unwind_i.h
new file mode 100644
index 00000000..6e4b99ba
--- /dev/null
+++ b/src/s390x/unwind_i.h
@@ -0,0 +1,48 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2002, 2005 Hewlett-Packard Co
+        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+   Modified for x86_64 by Max Asbock <masbock@us.ibm.com>
+   Modified for s390x by Michael Munday <mike.munday@ibm.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.  */
+
+#ifndef unwind_i_h
+#define unwind_i_h
+
+#include <stdint.h>
+
+#include <libunwind-s390x.h>
+
+#include "libunwind_i.h"
+#include <sys/ucontext.h>
+
+#define s390x_lock                     UNW_OBJ(lock)
+#define s390x_local_resume             UNW_OBJ(local_resume)
+#define s390x_local_addr_space_init    UNW_OBJ(local_addr_space_init)
+#define setcontext                     UNW_ARCH_OBJ(setcontext)
+
+extern void s390x_local_addr_space_init (void);
+extern int s390x_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg);
+extern int setcontext (const ucontext_t *ucp);
+
+#endif /* unwind_i_h */
diff --git a/tests/check-namespace.sh.in b/tests/check-namespace.sh.in
index 6d008173..5ed94fd2 100644
--- a/tests/check-namespace.sh.in
+++ b/tests/check-namespace.sh.in
@@ -176,6 +176,14 @@ check_local_unw_abi () {
 	    match _U${plat}_get_exe_image_path
             match ${plat}_lock
             ;;
+	s390x)
+	    match _U${plat}_get_elf_image
+	    match _U${plat}_get_exe_image_path
+	    match _U${plat}_is_fpreg
+	    match _UL${plat}_dwarf_search_unwind_table
+	    match _UL${plat}_dwarf_find_unwind_table
+	    match _U${plat}_setcontext
+	    ;;
 
 	*)
 	    match _U${plat}_is_fpreg
@@ -276,6 +284,13 @@ check_generic_unw_abi () {
             match _U${plat}_local_addr_space_init
             match ${plat}_lock
             ;;
+	s390x)
+	    match _U${plat}_is_fpreg
+	    match _U${plat}_get_elf_image
+	    match _U${plat}_get_exe_image_path
+	    match _U${plat}_dwarf_search_unwind_table
+	    match _U${plat}_dwarf_find_unwind_table
+	    ;;
 	*)
 	    match _U${plat}_is_fpreg
 	    match _U${plat}_dwarf_search_unwind_table