Support powerpc64le-linux platform

This patch adds support for the powerpc64le-linux platform.  It consists
of two main features:

- Support little-endian byte order
  This is done via a "big_endian" member of struct unw_addr_space,
  which is evaluated by common code via the dwarf_is_big_endian
  macro, and also in endian-aware code in unw_is_signal_frame.

- Support the ELFv2 ABI
  This is done via an "abi" member of struct unw_addr_space.  This
  is currently only needed in tdep_get_func_addr, since the ELFv2
  ABI does not use function descriptors.

Both new members are initialized in unw_create_addr_space and
ppc64_local_addr_space_init, following the mips precedent.

Since ppc32 and ppc64 now no longer share the unw_create_addr_space
implementation, the file is duplicated from the ppc directory into
ppc32/ppc64.

Tested on powerpc64-linux and powerpc64le-linux.  Support on LE
seems to be as good as existing BE support; I have not attempted to
fix the existing shortcomings of PPC support that already cause a
number to tests to fail due to unimplemented features.

Signed-off-by: Ulrich Weigand <uweigand@de.ibm.com>

include/libunwind-ppc64.h

@@ -222,6 +222,13 @@ typedef enum
   }
 ppc64_regnum_t;
 
+typedef enum
+  {
+    UNW_PPC64_ABI_ELFv1,
+    UNW_PPC64_ABI_ELFv2
+  }
+ppc64_abi_t;
+
 /*
  * According to David Edelsohn, GNU gcc uses R3, R4, R5, and maybe R6 for
  * passing parameters to exception handlers.

include/tdep-ppc64/dwarf-config.h

@@ -38,7 +38,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 #define DWARF_REGNUM_MAP_LENGTH		115
 
 /* Return TRUE if the ADDR_SPACE uses big-endian byte-order.  */
-#define dwarf_is_big_endian(addr_space) 1
+#define dwarf_is_big_endian(addr_space)	((addr_space)->big_endian)
 
 /* Convert a pointer to a dwarf_cursor structure to a pointer to
    unw_cursor_t.  */

include/tdep-ppc64/libunwind_i.h

@@ -51,6 +51,8 @@ unw_tdep_frame_t;
 struct unw_addr_space
 {
   struct unw_accessors acc;
+  int big_endian;
+  ppc64_abi_t abi;
   unw_caching_policy_t caching_policy;
 #ifdef HAVE_ATOMIC_OPS_H
   AO_t cache_generation;
@@ -289,7 +291,7 @@ extern int tdep_fetch_proc_info_post (struct dwarf_cursor *c, unw_word_t ip,
 #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
+#define tdep_big_endian(as)		((as)->big_endian)
 
 extern int tdep_init_done;
 

src/Makefile.am

@@ -342,12 +342,12 @@ libunwind_x86_64_la_SOURCES_x86_64 = $(libunwind_la_SOURCES_x86_64_common)  \
 	x86_64/Gstash_frame.c x86_64/Gstep.c x86_64/Gtrace.c
 
 # The list of local files that go to Power 64 and 32:
-libunwind_la_SOURCES_ppc = ppc/Lcreate_addr_space.c 			\
+libunwind_la_SOURCES_ppc = \
 	ppc/Lget_proc_info.c ppc/Lget_save_loc.c ppc/Linit_local.c	\
 	ppc/Linit_remote.c ppc/Lis_signal_frame.c
 
 # The list of generic files that go to Power 64 and 32:
-libunwind_ppc_la_SOURCES_ppc_generic = ppc/Gcreate_addr_space.c		\
+libunwind_ppc_la_SOURCES_ppc_generic = \
 	ppc/Gget_proc_info.c ppc/Gget_save_loc.c ppc/Ginit_local.c	\
 	ppc/Ginit_remote.c ppc/Gis_signal_frame.c
 
@@ -360,6 +360,7 @@ libunwind_la_SOURCES_ppc32_common = $(libunwind_la_SOURCES_common)      \
 libunwind_la_SOURCES_ppc32 = $(libunwind_la_SOURCES_ppc32_common)       \
 	$(libunwind_la_SOURCES_local)                                   \
 	$(libunwind_la_SOURCES_ppc)					\
+	ppc32/Lcreate_addr_space.c					\
 	ppc32/Lglobal.c ppc32/Linit.c					\
 	ppc32/Lregs.c ppc32/Lresume.c ppc32/Lstep.c
 
@@ -367,6 +368,7 @@ libunwind_la_SOURCES_ppc32 = $(libunwind_la_SOURCES_ppc32_common)       \
 libunwind_ppc32_la_SOURCES_ppc32 = $(libunwind_la_SOURCES_ppc32_common) \
 	$(libunwind_la_SOURCES_generic)                                 \
 	$(libunwind_ppc_la_SOURCES_ppc_generic)				\
+	ppc32/Gcreate_addr_space.c					\
 	ppc32/Gglobal.c ppc32/Ginit.c					\
 	ppc32/Gregs.c ppc32/Gresume.c ppc32/Gstep.c
 
@@ -379,6 +381,7 @@ libunwind_la_SOURCES_ppc64_common = $(libunwind_la_SOURCES_common)      \
 libunwind_la_SOURCES_ppc64 = $(libunwind_la_SOURCES_ppc64_common)       \
         $(libunwind_la_SOURCES_local)                                   \
 	$(libunwind_la_SOURCES_ppc)					\
+	ppc64/Lcreate_addr_space.c					\
 	ppc64/Lglobal.c ppc64/Linit.c					\
 	ppc64/Lregs.c ppc64/Lresume.c ppc64/Lstep.c
 
@@ -386,6 +389,7 @@ libunwind_la_SOURCES_ppc64 = $(libunwind_la_SOURCES_ppc64_common)       \
 libunwind_ppc64_la_SOURCES_ppc64 = $(libunwind_la_SOURCES_ppc64_common) \
         $(libunwind_la_SOURCES_generic)                                 \
 	$(libunwind_ppc_la_SOURCES_ppc_generic)				\
+	ppc64/Gcreate_addr_space.c					\
 	ppc64/Gglobal.c ppc64/Ginit.c					\
 	ppc64/Gregs.c ppc64/Gresume.c ppc64/Gstep.c
 

src/ppc/Gis_signal_frame.c

@@ -31,7 +31,7 @@ PROTECTED int
 unw_is_signal_frame (unw_cursor_t * cursor)
 {
   struct cursor *c = (struct cursor *) cursor;
-  unw_word_t w0, w1, ip;
+  unw_word_t w0, w1, i0, i1, i2, ip;
   unw_addr_space_t as;
   unw_accessors_t *a;
   void *arg;
@@ -60,7 +60,19 @@ unw_is_signal_frame (unw_cursor_t * cursor)
   if ((ret = (*a->access_mem) (as, ip, &w0, 0, arg)) < 0
       || (ret = (*a->access_mem) (as, ip + 8, &w1, 0, arg)) < 0)
     return 0;
-  w1 >>= 32;
-  return (w0 == 0x38210080380000ac && w1 == 0x44000002);
 
+  if (tdep_big_endian (as))
+    {
+      i0 = w0 >> 32;
+      i1 = w0 & 0xffffffffUL;
+      i2 = w1 >> 32;
+    }
+  else
+    {
+      i0 = w0 & 0xffffffffUL;
+      i1 = w0 >> 32;
+      i2 = w1 & 0xffffffffUL;
+    }
+
+  return (i0 == 0x38210080 && i1 == 0x380000ac && i2 == 0x44000002);
 }

src/ppc32/Gcreate_addr_space.c

@@ -38,7 +38,7 @@ unw_create_addr_space (unw_accessors_t *a, int byte_order)
   unw_addr_space_t as;
 
   /*
-   * Linux ppc64 supports only big-endian.
+   * We support only big-endian on Linux ppc32.
    */
   if (byte_order != 0 && byte_order != __BIG_ENDIAN)
     return NULL;

src/ppc64/Gcreate_addr_space.c

@@ -0,0 +1,71 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2006-2007 IBM
+   Contributed by
+     Corey Ashford <cjashfor@us.ibm.com>
+     Jose Flavio Aguilar Paulino <jflavio@br.ibm.com> <joseflavio@gmail.com>
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+#include <stdlib.h>
+
+#include <libunwind_i.h>
+
+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;
+
+  /*
+   * We support both big- and little-endian on Linux ppc64.
+   */
+  if (byte_order != 0
+      && byte_order != __LITTLE_ENDIAN
+      && byte_order != __BIG_ENDIAN)
+    return NULL;
+
+  as = malloc (sizeof (*as));
+  if (!as)
+    return NULL;
+
+  memset (as, 0, sizeof (*as));
+
+  as->acc = *a;
+
+  if (byte_order == 0)
+    /* use host default: */
+    as->big_endian = (__BYTE_ORDER == __BIG_ENDIAN);
+  else
+    as->big_endian = (byte_order == __BIG_ENDIAN);
+
+  /* FIXME!  There is no way to specify the ABI.
+     Default to ELFv1 on big-endian and ELFv2 on little-endian.  */
+  if (as->big_endian)
+    as->abi = UNW_PPC64_ABI_ELFv1;
+  else
+    as->abi = UNW_PPC64_ABI_ELFv2;
+
+  return as;
+#endif
+}

src/ppc64/Ginit.c

@@ -210,6 +210,12 @@ HIDDEN void
 ppc64_local_addr_space_init (void)
 {
   memset (&local_addr_space, 0, sizeof (local_addr_space));
+  local_addr_space.big_endian = (__BYTE_ORDER == __BIG_ENDIAN);
+#if _CALL_ELF == 2
+  local_addr_space.abi = UNW_PPC64_ABI_ELFv2;
+#else
+  local_addr_space.abi = UNW_PPC64_ABI_ELFv1;
+#endif
   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;

src/ppc64/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

src/ppc64/get_func_addr.c

@@ -31,15 +31,21 @@ int
 tdep_get_func_addr (unw_addr_space_t as, unw_word_t addr,
 		    unw_word_t *entry_point)
 {
-  unw_accessors_t *a;
-  int ret;
+  if (as->abi == UNW_PPC64_ABI_ELFv1)
+    {
+      unw_accessors_t *a;
+      int ret;
+
+      a = unw_get_accessors (as);
+      /* Entry-point is stored in the 1st word of the function descriptor.
+         In case that changes in the future, we'd have to update the line
+         below and read the word at addr + offset: */
+      ret = (*a->access_mem) (as, addr, entry_point, 0, NULL);
+      if (ret < 0)
+	return ret;
+    }
+  else
+    *entry_point = addr;
 
-  a = unw_get_accessors (as);
-  /* Entry-point is stored in the 1st word of the function descriptor.
-     In case that changes in the future, we'd have to update the line
-     below and read the word at addr + offset: */
-  ret = (*a->access_mem) (as, addr, entry_point, 0, NULL);
-  if (ret < 0)
-    return ret;
   return 0;
 }