Fix gdbserver's regcache_raw_read_unsigned on big endian hosts

The regcache_raw_read_unsigned function is memcpy'ing a 32-bit value
directly into a 64-bit variable, which doesn't work on big endian
targets.

Fix this by memcpy'ing to a buffer, and then using
extract_unsigned_integer, just like gdb's version.

gdb/gdbserver/ChangeLog:
2016-02-11  Pedro Alves  <palves@redhat.com>

	* Makefile.in (SFILES): Add $(srcdir)/common/gdb-byteswap.c.
	(gdb-byteswap.o): New rule.
	* regcache.c: Include "gdb-byteswap.h".
	(host_bfd_endian): New function.
	(regcache_raw_read_unsigned): Use extract_unsigned_integer and
	host_bfd_endian.

bfd/bfd-in.h

@@ -35,6 +35,7 @@ extern "C" {
 #include "ansidecl.h"
 #include "symcat.h"
 #include <sys/stat.h>
+#include "bfd-types.h"
 
 #if defined (__STDC__) || defined (ALMOST_STDC) || defined (HAVE_STRINGIZE)
 #ifndef SABER

bfd/bfd-in2.h

@@ -42,6 +42,7 @@ extern "C" {
 #include "ansidecl.h"
 #include "symcat.h"
 #include <sys/stat.h>
+#include "bfd-types.h"
 
 #if defined (__STDC__) || defined (ALMOST_STDC) || defined (HAVE_STRINGIZE)
 #ifndef SABER
@@ -7124,8 +7125,6 @@ enum bfd_flavour
   bfd_target_sym_flavour
 };
 
-enum bfd_endian { BFD_ENDIAN_BIG, BFD_ENDIAN_LITTLE, BFD_ENDIAN_UNKNOWN };
-
 /* Forward declaration.  */
 typedef struct bfd_link_info _bfd_link_info;
 

bfd/targets.c

@@ -171,8 +171,6 @@ DESCRIPTION
 .  bfd_target_sym_flavour
 .};
 .
-.enum bfd_endian { BFD_ENDIAN_BIG, BFD_ENDIAN_LITTLE, BFD_ENDIAN_UNKNOWN };
-.
 .{* Forward declaration.  *}
 .typedef struct bfd_link_info _bfd_link_info;
 .

gdb/Makefile.in

@@ -896,6 +896,7 @@ SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c ada-tasks.c \
 	target/waitstatus.c common/print-utils.c common/rsp-low.c \
 	common/errors.c common/common-debug.c common/common-exceptions.c \
 	common/btrace-common.c common/fileio.c common/common-regcache.c \
+	common/gdb-byteswap.c \
 	$(SUBDIR_GCC_COMPILE_SRCS)
 
 LINTFILES = $(SFILES) $(YYFILES) $(CONFIG_SRCS) init.c
@@ -988,7 +989,9 @@ common/common-exceptions.h target/target.h common/symbol.h \
 common/common-regcache.h fbsd-tdep.h nat/linux-personality.h \
 common/fileio.h nat/x86-linux.h nat/x86-linux-dregs.h nat/amd64-linux-siginfo.h\
 nat/linux-namespaces.h arch/arm.h common/gdb_sys_time.h arch/aarch64-insn.h \
-tid-parse.h
+tid-parse.h \
+common/gdb-byteswap.h
+
 
 # Header files that already have srcdir in them, or which are in objdir.
 
@@ -1087,7 +1090,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
 	format.o registry.o btrace.o record-btrace.o waitstatus.o \
 	print-utils.o rsp-low.o errors.o common-debug.o debug.o \
 	common-exceptions.o btrace-common.o fileio.o \
-	common-regcache.o \
+	common-regcache.o gdb-byteswap.o \
 	$(SUBDIR_GCC_COMPILE_OBS)
 
 TSOBS = inflow.o
@@ -2275,6 +2278,10 @@ common-regcache.o: ${srcdir}/common/common-regcache.c
 	$(COMPILE) $(srcdir)/common/common-regcache.c
 	$(POSTCOMPILE)
 
+gdb-byteswap.o: ${srcdir}/common/gdb-byteswap.c
+	$(COMPILE) $(srcdir)/common/gdb-byteswap.c
+	$(POSTCOMPILE)
+
 #
 # gdb/target/ dependencies
 #

gdb/common/common-types.h

@@ -20,6 +20,10 @@
 #ifndef COMMON_TYPES_H
 #define COMMON_TYPES_H
 
+/* This header is always available, even when BFD is not
+   configured.  */
+#include "bfd-types.h"
+
 #ifdef GDBSERVER
 
 /* * A byte from the program being debugged.  */

gdb/common/gdb-byteswap.c

@@ -0,0 +1,201 @@
+/* Basic byte-swapping routines, for GDB, the GNU debugger.
+
+   Copyright (C) 1986-2016 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+#include "gdb-byteswap.h"
+#include "host-defs.h"
+
+/* See gdb-byteswap.h.  */
+
+LONGEST
+extract_signed_integer (const gdb_byte *addr, int len,
+			enum bfd_endian byte_order)
+{
+  LONGEST retval;
+  const unsigned char *p;
+  const unsigned char *startaddr = addr;
+  const unsigned char *endaddr = startaddr + len;
+
+  if (len > (int) sizeof (LONGEST))
+    error (_("\
+That operation is not available on integers of more than %d bytes."),
+	   (int) sizeof (LONGEST));
+
+  /* Start at the most significant end of the integer, and work towards
+     the least significant.  */
+  if (byte_order == BFD_ENDIAN_BIG)
+    {
+      p = startaddr;
+      /* Do the sign extension once at the start.  */
+      retval = ((LONGEST) * p ^ 0x80) - 0x80;
+      for (++p; p < endaddr; ++p)
+	retval = (retval << 8) | *p;
+    }
+  else
+    {
+      p = endaddr - 1;
+      /* Do the sign extension once at the start.  */
+      retval = ((LONGEST) * p ^ 0x80) - 0x80;
+      for (--p; p >= startaddr; --p)
+	retval = (retval << 8) | *p;
+    }
+  return retval;
+}
+
+/* See gdb-byteswap.h.  */
+
+ULONGEST
+extract_unsigned_integer (const gdb_byte *addr, int len,
+			  enum bfd_endian byte_order)
+{
+  ULONGEST retval;
+  const unsigned char *p;
+  const unsigned char *startaddr = addr;
+  const unsigned char *endaddr = startaddr + len;
+
+  if (len > (int) sizeof (ULONGEST))
+    error (_("\
+That operation is not available on integers of more than %d bytes."),
+	   (int) sizeof (ULONGEST));
+
+  /* Start at the most significant end of the integer, and work towards
+     the least significant.  */
+  retval = 0;
+  if (byte_order == BFD_ENDIAN_BIG)
+    {
+      for (p = startaddr; p < endaddr; ++p)
+	retval = (retval << 8) | *p;
+    }
+  else
+    {
+      for (p = endaddr - 1; p >= startaddr; --p)
+	retval = (retval << 8) | *p;
+    }
+  return retval;
+}
+
+/* See gdb_byteswap.h.  */
+
+int
+extract_long_unsigned_integer (const gdb_byte *addr, int orig_len,
+			       enum bfd_endian byte_order, LONGEST *pval)
+{
+  const gdb_byte *p;
+  const gdb_byte *first_addr;
+  int len;
+
+  len = orig_len;
+  if (byte_order == BFD_ENDIAN_BIG)
+    {
+      for (p = addr;
+	   len > (int) sizeof (LONGEST) && p < addr + orig_len;
+	   p++)
+	{
+	  if (*p == 0)
+	    len--;
+	  else
+	    break;
+	}
+      first_addr = p;
+    }
+  else
+    {
+      first_addr = addr;
+      for (p = addr + orig_len - 1;
+	   len > (int) sizeof (LONGEST) && p >= addr;
+	   p--)
+	{
+	  if (*p == 0)
+	    len--;
+	  else
+	    break;
+	}
+    }
+
+  if (len <= (int) sizeof (LONGEST))
+    {
+      *pval = (LONGEST) extract_unsigned_integer (first_addr,
+						  sizeof (LONGEST),
+						  byte_order);
+      return 1;
+    }
+
+  return 0;
+}
+
+
+/* See gdb-byteswap.h.  */
+
+void
+store_signed_integer (gdb_byte *addr, int len,
+		      enum bfd_endian byte_order, LONGEST val)
+{
+  gdb_byte *p;
+  gdb_byte *startaddr = addr;
+  gdb_byte *endaddr = startaddr + len;
+
+  /* Start at the least significant end of the integer, and work towards
+     the most significant.  */
+  if (byte_order == BFD_ENDIAN_BIG)
+    {
+      for (p = endaddr - 1; p >= startaddr; --p)
+	{
+	  *p = val & 0xff;
+	  val >>= 8;
+	}
+    }
+  else
+    {
+      for (p = startaddr; p < endaddr; ++p)
+	{
+	  *p = val & 0xff;
+	  val >>= 8;
+	}
+    }
+}
+
+/* See gdb-byteswap.h.  */
+
+void
+store_unsigned_integer (gdb_byte *addr, int len,
+			enum bfd_endian byte_order, ULONGEST val)
+{
+  unsigned char *p;
+  unsigned char *startaddr = (unsigned char *) addr;
+  unsigned char *endaddr = startaddr + len;
+
+  /* Start at the least significant end of the integer, and work towards
+     the most significant.  */
+  if (byte_order == BFD_ENDIAN_BIG)
+    {
+      for (p = endaddr - 1; p >= startaddr; --p)
+	{
+	  *p = val & 0xff;
+	  val >>= 8;
+	}
+    }
+  else
+    {
+      for (p = startaddr; p < endaddr; ++p)
+	{
+	  *p = val & 0xff;
+	  val >>= 8;
+	}
+    }
+}

gdb/common/gdb-byteswap.h

@@ -0,0 +1,49 @@
+/* Basic byte-swapping routines, for GDB, the GNU debugger.
+
+   Copyright (C) 2009-2016 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef GDB_BYTESWAP_H
+#define GDB_BYTESWAP_H 1
+
+/* All 'extract' functions return a host-format integer from a
+   target-format integer at ADDR which is LEN bytes long.  */
+
+extern LONGEST extract_signed_integer (const gdb_byte *, int,
+				       enum bfd_endian);
+
+extern ULONGEST extract_unsigned_integer (const gdb_byte *, int,
+					  enum bfd_endian);
+
+/* Sometimes a long long unsigned integer can be extracted as a
+   LONGEST value.  This is done so that we can print these values
+   better.  If this integer can be converted to a LONGEST, this
+   function returns 1 and sets *PVAL.  Otherwise it returns 0.  */
+
+extern int extract_long_unsigned_integer (const gdb_byte *, int,
+					  enum bfd_endian, LONGEST *);
+
+/* All 'store' functions accept a host-format integer and store a
+   target-format integer at ADDR which is LEN bytes long.  */
+
+extern void store_signed_integer (gdb_byte *, int,
+				  enum bfd_endian, LONGEST);
+
+extern void store_unsigned_integer (gdb_byte *, int,
+				    enum bfd_endian, ULONGEST);
+
+#endif

gdb/defs.h

@@ -594,26 +594,13 @@ extern double atof (const char *);	/* X3.159-1989  4.10.1.1 */
 
 enum { MAX_REGISTER_SIZE = 64 };
 
+#include "gdb-byteswap.h"
+
 /* In findvar.c.  */
 
-extern LONGEST extract_signed_integer (const gdb_byte *, int,
-				       enum bfd_endian);
-
-extern ULONGEST extract_unsigned_integer (const gdb_byte *, int,
-					  enum bfd_endian);
-
-extern int extract_long_unsigned_integer (const gdb_byte *, int,
-					  enum bfd_endian, LONGEST *);
-
 extern CORE_ADDR extract_typed_address (const gdb_byte *buf,
 					struct type *type);
 
-extern void store_signed_integer (gdb_byte *, int,
-				  enum bfd_endian, LONGEST);
-
-extern void store_unsigned_integer (gdb_byte *, int,
-				    enum bfd_endian, ULONGEST);
-
 extern void store_typed_address (gdb_byte *buf, struct type *type,
 				 CORE_ADDR addr);
 

gdb/findvar.c

@@ -34,136 +34,6 @@
 #include "language.h"
 #include "dwarf2loc.h"
 
-/* Basic byte-swapping routines.  All 'extract' functions return a
-   host-format integer from a target-format integer at ADDR which is
-   LEN bytes long.  */
-
-#if TARGET_CHAR_BIT != 8 || HOST_CHAR_BIT != 8
-  /* 8 bit characters are a pretty safe assumption these days, so we
-     assume it throughout all these swapping routines.  If we had to deal with
-     9 bit characters, we would need to make len be in bits and would have
-     to re-write these routines...  */
-you lose
-#endif
-
-LONGEST
-extract_signed_integer (const gdb_byte *addr, int len,
-			enum bfd_endian byte_order)
-{
-  LONGEST retval;
-  const unsigned char *p;
-  const unsigned char *startaddr = addr;
-  const unsigned char *endaddr = startaddr + len;
-
-  if (len > (int) sizeof (LONGEST))
-    error (_("\
-That operation is not available on integers of more than %d bytes."),
-	   (int) sizeof (LONGEST));
-
-  /* Start at the most significant end of the integer, and work towards
-     the least significant.  */
-  if (byte_order == BFD_ENDIAN_BIG)
-    {
-      p = startaddr;
-      /* Do the sign extension once at the start.  */
-      retval = ((LONGEST) * p ^ 0x80) - 0x80;
-      for (++p; p < endaddr; ++p)
-	retval = (retval << 8) | *p;
-    }
-  else
-    {
-      p = endaddr - 1;
-      /* Do the sign extension once at the start.  */
-      retval = ((LONGEST) * p ^ 0x80) - 0x80;
-      for (--p; p >= startaddr; --p)
-	retval = (retval << 8) | *p;
-    }
-  return retval;
-}
-
-ULONGEST
-extract_unsigned_integer (const gdb_byte *addr, int len,
-			  enum bfd_endian byte_order)
-{
-  ULONGEST retval;
-  const unsigned char *p;
-  const unsigned char *startaddr = addr;
-  const unsigned char *endaddr = startaddr + len;
-
-  if (len > (int) sizeof (ULONGEST))
-    error (_("\
-That operation is not available on integers of more than %d bytes."),
-	   (int) sizeof (ULONGEST));
-
-  /* Start at the most significant end of the integer, and work towards
-     the least significant.  */
-  retval = 0;
-  if (byte_order == BFD_ENDIAN_BIG)
-    {
-      for (p = startaddr; p < endaddr; ++p)
-	retval = (retval << 8) | *p;
-    }
-  else
-    {
-      for (p = endaddr - 1; p >= startaddr; --p)
-	retval = (retval << 8) | *p;
-    }
-  return retval;
-}
-
-/* Sometimes a long long unsigned integer can be extracted as a
-   LONGEST value.  This is done so that we can print these values
-   better.  If this integer can be converted to a LONGEST, this
-   function returns 1 and sets *PVAL.  Otherwise it returns 0.  */
-
-int
-extract_long_unsigned_integer (const gdb_byte *addr, int orig_len,
-			       enum bfd_endian byte_order, LONGEST *pval)
-{
-  const gdb_byte *p;
-  const gdb_byte *first_addr;
-  int len;
-
-  len = orig_len;
-  if (byte_order == BFD_ENDIAN_BIG)
-    {
-      for (p = addr;
-	   len > (int) sizeof (LONGEST) && p < addr + orig_len;
-	   p++)
-	{
-	  if (*p == 0)
-	    len--;
-	  else
-	    break;
-	}
-      first_addr = p;
-    }
-  else
-    {
-      first_addr = addr;
-      for (p = addr + orig_len - 1;
-	   len > (int) sizeof (LONGEST) && p >= addr;
-	   p--)
-	{
-	  if (*p == 0)
-	    len--;
-	  else
-	    break;
-	}
-    }
-
-  if (len <= (int) sizeof (LONGEST))
-    {
-      *pval = (LONGEST) extract_unsigned_integer (first_addr,
-						  sizeof (LONGEST),
-						  byte_order);
-      return 1;
-    }
-
-  return 0;
-}
-
-
 /* Treat the bytes at BUF as a pointer of type TYPE, and return the
    address it represents.  */
 CORE_ADDR
@@ -178,65 +48,6 @@ extract_typed_address (const gdb_byte *buf, struct type *type)
   return gdbarch_pointer_to_address (get_type_arch (type), type, buf);
 }
 
-/* All 'store' functions accept a host-format integer and store a
-   target-format integer at ADDR which is LEN bytes long.  */
-
-void
-store_signed_integer (gdb_byte *addr, int len,
-		      enum bfd_endian byte_order, LONGEST val)
-{
-  gdb_byte *p;
-  gdb_byte *startaddr = addr;
-  gdb_byte *endaddr = startaddr + len;
-
-  /* Start at the least significant end of the integer, and work towards
-     the most significant.  */
-  if (byte_order == BFD_ENDIAN_BIG)
-    {
-      for (p = endaddr - 1; p >= startaddr; --p)
-	{
-	  *p = val & 0xff;
-	  val >>= 8;
-	}
-    }
-  else
-    {
-      for (p = startaddr; p < endaddr; ++p)
-	{
-	  *p = val & 0xff;
-	  val >>= 8;
-	}
-    }
-}
-
-void
-store_unsigned_integer (gdb_byte *addr, int len,
-			enum bfd_endian byte_order, ULONGEST val)
-{
-  unsigned char *p;
-  unsigned char *startaddr = (unsigned char *) addr;
-  unsigned char *endaddr = startaddr + len;
-
-  /* Start at the least significant end of the integer, and work towards
-     the most significant.  */
-  if (byte_order == BFD_ENDIAN_BIG)
-    {
-      for (p = endaddr - 1; p >= startaddr; --p)
-	{
-	  *p = val & 0xff;
-	  val >>= 8;
-	}
-    }
-  else
-    {
-      for (p = startaddr; p < endaddr; ++p)
-	{
-	  *p = val & 0xff;
-	  val >>= 8;
-	}
-    }
-}
-
 /* Store the address ADDR as a pointer of type TYPE at BUF, in target
    form.  */
 void

gdb/gdbserver/Makefile.in

@@ -185,7 +185,8 @@ SFILES=	$(srcdir)/gdbreplay.c $(srcdir)/inferiors.c $(srcdir)/dll.c \
 	$(srcdir)/common/btrace-common.c \
 	$(srcdir)/common/fileio.c $(srcdir)/nat/linux-namespaces.c \
 	$(srcdir)/arch/arm.c $(srcdir)/common/common-regcache.c \
-	$(srcdir)/arch/arm-linux.c $(srcdir)/arch/arm-get-next-pcs.c
+	$(srcdir)/arch/arm-linux.c $(srcdir)/arch/arm-get-next-pcs.c \
+	$(srcdir)/common/gdb-byteswap.c
 
 DEPFILES = @GDBSERVER_DEPFILES@
 
@@ -200,6 +201,7 @@ OBS = agent.o ax.o inferiors.o regcache.o remote-utils.o server.o signals.o \
       common-utils.o ptid.o buffer.o format.o filestuff.o dll.o notif.o \
       tdesc.o print-utils.o rsp-low.o errors.o common-debug.o cleanups.o \
       common-exceptions.o symbol.o btrace-common.o fileio.o common-regcache.o \
+      gdb-byteswap.o \
       $(XML_BUILTIN) $(DEPFILES) $(LIBOBJS)
 GDBREPLAY_OBS = gdbreplay.o version.o
 GDBSERVER_LIBS = @GDBSERVER_LIBS@
@@ -590,6 +592,9 @@ fileio.o: ../common/fileio.c
 common-regcache.o: ../common/common-regcache.c
 	$(COMPILE) $<
 	$(POSTCOMPILE)
+gdb-byteswap.o: ../common/gdb-byteswap.c
+	$(COMPILE) $<
+	$(POSTCOMPILE)
 
 # Arch object files rules form ../arch
 

gdb/gdbserver/regcache.c

@@ -21,6 +21,9 @@
 #include "gdbthread.h"
 #include "tdesc.h"
 #include "rsp-low.h"
+#include "bfd-types.h"
+#include "gdb-byteswap.h"
+
 #ifndef IN_PROCESS_AGENT
 
 struct regcache *
@@ -424,14 +427,25 @@ collect_register (struct regcache *regcache, int n, void *buf)
 	  register_size (regcache->tdesc, n));
 }
 
+#ifndef IN_PROCESS_AGENT
+
+/* Return host endianness as an enum bfd_endian.  */
+
+static enum bfd_endian
+host_bfd_endian (void)
+{
+  return (__BYTE_ORDER == __LITTLE_ENDIAN
+	  ? BFD_ENDIAN_LITTLE
+	  : BFD_ENDIAN_BIG);
+}
+
 enum register_status
 regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
 			    ULONGEST *val)
 {
   int size;
-
-  gdb_assert (regcache != NULL);
-  gdb_assert (regnum >= 0 && regnum < regcache->tdesc->num_registers);
+  gdb_byte *buf;
+  enum bfd_endian byteorder;
 
   size = register_size (regcache->tdesc, regnum);
 
@@ -440,14 +454,17 @@ regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
             "%d bytes."),
           (int) sizeof (ULONGEST));
 
-  *val = 0;
-  collect_register (regcache, regnum, val);
+  buf = (gdb_byte *) alloca (size);
+  collect_register (regcache, regnum, buf);
 
+  /* Assume the inferior's byte order is the same as gdbserver's (the
+     host).  */
+  byteorder = host_bfd_endian ();
+
+  *val = extract_unsigned_integer (buf, size, byteorder);
   return REG_VALID;
 }
 
-#ifndef IN_PROCESS_AGENT
-
 void
 collect_register_as_string (struct regcache *regcache, int n, char *buf)
 {

include/bfd-types.h

@@ -0,0 +1,26 @@
+/* bfd core types that do not depend on configuration.
+
+   Copyright (C) 1990-2016 Free Software Foundation, Inc.
+
+   This file is part of BFD, the Binary File Descriptor library.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#ifndef BFD_TYPES_H
+#define BFD_TYPES_H
+
+enum bfd_endian { BFD_ENDIAN_BIG, BFD_ENDIAN_LITTLE, BFD_ENDIAN_UNKNOWN };
+
+#endif