netbsd.h (ENABLE_EXECUTE_STACK): Remove.

2011-05-29  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
	    Joseph Myers  <joseph@codesourcery.com>

	gcc:
	* config/alpha/netbsd.h (ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	* config/alpha/osf5.h (ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	* config/darwin.h (ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	* config/i386/mingw32.h (MINGW_ENABLE_EXECUTE_STACK): Remove.
	(ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	[IN_LIBGCC2]: Don't include <windows.h>.
	* config/i386/netbsd-elf.h (ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	* config/i386/netbsd64.h (ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	* config/netbsd.h (NETBSD_ENABLE_EXECUTE_STACK): Remove.
	* config/openbsd.h (ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	* config/sol2.h (ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	* config/sparc/freebsd.h (ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	* config/sparc/netbsd-elf.h (ENABLE_EXECUTE_STACK): Remove.
	(HAVE_ENABLE_EXECUTE_STACK): Define.
	* config/alpha/alpha.c (alpha_trampoline_init): Test
	HAVE_ENABLE_EXECUTE_STACK.
	* config/i386/i386.c (ix86_trampoline_init): Likewise.
	* config/sparc/sparc.c (sparc32_initialize_trampoline): Likewise.
	(sparc64_initialize_trampoline): Likewise.
	* libgcc2.c [L_enable_execute_stack]: Remove.
	* system.h (ENABLE_EXECUTE_STACK): Poison.
	* doc/tm.texi.in (Trampolines, ENABLE_EXECUTE_STACK): Remove.
	* doc/tm.texi: Regenerate.
	* Makefile.in (LIBGCC2_CFLAGS): Add -fbuilding-libgcc.

	gcc/c-family:
	* c.opt (fbuilding-libgcc): New option.
	* c-cppbuiltin.c (c_cpp_builtins): Define
	__LIBGCC_TRAMPOLINE_SIZE__ if flag_building_libgcc.

	libgcc:
	* enable-execute-stack-empty.c: New file.
	* enable-execute-stack-mprotect.c: New file.
	* config/i386/enable-execute-stack-mingw32.c: New file.
	* config.host (enable_execute_stack): New variable.
	Select appropriate variants.
	* configure.ac: Link enable-execute-stack.c to
	$enable_execute_stack.
	* configure: Regenerate.
	* Makefile.in (LIB2ADD): Add enable-execute-stack.c.
	(lib2funcs): Remove _enable_execute_stack.

Co-Authored-By: Joseph Myers <joseph@codesourcery.com>

From-SVN: r174843

23 files changed, 72 insertions, 265 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 81aaf76..b2251e9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,39 @@
+2011-06-09  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+
+	* config/alpha/netbsd.h (ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	* config/alpha/osf5.h (ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	* config/darwin.h (ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	* config/i386/mingw32.h (MINGW_ENABLE_EXECUTE_STACK): Remove.
+	(ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	[IN_LIBGCC2]: Don't include <windows.h>.
+	* config/i386/netbsd-elf.h (ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	* config/i386/netbsd64.h (ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	* config/netbsd.h (NETBSD_ENABLE_EXECUTE_STACK): Remove.
+	* config/openbsd.h (ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	* config/sol2.h (ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	* config/sparc/freebsd.h (ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	* config/sparc/netbsd-elf.h (ENABLE_EXECUTE_STACK): Remove.
+	(HAVE_ENABLE_EXECUTE_STACK): Define.
+	* config/alpha/alpha.c (alpha_trampoline_init): Test
+	HAVE_ENABLE_EXECUTE_STACK.
+	* config/i386/i386.c (ix86_trampoline_init): Likewise.
+	* config/sparc/sparc.c (sparc32_initialize_trampoline): Likewise.
+	(sparc64_initialize_trampoline): Likewise.
+	* libgcc2.c [L_enable_execute_stack]: Remove.
+	* system.h (ENABLE_EXECUTE_STACK): Poison.
+	* doc/tm.texi.in (Trampolines, ENABLE_EXECUTE_STACK): Remove.
+	* doc/tm.texi: Regenerate.
+	* Makefile.in (LIBGCC2_CFLAGS): Add -fbuilding-libgcc.
+
 2011-06-09  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/49308
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 496177c..0d297c3 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -661,7 +661,7 @@ LIBGCC2_DEBUG_CFLAGS = -g
 LIBGCC2_CFLAGS = -O2 $(LIBGCC2_INCLUDES) $(GCC_CFLAGS) $(TARGET_LIBGCC2_CFLAGS) \
 		 $(LIBGCC2_DEBUG_CFLAGS) $(GTHREAD_FLAGS) \
 		 -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED \
-		 -fno-stack-protector \
+		 -fbuilding-libgcc -fno-stack-protector \
 		 $(INHIBIT_LIBC_CFLAGS)
 
 # Additional options to use when compiling libgcc2.a.
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 97913c4..733d771 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,10 @@
+2011-06-09  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+	    Joseph Myers  <joseph@codesourcery.com>
+
+	* c.opt (fbuilding-libgcc): New option.
+	* c-cppbuiltin.c (c_cpp_builtins): Define
+	__LIBGCC_TRAMPOLINE_SIZE__ if flag_building_libgcc.
+
 2011-06-07  Jason Merrill  <jason@redhat.com>
 
 	* c-common.c (max_tinst_depth): Lower default to 900.
diff --git a/gcc/c-family/c-cppbuiltin.c b/gcc/c-family/c-cppbuiltin.c
index 576074c..bc75e02 100644
--- a/gcc/c-family/c-cppbuiltin.c
+++ b/gcc/c-family/c-cppbuiltin.c
@@ -1,5 +1,5 @@
 /* Define builtin-in macros for the C family front ends.
-   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -727,6 +727,12 @@ c_cpp_builtins (cpp_reader *pfile)
       builtin_define_fixed_point_constants ("UTA", "", uta_type_node);
     }
 
+  /* For libgcc-internal use only.  */
+  if (flag_building_libgcc)
+    /* For libgcc enable-execute-stack.c.  */
+    builtin_define_with_int_value ("__LIBGCC_TRAMPOLINE_SIZE__",
+				   TRAMPOLINE_SIZE);
+
   /* For use in assembly language.  */
   builtin_define_with_value ("__REGISTER_PREFIX__", REGISTER_PREFIX, 0);
   builtin_define_with_value ("__USER_LABEL_PREFIX__", user_label_prefix, 0);
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index c4cf4d0..00bdd93 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -700,6 +700,10 @@ fasm
 C ObjC C++ ObjC++ Var(flag_no_asm, 0)
 Recognize the \"asm\" keyword
 
+; Define extra predefined macros for use in libgcc.
+fbuilding-libgcc
+C ObjC C++ ObjC++ Undocumented Var(flag_building_libgcc)
+
 fbuiltin
 C ObjC C++ ObjC++ Var(flag_no_builtin, 0)
 Recognize built-in functions
diff --git a/gcc/config/alpha/alpha.c b/gcc/config/alpha/alpha.c
index 7323329..adef2c6 100644
--- a/gcc/config/alpha/alpha.c
+++ b/gcc/config/alpha/alpha.c
@@ -5395,7 +5395,7 @@ alpha_trampoline_init (rtx m_tramp, tree fndecl, rtx chain_value)
   if (TARGET_ABI_OSF)
     {
       emit_insn (gen_imb ());
-#ifdef ENABLE_EXECUTE_STACK
+#ifdef HAVE_ENABLE_EXECUTE_STACK
       emit_library_call (init_one_libfunc ("__enable_execute_stack"),
 			 LCT_NORMAL, VOIDmode, 1, XEXP (m_tramp, 0), Pmode);
 #endif
diff --git a/gcc/config/alpha/netbsd.h b/gcc/config/alpha/netbsd.h
index 65e8991..2d7158e 100644
--- a/gcc/config/alpha/netbsd.h
+++ b/gcc/config/alpha/netbsd.h
@@ -73,7 +73,4 @@ along with GCC; see the file COPYING3.  If not see
   "%{Ofast|ffast-math|funsafe-math-optimizations:crtfm%O%s} \
    %(netbsd_endfile_spec)"
 
-
-/* Attempt to enable execute permissions on the stack.  */
-
-#define ENABLE_EXECUTE_STACK NETBSD_ENABLE_EXECUTE_STACK
+#define HAVE_ENABLE_EXECUTE_STACK
diff --git a/gcc/config/alpha/osf5.h b/gcc/config/alpha/osf5.h
index 995f35d..28aff06 100644
--- a/gcc/config/alpha/osf5.h
+++ b/gcc/config/alpha/osf5.h
@@ -165,22 +165,7 @@ along with GCC; see the file COPYING3.  If not see
 #define HAVE_STAMP_H 1
 #endif
 
-/* Attempt to turn on access permissions for the stack.  */
-
-#define ENABLE_EXECUTE_STACK						\
-void									\
-__enable_execute_stack (void *addr)					\
-{									\
-  extern int mprotect (const void *, size_t, int);			\
-  long size = getpagesize ();						\
-  long mask = ~(size-1);						\
-  char *page = (char *) (((long) addr) & mask);				\
-  char *end  = (char *) ((((long) (addr + TRAMPOLINE_SIZE)) & mask) + size); \
-									\
-  /* 7 is PROT_READ | PROT_WRITE | PROT_EXEC */				\
-  if (mprotect (page, end - page, 7) < 0)				\
-    perror ("mprotect of trampoline code");				\
-}
+#define HAVE_ENABLE_EXECUTE_STACK
 
 /* Digital UNIX V4.0E (1091)/usr/include/sys/types.h 4.3.49.9 1997/08/14 */
 #define SIZE_TYPE	"long unsigned int"
diff --git a/gcc/config/darwin.h b/gcc/config/darwin.h
index 4725015..41c0d74 100644
--- a/gcc/config/darwin.h
+++ b/gcc/config/darwin.h
@@ -919,43 +919,7 @@ void add_framework_path (char *);
 #define TARGET_ASM_OUTPUT_ANCHOR NULL
 #define DARWIN_SECTION_ANCHORS 0
 
-/* Attempt to turn on execute permission for the stack.  This may be
-    used by TARGET_TRAMPOLINE_INIT if the target needs it (that is,
-    if the target machine can change execute permissions on a page).
-
-    There is no way to query the execute permission of the stack, so
-    we always issue the mprotect() call.
-
-    Unfortunately it is not possible to make this namespace-clean.
-
-    Also note that no errors should be emitted by this code; it is
-    considered dangerous for library calls to send messages to
-    stdout/stderr.  */
-
-#define ENABLE_EXECUTE_STACK                                            \
-extern void __enable_execute_stack (void *);                            \
-void                                                                    \
-__enable_execute_stack (void *addr)                                     \
-{                                                                       \
-   extern int mprotect (void *, size_t, int);                           \
-   extern int getpagesize (void);					\
-   static int size;                                                     \
-   static long mask;                                                    \
-                                                                        \
-   char *page, *end;                                                    \
-                                                                        \
-   if (size == 0)                                                       \
-     {                                                                  \
-       size = getpagesize();						\
-       mask = ~((long) size - 1);                                       \
-     }                                                                  \
-                                                                        \
-   page = (char *) (((long) addr) & mask);                              \
-   end  = (char *) ((((long) (addr + (TARGET_64BIT ? 48 : 40))) & mask) + size); \
-                                                                        \
-   /* 7 == PROT_READ | PROT_WRITE | PROT_EXEC */                        \
-   (void) mprotect (page, end - page, 7);                               \
-}
+#define HAVE_ENABLE_EXECUTE_STACK
 
 /* For Apple KEXTs, we make the constructors return this to match gcc
    2.95.  */
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 0bcb2db..7b266b9 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -23387,7 +23387,7 @@ ix86_trampoline_init (rtx m_tramp, tree fndecl, rtx chain_value)
       gcc_assert (offset <= TRAMPOLINE_SIZE);
     }
 
-#ifdef ENABLE_EXECUTE_STACK
+#ifdef HAVE_ENABLE_EXECUTE_STACK
 #ifdef CHECK_EXECUTE_STACK_ENABLED
   if (CHECK_EXECUTE_STACK_ENABLED)
 #endif
diff --git a/gcc/config/i386/mingw32.h b/gcc/config/i386/mingw32.h
index c1c1277..3c835c6 100644
--- a/gcc/config/i386/mingw32.h
+++ b/gcc/config/i386/mingw32.h
@@ -219,28 +219,10 @@ do {						         \
 /* Let defaults.h definition of TARGET_USE_JCR_SECTION apply. */
 #undef TARGET_USE_JCR_SECTION
 
-#undef MINGW_ENABLE_EXECUTE_STACK
-#define MINGW_ENABLE_EXECUTE_STACK     \
-extern void __enable_execute_stack (void *);    \
-void         \
-__enable_execute_stack (void *addr)					\
-{									\
-  MEMORY_BASIC_INFORMATION b;						\
-  if (!VirtualQuery (addr, &b, sizeof(b)))				\
-    abort ();								\
-  VirtualProtect (b.BaseAddress, b.RegionSize, PAGE_EXECUTE_READWRITE,	\
-		  &b.Protect);						\
-}
-
-#undef ENABLE_EXECUTE_STACK
-#define ENABLE_EXECUTE_STACK MINGW_ENABLE_EXECUTE_STACK
+#define HAVE_ENABLE_EXECUTE_STACK
 #undef  CHECK_EXECUTE_STACK_ENABLED
 #define CHECK_EXECUTE_STACK_ENABLED flag_setstackexecutable
 
-#ifdef IN_LIBGCC2
-#include <windows.h>
-#endif
-
 /* This matches SHLIB_SONAME and SHLIB_SOVERSION in t-cygming. */
 /* This matches SHLIB_SONAME and SHLIB_SOVERSION in t-cygwin. */
 #if DWARF2_UNWIND_INFO
diff --git a/gcc/config/i386/netbsd-elf.h b/gcc/config/i386/netbsd-elf.h
index 449a3a7..d79bbfb 100644
--- a/gcc/config/i386/netbsd-elf.h
+++ b/gcc/config/i386/netbsd-elf.h
@@ -118,5 +118,4 @@ along with GCC; see the file COPYING3.  If not see
    we don't care about compatibility with older gcc versions.  */
 #define DEFAULT_PCC_STRUCT_RETURN 1
 
-/* Attempt to enable execute permissions on the stack.  */
-#define ENABLE_EXECUTE_STACK NETBSD_ENABLE_EXECUTE_STACK
+#define HAVE_ENABLE_EXECUTE_STACK
diff --git a/gcc/config/i386/netbsd64.h b/gcc/config/i386/netbsd64.h
index e13d16d..584074f 100644
--- a/gcc/config/i386/netbsd64.h
+++ b/gcc/config/i386/netbsd64.h
@@ -66,5 +66,4 @@ along with GCC; see the file COPYING3.  If not see
     fprintf (FILE, "\tcall __mcount\n");				\
 }
 
-/* Attempt to enable execute permissions on the stack.  */
-#define ENABLE_EXECUTE_STACK NETBSD_ENABLE_EXECUTE_STACK
+#define HAVE_ENABLE_EXECUTE_STACK
diff --git a/gcc/config/netbsd.h b/gcc/config/netbsd.h
index ddf6567..e9290c2 100644
--- a/gcc/config/netbsd.h
+++ b/gcc/config/netbsd.h
@@ -1,6 +1,6 @@
 /* Base configuration file for all NetBSD targets.
    Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
-   2007, 2009, 2010 Free Software Foundation, Inc.
+   2007, 2009, 2010, 2011 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -173,50 +173,3 @@ along with GCC; see the file COPYING3.  If not see
 
 #undef WINT_TYPE
 #define WINT_TYPE "int"
-
-
-/* Attempt to turn on execute permission for the stack.  This may be
-   used by TARGET_TRAMPOLINE_INIT if the target needs it (that is,
-   if the target machine can change execute permissions on a page).
-
-   There is no way to query the execute permission of the stack, so
-   we always issue the mprotect() call.
-
-   Note that we go out of our way to use namespace-non-invasive calls
-   here.  Unfortunately, there is no libc-internal name for mprotect().
-
-   Also note that no errors should be emitted by this code; it is considered
-   dangerous for library calls to send messages to stdout/stderr.  */
-
-#define NETBSD_ENABLE_EXECUTE_STACK					\
-extern void __enable_execute_stack (void *);				\
-void									\
-__enable_execute_stack (void *addr)					\
-{									\
-  extern int mprotect (void *, size_t, int);				\
-  extern int __sysctl (int *, unsigned int, void *, size_t *,		\
-		       void *, size_t);					\
-									\
-  static int size;							\
-  static long mask;							\
-									\
-  char *page, *end;							\
-									\
-  if (size == 0)							\
-    {									\
-      int mib[2];							\
-      size_t len;							\
-									\
-      mib[0] = 6; /* CTL_HW */						\
-      mib[1] = 7; /* HW_PAGESIZE */					\
-      len = sizeof (size);						\
-      (void) __sysctl (mib, 2, &size, &len, NULL, 0);			\
-      mask = ~((long) size - 1);					\
-    }									\
-									\
-  page = (char *) (((long) addr) & mask);				\
-  end  = (char *) ((((long) (addr + TRAMPOLINE_SIZE)) & mask) + size);	\
-									\
-  /* 7 == PROT_READ | PROT_WRITE | PROT_EXEC */				\
-  (void) mprotect (page, end - page, 7);				\
-}
diff --git a/gcc/config/openbsd.h b/gcc/config/openbsd.h
index ae08ed8..aa279ed 100644
--- a/gcc/config/openbsd.h
+++ b/gcc/config/openbsd.h
@@ -281,20 +281,4 @@ do {									 \
 /* Storage layout.  */
 
 
-/* Stack is explicitly denied execution rights on OpenBSD platforms.  */
-#define ENABLE_EXECUTE_STACK						\
-extern void __enable_execute_stack (void *);				\
-void									\
-__enable_execute_stack (void *addr)					\
-{									\
-  long size = getpagesize ();						\
-  long mask = ~(size-1);						\
-  char *page = (char *) (((long) addr) & mask); 			\
-  char *end  = (char *) ((((long) (addr + TRAMPOLINE_SIZE)) & mask) + size); \
-								      \
-  if (mprotect (page, end - page, PROT_READ | PROT_WRITE | PROT_EXEC) < 0) \
-    perror ("mprotect of trampoline code");				\
-}
-
-#include <sys/types.h>
-#include <sys/mman.h>
+#define HAVE_ENABLE_EXECUTE_STACK
diff --git a/gcc/config/sol2.h b/gcc/config/sol2.h
index 3d539d7..d1e98e4 100644
--- a/gcc/config/sol2.h
+++ b/gcc/config/sol2.h
@@ -207,52 +207,7 @@ along with GCC; see the file COPYING3.  If not see
 
 #define STDC_0_IN_SYSTEM_HEADERS 1
 
-/*
- * Attempt to turn on access permissions for the stack.
- *
- * _SC_STACK_PROT is only defined for post 2.6, but we want this code
- * to run always.  2.6 can change the stack protection but has no way to
- * query it.
- *
- */
-
-/* sys/mman.h is not present on some non-Solaris configurations
-   that use sol2.h, so ENABLE_EXECUTE_STACK must use a magic
-   number instead of the appropriate PROT_* flags.  */
-
-#define ENABLE_EXECUTE_STACK					\
-									\
-/* #define STACK_PROT_RWX (PROT_READ | PROT_WRITE | PROT_EXEC) */	\
-									\
-static int need_enable_exec_stack;					\
-									\
-static void check_enabling(void) __attribute__ ((constructor));		\
-static void check_enabling(void)					\
-{									\
-  extern long sysconf(int);						\
-									\
-  int prot = (int) sysconf(515 /* _SC_STACK_PROT */);			\
-  if (prot != 7 /* STACK_PROT_RWX */)					\
-    need_enable_exec_stack = 1;						\
-}									\
-									\
-extern void __enable_execute_stack (void *);				\
-void									\
-__enable_execute_stack (void *addr)					\
-{									\
-  extern int mprotect(void *, size_t, int);				\
-  if (!need_enable_exec_stack)						\
-    return;								\
-  else {								\
-    long size = getpagesize ();						\
-    long mask = ~(size-1);						\
-    char *page = (char *) (((long) addr) & mask); 			\
-    char *end  = (char *) ((((long) (addr + TRAMPOLINE_SIZE)) & mask) + size); \
-									\
-    if (mprotect (page, end - page, 7 /* STACK_PROT_RWX */) < 0)	\
-      perror ("mprotect of trampoline code");				\
-  }									\
-}
+#define HAVE_ENABLE_EXECUTE_STACK
 
 /* Support Solaris-specific format checking for cmn_err.  */
 #define TARGET_N_FORMAT_TYPES 1
diff --git a/gcc/config/sparc/freebsd.h b/gcc/config/sparc/freebsd.h
index ed83eed..3444c0e 100644
--- a/gcc/config/sparc/freebsd.h
+++ b/gcc/config/sparc/freebsd.h
@@ -98,31 +98,7 @@ along with GCC; see the file COPYING3.  If not see
 #undef  SPARC_DEFAULT_CMODEL
 #define SPARC_DEFAULT_CMODEL	CM_MEDLOW
 
-#define ENABLE_EXECUTE_STACK						\
-  static int need_enable_exec_stack;					\
-  static void check_enabling(void) __attribute__ ((constructor));	\
-  static void check_enabling(void)					\
-  {									\
-    extern int sysctlbyname(const char *, void *, size_t *, void *, size_t);\
-    int prot = 0;							\
-    size_t len = sizeof(prot);						\
-									\
-    sysctlbyname ("kern.stackprot", &prot, &len, NULL, 0);		\
-    if (prot != 7)							\
-      need_enable_exec_stack = 1;					\
-  }									\
-  extern void __enable_execute_stack (void *);				\
-  void __enable_execute_stack (void *addr)				\
-  {									\
-    if (!need_enable_exec_stack)					\
-      return;								\
-    else {								\
-      /* 7 is PROT_READ | PROT_WRITE | PROT_EXEC */ 			\
-      if (mprotect (addr, TRAMPOLINE_SIZE, 7) < 0)			\
-        perror ("mprotect of trampoline code");				\
-    }									\
-  }
-
+#define HAVE_ENABLE_EXECUTE_STACK
 
 /************************[  Assembler stuff  ]********************************/
 
diff --git a/gcc/config/sparc/netbsd-elf.h b/gcc/config/sparc/netbsd-elf.h
index ab161a4..d19615b 100644
--- a/gcc/config/sparc/netbsd-elf.h
+++ b/gcc/config/sparc/netbsd-elf.h
@@ -74,8 +74,7 @@ along with GCC; see the file COPYING3.  If not see
 
 #undef STDC_0_IN_SYSTEM_HEADERS
 
-/* Attempt to enable execute permissions on the stack.  */
-#define ENABLE_EXECUTE_STACK NETBSD_ENABLE_EXECUTE_STACK
+#define HAVE_ENABLE_EXECUTE_STACK
 
 /* Below here exists the merged NetBSD/sparc & NetBSD/sparc64 compiler
    description, allowing one to build 32-bit or 64-bit applications
diff --git a/gcc/config/sparc/sparc.c b/gcc/config/sparc/sparc.c
index 59738af..ae35cf8 100644
--- a/gcc/config/sparc/sparc.c
+++ b/gcc/config/sparc/sparc.c
@@ -8004,7 +8004,7 @@ sparc32_initialize_trampoline (rtx m_tramp, rtx fnaddr, rtx cxt)
 
   /* Call __enable_execute_stack after writing onto the stack to make sure
      the stack address is accessible.  */
-#ifdef ENABLE_EXECUTE_STACK
+#ifdef HAVE_ENABLE_EXECUTE_STACK
   emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__enable_execute_stack"),
                      LCT_NORMAL, VOIDmode, 1, XEXP (m_tramp, 0), Pmode);
 #endif
@@ -8047,7 +8047,7 @@ sparc64_initialize_trampoline (rtx m_tramp, rtx fnaddr, rtx cxt)
 
   /* Call __enable_execute_stack after writing onto the stack to make sure
      the stack address is accessible.  */
-#ifdef ENABLE_EXECUTE_STACK
+#ifdef HAVE_ENABLE_EXECUTE_STACK
   emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__enable_execute_stack"),
                      LCT_NORMAL, VOIDmode, 1, XEXP (m_tramp, 0), Pmode);
 #endif
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index e248b81..ebc876f 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -5189,19 +5189,6 @@ typically be a series of @code{asm} statements.  Both @var{beg} and
 @var{end} are both pointer expressions.
 @end defmac
 
-The operating system may also require the stack to be made executable
-before calling the trampoline.  To implement this requirement, define
-the following macro.
-
-@defmac ENABLE_EXECUTE_STACK
-Define this macro if certain operations must be performed before executing
-code located on the stack.  The macro should expand to a series of C
-file-scope constructs (e.g.@: functions) and provide a unique entry point
-named @code{__enable_execute_stack}.  The target is responsible for
-emitting calls to the entry point in the code, for example from the
-@code{TARGET_TRAMPOLINE_INIT} hook.
-@end defmac
-
 To use a standard subroutine, define the following macro.  In addition,
 you must make sure that the instructions in a trampoline fill an entire
 cache line with identical instructions, or else ensure that the
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 528ac13..85fcfb1 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -5141,19 +5141,6 @@ typically be a series of @code{asm} statements.  Both @var{beg} and
 @var{end} are both pointer expressions.
 @end defmac
 
-The operating system may also require the stack to be made executable
-before calling the trampoline.  To implement this requirement, define
-the following macro.
-
-@defmac ENABLE_EXECUTE_STACK
-Define this macro if certain operations must be performed before executing
-code located on the stack.  The macro should expand to a series of C
-file-scope constructs (e.g.@: functions) and provide a unique entry point
-named @code{__enable_execute_stack}.  The target is responsible for
-emitting calls to the entry point in the code, for example from the
-@code{TARGET_TRAMPOLINE_INIT} hook.
-@end defmac
-
 To use a standard subroutine, define the following macro.  In addition,
 you must make sure that the instructions in a trampoline fill an entire
 cache line with identical instructions, or else ensure that the
diff --git a/gcc/libgcc2.c b/gcc/libgcc2.c
index 5312a10..94763d6 100644
--- a/gcc/libgcc2.c
+++ b/gcc/libgcc2.c
@@ -1,7 +1,7 @@
 /* More subroutines needed by GCC output code on some machines.  */
 /* Compile this one with gcc.  */
 /* Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
-   2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
+   2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -2027,19 +2027,6 @@ __clear_cache (char *beg __attribute__((__unused__)),
 
 #endif /* L_clear_cache */
 
-#ifdef L_enable_execute_stack
-/* Attempt to turn on execute permission for the stack.  */
-
-#ifdef ENABLE_EXECUTE_STACK
-  ENABLE_EXECUTE_STACK
-#else
-void
-__enable_execute_stack (void *addr __attribute__((__unused__)))
-{}
-#endif /* ENABLE_EXECUTE_STACK */
-
-#endif /* L_enable_execute_stack */
-
 #ifdef L_trampoline
 
 /* Jump to a trampoline, loading the static chain address.  */
diff --git a/gcc/system.h b/gcc/system.h
index d081661..baf5e2d 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -764,7 +764,7 @@ extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
 /* Target macros only used for code built for the target, that have
    moved to libgcc-tm.h or have never been present elsewhere.  */
  #pragma GCC poison DECLARE_LIBRARY_RENAMES LIBGCC2_GNU_PREFIX		\
-	MD_UNWIND_SUPPORT
+	MD_UNWIND_SUPPORT ENABLE_EXECUTE_STACK
 
 /* Other obsolete target macros, or macros that used to be in target
    headers and were not used, and may be obsolete or may never have