freebsd.h (TRANSFER_FROM_TRAMPOLINE): Define __enable_execute_stack function.

2002-10-31  David O'Brien  <obrien@FreeBSD.org>
	* config/sparc/freebsd.h (TRANSFER_FROM_TRAMPOLINE): Define
	__enable_execute_stack function.

Approved by:  David S. Miller <davem@redhat.com>
              Message-Id: <20021031.005015.22856738.davem@redhat.com>

From-SVN: r58674

gcc/ChangeLog

+2002-10-31  David O'Brien  <obrien@FreeBSD.org>
+
+	* config/sparc/freebsd.h (TRANSFER_FROM_TRAMPOLINE): Define
+	__enable_execute_stack function.
+
 2002-10-30  Aldy Hernandez  <aldyh@redhat.com>
 
         * c-common.c: Add GTY to vector_type_node_list.

gcc/config/sparc/freebsd.h

@@ -96,6 +96,37 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 #undef  SPARC_DEFAULT_CMODEL
 #define SPARC_DEFAULT_CMODEL	CM_MEDLOW
 
+#define TRANSFER_FROM_TRAMPOLINE					\
+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);\
+  size_t len;								\
+  int prot;								\
+									\
+  prot = 0;								\
+  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 (addr)						\
+     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");				\
+  }									\
+}
+
 
 /************************[  Assembler stuff  ]********************************/