Enable no-exec stacks for more targets using the Linux kernel.

Building glibc for many different configurations and running the
compilation parts of the testsuite runs into failures of the
elf/check-execstack test for hppa and microblaze.  Those
configurations default to executable stacks in the Linux kernel
because of VM_DATA_DEFAULT_FLAGS definitions including VM_EXEC
(VM_DATA_DEFAULT_FLAGS being the default definition of
VM_STACK_DEFAULT_FLAGS).

This fails because those configurations are not generating
.note.GNU-stack sections to indicate that programs do not need an
executable stack.  This patch fixes GCC to generate those sections on
those architectures (when configured for a target using the Linux
kernel), as it does on other architectures, together with adding that
section to libgcc .S sources, with the same code as used on other
architectures (or a variant using "#ifdef __linux__" instead of the
usual "#if defined(__ELF__) && defined(__linux__)" for microblaze, as
that configuration doesn't use elfos.h and so doesn't define __ELF__).

This suffices to eliminate that glibc test failure.  (For hppa, the
compilation parts of the glibc testsuite still fail because of the
separate elf/check-textrel failure.)

gcc:
	* config/microblaze/linux.h (TARGET_ASM_FILE_END): Likewise.
	* config/pa/pa.h (NEED_INDICATE_EXEC_STACK): Likewise.
	* config/pa/pa-linux.h (NEED_INDICATE_EXEC_STACK): Likewise.
	* config/pa/pa.c (pa_hpux_file_end): Rename to pa_file_end.
	Define unconditionally, with [ASM_OUTPUT_EXTERNAL_REAL]
	conditionals inside the function instead of around it.  Call
	file_end_indicate_exec_stack if NEED_INDICATE_EXEC_STACK.
	(TARGET_ASM_FILE_END): Define unconditionally to pa_file_end.

libgcc:
	* config/microblaze/crti.S, config/microblaze/crtn.S,
	config/microblaze/divsi3.S, config/microblaze/moddi3.S,
	config/microblaze/modsi3.S, config/microblaze/muldi3_hard.S,
	config/microblaze/mulsi3.S,
	config/microblaze/stack_overflow_exit.S,
	config/microblaze/udivsi3.S, config/microblaze/umodsi3.S,
	config/pa/milli64.S: Add .note.GNU-stack section.

From-SVN: r253204

gcc/ChangeLog

+2017-09-26  Joseph Myers  <joseph@codesourcery.com>
+
+	* config/microblaze/linux.h (TARGET_ASM_FILE_END): Likewise.
+	* config/pa/pa.h (NEED_INDICATE_EXEC_STACK): Likewise.
+	* config/pa/pa-linux.h (NEED_INDICATE_EXEC_STACK): Likewise.
+	* config/pa/pa.c (pa_hpux_file_end): Rename to pa_file_end.
+	Define unconditionally, with [ASM_OUTPUT_EXTERNAL_REAL]
+	conditionals inside the function instead of around it.  Call
+	file_end_indicate_exec_stack if NEED_INDICATE_EXEC_STACK.
+	(TARGET_ASM_FILE_END): Define unconditionally to pa_file_end.
+
 2017-09-26  Richard Biener  <rguenther@suse.de>
 
 	* graphite-scop-detection.c (scop_detection::build_scop_depth): Rewrite,

gcc/config/microblaze/linux.h

@@ -57,3 +57,5 @@
 /* For the microblaze-*-linux* subtarget.  */
 #undef TARGET_OS_CPP_BUILTINS
 #define TARGET_OS_CPP_BUILTINS() GNU_USER_TARGET_OS_CPP_BUILTINS()
+
+#define TARGET_ASM_FILE_END file_end_indicate_exec_stack

gcc/config/pa/pa-linux.h

@@ -141,3 +141,6 @@ along with GCC; see the file COPYING3.  If not see
 #define HAVE_sync_compare_and_swaphi 1
 #define HAVE_sync_compare_and_swapsi 1
 #define HAVE_sync_compare_and_swapdi 1
+
+#undef NEED_INDICATE_EXEC_STACK
+#define NEED_INDICATE_EXEC_STACK 1

gcc/config/pa/pa.c

@@ -159,9 +159,7 @@ static void pa_hpux64_gas_file_start (void) ATTRIBUTE_UNUSED;
 static void pa_hpux64_hpas_file_start (void) ATTRIBUTE_UNUSED;
 static void output_deferred_plabels (void);
 static void output_deferred_profile_counters (void) ATTRIBUTE_UNUSED;
-#ifdef ASM_OUTPUT_EXTERNAL_REAL
-static void pa_hpux_file_end (void);
-#endif
+static void pa_file_end (void);
 static void pa_init_libfuncs (void);
 static rtx pa_struct_value_rtx (tree, int);
 static bool pa_pass_by_reference (cumulative_args_t, machine_mode,
@@ -301,11 +299,7 @@ static size_t n_deferred_plabels = 0;
 #define TARGET_ASM_CAN_OUTPUT_MI_THUNK default_can_output_mi_thunk_no_vcall
 
 #undef TARGET_ASM_FILE_END
-#ifdef ASM_OUTPUT_EXTERNAL_REAL
-#define TARGET_ASM_FILE_END pa_hpux_file_end
-#else
-#define TARGET_ASM_FILE_END output_deferred_plabels
-#endif
+#define TARGET_ASM_FILE_END pa_file_end
 
 #undef TARGET_ASM_RELOC_RW_MASK
 #define TARGET_ASM_RELOC_RW_MASK pa_reloc_rw_mask
@@ -9979,22 +9973,26 @@ pa_hpux_asm_output_external (FILE *file, tree decl, const char *name)
   extern_symbol p = {decl, name};
   vec_safe_push (extern_symbols, p);
 }
+#endif
 
 /* Output text required at the end of an assembler file.
    This includes deferred plabels and .import directives for
    all external symbols that were actually referenced.  */
 
 static void
-pa_hpux_file_end (void)
+pa_file_end (void)
 {
+#ifdef ASM_OUTPUT_EXTERNAL_REAL
   unsigned int i;
   extern_symbol *p;
 
   if (!NO_DEFERRED_PROFILE_COUNTERS)
     output_deferred_profile_counters ();
+#endif
 
   output_deferred_plabels ();
 
+#ifdef ASM_OUTPUT_EXTERNAL_REAL
   for (i = 0; vec_safe_iterate (extern_symbols, i, &p); i++)
     {
       tree decl = p->decl;
@@ -10005,9 +10003,12 @@ pa_hpux_file_end (void)
     }
 
   vec_free (extern_symbols);
-}
 #endif
 
+  if (NEED_INDICATE_EXEC_STACK)
+    file_end_indicate_exec_stack ();
+}
+
 /* Implement TARGET_CAN_CHANGE_MODE_CLASS.  */
 
 static bool

gcc/config/pa/pa.h

@@ -1306,3 +1306,5 @@ do {									     \
    seven and four instructions, respectively.  */  
 #define MAX_PCREL17F_OFFSET \
   (flag_pic ? (TARGET_HPUX ? 198164 : 221312) : 240000)
+
+#define NEED_INDICATE_EXEC_STACK 0

libgcc/ChangeLog

+2017-09-26  Joseph Myers  <joseph@codesourcery.com>
+
+	* config/microblaze/crti.S, config/microblaze/crtn.S,
+	config/microblaze/divsi3.S, config/microblaze/moddi3.S,
+	config/microblaze/modsi3.S, config/microblaze/muldi3_hard.S,
+	config/microblaze/mulsi3.S,
+	config/microblaze/stack_overflow_exit.S,
+	config/microblaze/udivsi3.S, config/microblaze/umodsi3.S,
+	config/pa/milli64.S: Add .note.GNU-stack section.
+
 2017-09-23  Daniel Santos  <daniel.santos@pobox.com>
 
 	* configure.ac: Add Check for HAVE_AS_AVX.

libgcc/config/microblaze/crti.S

@@ -24,6 +24,12 @@
    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
     .section .init, "ax"
     .global __init
 

libgcc/config/microblaze/crtn.S

@@ -24,6 +24,12 @@
    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
     .section .init, "ax"
     lw      r15, r0, r1
     rtsd    r15, 8 

libgcc/config/microblaze/divsi3.S

@@ -32,6 +32,12 @@
 # 
 #######################################
 	
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
 	.globl	__divsi3
 	.ent	__divsi3
 	.type	__divsi3,@function

libgcc/config/microblaze/moddi3.S

@@ -30,6 +30,12 @@
 #######################################
 
 
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
 	.globl	__moddi3
 	.ent	__moddi3
 __moddi3:

libgcc/config/microblaze/modsi3.S

@@ -32,6 +32,12 @@
 # 
 #######################################
 
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
 	.globl	__modsi3
 	.ent	__modsi3
 	.type	__modsi3,@function

libgcc/config/microblaze/muldi3_hard.S

@@ -47,6 +47,12 @@
 #
 #######################################
 
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
 	.globl	muldi3_hardproc
 	.ent	muldi3_hardproc
 muldi3_hardproc:

libgcc/config/microblaze/mulsi3.S

@@ -32,6 +32,12 @@
 # 
 #######################################
 
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
 	.globl	__mulsi3
 	.ent	__mulsi3
 	.type	__mulsi3,@function

libgcc/config/microblaze/stack_overflow_exit.S

@@ -33,6 +33,12 @@
 # 
 #######################################
 
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
 	.globl	_stack_overflow_error
 	.data
 	.align	2

libgcc/config/microblaze/udivsi3.S

@@ -32,6 +32,12 @@
 # 
 #######################################
 	
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
 	.globl	__udivsi3
 	.ent	__udivsi3
 	.type	__udivsi3,@function

libgcc/config/microblaze/umodsi3.S

@@ -32,6 +32,12 @@
 # 
 #######################################
 	
+/* An executable stack is *not* required for these functions.  */
+#ifdef __linux__
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
 	.globl	__umodsi3
 	.ent	__umodsi3
 	.type	__umodsi3,@function

libgcc/config/pa/milli64.S

@@ -25,6 +25,12 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+/* An executable stack is *not* required for these functions.  */
+#if defined(__ELF__) && defined(__linux__)
+.section .note.GNU-stack,"",%progbits
+.previous
+#endif
+
 #ifdef pa64
         .level  2.0w
 #endif