x86: Support Intel Shadow Stack with SHSTK property

To support Intel Shadow Stack (SHSTK) in Intel Control-flow Enforcement
Technology (CET) instructions:

https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf

 #define GNU_PROPERTY_X86_FEATURE_1_SHSTK (1U << 1)

is added to GNU program properties to indicate that all executable sections
are compatible with SHSTK where return address popped from shadow stack
always matches return address popped from normal stack.

GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on output only if it is set on all
relocatable inputs.

bfd/

	* elf32-i386.c (elf_i386_merge_gnu_properties): If info->shstk
	is set, turn on GNU_PROPERTY_X86_FEATURE_1_SHSTK.
	(elf_i386_link_setup_gnu_properties): If info->shstk is set,
	turn on GNU_PROPERTY_X86_FEATURE_1_IBT.
	* elf64-x86-64.c (elf_x86_64_merge_gnu_properties): If
	info->shstk is set, turn on GNU_PROPERTY_X86_FEATURE_1_SHSTK.
	(elf_x86_64_link_setup_gnu_properties): If info->shstk is set,
	turn on GNU_PROPERTY_X86_FEATURE_1_IBT.

binutils/

	* readelf.c (decode_x86_feature): Decode
	GNU_PROPERTY_X86_FEATURE_1_SHSTK.
	* testsuite/binutils-all/i386/shstk.d: New file.
	* testsuite/binutils-all/i386/shstk.s: Likewise.
	* testsuite/binutils-all/x86-64/shstk-x32.d: Likewise.
	* testsuite/binutils-all/x86-64/shstk.d: Likewise.
	* testsuite/binutils-all/x86-64/shstk.s: Likewise.

include/

	* bfdlink.h (bfd_link_info): Add shstk.
	* elf/common.h (GNU_PROPERTY_X86_FEATURE_1_SHSTK): New.

ld/

	* NEWS: Mention -z shstk and GNU_PROPERTY_X86_FEATURE_1_SHSTK.
	* emulparams/cet.sh (PARSE_AND_LIST_OPTIONS_CET): Add "-z shstk".
	(PARSE_AND_LIST_ARGS_CASE_Z_CET): Support "-z shstk".
	* ld.texinfo: Document -z shstk.
	* testsuite/ld-i386/i386.exp: Run SHSTK tests.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/property-x86-shstk.s: New file.
	* testsuite/ld-i386/property-x86-shstk1a.d: Likewise.
	* testsuite/ld-i386/property-x86-shstk1b.d: Likewise.
	* testsuite/ld-i386/property-x86-shstk2.d: Likewise.
	* testsuite/ld-i386/property-x86-shstk3a.d: Likewise.
	* testsuite/ld-i386/property-x86-shstk3b.d: Likewise.
	* testsuite/ld-i386/property-x86-shstk4.d: Likewise.
	* testsuite/ld-i386/property-x86-shstk5.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk.s: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk1a-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk1a.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk1b-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk1b.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk2-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk2.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk3a-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk3a.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk3b-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk3b.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk4-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk4.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk5-x32.d: Likewise.
	* testsuite/ld-x86-64/property-x86-shstk5.d: Likewise.

7 files changed, 103 insertions, 0 deletions

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 3870711..484632a 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,5 +1,15 @@
 2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
 
+	* readelf.c (decode_x86_feature): Decode
+	GNU_PROPERTY_X86_FEATURE_1_SHSTK.
+	* testsuite/binutils-all/i386/shstk.d: New file.
+	* testsuite/binutils-all/i386/shstk.s: Likewise.
+	* testsuite/binutils-all/x86-64/shstk-x32.d: Likewise.
+	* testsuite/binutils-all/x86-64/shstk.d: Likewise.
+	* testsuite/binutils-all/x86-64/shstk.s: Likewise.
+
+2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
+
 	* readelf.c (decode_x86_feature): New.
 	(print_gnu_property_note): Call decode_x86_feature on
 	GNU_PROPERTY_X86_FEATURE_1_AND.
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 50354c1..d23a020 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -16358,6 +16358,17 @@ decode_x86_feature (unsigned int type, unsigned int bitmask)
 	      abort ();
 	    }
 	  break;
+	case GNU_PROPERTY_X86_FEATURE_1_SHSTK:
+	  switch (type)
+	    {
+	    case GNU_PROPERTY_X86_FEATURE_1_AND:
+	      printf ("SHSTK");
+	      break;
+	    default:
+	      /* This should never happen.  */
+	      abort ();
+	    }
+	  break;
 	default:
 	  printf (_("<unknown: %x>"), bit);
 	  break;
diff --git a/binutils/testsuite/binutils-all/i386/shstk.d b/binutils/testsuite/binutils-all/i386/shstk.d
new file mode 100644
index 0000000..933704c
--- /dev/null
+++ b/binutils/testsuite/binutils-all/i386/shstk.d
@@ -0,0 +1,9 @@
+#PROG: objcopy
+#as: --32
+#objcopy:
+#readelf: -n
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x0000000c	NT_GNU_PROPERTY_TYPE_0
+      Properties: x86 feature: SHSTK
diff --git a/binutils/testsuite/binutils-all/i386/shstk.s b/binutils/testsuite/binutils-all/i386/shstk.s
new file mode 100644
index 0000000..4c3218a
--- /dev/null
+++ b/binutils/testsuite/binutils-all/i386/shstk.s
@@ -0,0 +1,27 @@
+	.section ".note.gnu.property", "a"
+.ifdef __64_bit__
+	.p2align 3
+.else
+	.p2align 2
+.endif
+	.long 1f - 0f		/* name length */
+	.long 5f - 2f		/* data length */
+	.long 5			/* note type */
+0:	.asciz "GNU"		/* vendor name */
+1:
+.ifdef __64_bit__
+	.p2align 3
+.else
+	.p2align 2
+.endif
+2:	.long 0xc0000002	/* pr_type.  */
+	.long 4f - 3f		/* pr_datasz.  */
+3:
+	.long 0x2
+4:
+.ifdef __64_bit__
+	.p2align 3
+.else
+	.p2align 2
+.endif
+5:
diff --git a/binutils/testsuite/binutils-all/x86-64/shstk-x32.d b/binutils/testsuite/binutils-all/x86-64/shstk-x32.d
new file mode 100644
index 0000000..1dfc4fd
--- /dev/null
+++ b/binutils/testsuite/binutils-all/x86-64/shstk-x32.d
@@ -0,0 +1,10 @@
+#source: shstk.s
+#PROG: objcopy
+#as: --x32
+#objcopy:
+#readelf: -n
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x0000000c	NT_GNU_PROPERTY_TYPE_0
+      Properties: x86 feature: SHSTK
diff --git a/binutils/testsuite/binutils-all/x86-64/shstk.d b/binutils/testsuite/binutils-all/x86-64/shstk.d
new file mode 100644
index 0000000..1f131b8
--- /dev/null
+++ b/binutils/testsuite/binutils-all/x86-64/shstk.d
@@ -0,0 +1,9 @@
+#PROG: objcopy
+#as: --64 -defsym __64_bit__=1
+#objcopy:
+#readelf: -n
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000010	NT_GNU_PROPERTY_TYPE_0
+      Properties: x86 feature: SHSTK
diff --git a/binutils/testsuite/binutils-all/x86-64/shstk.s b/binutils/testsuite/binutils-all/x86-64/shstk.s
new file mode 100644
index 0000000..4c3218a
--- /dev/null
+++ b/binutils/testsuite/binutils-all/x86-64/shstk.s
@@ -0,0 +1,27 @@
+	.section ".note.gnu.property", "a"
+.ifdef __64_bit__
+	.p2align 3
+.else
+	.p2align 2
+.endif
+	.long 1f - 0f		/* name length */
+	.long 5f - 2f		/* data length */
+	.long 5			/* note type */
+0:	.asciz "GNU"		/* vendor name */
+1:
+.ifdef __64_bit__
+	.p2align 3
+.else
+	.p2align 2
+.endif
+2:	.long 0xc0000002	/* pr_type.  */
+	.long 4f - 3f		/* pr_datasz.  */
+3:
+	.long 0x2
+4:
+.ifdef __64_bit__
+	.p2align 3
+.else
+	.p2align 2
+.endif
+5: