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.

42 files changed, 457 insertions, 9 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index ac13db3..647af61 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,16 @@
 2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
 
+	* 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.
+
+2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
+
 	* elf32-i386.c (elf_i386_lazy_ibt_plt0_entry): New.
 	(elf_i386_lazy_ibt_plt_entry): Likewise.
 	(elf_i386_pic_lazy_ibt_plt0_entry): Likewise.
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index d662816..ee8219c 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -6751,8 +6751,11 @@ elf_i386_merge_gnu_properties (struct bfd_link_info *info,
 	  features = 0;
 	  if (info->ibt)
 	    features = GNU_PROPERTY_X86_FEATURE_1_IBT;
+	  if (info->shstk)
+	    features |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
 	  number = aprop->u.number;
-	  /* Add GNU_PROPERTY_X86_FEATURE_1_IBT.  */
+	  /* Add GNU_PROPERTY_X86_FEATURE_1_IBT and
+	     GNU_PROPERTY_X86_FEATURE_1_SHSTK.  */
 	  aprop->u.number = (number & bprop->u.number) | features;
 	  updated = number != (unsigned int) aprop->u.number;
 	  /* Remove the property if all feature bits are cleared.  */
@@ -6764,9 +6767,12 @@ elf_i386_merge_gnu_properties (struct bfd_link_info *info,
 	  features = 0;
 	  if (info->ibt)
 	    features = GNU_PROPERTY_X86_FEATURE_1_IBT;
+	  if (info->shstk)
+	    features |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
 	  if (features)
 	    {
-	      /* Add GNU_PROPERTY_X86_FEATURE_1_IBT.  */
+	      /* Add GNU_PROPERTY_X86_FEATURE_1_IBT and
+		 GNU_PROPERTY_X86_FEATURE_1_SHSTK.  */
 	      if (aprop != NULL)
 		{
 		  number = aprop->u.number;
@@ -6813,9 +6819,12 @@ elf_i386_link_setup_gnu_properties (struct bfd_link_info *info)
   features = 0;
   if (info->ibt)
     features = GNU_PROPERTY_X86_FEATURE_1_IBT;
+  if (info->shstk)
+    features |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
   if (features)
     {
-      /* Turn on GNU_PROPERTY_X86_FEATURE_1_IBT.  */
+      /* Turn on GNU_PROPERTY_X86_FEATURE_1_IBT and
+	 GNU_PROPERTY_X86_FEATURE_1_SHSTK.  */
       bfd *ebfd = NULL;
       elf_property *prop;
 
@@ -6833,7 +6842,8 @@ elf_i386_link_setup_gnu_properties (struct bfd_link_info *info)
 		prop = _bfd_elf_get_property (pbfd,
 					      GNU_PROPERTY_X86_FEATURE_1_AND,
 					      4);
-		/* Add GNU_PROPERTY_X86_FEATURE_1_IBT.  */
+		/* Add GNU_PROPERTY_X86_FEATURE_1_IBT and
+		   GNU_PROPERTY_X86_FEATURE_1_SHSTK.  */
 		prop->u.number |= features;
 		prop->pr_kind = property_number;
 		break;
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 1f8e6d0..1a9bebe 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -7286,8 +7286,11 @@ elf_x86_64_merge_gnu_properties (struct bfd_link_info *info,
 	  features = 0;
 	  if (info->ibt)
 	    features = GNU_PROPERTY_X86_FEATURE_1_IBT;
+	  if (info->shstk)
+	    features |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
 	  number = aprop->u.number;
-	  /* Add GNU_PROPERTY_X86_FEATURE_1_IBT.  */
+	  /* Add GNU_PROPERTY_X86_FEATURE_1_IBT and
+	     GNU_PROPERTY_X86_FEATURE_1_SHSTK.  */
 	  aprop->u.number = (number & bprop->u.number) | features;
 	  updated = number != (unsigned int) aprop->u.number;
 	  /* Remove the property if all feature bits are cleared.  */
@@ -7299,9 +7302,12 @@ elf_x86_64_merge_gnu_properties (struct bfd_link_info *info,
 	  features = 0;
 	  if (info->ibt)
 	    features = GNU_PROPERTY_X86_FEATURE_1_IBT;
+	  if (info->shstk)
+	    features |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
 	  if (features)
 	    {
-	      /* Add GNU_PROPERTY_X86_FEATURE_1_IBT.  */
+	      /* Add GNU_PROPERTY_X86_FEATURE_1_IBT and
+		 GNU_PROPERTY_X86_FEATURE_1_SHSTK.  */
 	      if (aprop != NULL)
 		{
 		  number = aprop->u.number;
@@ -7348,9 +7354,12 @@ elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
   features = 0;
   if (info->ibt)
     features = GNU_PROPERTY_X86_FEATURE_1_IBT;
+  if (info->shstk)
+    features |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
   if (features)
     {
-      /* Turn on GNU_PROPERTY_X86_FEATURE_1_IBT.  */
+      /* Turn on GNU_PROPERTY_X86_FEATURE_1_IBT and
+	 GNU_PROPERTY_X86_FEATURE_1_SHSTK.  */
       bfd *ebfd = NULL;
       elf_property *prop;
 
@@ -7368,7 +7377,8 @@ elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
 		prop = _bfd_elf_get_property (pbfd,
 					      GNU_PROPERTY_X86_FEATURE_1_AND,
 					      4);
-		/* Add GNU_PROPERTY_X86_FEATURE_1_IBT.  */
+		/* Add GNU_PROPERTY_X86_FEATURE_1_IBT and
+		   GNU_PROPERTY_X86_FEATURE_1_SHSTK.  */
 		prop->u.number |= features;
 		prop->pr_kind = property_number;
 		break;
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:
diff --git a/include/ChangeLog b/include/ChangeLog
index 4858699..d8730de 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,5 +1,10 @@
 2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
 
+	* bfdlink.h (bfd_link_info): Add shstk.
+	* elf/common.h (GNU_PROPERTY_X86_FEATURE_1_SHSTK): New.
+
+2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
+
 	* bfdlink.h (bfd_link_info): Add ibtplt and ibt.
 	* elf/common.h (GNU_PROPERTY_X86_FEATURE_1_AND): New.
 	(GNU_PROPERTY_X86_FEATURE_1_IBT): Likewise.
diff --git a/include/bfdlink.h b/include/bfdlink.h
index 3b4dce9..e7c7836 100644
--- a/include/bfdlink.h
+++ b/include/bfdlink.h
@@ -477,6 +477,9 @@ struct bfd_link_info
   /* TRUE if GNU_PROPERTY_X86_FEATURE_1_IBT should be generated.  */
   unsigned int ibt: 1;
 
+  /* TRUE if GNU_PROPERTY_X86_FEATURE_1_SHSTK should be generated.  */
+  unsigned int shstk: 1;
+
   /* TRUE if generation of .interp/PT_INTERP should be suppressed.  */
   unsigned int nointerp: 1;
 
diff --git a/include/elf/common.h b/include/elf/common.h
index e638ba0..8ca14bc 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -731,6 +731,7 @@
 #define GNU_PROPERTY_X86_ISA_1_AVX512BW      (1U << 17)
 
 #define GNU_PROPERTY_X86_FEATURE_1_IBT       (1U << 0)
+#define GNU_PROPERTY_X86_FEATURE_1_SHSTK     (1U << 1)
 
 /* Values used in GNU .note.ABI-tag notes (NT_GNU_ABI_TAG).  */
 #define GNU_ABI_TAG_LINUX	0
diff --git a/ld/ChangeLog b/ld/ChangeLog
index b3567e1..bdc5853 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,5 +1,37 @@
 2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
 
+	* 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.
+
+2017-06-22  H.J. Lu  <hongjiu.lu@intel.com>
+
 	* Makefile.am (ELF_X86_DEPS): Add $(srcdir)/emulparams/cet.sh.
 	* Makefile.in: Regenerated.
 	* NEWS: Mention GNU_PROPERTY_X86_FEATURE_1_IBT, -z ibtplt
diff --git a/ld/NEWS b/ld/NEWS
index b115843..e9ef713 100644
--- a/ld/NEWS
+++ b/ld/NEWS
@@ -1,6 +1,13 @@
 -*- text -*-
 
+* Support for -z shstk in the x86 ELF linker to generate
+  GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
+
+* Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
+  properties in the x86 ELF linker.
+
 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
+  properties in the x86 ELF linker.
 
 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
   PLT.
diff --git a/ld/emulparams/cet.sh b/ld/emulparams/cet.sh
index 62ff105..1973413 100644
--- a/ld/emulparams/cet.sh
+++ b/ld/emulparams/cet.sh
@@ -1,13 +1,16 @@
 PARSE_AND_LIST_OPTIONS_CET='
   fprintf (file, _("\
   -z ibtplt                   Generate IBT-enabled PLT entries\n\
-  -z ibt                      Generate GNU_PROPERTY_X86_FEATURE_1_IBT\n"));
+  -z ibt                      Generate GNU_PROPERTY_X86_FEATURE_1_IBT\n\
+  -z shstk                    Generate GNU_PROPERTY_X86_FEATURE_1_SHSTK\n"));
 '
 PARSE_AND_LIST_ARGS_CASE_Z_CET='
       else if (strcmp (optarg, "ibtplt") == 0)
 	link_info.ibtplt = TRUE;
       else if (strcmp (optarg, "ibt") == 0)
 	link_info.ibt = TRUE;
+      else if (strcmp (optarg, "shstk") == 0)
+	link_info.shstk = TRUE;
 '
 
 PARSE_AND_LIST_OPTIONS="$PARSE_AND_LIST_OPTIONS $PARSE_AND_LIST_OPTIONS_CET"
diff --git a/ld/ld.texinfo b/ld/ld.texinfo
index 4f7873c..77b5d3e 100644
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@@ -1270,6 +1270,11 @@ Generate GNU_PROPERTY_X86_FEATURE_1_IBT in .note.gnu.property section
 to indicate compatibility with IBT.  This also implies @option{ibtplt}.
 Supported for Linux/i386 and Linux/x86_64.
 
+@item shstk
+Generate GNU_PROPERTY_X86_FEATURE_1_SHSTK in .note.gnu.property section
+to indicate compatibility with Intel Shadow Stack.  Supported for
+Linux/i386 and Linux/x86_64.
+
 @end table
 
 Other keywords are ignored for Solaris compatibility.
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index d30dc76..1cecea4 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -427,6 +427,13 @@ run_dump_test "property-x86-ibt3a"
 run_dump_test "property-x86-ibt3b"
 run_dump_test "property-x86-ibt4"
 run_dump_test "property-x86-ibt5"
+run_dump_test "property-x86-shstk1a"
+run_dump_test "property-x86-shstk1b"
+run_dump_test "property-x86-shstk2"
+run_dump_test "property-x86-shstk3a"
+run_dump_test "property-x86-shstk3b"
+run_dump_test "property-x86-shstk4"
+run_dump_test "property-x86-shstk5"
 
 if { !([istarget "i?86-*-linux*"]
        || [istarget "i?86-*-gnu*"]
diff --git a/ld/testsuite/ld-i386/property-x86-shstk.s b/ld/testsuite/ld-i386/property-x86-shstk.s
new file mode 100644
index 0000000..4c3218a
--- /dev/null
+++ b/ld/testsuite/ld-i386/property-x86-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/ld/testsuite/ld-i386/property-x86-shstk1a.d b/ld/testsuite/ld-i386/property-x86-shstk1a.d
new file mode 100644
index 0000000..238cebe
--- /dev/null
+++ b/ld/testsuite/ld-i386/property-x86-shstk1a.d
@@ -0,0 +1,6 @@
+#source: property-x86-empty.s
+#source: property-x86-shstk.s
+#as: --32
+#ld: -r -melf_i386
+#readelf: -n
+
diff --git a/ld/testsuite/ld-i386/property-x86-shstk1b.d b/ld/testsuite/ld-i386/property-x86-shstk1b.d
new file mode 100644
index 0000000..faa2ea7
--- /dev/null
+++ b/ld/testsuite/ld-i386/property-x86-shstk1b.d
@@ -0,0 +1,6 @@
+#source: property-x86-shstk.s
+#source: property-x86-empty.s
+#as: --32
+#ld: -r -melf_i386
+#readelf: -n
+
diff --git a/ld/testsuite/ld-i386/property-x86-shstk2.d b/ld/testsuite/ld-i386/property-x86-shstk2.d
new file mode 100644
index 0000000..b39fa58
--- /dev/null
+++ b/ld/testsuite/ld-i386/property-x86-shstk2.d
@@ -0,0 +1,9 @@
+#source: property-x86-shstk.s
+#as: --32
+#ld: -r -melf_i386
+#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/ld/testsuite/ld-i386/property-x86-shstk3a.d b/ld/testsuite/ld-i386/property-x86-shstk3a.d
new file mode 100644
index 0000000..e261038
--- /dev/null
+++ b/ld/testsuite/ld-i386/property-x86-shstk3a.d
@@ -0,0 +1,11 @@
+#source: property-x86-3.s
+#source: property-x86-shstk.s
+#as: --32
+#ld: -r -melf_i386
+#readelf: -n
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000018	NT_GNU_PROPERTY_TYPE_0
+      Properties: x86 ISA used: i486, 586, SSE2, SSE3
+	x86 ISA needed: 586, SSE, SSE3, SSE4_1
diff --git a/ld/testsuite/ld-i386/property-x86-shstk3b.d b/ld/testsuite/ld-i386/property-x86-shstk3b.d
new file mode 100644
index 0000000..25f3d23
--- /dev/null
+++ b/ld/testsuite/ld-i386/property-x86-shstk3b.d
@@ -0,0 +1,11 @@
+#source: property-x86-shstk.s
+#source: property-x86-3.s
+#as: --32
+#ld: -r -melf_i386
+#readelf: -n
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000018	NT_GNU_PROPERTY_TYPE_0
+      Properties: x86 ISA used: i486, 586, SSE2, SSE3
+	x86 ISA needed: 586, SSE, SSE3, SSE4_1
diff --git a/ld/testsuite/ld-i386/property-x86-shstk4.d b/ld/testsuite/ld-i386/property-x86-shstk4.d
new file mode 100644
index 0000000..d962eab
--- /dev/null
+++ b/ld/testsuite/ld-i386/property-x86-shstk4.d
@@ -0,0 +1,9 @@
+#source: property-x86-empty.s
+#as: --32
+#ld: -r -melf_i386 -z shstk
+#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/ld/testsuite/ld-i386/property-x86-shstk5.d b/ld/testsuite/ld-i386/property-x86-shstk5.d
new file mode 100644
index 0000000..6d6371f
--- /dev/null
+++ b/ld/testsuite/ld-i386/property-x86-shstk5.d
@@ -0,0 +1,9 @@
+#source: start.s
+#as: --32
+#ld: -r -melf_i386 -z shstk
+#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/ld/testsuite/ld-x86-64/property-x86-shstk.s b/ld/testsuite/ld-x86-64/property-x86-shstk.s
new file mode 100644
index 0000000..4c3218a
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-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/ld/testsuite/ld-x86-64/property-x86-shstk1a-x32.d b/ld/testsuite/ld-x86-64/property-x86-shstk1a-x32.d
new file mode 100644
index 0000000..312d1ea
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk1a-x32.d
@@ -0,0 +1,6 @@
+#source: property-x86-empty.s
+#source: property-x86-shstk.s
+#as: --x32
+#ld: -r -m elf32_x86_64
+#readelf: -n
+
diff --git a/ld/testsuite/ld-x86-64/property-x86-shstk1a.d b/ld/testsuite/ld-x86-64/property-x86-shstk1a.d
new file mode 100644
index 0000000..39a996e
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk1a.d
@@ -0,0 +1,6 @@
+#source: property-x86-empty.s
+#source: property-x86-shstk.s
+#as: --64 -defsym __64_bit__=1
+#ld: -r -melf_x86_64
+#readelf: -n
+
diff --git a/ld/testsuite/ld-x86-64/property-x86-shstk1b-x32.d b/ld/testsuite/ld-x86-64/property-x86-shstk1b-x32.d
new file mode 100644
index 0000000..9e91c5c
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk1b-x32.d
@@ -0,0 +1,6 @@
+#source: property-x86-shstk.s
+#source: property-x86-empty.s
+#as: --x32
+#ld: -r -m elf32_x86_64
+#readelf: -n
+
diff --git a/ld/testsuite/ld-x86-64/property-x86-shstk1b.d b/ld/testsuite/ld-x86-64/property-x86-shstk1b.d
new file mode 100644
index 0000000..a9b9e62
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk1b.d
@@ -0,0 +1,6 @@
+#source: property-x86-shstk.s
+#source: property-x86-empty.s
+#as: --64 -defsym __64_bit__=1
+#ld: -r -melf_x86_64
+#readelf: -n
+
diff --git a/ld/testsuite/ld-x86-64/property-x86-shstk2-x32.d b/ld/testsuite/ld-x86-64/property-x86-shstk2-x32.d
new file mode 100644
index 0000000..7155f3f
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk2-x32.d
@@ -0,0 +1,9 @@
+#source: property-x86-shstk.s
+#as: --x32
+#ld: -r -m elf32_x86_64
+#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/ld/testsuite/ld-x86-64/property-x86-shstk2.d b/ld/testsuite/ld-x86-64/property-x86-shstk2.d
new file mode 100644
index 0000000..7fbafe8
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk2.d
@@ -0,0 +1,9 @@
+#source: property-x86-shstk.s
+#as: --64 -defsym __64_bit__=1
+#ld: -r -melf_x86_64
+#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/ld/testsuite/ld-x86-64/property-x86-shstk3a-x32.d b/ld/testsuite/ld-x86-64/property-x86-shstk3a-x32.d
new file mode 100644
index 0000000..819542d
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk3a-x32.d
@@ -0,0 +1,11 @@
+#source: property-x86-3.s
+#source: property-x86-shstk.s
+#as: --x32
+#ld: -r -m elf32_x86_64
+#readelf: -n
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000018	NT_GNU_PROPERTY_TYPE_0
+      Properties: x86 ISA used: 586, SSE, SSE3, SSE4_1
+	x86 ISA needed: i486, 586, SSE2, SSE3
diff --git a/ld/testsuite/ld-x86-64/property-x86-shstk3a.d b/ld/testsuite/ld-x86-64/property-x86-shstk3a.d
new file mode 100644
index 0000000..4c5d0e0
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk3a.d
@@ -0,0 +1,11 @@
+#source: property-x86-3.s
+#source: property-x86-shstk.s
+#as: --64 -defsym __64_bit__=1
+#ld: -r -melf_x86_64
+#readelf: -n
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000020	NT_GNU_PROPERTY_TYPE_0
+      Properties: x86 ISA used: 586, SSE, SSE3, SSE4_1
+	x86 ISA needed: i486, 586, SSE2, SSE3
diff --git a/ld/testsuite/ld-x86-64/property-x86-shstk3b-x32.d b/ld/testsuite/ld-x86-64/property-x86-shstk3b-x32.d
new file mode 100644
index 0000000..ba181e0
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk3b-x32.d
@@ -0,0 +1,11 @@
+#source: property-x86-shstk.s
+#source: property-x86-3.s
+#as: --x32
+#ld: -r -m elf32_x86_64
+#readelf: -n
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000018	NT_GNU_PROPERTY_TYPE_0
+      Properties: x86 ISA used: 586, SSE, SSE3, SSE4_1
+	x86 ISA needed: i486, 586, SSE2, SSE3
diff --git a/ld/testsuite/ld-x86-64/property-x86-shstk3b.d b/ld/testsuite/ld-x86-64/property-x86-shstk3b.d
new file mode 100644
index 0000000..5216f38
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk3b.d
@@ -0,0 +1,11 @@
+#source: property-x86-shstk.s
+#source: property-x86-3.s
+#as: --64 -defsym __64_bit__=1
+#ld: -r -melf_x86_64
+#readelf: -n
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000020	NT_GNU_PROPERTY_TYPE_0
+      Properties: x86 ISA used: 586, SSE, SSE3, SSE4_1
+	x86 ISA needed: i486, 586, SSE2, SSE3
diff --git a/ld/testsuite/ld-x86-64/property-x86-shstk4-x32.d b/ld/testsuite/ld-x86-64/property-x86-shstk4-x32.d
new file mode 100644
index 0000000..61b7826
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk4-x32.d
@@ -0,0 +1,9 @@
+#source: property-x86-empty.s
+#as: --x32
+#ld: -r -m elf32_x86_64 -z shstk
+#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/ld/testsuite/ld-x86-64/property-x86-shstk4.d b/ld/testsuite/ld-x86-64/property-x86-shstk4.d
new file mode 100644
index 0000000..c2a7b36
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk4.d
@@ -0,0 +1,9 @@
+#source: property-x86-empty.s
+#as: --64 -defsym __64_bit__=1
+#ld: -r -melf_x86_64 -z shstk
+#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/ld/testsuite/ld-x86-64/property-x86-shstk5-x32.d b/ld/testsuite/ld-x86-64/property-x86-shstk5-x32.d
new file mode 100644
index 0000000..83c6a68
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk5-x32.d
@@ -0,0 +1,9 @@
+#source: start.s
+#as: --x32
+#ld: -r -m elf32_x86_64 -z shstk
+#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/ld/testsuite/ld-x86-64/property-x86-shstk5.d b/ld/testsuite/ld-x86-64/property-x86-shstk5.d
new file mode 100644
index 0000000..9a4b186
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-shstk5.d
@@ -0,0 +1,9 @@
+#source: start.s
+#as: --64 -defsym __64_bit__=1
+#ld: -r -melf_x86_64 -z shstk
+#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/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index 6cde22f..9b83e1c 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -349,6 +349,20 @@ run_dump_test "property-x86-ibt4"
 run_dump_test "property-x86-ibt4-x32"
 run_dump_test "property-x86-ibt5"
 run_dump_test "property-x86-ibt5-x32"
+run_dump_test "property-x86-shstk1a"
+run_dump_test "property-x86-shstk1b"
+run_dump_test "property-x86-shstk1a-x32"
+run_dump_test "property-x86-shstk1b-x32"
+run_dump_test "property-x86-shstk2"
+run_dump_test "property-x86-shstk2-x32"
+run_dump_test "property-x86-shstk3a"
+run_dump_test "property-x86-shstk3b"
+run_dump_test "property-x86-shstk3a-x32"
+run_dump_test "property-x86-shstk3b-x32"
+run_dump_test "property-x86-shstk4"
+run_dump_test "property-x86-shstk4-x32"
+run_dump_test "property-x86-shstk5"
+run_dump_test "property-x86-shstk5-x32"
 
 if { ![istarget "x86_64-*-linux*"] && ![istarget "x86_64-*-nacl*"]} {
     return