[BFD, LD, AArch64, 1/3] Add support for GNU PROPERTIES in AArch64 for BTI and PAC

This is part of the patch series to add support for BTI and
PAC in AArch64 linker.

This patch implements the following:
1) This extends in the gnu property support in the linker for
AArch64 by defining backend hooks for elf_backend_setup_gnu_properties,
elf_backend_merge_gnu_properties and elf_backend_parse_gnu_properties.
2) It defines AArch64 specific GNU property
GNU_PROPERTY_AARCH64_FEATURE_1_AND and 2 bit for BTI and PAC in it.
3) It also adds support in readelf.c to read and print these new
GNU properties in AArch64.
All these are made according to the new AArch64 ELF ABI
https://developer.arm.com/docs/ihi0056/latest/elf-for-the-arm-64-bit-architecture-aarch64-abi-2018q4

*** bfd/ChangeLog ***

2019-03-13  Sudakshina Das  <sudi.das@arm.com>

	* elf-properties.c (_bfd_elf_link_setup_gnu_properties): Exclude
	linker created inputs from merge.
	* elfnn-aarch64.c (struct elf_aarch64_obj_tdata): Add field for
	GNU_PROPERTY_AARCH64_FEATURE_1_AND properties.
	(elfNN_aarch64_link_setup_gnu_properties): New.
	(elfNN_aarch64_merge_gnu_properties): New.
	(elf_backend_setup_gnu_properties): Define for AArch64.
	(elf_backend_merge_gnu_properties): Likewise.
	* elfxx-aarch64.c (_bfd_aarch64_elf_link_setup_gnu_properties): Define.
	(_bfd_aarch64_elf_parse_gnu_properties): Define.
	(_bfd_aarch64_elf_merge_gnu_properties): Define.
	* elfxx-aarch64.h (_bfd_aarch64_elf_link_setup_gnu_properties): Declare.
	(_bfd_aarch64_elf_parse_gnu_properties): Declare.
	(_bfd_aarch64_elf_merge_gnu_properties): Declare.
	(elf_backend_parse_gnu_properties): Define for AArch64.

*** binutils/ChangeLog ***

2019-03-13  Sudakshina Das  <sudi.das@arm.com>

	* readelf.c (decode_aarch64_feature_1_and): New.
	(print_gnu_property_note): Add case for AArch64 gnu notes.

*** include/ChangeLog ***

2019-03-13  Sudakshina Das  <sudi.das@arm.com>

	* elf/common.h (GNU_PROPERTY_AARCH64_FEATURE_1_AND): New.
	(GNU_PROPERTY_AARCH64_FEATURE_1_BTI): New.
	(GNU_PROPERTY_AARCH64_FEATURE_1_PAC): New.

*** ld/ChangeLog ***

2019-03-13  Sudakshina Das  <sudi.das@arm.com>

	* NEWS: Document GNU_PROPERTY_AARCH64_FEATURE_1_BTI and
	GNU_PROPERTY_AARCH64_FEATURE_1_PAC.
	* testsuite/ld-aarch64/aarch64-elf.exp: Add run commands for new tests.
	* testsuite/ld-aarch64/property-bti-pac1.d: New test.
	* testsuite/ld-aarch64/property-bti-pac1.s: New test.
	* testsuite/ld-aarch64/property-bti-pac2.d: New test.
	* testsuite/ld-aarch64/property-bti-pac2.s: New test.
	* testsuite/ld-aarch64/property-bti-pac3.d: New test.

8 files changed, 147 insertions, 0 deletions

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 3722d4f..32b5387 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,14 @@
+2019-03-13  Sudakshina Das  <sudi.das@arm.com>
+
+	* NEWS: Document GNU_PROPERTY_AARCH64_FEATURE_1_BTI and
+	GNU_PROPERTY_AARCH64_FEATURE_1_PAC.
+	* testsuite/ld-aarch64/aarch64-elf.exp: Add run commands for new tests.
+	* testsuite/ld-aarch64/property-bti-pac1.d: New test.
+	* testsuite/ld-aarch64/property-bti-pac1.s: New test.
+	* testsuite/ld-aarch64/property-bti-pac2.d: New test.
+	* testsuite/ld-aarch64/property-bti-pac2.s: New test.
+	* testsuite/ld-aarch64/property-bti-pac3.d: New test.
+
 2019-03-13  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/24322
diff --git a/ld/NEWS b/ld/NEWS
index d737af7..dcf1185 100644
--- a/ld/NEWS
+++ b/ld/NEWS
@@ -1,5 +1,15 @@
 -*- text -*-
 
+Changes in 2.33:
+
+* Add target handlers for AArch64 for ELF GNU program properties.
+
+* Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
+  properties in the AArch64 ELF linker.
+
+* Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
+  properties in the AArch64 ELF linker.
+
 Changes in 2.32:
 
 * Report property change in linker map file when merging GNU properties.
diff --git a/ld/testsuite/ld-aarch64/aarch64-elf.exp b/ld/testsuite/ld-aarch64/aarch64-elf.exp
index 2b9fad5..c6fefbb 100644
--- a/ld/testsuite/ld-aarch64/aarch64-elf.exp
+++ b/ld/testsuite/ld-aarch64/aarch64-elf.exp
@@ -371,6 +371,10 @@ run_dump_test_lp64 "rela-abs-relative-opt"
 
 run_dump_test_lp64 "pie-bind-locally"
 
+run_dump_test "property-bti-pac1"
+run_dump_test "property-bti-pac2"
+run_dump_test "property-bti-pac3"
+
 set aarch64elflinktests {
   {"ld-aarch64/so with global symbol" "-shared" "" "" {copy-reloc-so.s}
     {} "copy-reloc-so.so"}
diff --git a/ld/testsuite/ld-aarch64/property-bti-pac1.d b/ld/testsuite/ld-aarch64/property-bti-pac1.d
new file mode 100644
index 0000000..a681ad9
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/property-bti-pac1.d
@@ -0,0 +1,11 @@
+#name: GNU Property (single input, combine section)
+#source: property-bti-pac1.s
+#as: -march=armv8.5-a -defsym __mult__=0
+#ld: -shared
+#readelf: -n
+#target: *linux*
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000010	NT_GNU_PROPERTY_TYPE_0
+      Properties: AArch64 feature: BTI, PAC
diff --git a/ld/testsuite/ld-aarch64/property-bti-pac1.s b/ld/testsuite/ld-aarch64/property-bti-pac1.s
new file mode 100644
index 0000000..414c927
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/property-bti-pac1.s
@@ -0,0 +1,37 @@
+	.text
+	.globl _start
+	.type _start,@function
+_start:
+	mov x1, #2
+.ifndef __mult__
+	bl foo
+.endif
+	.section ".note.gnu.property", "a"
+	.p2align 3
+	.long 1f - 0f		/* name length */
+	.long 5f - 2f		/* data length */
+	.long 5			/* note type */
+0:	.asciz "GNU"		/* vendor name */
+1:
+	.p2align 3
+2:	.long 0xc0000000	/* pr_type.  */
+	.long 4f - 3f		/* pr_datasz.  */
+3:
+	.long 0x2		/* PAC.  */
+4:
+	.p2align 3
+5:
+	.p2align 3
+	.long 1f - 0f		/* name length */
+	.long 5f - 2f		/* data length */
+	.long 5			/* note type */
+0:	.asciz "GNU"		/* vendor name */
+1:
+	.p2align 3
+2:	.long 0xc0000000	/* pr_type.  */
+	.long 4f - 3f		/* pr_datasz.  */
+3:
+	.long 0x1		/* BTI.  */
+4:
+	.p2align 3
+5:
diff --git a/ld/testsuite/ld-aarch64/property-bti-pac2.d b/ld/testsuite/ld-aarch64/property-bti-pac2.d
new file mode 100644
index 0000000..bc2eaad
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/property-bti-pac2.d
@@ -0,0 +1,12 @@
+#name: GNU Property (combine multiple with BTI)
+#source: property-bti-pac1.s
+#source: property-bti-pac2.s
+#as: -mabi=lp64 -defsym __property_bti__=1
+#ld: -e _start
+#readelf: -n
+#target: *linux*
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000010	NT_GNU_PROPERTY_TYPE_0
+      Properties: AArch64 feature: BTI
diff --git a/ld/testsuite/ld-aarch64/property-bti-pac2.s b/ld/testsuite/ld-aarch64/property-bti-pac2.s
new file mode 100644
index 0000000..cdec8d9
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/property-bti-pac2.s
@@ -0,0 +1,50 @@
+	.text
+	.global	foo
+	.type	foo, %function
+foo:
+	sub	sp, sp, #16
+	mov	w0, 9
+	str	w0, [sp, 12]
+	ldr	w0, [sp, 12]
+	add	w0, w0, 4
+	str	w0, [sp, 12]
+	nop
+	add	sp, sp, 16
+	ret
+	.size	foo, .-foo
+	.global	bar
+	.type	bar, %function
+.ifdef __property_bti__
+	.section ".note.gnu.property", "a"
+	.p2align 3
+	.long 1f - 0f		/* name length */
+	.long 5f - 2f		/* data length */
+	.long 5			/* note type */
+0:	.asciz "GNU"		/* vendor name */
+1:
+	.p2align 3
+2:	.long 0xc0000000	/* pr_type.  */
+	.long 4f - 3f		/* pr_datasz.  */
+3:
+	.long 0x1		/* BTI.  */
+4:
+	.p2align 3
+5:
+.endif
+.ifdef __property_pac__
+	.section ".note.gnu.property", "a"
+	.p2align 3
+	.long 1f - 0f		/* name length */
+	.long 5f - 2f		/* data length */
+	.long 5			/* note type */
+0:	.asciz "GNU"		/* vendor name */
+1:
+	.p2align 3
+2:	.long 0xc0000000	/* pr_type.  */
+	.long 4f - 3f		/* pr_datasz.  */
+3:
+	.long 0x2		/* PAC.  */
+4:
+	.p2align 3
+5:
+.endif
diff --git a/ld/testsuite/ld-aarch64/property-bti-pac3.d b/ld/testsuite/ld-aarch64/property-bti-pac3.d
new file mode 100644
index 0000000..5290f4b
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/property-bti-pac3.d
@@ -0,0 +1,12 @@
+#name: GNU Property (combine multiple with PAC)
+#source: property-bti-pac1.s
+#source: property-bti-pac2.s
+#as: -mabi=lp64 -defsym __property_pac__=1
+#ld: -e _start
+#readelf: -n
+#target: *linux*
+
+Displaying notes found in: .note.gnu.property
+  Owner                 Data size	Description
+  GNU                  0x00000010	NT_GNU_PROPERTY_TYPE_0
+      Properties: AArch64 feature: PAC