RISC-V: Add PT_RISCV_ATTRIBUTES and add it to PHDR.

We added PT_RISCV_ATTRIBUTES to program header to make
.riscv.attribute easier to find in dynamic loader or kernel.

Ref:
https://github.com/riscv/riscv-elf-psabi-doc/pull/71

ChangeLog:

bfd/

	* elfnn-riscv.c(RISCV_ATTRIBUTES_SECTION_NAME): New.
	(riscv_elf_additional_program_headers): Ditto.
	(riscv_elf_modify_segment_map): Ditto.
	(elf_backend_additional_program_headers): Ditto.
	(elf_backend_modify_segment_map): Ditto.
	(elf_backend_obj_attrs_section): Use RISCV_ATTRIBUTES_SECTION_NAME
	rather than string literal.

binutils/

	* readelf.c(get_riscv_segment_type): New.
	(get_segment_type): Handle EM_RISCV.

include/

	* elf/riscv.h (PT_RISCV_ATTRIBUTES): New.
	* testsuite/ld-elf/orphan-region.ld: Discard .riscv.attributes
	section for simplify testcase.
	* testsuite/ld-riscv-elf/attr-phdr.d: New.
	* testsuite/ld-riscv-elf/attr-phdr.s: Ditto.
	* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Add attr-phdr to
	testcase.

1 files changed, 13 insertions, 0 deletions

diff --git a/binutils/readelf.c b/binutils/readelf.c
index a6073f7..2215339 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -4095,6 +4095,16 @@ get_tic6x_segment_type (unsigned long type)
 }
 
 static const char *
+get_riscv_segment_type (unsigned long type)
+{
+  switch (type)
+    {
+    case PT_RISCV_ATTRIBUTES: return "RISCV_ATTRIBUTES";
+    default:                  return NULL;
+    }
+}
+
+static const char *
 get_hpux_segment_type (unsigned long type, unsigned e_machine)
 {
   if (e_machine == EM_PARISC)
@@ -4203,6 +4213,9 @@ get_segment_type (Filedata * filedata, unsigned long p_type)
 	    case EM_S390_OLD:
 	      result = get_s390_segment_type (p_type);
 	      break;
+	    case EM_RISCV:
+	      result = get_riscv_segment_type (p_type);
+	      break;
 	    default:
 	      result = NULL;
 	      break;