Support ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX

Mark an ALLOC section, which should be placed in special memory area,
with SHF_GNU_MBIND.  Its sh_info field indicates the special memory
type.  GNU_MBIND section names start with ".mbind" so that they are
placed as orphan sections by linker.  All input GNU_MBIND sections
with the same sh_type, sh_flags and sh_info are placed in one output
GNU_MBIND section.  In executable and shared object, create a
GNU_MBIND segment for each GNU_MBIND section and its segment type is
PT_GNU_MBIND_LO plus the sh_info value.  Each GNU_MBIND segment is
aligned at page boundary.

The assembler syntax:

    .section .mbind.foo,"adx",%progbits
                          ^             0: Special memory type.
                          |
                         'd' for SHF_GNU_MBIND.

    .section .mbind.foo,"adx",%progbits,0x1
                          ^             1: Special memory type.
                          |
                         'd' for SHF_GNU_MBIND.

    .section .mbind.bar,"adG",%progbits,.foo_group,comdat,0x2
                          ^                               2: Special memory type.
                          |
                         'd' for SHF_GNU_MBIND.

bfd/

	* elf.c (get_program_header_size): Add a GNU_MBIND segment for
	each GNU_MBIND section and align GNU_MBIND section to page size.
	(_bfd_elf_map_sections_to_segments): Create a GNU_MBIND
	segment for each GNU_MBIND section.
	(_bfd_elf_init_private_section_data): Copy sh_info from input
	for GNU_MBIND section.

binutils/

	* NEWS: Mention support for ELF SHF_GNU_MBIND and
	PT_GNU_MBIND_XXX.
	* readelf.c (get_segment_type): Handle PT_GNU_MBIND_XXX.
	(get_elf_section_flags): Handle SHF_GNU_MBIND.
	(process_section_headers): Likewise.
	* testsuite/binutils-all/mbind1.s: New file.
	* testsuite/binutils-all/objcopy.exp: Run readelf test on
	mbind1.s.

gas/

	* NEWS: Mention support for ELF SHF_GNU_MBIND.
	* config/obj-elf.c (section_match): New.
	(get_section): Match both sh_info and group name.
	(obj_elf_change_section): Add argument for sh_info.  Pass both
	sh_info and group name to get_section. Issue an error for
	SHF_GNU_MBIND section without SHF_ALLOC.  Set sh_info.
	(obj_elf_parse_section_letters): Set SHF_GNU_MBIND for 'd'.
	(obj_elf_section): Support SHF_GNU_MBIND section info.
	* config/obj-elf.h (obj_elf_change_section): Add argument for
	sh_info.
	* config/tc-arm.c (start_unwind_section): Pass 0 as sh_info to
	obj_elf_change_section.
	* config/tc-ia64.c (obj_elf_vms_common): Likewise.
	* config/tc-microblaze.c (microblaze_s_data): Likewise.
	(microblaze_s_sdata): Likewise.
	(microblaze_s_rdata): Likewise.
	(microblaze_s_bss): Likewise.
	* config/tc-mips.c (s_change_section): Likewise.
	* config/tc-msp430.c (msp430_profiler): Likewise.
	* config/tc-rx.c (parse_rx_section): Likewise.
	* config/tc-tic6x.c (tic6x_start_unwind_section): Likewise.
	* doc/as.texinfo: Document 'd' for SHF_GNU_MBIND.
	* testsuite/gas/elf/elf.exp: Run section12a, section12b and
	section13.
	* testsuite/gas/elf/section10.d: Updated.
	* testsuite/gas/elf/section10.s: Likewise.
	* testsuite/gas/elf/section12.s: New file.
	* testsuite/gas/elf/section12a.d: Likewise.
	* testsuite/gas/elf/section12b.d: Likewise.
	* testsuite/gas/elf/section13.l: Likewise.
	* testsuite/gas/elf/section13.d: Likewise.
	* testsuite/gas/elf/section13.s: Likewise.

include/

	* elf/common.h (PT_GNU_MBIND_NUM): New.
	(PT_GNU_MBIND_LO): Likewise.
	(PT_GNU_MBIND_HI): Likewise.
	(SHF_GNU_MBIND): Likewise.

ld/

	* NEWS: Mention support for ELF SHF_GNU_MBIND and
	PT_GNU_MBIND_XXX.
	* emultempl/elf32.em (gld${EMULATION_NAME}_place_orphan): Place
	input GNU_MBIND sections with the same type, attributes and
	sh_info field into a single output GNU_MBIND section.
	* testsuite/ld-elf/elf.exp: Run mbind2a and mbind2b.
	* testsuite/ld-elf/mbind1.s: New file.
	* testsuite/ld-elf/mbind1a.d: Likewise.
	* testsuite/ld-elf/mbind1b.d: Likewise.
	* testsuite/ld-elf/mbind1c.d: Likewise.
	* testsuite/ld-elf/mbind2a.s: Likewise.
	* testsuite/ld-elf/mbind2b.c: Likewise.

2 files changed, 73 insertions, 2 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 5b0211f..46d92a0 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2017-04-04  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* elf.c (get_program_header_size): Add a GNU_MBIND segment for
+	each GNU_MBIND section and align GNU_MBIND section to page size.
+	(_bfd_elf_map_sections_to_segments): Create a GNU_MBIND
+	segment for each GNU_MBIND section.
+	(_bfd_elf_init_private_section_data): Copy sh_info from input
+	for GNU_MBIND section.
+
 2017-04-03  Palmer Dabbelt  <palmer@dabbelt.com>
 
 	* elfnn-riscv.c (GP_NAME): Delete.
diff --git a/bfd/elf.c b/bfd/elf.c
index d4d91b6..dcb0e6f 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -4330,9 +4330,33 @@ get_program_header_size (bfd *abfd, struct bfd_link_info *info)
 	}
     }
 
-  /* Let the backend count up any program headers it might need.  */
   bed = get_elf_backend_data (abfd);
-  if (bed->elf_backend_additional_program_headers)
+
+ if ((abfd->flags & D_PAGED) != 0)
+   {
+     /* Add a PT_GNU_MBIND segment for each mbind section.  */
+     unsigned int page_align_power = bfd_log2 (bed->commonpagesize);
+     for (s = abfd->sections; s != NULL; s = s->next)
+       if (elf_section_flags (s) & SHF_GNU_MBIND)
+	 {
+	   if (elf_section_data (s)->this_hdr.sh_info
+	       > PT_GNU_MBIND_NUM)
+	     {
+	       _bfd_error_handler
+		 /* xgettext:c-format */
+		 (_("%B: GNU_MBIN section `%A' has invalid sh_info field: %d"),
+		     abfd, s, elf_section_data (s)->this_hdr.sh_info);
+	       continue;
+	     }
+	   /* Align mbind section to page size.  */
+	   if (s->alignment_power < page_align_power)
+	     s->alignment_power = page_align_power;
+	   segs ++;
+	 }
+   }
+
+ /* Let the backend count up any program headers it might need.  */
+ if (bed->elf_backend_additional_program_headers)
     {
       int a;
 
@@ -4504,6 +4528,7 @@ _bfd_elf_map_sections_to_segments (bfd *abfd, struct bfd_link_info *info)
       bfd_boolean writable;
       int tls_count = 0;
       asection *first_tls = NULL;
+      asection *first_mbind = NULL;
       asection *dynsec, *eh_frame_hdr;
       bfd_size_type amt;
       bfd_vma addr_mask, wrap_to = 0;
@@ -4836,6 +4861,9 @@ _bfd_elf_map_sections_to_segments (bfd *abfd, struct bfd_link_info *info)
 		first_tls = s;
 	      tls_count++;
 	    }
+	  if (first_mbind == NULL
+	      && (elf_section_flags (s) & SHF_GNU_MBIND) != 0)
+	    first_mbind = s;
 	}
 
       /* If there are any SHF_TLS output sections, add PT_TLS segment.  */
@@ -4883,6 +4911,35 @@ _bfd_elf_map_sections_to_segments (bfd *abfd, struct bfd_link_info *info)
 	  pm = &m->next;
 	}
 
+      if (first_mbind && (abfd->flags & D_PAGED) != 0)
+	for (s = first_mbind; s != NULL; s = s->next)
+	  if ((elf_section_flags (s) & SHF_GNU_MBIND) != 0
+	      && (elf_section_data (s)->this_hdr.sh_info
+		  <= PT_GNU_MBIND_NUM))
+	    {
+	      /* Mandated PF_R.  */
+	      unsigned long p_flags = PF_R;
+	      if ((s->flags & SEC_READONLY) == 0)
+		p_flags |= PF_W;
+	      if ((s->flags & SEC_CODE) != 0)
+		p_flags |= PF_X;
+
+	      amt = sizeof (struct elf_segment_map) + sizeof (asection *);
+	      m = bfd_zalloc (abfd, amt);
+	      if (m == NULL)
+		goto error_return;
+	      m->next = NULL;
+	      m->p_type = (PT_GNU_MBIND_LO
+			   + elf_section_data (s)->this_hdr.sh_info);
+	      m->count = 1;
+	      m->p_flags_valid = 1;
+	      m->sections[0] = s;
+	      m->p_flags = p_flags;
+
+	      *pm = m;
+	      pm = &m->next;
+	    }
+
       /* If there is a .eh_frame_hdr section, throw in a PT_GNU_EH_FRAME
 	 segment.  */
       eh_frame_hdr = elf_eh_frame_hdr (abfd);
@@ -7359,6 +7416,11 @@ _bfd_elf_init_private_section_data (bfd *ibfd,
   elf_section_flags (osec) |= (elf_section_flags (isec)
 			       & (SHF_MASKOS | SHF_MASKPROC));
 
+  /* Copy sh_info from input for mbind section.  */
+  if (elf_section_flags (isec) & SHF_GNU_MBIND)
+    elf_section_data (osec)->this_hdr.sh_info
+      = elf_section_data (isec)->this_hdr.sh_info;
+
   /* Set things up for objcopy and relocatable link.  The output
      SHT_GROUP section will have its elf_next_in_group pointing back
      to the input group members.  Ignore linker created group section.